hydrothermal transformations of glycerol into value-added chemicals using zeolite-based catalysts

Hydrothermal Transformations of Glycerol

into value-added Chemicals using Zeolite-based

Catalysts

Suna Srisamai

Supervised by Prof Klaus Hellgardt

A thesis submitted for the Degree of Doctor of Philosophy

at the Department of Chemical Engineering

Imperial College London UK

(January 2016)

ii

To my dear mother Nium

and in the memory of my dad Kaewta Srisamai

iii

Declaration

This Thesis is submitted to Imperial College London for the degree of Doctor of Philosophy

It is a record of the research carried out between February 2012 and January 2016 by the author

under the supervision of Professor Klaus Hellgardt It is believed to be wholly original except

where due acknowledgement is made and has not been submitted for any previous degree at

this or any other universities

Suna Srisamai

London January 2016

iv

The copyright of this thesis rests with the author and is made available under a Creative

Commons Attribution Non-Commercial No Derivatives licence Researchers are free to copy

distribute or transmit the thesis on the condition that they attribute it that they do not use it for

commercial purposes and that they do not alter transform or build upon it For any reuse or

redistribution researchers must make clear to others the licence terms of this work

v

Abstract

High availability and low price of crude glycerol the main by-product of the biodiesel

industry make it an attractive feedstock for transformations into value-added chemicals The

aim of this thesis was to improve our understanding of the hydrothermal conversion of glycerol

facilitated by zeolite-based catalysts

A range of Lewis acidic Ce- La- Sn- and Zn-doped ZSM-5 and Beta zeolites were

prepared by solid state ion exchange reaction The effect of those catalysts as well as their

parent NH4- and H-forms on the dehydration of glycerol was investigated under hydrothermal

conditions (270-360 degC 55-186 bar 5-300 min) in batch tubular reactors Several reaction

products were detected of which acrolein was the main liquid product with the highest

selectivity of ~38 mol achieved within the first 5 min at 330 degC on H-Beta zeolite At longer

reaction times acrolein decomposed and acetaldehyde became the main product (max

selectivity ~26 mol in 30 min) The addition of metal-doped zeolites did not increase the

degree of glycerol conversion but increased the total selectivity towards the liquid products

48 wt La-doped NH4-Beta zeolite resulted in a 56 mol glycerol conversion with a 36 mol

selectivity towards acetaldehyde

The oxidation of glycerol with H2O2 in subcritical water was investigated in a

continuous fixed bed reactor at 125-175 degC 35 bar 60-300 s using H-Beta zeolite 25 wt-

and 48 wt Cu-doped H-Beta zeolite extruded with γ-Al2O3 As compared to non-catalysed

oxidation the addition of Cu-doped H-Beta zeolites did not increase the degree of conversion

but promoted the conversion rate of glycerol as well as the selectivity towards liquid products

The liquid products detected included dihydroxyacetone (DHA) formic acid (FA) acetic acid

glycolic acid pyruvaldehyde and lactic acid (LA) The distribution of these products varies

with the temperature residence time and the type of catalyst The top-three main products

vi

obtained were DHA FA and LA The highest yield of DHA (~8 mol) was achieved with 48

wt CuH-Betaγ-Al2O3 (MC) at 150 degC 60 s The same catalyst also provided LA with the

highest yield of 115 mol at 175 degC 240 s FA was detected with the highest yield of ~9

mol at 175 degC 60 s on H-Betaγ-Al2O3 (MC)

vii

Acknowledgments

First and foremost I sincerely thank my supervisor Prof Klaus Hellgardt for the

opportunity to work on a challenging project his guidance and encouragement throughout my

PhD studies I am also very grateful to Dr Radim Skapa for his advice feedback and support

provided throughout the last four years

I would like to thank Prof Kang Li and Dr Zhentao Wu for providing the ceramic

hollow fibres I am grateful to Dr Peter DiMaggio for allowing me to use the centrifuge

I am indebted to the people whose feedback and kind help have resulted in a substantial

contribution to my research project Dr Christos Kalamaras Dr John Brazier Dr Mimi Hii

Dr Pongsathorn Dechatiwongse Andrew Leung and Arash Izadpanah Special thanks for my

genius MSc students Cheok Neng Lucas Ho Mayuresh Patel and Lixin Song - Thanks guys

for all the smiles and laugh you put on my face

I have received great support from all of the members of the REaCT group Thank you

all for being very friendly and useful Dr Fessehaye Zemichael Dr Chun-Yee Cheng Dr

Oluseye Agbede Dr Franck Essiagne Dr Palang Bumroongsakulsawat Dr Maha Alsayegh

Dr Chin Kin Ong Dr Ju Zhu Bhavish Patel Muhammad Ibadurrohman Dr Lisa Kleiminger

Dr Sergio Lima Isaac Gentle Faye Al Hersh and Irina Harun

I really appreciate the tremendous support and fantastic caring warmth from Radim

Skapa thanks for all of his love inspiration and kindness I would also like to thank my friend

Wiparat Traisilanan for all her help all these years

Finally I sincerely and faithfully thank my family without whose love and support my

life would never been as wonderful as this

viii

Nomenclature

Symbol Meaning Usual Units

1H-NMR proton nuclear magnetic resonance spectroscopy

A pre-exponential factor s-1

BET Brunauer-Emmett-Teller

CHFM ceramic hollow fibre membranes

deAl-Beta dealuminated Beta zeolite

DHA dihydroxyacetone

Ɛ dielectric constant

Ɛ void fraction

Ea activation energy Jmol-1

EHS environment health and safety

FA formic acid

GC gas chromatography

GC-FID gas chromatography - flame ionisation detector

HLW hot liquid water

HMQC heteronuclear multiple quantum coherence

HPLC high-performance liquid chromatograph

HTW high-temperature water

ICP-OES inductively coupled plasma - optical emission

spectrometry

K equilibrium constant

k reaction rate constant s-1 (1st order reaction)

Kw ion dissociation constant of water

LA lactic acid

LCA life-cycle assessment

ix

MC methyl cellulose

MHz megahertz

mM millimolar

MPa megapascal

R universal gas constant (83145 JmiddotK-1middotmol-1)

RT room temperature

SCW supercritical water

SEM scanning electron microscopy

119878119864 standard error of mean

SSIE solid state ion exchange

sub-CW subcritical water

TEA triethanolamine

TEAOH tetraethylammonium hydroxide

TEM transmission electron microscopy

EDX energy-dispersive X-ray spectroscopy

TEOS tetraethylorthosilicate

TGA thermal gravimetric analysis

TPD temperature-programmed desorption

TUD-1 mesoporous silica matric named after the Technische

Universiteit Delft

UV-VIS ultraviolet-visible spectroscopy

XRD X-ray diffraction spectroscopy

XRF X-ray fluorescence spectroscopy

δ chemical shift ppm

ρ density kgmiddotm-3

All other abbreviations are described in the text as they occur

x

Table of Contents

Declaration iii

Abstract v

Acknowledgments vii

Nomenclature viii

Table of Contents x

1 Introduction 1

11 Glycerol conversion into value-added chemicals 3

12 Catalytic hydrothermal conversion as a process for converting glycerol 5

2 Literature review 9

21 Water under hydrothermal conditions 9

211 Applications of high temperature - high pressure water 9

212 Physicochemical properties of high temperature - high pressure water 10

213 Water and other green solvents 16

22 State of the art hydrothermal technology in the conversion of biomass and glycerol

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18

221 Production of liquid fuels by hydrothermal liquefaction of biomass and glycerol 20

2211 Biomass 20

2212 Glycerol 23

222 Production of gaseous fuels by hydrothermal gasification 23

2221 Biomass 25

2222 Glycerol 26

223 Production of bio-chemicals by hydrothermal conversion of biomass 33

224 Production of bio-chemicals by hydrothermal conversion of glycerol 42

2241 Non-catalytic hydrothermal conversion of glycerol 48

xi

2242 Hydrothermal conversion of glycerol catalysed by acids 51

2243 Hydrothermal conversion of glycerol catalysed by bases 56

2244 Hydrothermal conversion of glycerol with H2O2 62

23 Zeolite-based catalysts 65

231 Zeolites and their Broslashnsted and Lewis acidity 65

232 Stability of zeolites under hydrothermal conditions 67

233 Zeolite catalysts in the hydrothermal conversion of polyols to chemicals 74

234 Preparation of Lewis acidic zeolite catalysts 78

235 Immobilisation and shaping of powder zeolite catalysts 80

2351 Immobilisation of zeolites on inorganic membrane (zeolite membrane) 80

2352 Shaping of zeolite powder 83

2353 Agglomeration of zeolite powder 86

3 Aim of study 89

31 Aim 89

32 Objectives 90

4 Experimental protocols and methodology 94

41 Characterisation of solid samples 94

411 BrunauerndashEmmettndashTeller (BET) analysis 94

412 X-ray Fluorescence (XRF) spectroscopy 97

413 Powder X-ray diffraction (XRD) spectroscopy 99

414 Electron microscopy 101

415 Temperature programed desorption of ammonia (TPD-NH3) 103

416 Thermogravimetric analysis (TGA) and Differential scanning calorimetry (DSC) 106

42 Characterisation of liquid and gaseous samples 107

421 Nuclear magnetic resonance (NMR) spectroscopy 107

4211 Identification of liquid products 108

4212 Quantitative 1H-NMR analysis 112

xii

4213 Validation of KHP 115

422 High-performance liquid chromatography (HPLC) 116

4221 Quantitative analysis of results from HPLC vs 1H-NMR 118

423 Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES) 118

424 Mass spectrometry (MS) 119

425 UV-VIS spectrophotometry 120

4251 Preparation of TiOSO4 solution 122

4252 Preparation of H2O2 stock solution 122

43 Chemicals and materials 124

44 Catalyst preparation 126

441 Preparation of H-Beta zeolite and H-ZSM-5 130

442 Preparation of metal-exchanged NH4-Beta H-Beta NH4-ZSM-5 and H-ZSM-5 zeolites

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip131

443 Preparation of metal-exchanged dealuminated H-Beta zeolite 132

444 Preparation of CeH-Beta zeolite on ceramic hollow fibre membranes 133

445 Preparation of H-Beta and metal-dopedH-Beta zeolites on TUD-1 matrix 136

446 Preparation of extruded zeolite catalysts 137

45 Hydrothermal dehydration of glycerol 140

451 Dehydration of glycerol 140

452 Dissolution of H-Beta zeolite in hot liquid water 141

453 Effect of dissolved Al and Si on the dehydration of glycerol 142

46 Hydrothermal oxidation of glycerol 143

461 Batch process 143

462 Continuous flow process 144

5 Catalyst characterisation 155

51 H-Beta zeolite and H-ZSM-5 155

511 Powder X-ray diffraction 155

xiii

512 BET N2 analysis 160

513 TPD-NH3 163

52 Metal-exchanged zeolites 172



523 TPD-NH3 180

53 Dealuminated H-ZSM-5 and H-Beta zeolite 184

531 Dealuminated ZSM-5 185

532 Dealuminated Beta zeolite 187

5321 Physical properties 187

5322 Surface acidity and the degree of Al extraction 194

533 Conclusions and discussion 196

54 Metal-exchanged dealuminated Beta zeolites 197


542 Surface acidity 209

55 Immobilisation and agglomeration of Beta zeolite-based catalysts 210

551 CeH-Beta zeolite on ceramic hollow fibre membranes 211

552 H-Beta and metal-dopedH-Beta zeolites embedded in TUD-1 matrix 216

553 Extruded catalysts 220

5531 Starting zeolite-based catalysts 220

5532 Beta zeolite-based catalysts extruded with bentonite clay 222

5533 Beta zeolite-based catalysts extruded with γ-Al2O3 225


61 Non catalysed hydrothermal dehydration of glycerol 232

62 H-ZSM-5 and H-Beta zeolite catalysed hydrothermal dehydration of glycerol 238

621 Conversion degree and selectivity to liquid products 238

622 Composition of liquid products 246

xiv

623 Reaction kinetic analysis 249

63 Effect of lanthanide and transition metal doping 256

64 Hydrothermal stability of H-Beta zeolite 263

641 Dissolution of H-Beta zeolite 263

642 Effect of dissolved Si and Al on the dehydration of glycerol 269

643 Conclusion 280

7 Hydrothermal oxidation of glycerol with H2O2 281


711 Non-catalysed oxidation 281

712 Zeolite-catalysed hydrothermal oxidation of glycerol 287


7122 Metal-exchanged Beta zeolite 291



73 Catalytic oxidation of glycerol 302

731 Effect of temperature on the catalytic oxidation of glycerol in subcritical water using H-

Betaγ-Al2O3 (MC) catalyst 302

732 Effect of residence time on the catalytic oxidation of glycerol in subcritical water using

H-Betaγ-Al2O3 (MC) catalyst 306

733 Effect of Cu-doped H-Betaγ-Al2O3 (MC) on the catalytic oxidation of glycerol in

subcritical water 307

7331 Conclusion 315

734 Stability of extruded Betaγ-Al2O3 (MC) catalysts 316

8 Summary and Future work 323

81 Summary 323

82 Future work 327


xv


9 References 329

10 Appendix 361

1

1 Introduction

In response to the ever-increasing price of fossil fuels as well as the environmental

issues associated with the use of these non-renewable resources the chemical industry has

focused its attention on alternative sustainable and renewable sources of fuels and chemicals

One example is the production of biodiesel by the transesterification of triglycerides the main

component of vegetable oils and animal fats with an alcohol see Figure 1

Figure 1 Biodiesel production process the transesterification of triglyceride (esters of

glycerol) with methanol yields fatty acid methyl esters and glycerol (adapted from Ciriminna

et al (2014))

Biodiesel is the second most used liquid biofuel after bioethanol The growth of the

biodiesel industry has been constant for many years (REN21 2014) Its global production was

about 26 billion litres in 2013 and it is projected to reach 40 billion litres in 2023 (OECDFAO

2014) A sharp increase of biodiesel production over the past decade resulted in a large surplus

of glycerol its main by-product as there is 1 kg of glycerol produced for every 9 kg of

biodiesel The production of glycerol by the biodiesel industry increased from 200000 tonnes

2

in 2004 (Mario Pagliaro and Rossi 2008) to more than 22 million tonnes in 2013 and it is

estimated to reach 35 million tonnes by 2023 (OECDFAO 2014) see Figure 2 The

overproduction of crude glycerol generated a problem of costly glycerol disposal making the

biodiesel production process economically less competitive On the other hand the

overproduction of glycerol resulted in a significant price drop (~ US $149tonne in November

2015 as compared to US $551tonne in 2004) (Pyle et al 2008 OPIS 2015) see Figure 2

making it an interesting feedstock for the production of value-added chemicals

00

05

10

15

20

25

30

35

Cru

de g

lycerol

[mil

lion

ton

ne]

Year

2004 2005 2006 2007 2008 2009 2010 2012 2014 2015 2023

0

100

200

300

400

500

Pric

e o

f cru

de g

lycerol (8

0

pu

re) [U

S $

ton

ne]

Figure 2 World crude glycerol production (bars) and its price (line) between 2004 and 2015

The crude glycerol production in 2004-2010 was reported by Almeida et al (2012) The

production in 2012-2023 was estimated based on the biodiesel production reported in

OECDFAO (2014) The crude glycerol (80 pure) prices were reported by Pyle et al (2008)

Clomburg and Gonzalez (2013) OPIS (2014) and OPIS (2015)

3

11 Glycerol conversion into value-added chemicals

The terms glycerol and glycerine (also called glycerin) are used interchangeably

although there are slight differences in their definitions and use (Bart et al 2010) Glycerol is

a pure chemical compound 123-propanetriol while glycerine is the commonly used

commercial name for products whose principal component is glycerol (typically ge 95) In

this work lsquoglycerolrsquo is used invariably without distinction between the two while the glycerine

obtained from the biodiesel process is specifically referred to as crude glycerol

Glycerol is non-toxic and highly hydrophilic due to the presence of three hydroxyl

groups which result in an extensive network of H-bonding (Katryniok et al 2009) It is one

of the top twelve platform chemicals identified by the United States Department of Energy

(DoE) (Werpy and Petersen 2004) and its potential to become a primary raw material for bio-

refineries has been demonstrated by numerous studies almost 5000 scientific papers

concerning the conversion of glycerol into value-added chemicals were published in peer-

reviewed scientific journals between 2000 and 2015 (Googlescholarcouk 2015)

In addition to its traditional uses in food pharmaceutical and cosmetic industries the

highly functionalised molecule of glycerol may be converted into a variety of higher value

compounds by numerous different conversion processes see Figure 3 few of which have been

commercialised (Katryniok et al 2011)

chlorination for the production of epichlorohydrin

gasification to yield syngas used for the manufacture of bio-methanol see Chapter

2222

indirect esterification for the manufacture of mono- and diacylglycerols and

fermentation for the production of dihydroxyacetone (DHA) see Chapter 224

4

A number of processes have not been transposed to the industrial scale due to their poor

economies associated with low selectivity andor high operation costs (Kongjao et al 2011)

One example is the catalytic conversion of glycerol under hydrothermal conditions The

hydrothermal conversion process gained significant attention in the last two decades (Peterson

et al 2008) due to its potential to overcome the difficulties associated with other methods of

glycerol transformations such as the long reaction time of fermentation

Figure 3 The known conversion processes of glycerol into value-added chemicals (adapted

from Pagliaro et al (2007) Zhou et al (2008) and Katryniok et al (2011))

Finding a commercially viable application of the waste glycerol would not only make

biodiesel production economically more competitive but also decrease the dependence of

5

society on fossil fuels This work focuses on catalytic hydrothermal conversion as a process

for converting glycerol into value-added chemicals

12 Catalytic hydrothermal conversion as a process for

converting glycerol

Hydrothermal technology has been investigated since the 1970rsquos (Bonn et al 1983)

and widely used for pre-treatment of biomass materials containing water such as

lignocellulosic biomass agricultural residues and municipal wastes (Peterson et al 2008) It

is considered to be one of the most suitable methods for processing of crude glycerol for the

following reasons (Peterson et al 2008)

The water present in crude glycerol see Table 1 for composition of crude glycerol

acts as a medium in hydrothermolysis eliminating expensive drying required for

other conversion methods

Hydrothermal technology is capable of processing mixed feedstocks containing

both organic and inorganic compounds eliminating the need for costly purification

There is no need to maintain microorganisms as required for fermentation process

The process efficiency may be controlled by adjusting the temperature and pressure

6

Table 1 The composition of crude glycerol produced as a by-product of biodiesel industry

(adapted from Ye and Ren (2014))

Composition [wt] Crude glycerol

Sample A1 Sample B2 Sample C3

glycerol 65-85 229-333 ~83

ash 4-6 27-30 Not determined

methanol 234-375 86-126 lt1

water 1-3 41-182 ~13

sodium 01-4 16-19 lt5

soap Not determined 205-262 Not determined

fatty acids methyl esters Not determined 193-288 Not determined

glycerides Not determined 12-7 Not determined

free fatty acids Not determined 10-30 Not determined 1 Crude glycerol produced from batch process in lab (Thompson and He 2006 Ciriminna et

al 2014) 2 Crude glycerol from PolyGreen Technologies LLC (Mansfield OH) (Hu et al

2012) 3 Crude glycerol from Cargillrsquos biodiesel plant (Kansas City MO)

It is known that water under hydrothermal conditions acts as a highly reactive acid-base

catalyst allowing short reaction times (Akiya and Savage 2002) The selectivity to desired

conversion products under hydrothermal conditions may be controlled by

(i) adjusting the temperature and pressure influencing the properties of subcritical

water (sub-CW) and supercritical water (SCW) andor

(ii) adding an additive or a catalyst

By controlling the nature of additives andor catalysts the glycerol typically undergoes

one of the following conversion reactions under hydrothermal conditions

acid-catalysed dehydration to acrolein

base-catalysed dehydrogenation followed by dehydrationrehydration to lactic acid and

7

wet oxidation using an oxidant to form low molecular weight organic acids

Inorganic acids and bases were reported to exhibit high performance The hydrothermal

dehydration of glycerol at 300-400 ordmC in the presence of H2SO4 or NaHSO4 resulted in ~22-86

mol yield of acrolein (Antal et al 1985 Ramayya et al 1987 Watanabe et al 2007) while

the conversion of glycerol in subcritical water (280-300 ordmC) using alkaline hydroxides such as

NaOH and KOH as catalysts led to high yields (85-90 mol) of lactate (metal salt of lactic

acid) (Kishida et al 2005 Shen et al 2009 Ramirez-Lopez et al 2010) However the use

of strong inorganic acids or bases has raised concerns over their corrosive effect on the

equipment prompting the research on alternative catalysts

The addition of noble or transition metal catalysts ie Ru Pt Au Rh Ir and Cu was

found to effectively catalyse the dehydrogenation of glycerol under alkaline hydrothermal

conditions resulting in comparative lactate yields at temperature as low as 200 degC as compared

to 300 degC required for alkaline hydrothermal conversion (Maris and Davis 2007 Roy et al

2011 Auneau et al 2012) This process is however not without disadvantages since the

resulting lactate needed to be converted into free lactic acid by neutralizing with a strong acid

eg H2SO4 generating an issue associated with the separation and disposal of metal sulfates

Solid acid catalysts have recently gained significant interest as an alternative to mineral

acids for the dehydration of glycerol Solids acid catalysts are solids that possess acidic

functional groups on their surfaces functioning as catalysts just like water soluble acids such

as H2SO4 or HCl (Hattori and Ono 2015) Solid acid catalysts such as RuZrO2 and WO3TiO2

were demonstrated to have promising activity providing acrolein yield of approximately 50

mol (May et al 2010 Akizuki and Oshima 2012)

Zeolites are solid catalysts exhibiting both Broslashnsted and Lewis acidity promoting the

dehydration and dehydrogenation of glycerol respectively The high performance of zeolites

8

and metal-doped zeolites also known as Lewis-acidic zeolites in the conversion of glycerol

and other polyols to value-added chemicals has been successfully demonstrated by several

research groups (Taarning et al 2009 de Oliveira et al 2011 Gonzalez-Rivera et al 2014)

In spite of the fact that zeolites generally have limited stability under hydrothermal conditions

many studies reported the use of zeolites as catalysts under such conditions However more

work needs to be carried out to improve the understanding of hydrothermal conversion of

glycerol in the presence of zeolites

9

2 Literature review

This chapter presents a comprehensive review on the properties of water under

hydrothermal conditions followed by its applications in biomass conversion with special

reference to the dehydration dehydrogenation and oxidation of glycerol in aqueous phase

(Chapter 224) Finally the potential of zeolites as catalysts in the hydrothermal conversion of

glycerol and their modification are discussed in Chapter 23

21 Water under hydrothermal conditions

211 Applications of high temperature - high pressure water

Water often referred to as ldquogreen solventrdquo is one of the most environmentally and

economically attractive solvents because it is renewable non-toxic inflammable readily

accessible and inexpensive However water is a poor solvent for numerous organic compounds

reactions reducing its potential for replacing conventional non-aqueous non-polar solvents

derived from petroleum crude oils On the other hand at high temperature - high pressure

water has the properties enabling it to dissolve non-polar compounds

A thermochemical process in which water at high temperature - high pressure (HTP-

water) is used as a reaction medium is called hydrothermal process The hydrothermal medium

is also referred to as subcritical water (sub-CW) amp supercritical water (SCW) hot-compressed

water (HCW) pressurised-hot water (PHW) or superheated water in the present work

The HTP-water may not only be used as a solvent with a broad range of applications

but also as a catalyst in chemical synthesis biomass conversion coal liquefaction plastics

10

recycling and waste destruction (Calvo and Vallejo 2002 Galkin and Lunin 2005 Peterson

et al 2008 Hayashi and Hakuta 2010) It may also be used as a medium for instance to

extractisolate natural products (Herrero et al 2006) heavy metals hydrocarbons or polycyclic

aromatic hydrocarbons (PAHs) from contaminated soils (Hawthorne et al 1994 Kronholm et

al 2002) The use of HTP-water in the above mentioned processes is mainly driven by the

benefit of more environmentally friendly economical and safer processes

212 Physicochemical properties of high temperature - high

pressure water

The physicochemical properties of water vary significantly with pressure and

temperature see Figure 4 for the pressure - temperature (PT) diagram of water The critical

point of water lies at 374 degC and 2206 bar marking the transition point between the subcritical

and supercritical regions While supercritical water (SCW) is typically defined as water above

its critical temperature and pressure the temperatures and pressures used to define subcritical

water (sub-CW) vary widely in different studies For instance Ramos et al (2002) defines the

sub-CW by the temperatures between 100 and 374 degC and pressures high enough to maintain

its liquid state Yu et al (2008) defines the sub-CW region by the temperatures above 150 degC

and various pressures whereas water at the temperature ranging from 100 to 360 degC at saturated

vapour pressure is a definition adopted by Pourali et al (2010) Many works on hydrothermal

biomass processing arbitrarily place the sub-CW region between 200 degC and 374 degC (Mok and

Antal 1992 Minowa et al 1998 Peterson et al 2008) In this work the sub-CW region is

defined by the temperatures ranging between 100 degC and 374 degC (Clifford 2007 Cheng and

Ye 2010) and the pressure equals to or is higher than saturated vapour pressure of water

11

Figure 4 The pressure - temperature (PT) diagram of water with highlighted subcritical and

supercritical regions

As the temperature increases the number of hydrogen bonds between the water

molecules decreases reducing the dielectric constant and thus lowering the polarity (Mountain

1989 Mizan et al 1996) As a result the solubility of organic compounds in HTP-water is

much higher than in water under ambient conditions The selected physicochemical properties

of water such as density (ρ) dielectric constant (Ɛ) and ion dissociation constant (Kw) are

shown in Figure 5 as a function of temperature The values of all three physical properties

decrease with increasing temperature The density continuously decreases from 1000 kgmiddotm-3 at

25 degC to 600 kgmiddotm-3 at 350 degC and then further drops to 150 kgmiddotm-3 at 450 degC The dielectric

constant falls from 80 to less than 2 as the temperature rises from 25 degC to 450 degC The ion

12

dissociation constant initially increases from 10-14 to 10-11 at just below 350 degC and then

plummets to 10-175 above 500 degC

Figure 5 Static dielectric constant (Ɛ) density (ρ) and ion dissociation constant (Kw) of water

at 300 bars as a function of temperature The values of all three physical properties decrease

with increasing temperature The figure was taken from Peterson et al (2008)

Several physicochemical properties of HTP-water are similar to those of common

organic solvents at ambient conditions (Bialkowski Smallwood 1996) Table 2 summarises

the characteristics of water under different conditions compared to acetone

13

Table 2 Characteristics of water under different conditions compared to acetone a common

organic solvent at ambient conditions (adapted from (Krammer and Vogel 2000) Galkin and

Lunin (2005) and Moumlllerthinsp et al (2011)) L liquid phase G gas phase

Characteristic Ambient

Water

Subcritical

Water

Supercritical

Water

Acetone

Temperature [degC] 0-100 100-374 gt374 RT

Vapour pressure

[bar]

003 (24 degC) 1 (100 degC) to 221

(374 degC)

gt221 024

(20 degC)

Aggregate state liquid liquid no phase separation liquid

Density [kg m-3] 997 (25 degC) 958 (101 degC 11

bar) 692 (330 degC

300 bar)

between gas-like and

liquid-like densities eg

252 at140 degC 300 bar

7899 (20

degC 11

bar)

Viscosity [microPas] L 884 G 99

(25 degC)

L 277 G123

(101 degC) L504

G 307 (371 degC)

low 330

(25 degC)

Heat capacity Cp

[kJ kg-1K-1]

422 (25 degC) 486 13 (400 degC 250 bar) 218

(20 degC)

Dielectric

constant

785 (25 degC 1

bar)

271 (250 degC 50

bar) 182 (330 degC

300 bar)

59 (400 degC 250 bar)

105 (400 degC 500 bar)

206

(20 degC)

Compressibility no slightly increased

but still a liquid

(at 370 degC)

yes na

-logKw 14 na 21 na

(Bialkowski Smallwood 1996) (Kerton 2009) Note L liquid phase G gas phase

The ionic product of water Kw determining the concentration of hydronium (H3O+)

and hydroxide (OH-) ions (see Figure 6) is another important factor describing the properties

of water The Kw of sub-CW at 350 degC is nearly 1000 times higher than that of ambient water

see Figure 5 Thus the higher concentration of H3O+ leads to much lower pH see Figure 7

meaning that the point of neutrality shifts from ~7 to ~55 In contrast the concentrations of

H3O+ and OH- in SCW are much lower than in ambient water resulting in pH of above 7 but

14

the free-radical chemistry starts to play more important role in this region (Akiya and Savage

2002) The properties of HTP-water are reviewed extensively by Akiya and Savage (2002)

Figure 6 The relationship between the water ion product (Kw) and the pH

Figure 7 pH of water as a function of temperature and pressure (taken form Cook and Olive

(2012))

15

The hydrogen bonding influences several important characteristics of water including

the dielectric constant polarity viscosity and diffusivity These properties change with density

which is greatly dependent upon temperature and pressure Figure 8 shows the temperature and

pressure dependence of the density of water

Figure 8 The temperature and pressure dependence of the density of water under hydrothermal

conditions (taken from Cook and Olive (2012))

Water in near-critical and supercritical region exhibits the properties of nearly an ideal

gas and thus the equation of state of an ideal gas Pv = nRT may also be used for near-critical

and SCW (Brunner 2009) The vapour pressure (P) volume (V) temperature (T) and the

transport properties eg diffusivity and viscosity of near-critical and SCW are similar to that

16

of supercritical fluids1 but the density of the former is slightly higher and is very sensitive to

minor changes in temperature and pressure

The solubility of most gases in water tends to decrease with increasing temperature

(Akiya and Savage 2002) however as the solubility reaches its minimum eg around 100 degC

for O2 (Battino et al 1983) it starts to increase at increased temperature and pressure The

solubility of gases and non-polar compounds in sub-CW increases with increasing temperature

reaching complete miscibility with SCW (Brunner 2009) SCW acts as a non-polar solvent

such as hexane (Mizan et al 1996 Akiya and Savage 2002) On the other hand the solubility

of inorganic salts in near-critical and SCW is much decreased (Mizan et al 1996)

213 Water and other green solvents

A large amount of organic solvents is used each year in the chemical industry for their

good heat amp mass transfer and diffusion of reactants However the environmental and health

issues associated with organic solvents have prompted the research into the use of more

environmentally-friendly (green) solvents

The environmental footprint of solvents is most commonly assessed by (i) the

environment health and safety (EHS) method and (ii) the life-cycle assessment (LCA) method

(Capello et al 2007 Jessop 2011) The EHS method identifies the impact of a solvent on the

environment while the LCA method assesses the emissions to the environment as well as the

full life-cycle of a solvent

1 A supercritical fluid is any substance at above its critical temperature and pressure ie a temperature and pressure

above which distinct liquid and gas phases do not exist (Carlegraves 2010)

17

Water is the most environmentally friendly solvent with no negative impact on the

environment human health and safety It is also believed according to a survey by Jessop

(2011) to be the second best option after supercritical CO2 for reducing solvent-related

environmental damage Zhang et al (2008) compared an ionic liquid ([bmim]BF4) water

acetone benzene and lithium perchlorate diethyl ethers mixture (LPDE) in terms of

environmental impact by 11 factors including the impact of both the solvent itself and its

synthesis It was found that water has the lowest while the ionic liquid the highest

environmental impact in every category except ozone-layer depletion in which benzene

dominated Water is also the greenest solvent among those listed in the GlaxoSmithKline

(GSK) solvent guide for medicinal chemistry see Table 3 The guide highlights potential issues

of each solvent and provides possible alternatives It also includes life cycle assessment

information

Table 3 Selected examples of solvents listed in the GlaxoSmithKline (GSK) solvent guide for

medicinal chemistry (Henderson et al 2011)

Solvent MP

[ordmC]

BP

[ordmC]

Waste Environmental

impact

Health Flammability

amp Explosion

Reactivity

Stability

Life cycle

score

Legislation

Flag

EHS

Red Flag

Water 0 100 4 10 10 10 10 10

2-Propanol -88 82 3 9 8 6 8 4

1-Butanol -89 118 5 7 5 8 9 5

Ethanol -114 78 3 8 8 6 9 9

Methanol -98 65 4 9 5 5 10 9

Acetone -95 56 3 9 8 4 9 7

Acetic acid 17 118 4 8 6 8 7 8

Toluene -95 111 6 3 4 4 10 7

Heptane -91 98 6 3 8 3 10 7

xxxxxxxxxx Substitution recommended ndash There are no current restrictions but future regulatory restrictions may apply

xxxxxxxxxx Must be substituted ndash A regulatory ban applies

Note MP = melting point BP = boiling point EHS = environment health and safety

18

Despite several advantages the use of water is not without drawbacks as reflected by

the low score (only 4) in the waste recyclingtreatment in Table 3 also see Table 4 Firstly

water requires energy intensive distillation Secondly the production of a contaminated

aqueous waste stream may have significant environmental and economic impacts (Lancaster

2002) for example the concentration of contaminated water by distillation is energy intensive

as compared to concentration of a propanol waste stream Finally high specific heat capacity

of water makes it difficult to heat or cool rapidly

Table 4 Advantages and disadvantages of water as a solvent (adapted from Lancaster (2002))

Advantages Disadvantages

Non-toxic Distillation is energy intensive

Opportunity for replacing volatile organic

solvents

Contaminated waste streams may be difficult to

treat

Naturally occurring High specific heat capacity - difficult to heat or

cool rapidly

Inexpensive

Non-flammable

High specific heat capacity - exothermic

reactions can be more safely controlled

22 State of the art hydrothermal technology in the

conversion of biomass and glycerol

Hydrothermal processing is considered to be one of the most suitable technologies for

treatment of wet biomass and biomass-derived glycerol due to the intrinsic water content of

such feedstocks and the unique solvent properties of SCW (see Chapter 21) The technology

19

has been long used in processing of non-food plant biomass such as agricultural and municipal

wastes (Peterson et al 2008 Brunner 2009) and is expected to play an important role in

future production of fuels and chemicals from biomass This chapter reviews the state of the

art of the technology as a process for producing biofuels and biochemical utilizing both general

biomass materials as well as bio-derived glycerol as source materials

Hydrothermal processing of biomass may not only yield gaseous- but also liquid- and

solid biofuels Depending on the temperature and pressure the biomass conversion may

progress via see Figure 9 (Peterson et al 2008)

liquefaction (typically 200-370 degC 40-200 bar)

catalytic gasification (near-critical temperatures up to 500 degC) and

high-temperature gasification (typically ge500 degC)

The processes above are discussed in Chapters 221 and 222

20

Figure 9 Hydrothermal processing regions referenced to the pressure ndash temperature phase

diagram of water The figure was taken from Peterson et al (2008)

221 Production of liquid fuels by hydrothermal liquefaction of

biomass and glycerol

2211 Biomass

Hydrothermal liquefaction also known as hydrous pyrolysis (Obeid et al 2015) is a

thermochemical conversion process in which a high temperature (typically 200-370 degC) - high

pressure (50-400 bar) water is used to break the chemical bonds of biomass material producing

21

liquid biofuels such as bio-oil (Peterson et al 2008 Zhang 2010) In contrast to pyrolysis2 it

involves direct liquefaction of wet biomass into bio-crude (also known as liquid bio-oil) which

may be further processed to yield transport fuels andor various chemicals The potential of

biomass as a source of renewable fuels was realized as early as in the first half of the 20th

century when Berl (1944) reported that a petroleum-like product could be obtained by alkaline

hydrothermolysis (~230 degC) of feedstocks such as cornstalks sugarcane seaweed algae and

grass

Biomass materials typically contain 30-50 wt oxygen and have a heating value of 10

to 20 MJkg-1 (GCEP 2005) A liquefaction process involves contacting the biomass with high

temperaturepressure water (typically 200-370 degC 40-250 bar) to yield a bio-crude an oily

liquid with reduced oxygen content (10-20 wt) and a significantly increased heating value of

30 to 37 MJ kg-1 (Toor et al 2011) However the oxygen content of the bio-crude is still much

higher than that of petro-derived oil (lt1 ) (Aitani 2004) The high oxygen content of the

biomass liquefaction product results in undesirable properties such as lower energy capacity

lower volatility and reduced thermal stability Therefore it is desirable to further reduce the

oxygen content by its conversion either into CO2 or more desirably H2O

An increased interest of researchers in the liquefaction of cellulosic biomass was

recorded during the first oil crisis in 1970s A considerable amount of pioneering work was

done by a group of researchers at the Pittsburgh Energy Research Centre (PERC) of the United

States Bureau of Mines Appell et al (1971) developed a continuous flow process for

liquefaction of wood chips into heavy oil using recycled oil as a reaction medium and a source

of hydrogen at 330-370 degC and 200 bar in the presence of CO as a reducing gas and Na2CO3

as a catalyst Although a moderate oil yield was obtained (45-55 relative to the mass of dry

2 Pyrolysis is an anaerobic thermochemical decomposition process of dried biomass yielding solid gaseous and

liquid fuels (Demirbas 2001)

22

biomass used) the need for a large amount of recycled oil as a source of hydrogen is not

practical The use of recycled oil is not required in the process developed by the researchers at

Lawrence Berkeley Laboratory whose liquefaction process utilizes hydrothermal media

allowing the reactions to take place in a water-rich phase at high pressure (Peterson et al

2008) In this process the biomass is hydrolysed at 330 to 360 degC 100 to 240 bar in the presence

of H2SO4 followed by neutralization with Na2CO3 These two processes were demonstrated on

a pilot plant scale at Albany Oregon facility but further research was halted due to financial

reasons as well as the lack of basic scientific understanding of the process (Behrendt et al

2008) In 1982 the researchers at the Royal Dutch Shell Laboratory started to develop a so

called hydrothermal upgrading (HTU) process (Okkerse and van Bekkum 1999 Toor et al

2011) ie an biomass feedstock was treated in sub-CW at 300-350 degC 100-180 bar yielding a

bio-crude (Goudriaan et al 2005) The crude oil readily separates from water and due to its

low oxygen content it may be further upgraded cost-effectively by hydrodeoxygenation to a

clean diesel-type fuel with high cetane number (Okkerse and van Bekkum 1999) Additionally

in contrast to fossil fuels bio-crude does not require removal of inorganic contaminants such

as nitrogen and sulphur The research was abandoned in 1988 by the oil company but resumed

in 1997 by a Dutch consortium

Since the publication of the pioneering work on liquefaction of biomass by Appell et

al (1971) at the Pittsburgh Energy Research Centre (PERC) a number of research studies on

hydrothermal conversion of lignocellulosic biomass into liquid (bio-crude) gaseous and solid

fuels have been published up until July 2015 about 6700 articles concerning the hydrothermal

liquefaction were published in peer-reviewed online journals (Googlescholarcouk 2015)

However despite the intensive investigation so far all the existing works have been carried out

on a laboratory or bench-scale with only a few on demonstration plants (Toor et al 2011) The

hydrothermal technologies for liquefaction of biomass were reviewed by Behrendt et al

23

(2008) Peterson et al (2008) and Toor et al (2011) The proposed mechanisms of liquefaction

were reviewed by Demirbas (2000)

2212 Glycerol

The hydrothermal treatment of glycerol in the liquefaction region ie 200-370 degC and

40-200 bar does not result in an oil phase but rather in water-soluble compounds such as

acrolein acetaldehyde and acetic acid see Chapter 223 To the best of our knowledge a single

study reported a waxy-oil phase from hydrothermal conversion of glycerol Onwudili and

Williams (2010) attained ~62 wt yield of waxy-oil by non-catalytic hydrothermal

gasification (300-450 degC saturated vapour pressure) of crude glycerol containing 21 wt

methanol 42 wt glycerol and 33 wt fatty acid methyl esters As the temperature increased

from 300 degC to SCW conditions the waxy product transformed into a liquid oil at ge 380 degC

The formation of the waxyoil products may possibly be due to the presence of fatty acid methyl

esters in the crude glycerol as speculated by Leow et al (2015) who investigated the

hydrothermal liquefaction (HTL) of microalgae and found that the bio-crude yield and the

carbon distribution increased in proportion to the fatty acid content in microalgae feedstock

222 Production of gaseous fuels by hydrothermal gasification

Gasification is commonly defined as an aerobic thermochemical conversion process in

which dried biomass materials (lt 10 wt moisture) contacted with a controlled amount of

oxygen andor steam at high temperature (ge 371 degC) yield mainly a mixture of CO and H2 (also

known as synthesis gas or syngas) (Demirbas 2001 Elliott 2008) The requirement for dried

biomass results in high operating cost since the drying process is an energy- and time-

24

consuming step This may be avoided by gasification of wet biomass in sub-CW amp SCW see

Equation 1

Equation 1 Hydrothermal gasification of cellulose (C6H10O5) in SCW

Hydrothernal gasification may be applied in two practically possible scenarios known

as

(i) catalytic gasification and

(ii) high-temperature gasification

The former usually takes place in sub-CW or SCW at up to 500 degC with active metal catalyst

while the latter requires the temperatures above 500 degC with or without a catalyst typically

the activated carbon or alkali salts are used to inhibit the tarchar formation (Kruse et al 2000

Schmieder et al 2000 Osada et al 2006) Each method has both advantages and

disadvantages The catalytic gasification in SCW (374-500 degC) requires a transition metal

catalysts such as nickel and ruthenium whilst a highly active metal catalyst such as Raney

nickel or platinum with low weight hourly space velocities are usually used in sub-CW (Elliott

et al 1993 Davda and Dumesic 2004 Elliott et al 2006) Complete gasification of

lignocellulosic materials was reported using the catalytic gasification however the catalyst

deactivation is an issue and needs further optimisation On the other hand high-temperature

gasification usually leads to high feed conversion with high CO concentration due to low rate

25

of water-gas shift reaction but is energy intensive (Azadi and Farnood 2011) The SCW

gasification is reviewed extensively by Kruse (2008)

2221 Biomass

Hydrothermal gasification has been an intensive research topic for the last two decades

Its potential as an effective process to convert biomass to gaseous fuels was not realised until

Modell (1985) reported that maple wood sawdust treated in SCW (374 degC 220 bar) rapidly

decomposed to tar and gas composed mainly of H2 CO2 and CO without the formation of char

which represent one of the main issues in steam reforming usually carried out at ge 600 degC under

atmospheric pressure (Matsumura et al 2005) A study by Sealock and Elliott (1991) showed

that the degree of hydrothermal gasification of a wide range of lignocellulosic materials at 300

degC and ge101 bar was substantially promoted by the presence of a Ni metal or alkali-promoted

Ni catalyst ~40 gas yield comprising of CO2 H2 and CH4 was obtained The effect of alkali

on the carbon conversion to gases decreased in the following order Cs gt K gt Na Elliott et al

(1993) systematically evaluated the catalytic performance of various base metals3 and their

combinations noble metals and numerous support compositions for the process The metals

tested for gasification of biomass at 350 degC and autogenous pressure from 170-230 bar included

Co Cr Cu Mo Ni Pd Pt Rh Ru and Zn however only Ni Ru and Rh were found to be

active The supports stable in hot-compressed water were α-alumina and zirconia whereas other

types of alumina tested reacted with water to form boehmite losing the surface area and

physical strength Silica and titania were not susceptible to the hot-compressed water but their

tableted forms disintegrated

3The term ldquobase metalsrdquo (Smartmcx) refers to the metals that are not considered precious such as copper lead

nickel tin or zinc and are usually used in commercial and industrial applications for their high abundance and

much lower price as compared to precious metals

26

Minowa et al (1995) investigated the gasification of wet cellulose in sub-CW (350 degC

180 bar) using a reduced Ni catalyst The yield of gaseous products (H2 CO2 and CH4)

increased with the catalyst loading reaching 91 wt when 20 wt catalyst was used The high

gas yields obtained were in accordance with expectations since the Ni catalysts are well-known

highly performing catalysts however the nickel oxide was not found to be an active catalyst for

the SCW gasification of biomass (Modell 1985 Yamamura et al 2009) Other metal oxides

investigated included MoO3 ZrO2 and RuO2 all of which only RuO2 showed promising

activity and only in high temperature SCW (Izumizaki et al 2005 Yamamura et al 2009) In

addition to the reduced Ni and Raney (skeleton) Ni catalysts other reported active metal

catalysts for gasification in low-temperature subcritical water also known as aqueous phase

reforming (APR) were Pt-black PtTiO2 PtC and PtAl2O3 (Shabaker et al 2003)

Modification of commercially available industrial catalysts was reported to increase

their hydrothermal stability and activity in hydrothermal gasification Elliott et al (2006)

incorporated Ru Cu Ag Re or Sn into a BASF reforming catalyst increasing its stability in

hydrothermal environment Ru-incorporated BASF catalyst exhibited the highest stability and

activity for gasification and methanation Similarly the surface modification of Raney Ni with

small quantities of Sn was found to significantly enhance the H2 to CH4 ratio of the products

(Huber et al 2003 Shabaker and Dumesic 2004 Shabaker et al 2004 Shabaker et al 2005)

2222 Glycerol

Glycerol is an ideal feedstock for SCW gasification as it yields H2 and CO2 without the

coke formation see Equation 2 (Antal et al 2000 Buumlhler et al 2002 van Rossum et al

2009) Most studies on SCW gasification of glycerol aim to produce H2 a clean energy carrier

27

Equation 2 The SCW gasification of glycerol

Antal et al (1985) was first to study a non-catalysed glycerol decomposition in SCW

at 500 degC and 345 bar obtaining acetaldehyde acrolein and a gas mixture consisting of H2

CO2 CO CH4 C2H4 and C2H6 About 32 mol conversion of glycerol was obtained in ~15

min with H2 and CO2 as the main gaseous products possibly formed by the so called water-

gas shift reaction see Equation 3

Equation 3 Water-gas shift reaction

119862119874 + 1198672119874 harr 1198621198742 + 1198672

The non-catalytic SCW gasification of glycerol was also studied by Kersten et al

(2006) who reported a significant effect of temperature on the degree of conversion up to 650

degC Above this temperature the degree of conversion was a function of feed concentration and

only diluted glycerol solution was successfully completely converted to gas phase

Byrd et al (2008) demonstrated that near-theoretical H2 yield ie 7 mol H2mol

glycerol see Equation 2 was achieved by reforming 5 wt glycerol solution in SCW over a

RuAl2O3 catalyst at 800 degC 241 bar Although a high H2 yield was obtained the process

requires high energy input On the other hand May et al (2010) found that the SCW

28

gasification of 5 wt glycerol solution at 550 degC 350 bar led to a very low H2 yield less than

06 mol H2mol glycerol in the presence of RuZrO2

Chakinala et al (2010) hydrothermally gassified glycerol forming the backbone of

lipids (present up to 40 wt) in algae at 550-650 degC 250 bar 5 s residence time using a

continuous flow tubular reactor The effect of (i) amino acid (glycine L-alanine and L-proline)

and (ii) alkali salt (K2CO3) on the degree of glycerol conversion and the composition of its

conversion products were also tested The presence of amino acid was found to induce coke

formation whilst the addition of K2CO3 enhanced the gasification and promoted the H2

formation (~261 mol H2mol glycerol vs ~184 mol H2mol glycerol in a non-catalytic reaction

under identical conditions 600 degC 250 bar 5 s) The addition of alkaline catalysts is known to

inhibit char formation in SCW conversion of biomass resulting in higher oil andor gas yields

(Minowa et al 1998 Kruse et al 2000)

The majority of works on SCW gasification of glycerol were carried out on pure diluted

glycerol solutions Onwudili and Williams (2010) studied the hydrothermal gasification of

crude glycerol containing 21 wt methanol 42 wt glycerol and 33 wt fatty acid methyl

esters The non-catalysed reforming reactions carried out in a Hastelloy-C batch reactor at 300-

450 degC autogeneous pressure of 85-310 bar resulted in the products containing ~62 wt

oilwax which became liquid oil at ge380 degC ~10-19 wt of water-soluble products and ~3-18

wt of gases composed of H2 CO CO2 and light hydrocarbons were also produced When

NaOH was used as a catalyst at 380 degC a gas containing of up to 90 vol H2 ie an equivalent

to ~19 mol of H2 per mole of carbon in the feed was obtained The obtained H2 yield was

higher than that from pure glycerol under identical conditions No char formation was

observed The effect of high feed concentration (10-50 wt) and various alkaline catalysts

were also investigated at 445-600 degC 250 bar a residence time of 39-90 s by Guo et al

(2012) The gas yield increased with temperature and the gasification efficiency decreased with

29

increasing glycerol concentration The addition of alkali catalysts at the weight ratio of glycerol

to catalyst ~20 greatly enhanced the water-gas shift reaction increasing the H2 yield in the

following order K2CO3lt KOHlt Na2CO3ltNaOH The addition of a small amount of NaOH

(01 wt) led to the highest H2 yield of 493 molmol glycerol at 526 degC No char or tar

formation was observed in the experiments

The gasification in sub-CW also known as aqueous-phase reforming (APR) developed

by Cortright et al (2002) is another effective process for producing H2 from sugars and

alcohols including glycerol At 265 degC 56 bar 99 conversion of glycerol (1 wt solution)

with ~51 of selectivity to H2 was achieved over a Ptγ-Al2O3 catalyst (Cortright et al 2002)

A complete conversion of glycerol with 76 selectivity to H2 at 265 degC 514 bar was achieved

using inexpensive Raney Ni-Sn catalyst (Huber et al 2003) In addition to a lower

temperature as compared to typical hydrothermal gasification the APR yields less CO due to

the water-gas shift reaction see Equation 3 The works including the experimental conditions

and results reported on APR of glycerol are summarised in Table 5

30

Table 5 The list of works including the experimental conditions and results reported on aqueous phase reforming (APR) of glycerol The

percentages reported are in mol unless otherwise stated Note X = glycerol conversion S = selectivity Y = yield

[glycerol] Catalyst Reaction conditions

Results Ref Temp [degC] Press [bar]

[1 wt] Pt γ- Al2O3 265 56 X = 99 S (H2) = 51 Cortright et al (2002)

[1 wt] Raney Ni-Sn 265 514 X = 100 S (H2) = 76 Huber et al (2003)

[10 wt pure amp crude] 3 wt Ptvarious

Al2O3 - with different Pt precursors

250 20 (argon) Pt on a mixed γ- θ- δ- Al2O3 X = 45

S (H2) = 85

Lehnert and Claus (2008)

[5 wt amp10 wt] 03-12 wt Ptγ-Al2O3 180 - 220 114 - 25 X = 65 Y (H2) = 45 (at 5 wt glycerol) Luo et al (2008)

[1 wt] Niγ-Al2O3 (with Ce La Mg Zr

promoters)

225 30 La-Niγ-Al2O3 was most active X = 37 Y not

reported gas phase composition 32 H2 40

CO2 28 CH4

Iriondo et al (2008)

[10 wt] Pt Ni Co Cu on Al2O3 SAPO-

11 MgO H-USY SiO2 active C

230 32 PtAl2O3 was most active X = 19 Y not reported

70 H2 present in gas phase

Wen et al (2008)

[5 wt] Ni-Coγ- Al2O3 220 25 X = 45 Y (H2) = 40 Ce doping enhanced

catalytic activity

Luo et al (2010)

[10 wt] 1-3wt Re-3wt PtC 225 29 3wtRendash3wtRtC was most active X = ~88 S

(gas) = ~55 KOH increased H2 productivity and

selectivity to oxygenates in aqueous phase

King et al (2010)

[1 wt] Pt on Al2O3 ZrO2 MgO CeO2 225 autogenous X = 13-26 Y not reported 62-72 H2 in gas

phase

Menezes et al (2011)

[1 wt amp 10wt]

NiCeO2

250 270 autogenous

(375 527)

X = ~90 Y not reported ~90 H2 present in gas

phase the rest included CO CO2 and CH4

Manfro et al (2011)

[5-85 wt]

PtAl2O3

160 - 280 autogenous highest H2 content (63-67) of gas phase at 230 degC

at 5-45wt glycerol

Oumlzguumlr and Uysal (2011)

31

The use of low temperature in the APR process results in the need for a highly active

catalysts such as Pt-based catalysts which are among the most widely studied Cortright et al

(2002) and Lehnert and Claus (2008) studied several Pt catalysts supported on Al2O3 Alumina-

supported Pt catalysts prepared from different Pt precursors ie platinum ethanolamine

platinum(II)-nitrate platinum sulfite and tetraammine platinum(II)-nitrate exhibited

comparable activities (~45 glycerol conversion) and selectivity towards H2 (~85) The

selectivity to H2 was found to increase from 78-95 with increasing catalyst particle size

ranging from 16-32 nm while the degree of conversion remained constant at ~20 The use

of a mixture of γ- θ- and δ-Al2O3 as support materials resulted in an increase in H2 production

as compared to pure γ-Al2O3 Luo et al (2008) examined the effect of Ptγ-Al2O3 with Pt

loading up to 12 wt at 180-220 degC and 114-25 bar on APR of 5 wt and 10 wt glycerol

solution At 5 wt ~65 glycerol conversion with ~45 yield of H2 was obtained at 220 degC

25 bar and the time on stream of 7 h The authors inferred that the H2 generation on the Pt

catalysts is accompanied by other parallel reactions such as dehydration hydrogenation and

methanation The Al2O3 supports of the used 09 wt Ptγ-Al2O3 catalysts (temperature not

specified) transformed into boehmite The formation of carbonaceous entities on the used

catalysts were the main cause for catalysts deactivation

Despite the high performance the high price of Pt-based catalysts usually limits their

use to small scale or laboratory applications Alternative transition metal catalysts have

therefore gained increasing interest Iriondo et al (2008) carried out APR of 1 wt glycerol at

225 degC 30 bar over Ni catalysts supported with Al2O3 using Ce La Mg or Zr as promoters It

was found that the Ni catalysts suffered from severe deactivation due to gradual Ni oxidation

while the La promoted catalysts provided the highest glycerol conversion of 37 mol (product

yield was not reported) the gaseous products included 32 mol H2 40 mol CO2 and 28

mol CH4 while the liquid products composed of 57 mol propylenglycol and 34 mol

32

ethylenglycol Wen et al (2008) studied the activity of various metal catalysts including Pt

Ni Co and Cu and their supports including SAPO-11 MgO H-USY zeolite Al2O3 SiO2 and

active carbon (AC) for APR of 10 wt glycerol at 230 degC 32 bar using a fixed-bed reactor

The activity of the four metal catalysts supported on Al2O3 decreased in the following order

Pt gt Cu gt Ni gt Co PtAl2O3 provided ~19 glycerol conversion and a gas containing ~70

mol H2 the overall yield rate of H2 production was 572 micromolmin-1119892119888119886119905minus1 PtMgO catalysts

increased the H2 yield and its rate of formation by absorption of formed CO2 by the support

~14 mol glycerol conversion with the H2 production rate of 432 micromolmin-1119892119888119886119905minus1 was

reported which is 25 lower than that obtained with PtAl2O3 In contrast an acidic zeolite H-

USY or neutral Al2O3 tended to increase the alkane formation

The gasification of crude glycerol has been applied on industrial scale since 2010 by

the BioMCN in The Netherlands with a production capacity of 200 kty (Blokland 2011) The

resulting syngas is reformed at high temperature and pressure in a conventional packed bed

methanol synthesis reactor to yield bio-methanol and the whole process is referred to as

glycerol-to-methanol (GTM) process (Van Bennekom et al 2012) The full carbon cycle of

the biodiesel production can be achieved as the bio-methanol may be re-used as a reactant in

the upstream transesterification process The syngas obtained may also be used as a reactant in

the FischerndashTropsch reaction for the production of fuels and chemicals (BTGgroup 2012)

Despite these the GTM process is uneconomical the price of bio-methanol (approx euro475-

525) is higher than that of petroleum-based methanol (approx euro200-250) (BioMCN 2013

Broeren 2013) The SCW gasification of crude glycerol as an alternative process for the

production of H2 or syngas would offer significant economic advantage over the current

gasification process since it does not require expensive drying step Drying and distillation

33

often make up ~50 of the total energy required for example in the production of ethanol

from corn grain (Peterson et al 2008)

223 Production of bio-chemicals by hydrothermal conversion of

biomass

The conversion of biomass into value-added chemicals represents one of the main

potential applications of hydrothermal technology The fermentation process currently the

main industrial process for the production of biomass-based chemicals has a number of

drawbacks such as the sensitivity of enzymes small space-time yields (Dusselier et al 2013)

and the inability to process mixed or complex feedstocks like lignocellulosic materials (Badger

2002) The flexibility and the potential of hydrothermal technology to overcome the drawbacks

of competing technologies was noted by the industry resulting in intensive research efforts over

the last two decades to find more economical cleaner and safer process

Starch and sugars are the main sources of biomass feedstock of current biochemical

production processes For instance the fermentation of corn sugars (or sugarcane or other

crops) is used for the industrial production of ethanol and lactic acid The sugars contained in

these feedstocks are easy to extract and convert into a wide variety of compounds including

the top twelve building block chemicals identified by the US Department of Energy (DoE)

see Figure 10 (Werpy and Petersen 2004) These building block chemicals may be used as

starting materials for production of a number of chemicals and polymers via catalytic routes

reviewed by ten Dam and Hanefeld (2011) and Dusselier et al (2013)

34

Figure 10 Top twelve building block chemicals identified by the US Department of Energy

(DoE) (Werpy and Petersen 2004)

Hydrothermal conversion of sugars has been studied at a wide range of temperatures

and pressures with or without a catalyst Table 6 summarises the research studies including

experimental conditions and results reported on hydrothermal conversion of various sugars to

chemicals

35

Table 6 The summary of research studies including experimental conditions and results on hydrothermal conversion of various sugars into

chemicals The percentage values are given in mol unless stated otherwise

Feedstock Temperature Pressure

Time

Catalysts Key products

Ref

Sucrose 250 ˚C 345 bar 25-100s H2SO4 glucose fructose glyceraldehyde furfural

dihydroxyacetone (DHA) lactic acid

5-(hydroxymethyl)furfural (HMF)

Antal Jr et al (1990)

Fructose 250 ˚C 345 bar 25-100 s H2SO4 HMF furfural pyruvaldehyde glucose formic

acid levulinic acid lactic acid glyceraldehyde


glucose 300-400 ˚C 250-400 bar

002-2 s

- fructose glyceraldehyde DHA glycolaldehyde

pyruvaldehyde erythose 16-anhydro-D-glucose

Kabyemela et al (1999)

Fructose 300-400 ˚C 250-400 bar

002-2 s

- glyceraldehyde DHA erythrose Kabyemela et al (1999)

Glucose 250-350 ˚C 276 bar 5

min

NaOH lactic acid glycolic acid formic acid Calvo and Vallejo (2002)

cellobiose 350-400 ˚C 250-400 bar

001-054 s

- glucose erythrose glycolaldehyde Sasaki et al (2002)

D-glucose other

mono-saccharides

340 ˚C 275 bar 25-204 s HCl NaOH HMF glycolaldehyde glyceraldehyde formic acid

acetic acid lactic acid acrylic acid 2- furaldehyde

124-benzenetriol

Srokol et al (2004)

sucrose hexoses

trioses

300 ˚C 250 bar 10-180 s sulphate of

Co2+ Cu2+ Ni2+

Zn2+

lactic acid Bicker et al (2005)

D-fructose 200-320 ˚C autogeneous

75-180 s

HCl H2SO4

H3PO4 other

organic acids

HMF levulinic acid formic acid Salak Asghari and Yoshida

(2006)

36

The conversion of sugars under hydrothermal conditions typically occurs rapidly even

without a catalyst Kabyemela et al (1999) demonstrated that the decomposition of fructose

and glucose was almost complete within 2 s at 350 degC 250 bar while the carbon balance of

liquid products was above ~90 at short residence times but decreased at longer residence

times Despite the high conversion degree and conversion rate a mixture of several liquid

reaction products see Table 6 resulted in relatively low yields of individual compounds

As opposed to the non-catalysed reactions discussed above the catalysed reactions

generally provide higher yield of liquid products For instance the addition of H2SO4 in the

hydrothermal conversion (250 degC 345 bar) of fructose increased the yield of HMF from ~30

mol to ~55 mol (Antal Jr et al 1990) Takeuchi et al (2008) investigated the effect of

H3PO4 H2SO4 and HCl on the hydrothermal conversion of glucose at 250 degC autogenous

pressure and the reaction time of 1-10 min obtaining 40 C yield of HMF and ~10 C of

levulinic acid in the presence of H3PO4 at 250 degC in 5 min When HCl was used all HMF

rehydrated to form levulinic acid with the highest yield of ~55 C Yan et al (2010) employed

NaOH and Ca(OH)2 as catalysts in the transformation of glucose in sub-CW at 250-330 degC

273 bar finding lactic acid as the main product Similarly Esposito and Antonietti (2013)

examined the effect of NaOH NH4OH BaCl2 Ca(OH)2 Sr(OH)2 and NaOHBaCl2 on the

hydrothermal conversion of glucose at 220-250 degC autogenous pressure obtaining ~57 mol

yield of lactic acid at 250 degC using Ba(OH)2 at the base to glucose molar ratio of ~4 The

conversion of glucose under alkaline conditions has been long known to favour the formation

of lactic acid (Shaffer and Friedemann 1930) but Bicker et al (2005) demonstrated that the

sulphate of Co(II) Ni(II) Cu(II) and Zn(II) catalyse the conversion of various sugars to lactic

acid in sub-CW (300 degC 250 bar 10-180 s) 400 ppm ZnSO4 provided the lactic acid yields of

~42 wt and ~86 wt from sucrose and dihydroxyacetone respectively

37

Despite currently being an important feedstock for production of bio-chemicals the

sugars and starch containing materials form an integral part of human food chain resulting in

their high costs Using cheaper starting materials such as lignocellulose may reduce the cost

of bio-chemicals Lignocellulose naturally contained in wood and various fibrous plants is

abundant worldwide and outside of the human food chain The forests comprise approx 80

of the worldrsquos biomass (Badger 2002) hence the lignocellulosic biomass has been intensively

studied as a potential source of chemicals

Lignocellulosic materials are comprised of cellulose hemicellulose and lignin Due to

their polymeric and highly complex chemical structure the direct conversion of these materials

into chemicals requires a pre-treatment step to break down their structure into low molecular

weight sugars such as glucose (Mok and Antal 1992 Mok et al 1992 Adschiri et al 1993)

which can be further degraded into other valuable compounds by other conversion processes

such as fermentation and hydrogenation See Figure 11 for different treatment methods for

lignocellulosic materials and sugars

38

Figure 11 The treatment methods for lignocellulosic materials and sugars (adapted from E4tech et al (2015))

39

Mok and Antal (1992) investigated the non-catalysed hydrothermal treatment (200-230

degC 345 bar 0-15 min) of six woody and herbaceous biomass species containing mainly

hemicellulose (15-23) cellulose (30-45) and lignin (15-37) Between 40-60 of the

sample mass was solubilized the hemicellulose was completely solubilized resulting in 6-14

yield of monomeric sugar whereas the cellulose and lignin were only partially solubilized

Adschiri et al (1993) demonstrated that the yield of glucose may be increased by pre-treating

the biomass in SCW at 400 degC 250 bar where ~100 mol conversion of cellulose with ~34

mol yield of glucose was obtained within 15 s Despite being effective the process requires

high pressure and temperature On the other hand Mok et al (1992) reported ~71 mol yield

of glucose after a pre-treatment of cellulose in hot-compressed water at 215 degC 345 bar using

H2SO4 as a catalyst In fact acid-base catalysts are often preferred in hydrothermal treatment

of lignocellusolics making the process not only rapid but also highly selective However the

corrosiveness of the catalysts combined with that from the self-ionization of water leads to

severe equipment corrosion Onda et al (2008) examined the potential of several less corrosive

solid acid catalysts such as H-zeolites activated carbon (AC) SiO2 γ-Al2O3 AC-SO3H

sulfated zirconia and amberlyst 15 for the hydrothermal conversion of cellulose and starch at

150 degC autogenous pressure and a reaction time of 24 h AC-SO3H gave high yields of glucose

~405 C from cellulose and ge90 C from starch possibly due to its (i) high hydrothermal

stability and (ii) the presence of strong acid sites (-SO3H) and the hydrophobic surface Both

sulfated zirconia and amberlyst 15 catalysts gave relatively high yields of glucose with high

selectivity to water soluble by-products but were not stable under the conditions tested The H-

zeolite catalysts gave only slightly higher yields than the non-catalysed reactions whilst the γ-

Al2O3 and SiO2 were completely inactive

In addition to mono-sugars the hydrothermal conversion of lignocellulosic feedstocks

yields chemicals with high market value such as 5-(hydroxymethyl)furfural (HMF)

40

glyceraldehyde dihydroxyacetone (DHA) pyruvaldehyde and organic acids (see Table 7) all

of which are the decomposition or transformation products of mono-sugars A single-step

catalytic direct conversion of lignocellulosic biomass into chemicals gained significant interest

in recent years The studies published on this topic including the experimental conditions and

results are summarised in Table 7

41

Table 7 Subcritical and supercritical water conversion of various lignocellulosic biomass into chemicals The percentage values are given in mol

unless stated otherwise Note S = selectivity Y = yield


Time

Catalysts Key products Ref

cellulose 215 degC 345 bar 1-60 min H2SO4 glucose HMF levoglucosan cellobiose Mok et al (1992)

cellulose 200-400 degC 250 bar 5-

300 s

- glucose fructose erythrose glyceraldehyde organic

acids pyruvaldehyde DHA glycolaldehyde 16-

anhydro-D-glucose

Adschiri et al (1993)

microcrystalline

cellulose

320-400 degC 250 bar 005

to 10 s

- at 320 ordmC and 350 ordmC the main products were organic

acids with Y = 53 and 606 respectively

at 400 ordmC main product was oligomers with C gt6 with

Y = 51

Sasaki et al (2000)

rabbit food (municipal

solid waste)

200-350 degC na 20-150 s Y (glucose) = 33 Y (lactic acid) = 32 Y (acetic

acid) = 26

Goto et al (2004)

cherry (hard wood)

cypress (soft wood)

280 degC na 15 min K2CO3 50 wt total oil yields 10-20 wt gases ~24-43 wt

water soluble compounds (mainly acetic acid)

Bhaskar et al (2008)

cellulose starch

glucose

270-400 degC auto-

geneous 30-180 s

NaOH Ca(OH)2 Y (lactic acid) = 20-27 Yan et al (2010)

Cellulose 180-220 degC na 10-200

min

alkali alkaline

earth AlCl3 and

transition metal

chlorides

CrCl3 was exceptionally effective Y (levulinic acid) =

67

Peng et al (2010)

Cellulose 300 degC autogenous 5

min

Ni Zn activated

C in NaOH

Y (lactic acid) = 42 Zhang et al (2011)

Cellulose 325 ˚C autogenous 1 min CuO in NaOH Y (acetic glycolic lactic formic acids) = 43 Wang et al (2014)

42


glycerol

The majority of studies performed on hydrothermal conversion of glycerol tested the

effect of acid or base catalysts and oxidation agents such as H2O2 The acid catalysed

hydrothermolysis of glycerol resulted in dehydration and formation of acrolein acetaldehyde

and acetol (1-hydroxyacetone) (Watanabe et al 2007) while the bases induced

dehydrogenation usually followed by dehydration and re-hydration forming lactic acid one of

the oxidation products of glycerol (Kishida et al 2005 Ramirez-Lopez et al 2010) The

hydrothermal oxidation of glycerol led to a variety of decomposition products including

glyceric acid dihydroxyacetone lactic acid acetic acid formic acid etc (Katryniok et al

2011) Figure 12 shows the reaction pathways of glycerol and its conversion products under

hydrothermal conditions

43

Figure 12 The reaction pathways of glycerol under hydrothermal conditions (adapted from

Zhou et al (2008)) Katryniok et al (2011) Akizuki and Oshima (2012))

The current productionprocess price and applications of common reaction products of

glycerol (highlighted in green in Figure 12) are summarised in Table 8 and discussed in detail

in this section The hydrothermal conversion of glycerol in the presence of acids bases and

oxidants are discussed in detail in Chapters 2242 2243 and 2244 respectively

44

Table 8 The current productionprocess price and applications of selected reaction products

of glycerol

Compound Current production

process

Production

[tonnesyr]

Price

US $tonnes

Examples of applications

acrolein oxidation of propene 500k1 1850-20005 acrylic acid DL-methionine

acetaldehyde oxidation of ethylene 1280k2 4500-65005 pyridine (derivatives)

pentaerythritol

crotonaldehyde

lactic acid fermentation of

carbohydrates

400k3 1300-160056 Food amp food related

applications fibres green

solvents poly(lactic acid)

DHA fermentation of

glycerol

2k4 150000-16500057 Cosmetic industry

1(Patocka and Kuca 2014) 2(Eckert et al 2006) 3(Dusselier et al 2013) 4(Pagliaro et al 2007)

5(wwwalibabacom 2016) 6(L Nattrass 2010) 7(Katryniok et al 2011)

(i) Acrolein

Acrolein (prop-2-enal) the simplest unsaturated aldehyde is a colourless volatile

toxic and lacrimatory liquid with a strong odour (Etzkorn 2000) It is an important intermediate

commonly used in the chemical and agricultural industries Due to its toxicity and instability

acrolein is usually produced as an immediate which is immediately converted into other

chemicals mostly acrylic acid the key precursor of polyacrylic acid (Katryniok et al 2009)

Much smaller proportion of acrolein is isolated and used primarily for the synthesis of DL-

methionine (see Figure 13) an important amino acid used predominantly in meat production

to accelerate the animal growth (Etzkorn 2000 Katryniok et al 2009) The ever increasing

global demand for DL-methionine is currently satisfied by its industrial synthesis from

acrolein see Figure 13

45

Figure 13 The synthesis of DL-methionine from acrolein (adapted from Katryniok et al

(2009))

Acrolein is industrially manufactured by oxidation of propene using multicomponent

BiMoOx based catalysts (Arntz et al 2000) see Figure 14A Approximately half a million tons

of acrolein are produced annually however the dependence of this process on petrochemicals

makes it unsustainable (Patocka and Kuca 2014) Therefore the preparation of acrolein from

low cost crude glycerol is economically and environmentally more attractive see Figure 14B

Figure 14 The formation of acrolein by (A) selective oxidation of propene (B) dehydration of

glycerol

The acid catalysts are known to selectively catalyse the conversion of glycerol to

acrolein (Katryniok et al 2013) However the use of strong mineral acids such as H2SO4 to

catalyse the dehydration of glycerol to acrolein represents an issue which stimulated significant

research efforts in recent years on development of an acid-free process Various types of

46

catalysts including zeolites silica-alumina materials heteropoly acids metal oxides etc were

investigated see Chapter 2242

(ii) Acetaldehyde

Acetaldehyde is an important platform chemical and a dehydration product of glycerol

with a market price of US $ 4500-6500tonnes (wwwalibabacom 2016) It is an important

intermediate of pyridine pyridine derivatives pentaerythritol and crotonaldehyde production

(Sowin and Melcher 2001) It is a precursor for the synthesis of acetals such as 11-

diethoxyethane see Figure 15 used in the fragrance industry and a diesel additive increasing

its cetane number promoting complete combustion thus reducing the emissions of CO

unburnt-hydrocarbons and other smog-causing gases (Frusteri et al 2007) The preparation of

11-diethoxyethane from acetaldehyde and ethanol received significant attention since both

reactants may be obtained from renewable sources (Andrade et al 1986 Kaufhold and El-

Chahawi 1996 Capeletti et al 2000 Gomez et al 2004)

Figure 15 The production of 11-diethoxyethane from acetaldehyde and ethanol

The world-wide production of acetaldehyde estimated to be 128 Mtyear (Eckert et

al 2006) relies mainly on the Wacker-Hoechst direct oxidation of ethylene ie a non-

47

renewable chemical derived from petroleum The production of acetaldehyde from bioethanol

is an alternative sustainable process (Murray et al 1990 Moroz et al 2000) however the use

of crude glycerol a by-product of the biodiesel industry instead of bioethanol for the

production of acetaldehyde would potentially further improve the economy of the biodiesel

industry due to its higher availability and lower cost

(iii) Lactic acid

Lactic acid (LA) (2-hydroxypropanoic acid) is an important commodity chemical with

a price of US $1300-1600tonne ie at least six times higher than that of crude glycerol (L

Nattrass 2010) LA has been long used by a number of industries mainly in the food and food-

related applications (Datta and Henry 2006) Its worldwide production in 1995 reached 50000

tonnes and ~300000 to 400000 tonnes in 2014 (Datta and Tsai 1997 L Nattrass 2010

Dusselier et al 2013) Such increase may be accounted to its newly emerging uses as a benign

chemical feedstock for producing fibres green solvents oxygenated chemicals and more

importantly biodegradable poly(lactic acid) (PLA) PLA found a multitude of uses in the

medical industry for instance as biodegradable surgical sutures orthopaedic implants as well

as in controlled drug release (Okada et al 1994 Middleton and Tipton 2000 Narayanan

2004) PLA is one of the most commercially used biodegradable polymers with a market value

of US $2200tonne (Madhavan Nampoothiri et al 2010)

Currently LA is commercially produced via fermentation of carbohydrates such as

corn This process however suffers from several limitations as it requires a long reaction time

has a low efficiency and generates significant amount of waste gypsum resulting in high

operating cost (Dusselier et al 2013 Mazumdar et al 2013) Catalytic conversion of glycerol

to LA was demonstrated to be a promising alternative (see Chapter 2243)

48

(iv) Dihydroxyacetone

Dihydroxyacetone (DHA) (13-dihydroxypropanone) is a simple carbohydrate with

high market value ~150 US $kg used mainly in the cosmetic industry as an active ingredient

in sunless tanners (Katryniok et al 2011) It may also be used as a precursor for synthesis of

lactic acid High yield of lactic acid was reported using DHA 86 wt (Bicker et al 2005) 71

mol (West et al 2010)

DHA is industrially produced via glycerol fermentation Despite providing high

selectivity to DHA this process has several drawbacks such as low productivity and high

production cost A range of contributing factors exists for instance high glycerol

concentrations and the produced DHA inhibit microorganism growth The impurities in crude

glycerol if used may have a similar effect (Szymanowska-Powalowska and Bialas 2014)

These limitations prevent the fermentation process from reaching the desired effectivity and

meeting the market demands for DHA A more efficient production process of DHA from

glycerol such as catalytic hydrothermal conversion which is discussed in detail in Chapter

2244 is desirable

2241 Non-catalytic hydrothermal conversion of glycerol

Hydrothermal dehydration of glycerol to produce acrolein has been investigated as an

alternative to gas-phase dehydration claimed to be an economically feasible process but has

not proven competitive with the production route from petrochemicals The potential of

hydrothermal dehydration of glycerol not only for the preparation of acrolein but also for other

dehydration products such as acetol and acetaldehyde were demonstrated by a number of

studies

49

Antal et al (1985) were among the first to study the hydrothermal dehydration of

glycerol (at 360 degC and 500 degC 350 bar) detecting acetaldehyde acrolein H2 CO CO2 CH4

C2H2 and C2H6 as products The selectivity towards acetaldehyde was generally higher than

towards acrolein at 360 degC and much higher at 500 degC The non-catalysed glycerol degradation

was examined under at 200-400 degC 300 bar residence time of 20-60 min by Qadariyah et al

(2011) who observed ~100 mol glycerol conversion in a batch reactor at ge250 degC 300 bar

allyl alcohol was found only in SCW with a yield of 97 mol at 400 degC in 30 min

Acetaldehyde was detected in sub-CW region at 250 degC while acrolein was found in both sub-

and supercritical regions The dehydration of glycerol in a continuous flow system was studied

by Buumlhler et al (2002) who on the contrary observed acetaldehyde as the major product at

451 degC 450 bar with the yield increasing with the reaction time Table 9 summarises the works

reported on the non-catalysed hydrothermal conversion of glycerol

50

Table 9 The summary of experimental works including experimental conditions and results on non-catalysed hydrothermal conversion of

glycerol The percentage values are given in mol unless stated otherwise

Reactor Type Temperature Pressure Time Products Ref

- 360 degC 500 degC 350 bar 90 s X = 32 products acrolein acetaldehyde H2 CO CO2 CH4

C2H4 C2H6

Antal et al (1985)

flow 349-475 degC 250 350 450 bar

32-165 s

X = 04-31 products MeOH EtOH acetaldehyde

propionaldehyde acrolein allyl alcohol formaldehyde CO CO2

H2

Buumlhler et al (2002)

batch 300 degC saturated pressure 10-

60 min

X = 2-5 products acrolein acetaldehyde allyl alcohol

formaldehyde hydroxyacetone

Watanabe et al

(2007)

batch 200-400 degC 300 bar 20-60 min X = 999 products allyl alcohol (Y = 967) acetaldehyde

acrolein

Qadariyah et al

(2011)

Note X = glycerol conversion S = selectivity Y = yield

51

2242 Hydrothermal conversion of glycerol catalysed by acids

The non-catalysed dehydration of glycerol yields primarily acetaldehyde Buumlhler et al

(2002) reported a maximum of 31 mol dehydration of 019-057 M glycerol in water at 300-

474 degC 250 350 and 450 bar residence time of 32-165 s Acetaldehyde with the highest

selectivity of 81 mol was found to be the main liquid product under all conditions studied

This was previously observed by Antal et al (1985) who investigated the hydrothermal

decomposition of glycerol at 360 degC and 500 degC 350 bar finding that the selectivity towards

acetaldehyde was generally higher than towards acrolein at 360 degC and much higher at 500 degC

It was concluded that acetaldehyde may formed through three main routes see Figure 15 of

which the Route 3 was dominant in the absence of a catalyst On the other hand the addition

of NaHSO4 increased the acrolein formation at 360 degC whereas at 500 degC the ratio of

acetaldehyde to acrolein selectivities was not significantly affected by NaHSO4 possibly due

to the fact that the free radical chemistry may play the dominant role in glycerol decomposition

at higher temperatures

52

Figure 16 The dehydration reactions of glycerol under hydrothermal conditions (adapted

from Antal et al (1985))

Most of later studies focussed on the effect of catalysts to decrease the reaction

temperature as well as to increase the yield of desired products Table 10 summarises the

experimental works including experimental conditions and results on acid-catalysed

hydrothermal conversion of glycerol

53

Table 10 The summary of experimental works including experimental conditions and results on acid-catalysed hydrothermal conversion of

glycerol The percentage values are given in mol unless stated otherwise Note X = glycerol conversion S = selectivity Y = yield

Catalyst Reactor

Type

Temp Press Time Results

Ref

NaHSO4 - 360 degC 500 degC 350 bar 90 s S (acrolein) = 70 S (acetaldehyde) = 35 Antal et al (1985)

H2SO4 flow 300-350 degC 345 bar 16-39 s X = 10-55 products acrolein

acetaldehyde CO CO2 C2H4

Ramayya et al (1987)

H2SO4 flow 300-400 degC 250 300 345 bar

5-83 s

X = 90 S (acrolein) = ~80 Watanabe et al (2007)

ZnSO4 flow 300-390 degC 250-340 bar 10-

60 s

X = 50 S (acrolein) = 76 Ott et al (2006)

RuZrO2 flow 510-550 degC 350 bar 2-10 s X = 100 products acetaldehyde acetic

acid hydroxyacetone acrolein H2 COCO2

May et al (2010)

TiO2 WO3TiO2 flow 400 degC 330 bar WF (01-8)

x103 kg-cat sm-3

X = ~100 products acrolein

acetaldehyde hydroxyacetone allyl alcohol

Akizuki and Oshima (2012)

TiO2 WO3TiO2 flow 400 degC 250-410 bar WF

(005- 8) x103 kg-cat sm-3

acrolein acetaldehyde hydroxyacetone

lactic acid


H-Beta H-MFI zeolites Na-

Beta Na-MFI

flow 150-210 degC na flow rate 12

mlmiddoth-1

X = ~60 Y (acrolein) = 29 Lin et al (2013)

H-ZSM-5 H-Mordenite flow 180-340 ordmC 70 bar

LHSV = 2 h-1

acrolein Neher et al (1995)

H-Y H-Beta Mor SBA-15

ZSM-23

batch 250 ordmC 70 bar 10 h X = ~90 S (acrolein) = 100 de Oliveira et al (2011)

WF was used as an indicator of reaction time it is defined as the amount of catalyst divided by volumetric flow rate

54

Ramayya et al (1987) reported a high conversion (up to 55 mol) and high yield of

acrolein (up to 86 mol) from the H2SO4 catalysed hydrothermal conversion of glycerol at

300-350 degC 345 bar residence time of 16-39 s at the glycerol to H2SO4 molar ratio ~100 On

the other hand Antal et al (1990) found that only 1 of total glycerol in 01 M glycerol - 001

M H2SO4 solution converted at 250 degC 345 bar concluding that the optimum conditions for the

formation of acrolein include the temperatures above 250 degC and the use of a mineral acid

Identical conclusion was made by Watanabe et al (2007) who observed ~90 mol glycerol

conversion with ~80 mol acrolein selectivity in the H2SO4-catalysed degradation of glycerol

at 400 degC 345 bar

Despite the high conversions and acrolein yields reported the use of mineral acids for

the hydrothermal conversion of glycerol raised concerns over the corrosive effect on the

equipment used This issue may be alleviated by the use of alternative less corrosive catalysts

such as

metal salts

metal oxides and

zeolites

Metal salts

Ott et al (2006) found that ZnSO4 had a competitive catalytic effect to the more

corrosive H2SO4 50 mol glycerol conversion with a maximum acrolein selectivity of 75

mol at 300-390 degC 250-340 bar 10 to 60 s was obtained

55

Metal oxides

May et al (2010) reported the formation of dehydration products of glycerol during the

1 RuZrO2 catalysed gasification of glycerol in SCW at 550 degC 350 bar almost complete

glycerol conversion with ~55 mol selectivity to liquid products were achieved in 4 s Akizuki

and Oshima (2012) investigated the effect of WO3TiO2 on the conversion of glycerol in SCW

(400 degC 33 MPa) using a continuous flow reactor The concentration of acrolein the main

product was increasing with the WO3 concentration reaching a maximum yield of 53 at

100 glycerol conversion Other minor products included acetaldehyde propionic acid

hydroxyacetone lactic acid allyl alcohol propionaldehyde acetone acetic acid and acrylic

acid Despite the promising results of these metal oxide catalysts the high cost for working

under supercritical conditions may prevent this process from future commercialization

Zeolites

Due to the low thermal stability of zeolites in sub-CW amp SCW zeolite catalysts were

commonly used in gas phase- as opposed to liquid phase- glycerol conversion (Corma et al

2008 Kim et al 2010 Carrico et al 2013)

Neher et al (1995) patented a process for the production of acrolein by dehydration of

glycerol in both liquid- and gas phase using acidic solid catalysts such as H-ZSM-5 Na-ZSM-

5 γ-Al2O3 and Mordenite The liquid-phase dehydration of 10 wt glycerol was performed in

a fixed bed reactor with the liquid hourly space velocity (LHSV) of 2 h-1 at 180-340 deg C 70

bar H-ZSM-5 catalysts (SiO2Al2O3 = 60 and 28) showed the highest activity with ~16-20

conversion and ~71-75 selectivity to acrolein The catalysts maintained their activity even

after 50 h of operation Na-zeolite was inactive at all while γ-Al2O3 gave insufficient

selectivity

56

de Oliveira et al (2011) reported a high yield of acrolein from liquid-phase dehydration

of glycerol under hydrothermal conditions (250 degC 70 bar) using several protonic zeolites (H-

zeolites) of which protonic Y zeolite (H-Y) and protonic Mordenite zeolite (H-MOR) provided

the highest conversion (~90 mol) and selectivity (100 mol) to acrolein The liquid phase

dehydration of glycerol at 150-210 degC was studied by Lin et al (2013) The process was

investigated in a fixed bed reactor using microporous H-Beta zeolite (SiAl ratio = 158) and

H-MFI (SiAl = 174) with different concentrations of Broslashnsted acidic sites introduced by

partial replacement of the balancing H+ cation of the zeolites with non-active Na+ The acrolein

yield of 29 mol was achieved at 60 mol glycerol conversion at 200 degC demonstrating the

potential of zeolites as catalyst for hydrothermal dehydration of glycerol

2243 Hydrothermal conversion of glycerol catalysed by bases

The majority of studies on base-catalysed hydrothermal conversion of glycerol focusses

on optimising the conditions for maximum yield of lactic acid (Kishida et al 2005 Shen et

al 2009 Roy et al 2011) Table 11 summarises the studies including experimental

conditions and results on base-catalysed hydrothermal conversion of glycerol

57

Table 11 The summary of studies including experimental conditions and results on base-catalysed hydrothermal conversion of glycerol The

percentage values are given in mol unless stated otherwise

Glycerol Catalyst Reactor Type Temperature Pressure

Time

Conversion

[]

Yield of

LA2 [] [LA]3 gL Ref

033 M glycerol 125 M

NaOH

Batch 300 degC na 90 min 100 90 267 Kishida et al (2005)


KOH

Batch 300 degC ~90 bar1 60 min 100 90 267 Shen et al (2009)

25 M glycerol 275 M

NaOH

Batch 280 degC na 90 min 100 845 1903 Ramirez-Lopez et al

(2010)

011 M glycerol PtC

RuC in 08 M CaO NaOH

Semi-

batchwise

200 degC 40 bar H2 5 h 100 58 57 Maris and Davis (2007)

01 M glycerol PtCaCO3

in 01 M H3BO3

Batch 200 degC 40 bar H2 18 h 45 54 49 ten Dam et al (2011)

03 M glycerol CuO2 in

045 M NaOH

Batch 200 degC 14 bar N2 6 h 978 76 205 Roy et al (2011)

054 M glycerol IrC RhC

in 054 M NaOH

Batch 180 degC H2 or He na ~50 - Auneau et al (2012)

033 M glycerol

01 molL-1 CaO suspension

Batch 290 degC na 150 min 978 408 121 Chen et al (2014)

1 saturated vapour pressure 2 LA=lactic acid 3 concentration

58

Kishida et al (2005) achieved a complete conversion of glycerol with 90 mol yield

of lactate at 300 degC 90 min utilizing NaOH as a catalyst at the NaOH to glycerol molar ratio

of 379 Large amount of H2 was also detected Figure 17 shows the proposed mechanism of

the reaction between glycerol and NaOH forming sodium lactate and H2 under hydrothermal

conditions (Kishida et al 2005) An almost identical mechanism was proposed by Ramirez-

Lopez et al (2010) Under hydrothermal conditions glycerol first reacts with NaOH to form

sodium glyceroxide which loses a proton (becoming a hydride ion H-) to yield glyceraldehyde

Glyceraldehyde then undergoes hydrogen abstraction at the C2 atom by the released hydride

ion (H-) followed by OH elimination to give 2-hydroxypropenal By keto-enol tautomerization

2-hydroxypropenal transforms into pyruvaldehyde which is then converted into lactic acid via

benzilic acid rearrangement or internal Cannizaro reaction

Figure 17 The proposed reaction mechanism of the reaction between glycerol and NaOH

forming sodium lactate and H2 (Kishida et al 2005 Ramirez-Lopez et al 2010)

59

Shen et al (2009) investigated the effect of various alkaline catalysts on the

hydrothermal conversion of glycerol to lactic acid NaOH KOH LiOH Ba(OH)2 Sr(OH)2

Ca(OH)2 Mg(OH)2 and Al(OH)3 were investigated at 300 degC 90 bar 90 min at the base to

glycerol molar ratio of 379 All catalysts were found to be active except for Al(OH)3 High

yields of lactate salts (90 mol) were obtained using either KOH or NaOH which is in

accordance with previous observation made by Kishida et al (2005) The formation of lactate

in the hydrothermal conversion of glycerol depended not only on the hydroxide concentration

but also on the type of metal ions of catalysts For instance KOH was a better catalyst than

NaOH requiring lower concentration and a shorter reaction time to obtain a comparable lactate

yield The effectivity of catalysts decreased in the following order KOH gt NaOH gt LiOH gt

Ba(OH)2 gt Sr(OH)2 gt Ca(OH)2 gt Mg(OH)2

Aiming to develop an economically feasible industrial process for manufacturing of

lactic acid from glycerol Ramirez-Lopez et al (2010) investigated an alkaline hydrothermal

conversion of pure glycerol at glycerol concentration almost 10 times higher than that used by

Kishida et al (2005) and Shen et al (2009) The experiments were carried out at 250-290 degC

30-250 min and NaOH to glycerol molar ratio of 11-175 obtaining ~85 mol lactate yield at

280 degC within 90 min at the NaOH to glycerol molar ratio of 11 Identical yield was obtained

when crude glycerol was used The main by-product was sodium carbonate while other by-

products included sodium acrylate oxalate and formate

To avoid the high corrosiveness and problematic downstream separation associated

with the use of homogeneous alkali catalysts the potential of solid basic catalysts for the

hydrothermal conversion of glycerol to lactic acid was examined by Chen et al (2014) who

tested CaO Ca(OH)2 hydrotalcite dehydrated hydrotalcite and alumina loaded with 35 wt

KNO3 as catalysts The water content of glycerol used was 4-12 wt and the experiments were

carried out at 300 degC for 90 min with the catalyst to glycerol molar ratio of 379 A glycerol

60

conversion of 978 mol with 408 mol yield lactic acid was obtained on CaO at the base to

glycerol molar ratio of 03 290 degC 150 min Similar yield was obtained using crude glycerol

It was also found that the water content of glycerol higher than 10 wt decreased the yield of

lactic acid due to the formation of weakly basic Ca(OH)2

The addition of noble or transition metal catalysts is known to allow the alkaline

hydrothermal reactions to be performed at lower temperature Maris and Davis (2007) used

activated carbon-supported Ru and Pt catalysts in the aqueous-phase hydrogenolysis of

glycerol at 200 degC 40 bar H2 RuC showed better performance than PtC in the production of

ethylene glycol and propylene glycol In contrast the addition of bases (NaOH and CaO) led

to a significant lactate formation the extent of which was greater in the presence of Pt ~58

mol after 5 h as opposed to Ru ten Dam et al (2011) tested 19 commercially available

catalysts for the hydrogenolysis of glycerol to 12-propanediol at 150-200 degC 40 bar H2 The

PtCaCO3 was found to be active while the PtCaCO3 in the presence of H3BO3 decreased the

selectivity to 12-propanediol but increased the selectivity to lactic acid The role of H3BO3

was unclear It was possible to recycle PtCaCO3 without losing the selectivity although certain

degree of deactivation was observed Auneau et al (2012) investigated the carbon supported

Ir and Rh catalysed hydrothermal treatment of 5 wt glycerol solution at 160-180 degC under

He or H2 atmosphere and the glycerol to NaOH molar ratio of 1 A high yield of lactate ~50

mol was reported at 180 degC on the IrC catalyst under He atmosphere Roy et al (2011)

employed Cu2O in the conversion of glycerol at 200 degC in the presence of NaOH receiving 76

mol lactate yield after 6 h In addition to the use of low temperature unlike aqueous phase

hydrogenolysis the process required neither O2 nor H2 Also Cu2O showed good stability even

after several cycles of use However the concentration of feed glycerol (01-03M) was low

The reaction pathway of glycerol conversion to lactate under alkaline hydrothermal conditions

in the presence of metal-based catalysts was proposed to lead through the dehydrogenation of

61

glycerol to glyceraldehyde which is then induced by alkali to yield pyruvaldehyde

Pyruvaldehyde undergoes benzilic acid rearrangement to form lactate ion (Maris and Davis

2007 Auneau et al 2012) see Figure 18

Figure 18 The proposed conversion mechanism of glycerol to lactate under alkaline

hydrothermal conditions in the presence of metal-based catalysts Maris and Davis (2007)

Auneau et al (2012)

A batch hydrothermal electrolysis employing an Ir plate anode was reported by Yuksel

et al (2009) to be a promising method for the transformation of glycerol ~84 mol conversion

with 347 mol of lactate yield as well as H2 gas was obtained after the degradation of glycerol

at 280 degC in the presence of NaOH in 90 min A conversion exceeding 90 mol was later

reported (Yuksel et al 2010)

The performances of Ru Pt Au Rh Ir and Cu under alkali conditions at 180-200 degC

were competitive to that of alkaline metals at 280-300 degC (Maris and Davis 2007 Shen et al

2010 Roy et al 2011 Auneau et al 2012) This shows the potential of alkali hydrothermal

method as a process for preparing lactic acid from glycerol but the resulting lactate salts need

to be converted into free lactic acid by neutralizing with a strong acid (such as H2SO4)

generating metal salt wastes

62

2244 Hydrothermal conversion of glycerol with H2O2

Hydrothermal oxidation is a thermal oxidation process operating in hot-compressed

water using oxygen as an oxidizer It is also known as wet oxidation (WO) or wet air oxidation

(WAO) when air is used It has been commercialised since 1954 as an effective treatment

process for high water content organic waste not suitable for incineration (Zimmermann 1954)

Occasionally the oxidation of organics to CO2 and water is incomplete resulting in valuable

organic compounds such as acetic acid formic acid glycolic acid and lactic acid (Meyer et al

1995 Jin et al 2001 Jin et al 2001 Calvo and Vallejo 2002) and thus the hydrothermal

oxidation has gained an interest as a process for converting biomass into chemicals (Quitain et

al 2002 Jin et al 2005 Jin et al 2006)

Our literature survey reveals that the research on hydrothermal oxidation of glycerol

with an oxidant is most active in China The summary of works published is listed in Table 12

63

Table 12 Hydrothermal oxidation of various biomass into chemicals Percentages present are in mol unless stated otherwise

Feedstock Temperature

Pressure Time


Ref

045 M Crude

glycerol

150-450 degC saturated

vapour pressure with air

or O2 or H2O2

with or without NaOH Y (formic acid) = 31 co-products oxalic

acid Y (formic acid) = ~35 when NaOH

was added

Zhang et al (2013) Zhang(a)

et al (2014)

2 mmol glycerol 120-180 degC 5-15 bar

O2 1 h 40 mM FeCl3

Ru(OH)4 on

reduced graphite oxide

Y (formic acid) = 60 (carbon basis) Xu et al (2014)

1-90 wt

glycerol

150 degC 20-40 bar O2 3h vanadium-substituted

phosphomolybdic acids

(H3+nPVnMo12-nO40)

X = 95wt Y (formic acid) = ~36 wt

other products acetic acid and

formaldehyde

Zhang(b) et al (2014) Zhang

(2015)

glycerol to Ru mol ratio = 1000 Note X = glycerol conversion S = selectivity Y = yield

64

Zhang et al (2013) studied the hydrothermal oxidation of 045 M glycerol with H2O2

at 250 degC autogenic pressure (170 bar) 16 s The highest formic acid yield of 31 mol was

obtained at H2O2 to glycerol molar ratio of 24 while the addition of NaOH expected to prevent

the oxidative decomposition of formic acid provided only ~35 mol yield It was proposed

that glycerol under oxidative hydrothermal conditions may oxidise to yield formic and oxalic

acids of which the latter possibly inhibited further decomposition of formic acid It was found

that the slightly higher yield of formic acid obtained under alkaline conditions may be due to

the initial formation of lactic acid and its subsequent decomposition to formic acid The

addition of NaOH did not inhibit the decomposition of formic acid possibly explaining the

similar yields obtained with or without NaOH The work was patented in 2014 (Zhang(a) et

al 2014)

Zhang(b) et al (2014) and Zhang (2015) reported that glycerol was selectively

converted into formic acid by O2 under hydrothermal conditions using vanadium-substituted

phosphomolybdic acids (H3+nPVnMo12-nO40) as catalysts The experiments were conducted in

a batch reactor at 150 degC 20-40 bar O2 for 3 h using glycerol solutions of different

concentrations ranging from 1-90 wt A complete conversion of glycerol was achieved for 1

wt solution and the main liquid products were formic acid acetic acid and formaldehyde with

the selectivity of ~51 wt ~8 wt and ~7 wt respectively while CO2 was the only product

detected in the gas phase It was found that higher concentration of glycerol resulted in lower

degree of conversion but concurrently higher absolute yield of formic acid and acetic acid

Increasing the vanadium content of the phosphovanadomolybdic catalyst also enhanced the

conversion efficiency of glycerol to formic acid The highest absolute yield of formic acid (~36

wt) was obtained from 50 wt glycerol at 150 degC 20 bar O2 for 3 h using H6PV3Mo9O40

This method was patented in 2015 (Han and Zhang 2015)

65

Xu et al (2014) reported high yield of formic acid (~60 mol) from the hydrothermal

oxidation of glycerol (120-180 degC 5-15 bar O2 1 h) catalysed by Ru(OH)4 doped on reduced

graphite oxide (r-GO) in the presence of Lewis acidic FeCl3 Both Ru(OH)4r-GO and FeCl3

could individually catalyse the glycerol oxidation giving formic acid as the main liquid product

albeit low glycerol conversion (lt20 ) Other Lewis acids tested included AlCl3 CrCl3 and

ZnCl2 each of which exhibited insignificant activity in the oxidation of glycerol

In contrast to alkaline hydrothermal reactions wet oxidation of glycerol directly

produces organic acids such as lactic acid acetic acid and formic acid in their free acid forms

However further research are still required to develop a commercially feasible processes

23 Zeolite-based catalysts

231 Zeolites and their Broslashnsted and Lewis acidity

Zeolites are commonly used as both catalyst supporting materials and solid acid

catalysts in a broad range of commercial processes including fluid catalytic cracking (FCC)

due to their high catalytic performances high surface area high thermal stability high ion

exchange capacity and low cost (Weitkamp 2000) Zeolites are crystalline microporous

aluminosilicates with 3D framework formed by tetrahedral [SiO4] and [AlO4] units linked to

each other by sharing oxygen atoms at their vertices see Figure 19

66

Figure 19 Broslashnsted and Lewis acid sites on zeolite adapted from Kondo et al (2010) and

Almutairi (2013)

Zeolites may act as both Lewis and Broslashnsted acids4 The presence of Al atoms in the

zeolite structure causes negative charges on the zeolite framework which have to be

compensated by cations to maintain the structural stability A wide range of cations

determining the extent of BroslashnstedLewis acidity of zeolites may be used For instance H+ as

a charge balancing-cation provides the zeolites with Broslashnsted acidity while (AlO)+ or metal

cations with Lewis acidity (Almutairi 2013) Since the Al atoms are the source of protons the

Broslashnsted acidity increases with the increasing AlSi ratio On the other hand the Lewis acidity

of zeolites may be controlled by the nature of foreign ions introduced by an ion-exchange

reaction replacing the balancing cations andor the aluminium atoms within the frameworks by

various multivalent metal cations such as Sn4+ Ti4+ and Zr4+ (Hammond et al 2012 Gounder

and Davis 2013)

4 A Lewis acid is a compound with the ability to accept lone pairs of electrons due to having one or more empty

orbitals while Broslashnsted acid is a compound capable of donating protons (H+)

67

232 Stability of zeolites under hydrothermal conditions

Over the last two decades zeolites have gained increasing interest as solid acid catalysts

and catalyst supports for the conversion of biomass into fuels and chemicals (Triantafillidis et

al 2000 Taarning et al 2011) Their high surface acidity makes them one of the most

promising alternatives to highly-corrosive acid additives such as H2SO4 in the conversion of

glycerol carbohydrates and lignocellulosic materials (Klinowski 1984 Corma et al 2008

Katryniok et al 2013) However the stability of zeolites is limited when used in either steam

or hot liquid water (HLW) see Table 13 which is the likely solvent of choice for biomass

conversion because it is cheap and readily dissolves significant amounts of polar oxygenate

compounds from biomass (Ravenelle et al 2010)

The hydrothermal stability of zeolites in steam has been intensively investigated (Xiong

et al 2014) In the presence of steam zeolites may undergo dealumination in which the

framework aluminium atoms (FAl) are removed from the zeolite lattice (Sanz et al 1988

Triantafillidis et al 2000 Triantafillidis et al 2001 Van Donk et al 2003) The

dealumination may lead to a structural breakdown depending on the degree of dealumination

while the degree of dealumination depends on the type and SiAl ratio of zeolites as well as the

dealumination methods (Sanz et al 1988 Triantafillidis et al 2000 Triantafillidis et al

2001 Van Donk et al 2003) The Al atoms removed from the framework form extra-

framework aluminium (EFAl) species (Klinowski 1984) which may either reside separately

outside of the zeolite crystal (Sanz et al 1988 Stockenhuber and Lercher 1995 Ennaert et

al 2014) or be present as isolated charge-compensating cations in the zeolite cages see Figure

19 (Stockenhuber and Lercher 1995 Beyerlein et al 1997) The presence of EFAl in zeolites

results in several desired properties such as increased hydrothermal stability and Lewis acidity

(Ennaert et al 2014)

68

As opposed to the hydrothermal stability of zeolites in steam only a handful of studies

focused on the behaviour of zeolites in HLW at gt100 degC ie water in a condensed state The

studies on the hydrothermal stability of zeolites in HLW summarised in Table 13 are

discussed in this section

69

Table 13 A summary of studies on the hydrothermal stability of zeolites in hot liquid water (HLW)

Zeolite (zeolite type) - SiAl Temperature

Pressure Time

Note Ref

Zeolite Beta (BEA)-18 38 360

Mordenite (MOR)-20

Zeolite Y (FAU)-30

85 ˚C na 5 h Solubility of the zeolites decreased with increasing SiAl ratio

H-BEA-360 lt H-BEA-38 lt H-BEA-18

The solubility was affected by the framework type (i) H-MOR-

20 lt H-BEA-18 (ii) H-BEA-30 lt H-FAU-Y-30

Kruger et al (2014)

Zeolite Y (FAU)-5 14 41

ZSM-5 (MFI)-15 25 40

150 ˚C 200 ˚C

saturated vapour

pressure 1-6 h

All ZSM-5 were stable whereas zeolite Y samples were

degraded and transformed into amorphous

Ravenelle et al (2010)

Zeolite Y (FAU)-27 130 to 200 ˚C

saturated vapour

pressure 72 h

waterzeolite ratio =

100

Decomposition of zeolite H-Y increased with increasing

temperature The zeolite slowly decomposed into EFAl and Si

species at ge 150 ˚C while at 170 and 200 ˚C its structure rapidly

collapsed transforming into Kaolinite amorphous SiO2 and

metakaolinite

Dimitrijevic et al (2006)

ZSM-5 (MFI)-24 to 918

mordenite (MOR)-12 20

Zeolite Beta (BEA)-21 to 200

Zeolite Y (FAU)-5 to 265

130-240 ˚C saturated

vapour pressure 72

h waterzeolite ratio

= 50

ZSM-5 and mordenite were stable whereas zeolite Y and Beta

decomposed

Lutz et al (2005)

H-Y (FAU)-25

H-USY (FAU)-19 9 3

35 ppm of HCl 190

˚C under stirring at

750 rpm 50 bar H2

24 h

all US(Y) zeolites dissolved but showed structural stability for

24 h USY19 has the highest stability even after 120 h

Ennaert et al (2014)

ZSM-5 (MFI)

mordenite (MOR)

Zeolite Beta (BEA)

Zeolite Y (FAU)

200 ˚C saturated

vapour pressure vary

reaction time

The main factor determining the structural stability of zeolites

is the density of their Si-OH terminated defects

Zhang et al (2015)

70

Zeolites tend to be decomposed by water under hydrothermal conditions The degree

of decomposition of zeolites in HLW depends on several factors such as the type and the SiAl

ratio of zeolites see Table 13 Lutz et al (2005) investigated the structural stability of ZSM-5

(MFI) mordenite (MOR) zeolite Beta (BEA) and zeolite Y (FAU) of different SiAl ratios

The zeolites were exposed to the CO2-free hydrothermal environment at 130-240 ordmC under

saturated vapour pressure for 72 h at the waterzeolite ratio of 50 ZSM-5 and mordenite were

relatively stable under the conditions tested whereas zeolite Y and Beta decomposed The

higher stability of ZSM-5 and mordenite was attributed to their dense framework structures

The low stability of Zeolite Y (FAU) under hydrothermal conditions was in a good

agreement with the results reported by Dimitrijevic et al (2006) and Ravenelle et al (2010)

Dimitrijevic et al (2006) reported that the decomposition of zeolite H-Y (SiAl = 27) increased

with increasing temperature The destruction of the zeolite into EFAl and Si species was visible

at 150 degC while the structure collapse to kaolinitemetakaolin and amorphous substances SiO2

was strongly accelerated at the temperatures between 170 and 200 degC The transformation of

zeolite Y into amorphous solid was also observed by Ravenelle et al (2010)

The structural stability of Beta zeolite in hot liquid water is also low As reported by

Lutz et al (2005) Beta zeolite decomposed in liquid water at 130-240 degC saturated vapour

pressure 72 h Kruger et al (2013) analysed the reaction solution recovered from the aqueous

phase dehydration of fructose catalysed by H-Beta zeolite (SiO2Al2O3 ratio = 18) at 130 degC

for 5 h finding that 1-3 wt of the total zeolite dissolved into Al and Si species The zeolite

continued to generate aqueous Si and Al species even after the 2nd and 3rd use However it

should be noted that the researchers cooled down the mother liqueur to laboratory temperature

prior to sampling and analysis affecting a temperature dependent equilibrium concentration of

aqueous species due to precipitation Kruger et al (2014) subsequently studied the dehydration

of fructose carried out in aqueous solutions pre-equilibrated with various zeolites at 85 degC with

71

or without formic acid (or HCl) at pH = 3 The reason as to why the acid was added was to

mimic the conditions in which H-Beta zeolite present and the acidic products formed in the

reaction may influence the zeolite dissolution It was found that the solubility of the zeolites

decreased with increasing SiAl ratio H-BEA-18gt H-BEA-38gt H-BEA-360 where the

number indicates the SiO2Al2O3 ratio The solubility was also affected by the framework type

(i) H-BEA-18gt H-MOR-20 (ii) H-FAU-Y-30gt H-BEA-30

ZSM-5 (MFI) and mordenite (MOR) exhibit high stability in water at 130-240 degC (Lutz

et al 2005 Ravenelle et al 2010) but their long-term stability may be decreased when

subjected to such conditions repeatedly andor for longer time Another group of zeolites stable

in HLW is ldquoUltra stablerdquo Y zeolites (USY) Ennaert et al (2014) examined the hydrothermal

stability of H-Y (SiO2Al2O3 = 25) and H-USY (SiO2Al2O3 = 19 9 and 3) in water acidified

with 35 ppm of HCl at 190 degC under stirring at 750 rpm 50 bar H2 24 h Despite some degree

of dissolution all zeolites were stable under the conditions applied USY with SiO2Al2O3 of

19 exhibited the highest stability and maintained its structure even after 120 h The stability of

the (US)Y in HLW is influenced by the presence of FAl and EFAl species formed either by

steaming or treatment in HLW on the external surface The FAl protects zeolite lattice from

hydrolysis while the EFAl exhibiting low water solubility prevents solubilisation of zeolite

framework

It is well established that the dealumination of zeolites is enhanced by acids while the

desilication is facilitated by bases (Čimek et al 1997 Dimitrijevic et al 2006) Under

hydrothermal conditions the dissolution of zeolites may be facilitated by the presence of both

H+ and OH- ions Figure 20 and 21 show zeolite decomposition steps under hydrothermal

conditions The Si-O-Al and Si-O-Si bonds are attacked by the H+ and OH- ions of water

molecules respectively The latter usually starts at the terminal OH-groups on the surface

72

Figure 20 Decomposition of a low-silica zeolite framework by water Adapted from Lutz et

al (2005) and Ravenelle et al (2010)

Figure 21 Decomposition of a high-silica zeolite framework by water Adapted from Lutz et

al (2005)

73

The final products of zeolite decomposition include SiO2 Si(OH)4 and Al(OH)3 Other

products such as aluminosilicate species and amorphous solids andor crystalline SiO2 may

also be present (Čimek et al 1997) The solubility of SiO2 in water is generally low but

gradually increases with temperature and pressure up to the neighbourhood of the critical

temperature of water where the solubility changes significantly at relatively low pressures

with increasing temperature the solubility is very low (Brunner 2009) SiO2 dissolves in water

to H4SiO4(s) which is subsequently hydrolysed to form silicic acid H4SiO4(aq) see Equation 4

(Rimstidt and Barnes 1980)

Equation 4 Equilibrium of SiO2 in water

1198781198941198742(119904) + 21198672119874(119897) harr 11986741198781198941198744(119904)helliphelliphelliphelliphelliphelliphelliphellip (i)

11986741198781198941198744(119904) + 1198672119874(119897) harr 11986731198781198941198744minus(119886119902) + 1198673119874+helliphelliphelliphellip(ii)

Overall reaction 1198781198941198742(119904) + 21198672119874(119897) harr 11986741198781198941198744(119886119902)helliphelliphelliphelliphelliphelliphellip(iii)

The dissolution of zeolite Y in HLW has been proposed to proceed via hydrolysis of

Si-O-Si bonds (Ravenelle et al 2010) Increasing the SiAl ratio leads to an increase in its

hydrophobicity and thus increasing its stability in aqueous environments Zapata et al (2012)

reported that the structural stability of H-Y zeolites in HLW at 200 degC may be increased by

functionalization of the surface of Y-zeolites with hydrophobic octadecyltrichlorosilane This

increased the hydrophobicity of the zeolites without considerably reducing the density of acid

sites This approach was also adopted by Zhang et al (2015) who demonstrated that the main

factor affecting the stability of zeolites in HLW is as opposed to other studies the density of

74

Si-OH terminal groups The silylation of the Si-OH with ethyltrichlorosilane increased the

hydrophobicity and the stability in HLW

233 Zeolite catalysts in the hydrothermal conversion of polyols to

chemicals

Despite the generally low stability of zeolites in HLW (Ravenelle et al 2010 Kruger

et al 2014) several studies utilized zeolites catalysts for hydrothermal conversion of glycerol

(see Table 10 page 53) and other carbohydrate biomass materials (Neher et al 1995 Kato

and Sekine 2013 Dornath and Fan 2014 Gonzalez-Rivera et al 2014) Table 14 summarises

the research studies including experimental conditions and results on zeolite-catalysed

hydrothermal conversion of various carbohydrates into chemicals

75

Table 14 A summary of research studies including experimental conditions and results on hydrothermal conversion of various polyols into

chemicals using zeolite-based catalysts The percentage values are given in mol unless stated otherwise


Pressure Time


Ref

Cellulose (150 170 190 ˚C)

na (1 3 5 h)

PtH-Beta CO CO2 C1-C5 hydrocarbon

furfural HMF levulinic acid

Kato and Sekine (2013)

Cellulose 210 ˚C 18 bar 30

min microwave-

assisted

H-Beta Sn- Zn- K-doped

Beta zeolite

glucose HMF levulinic acid acetic

acid lactic acid

Gonzalez-Rivera et al (2014)

Fructose (120 150 165 ˚C)

autogenous 05-2 h

H-Beta with carbon black as

an adsorbent

Y (HMF amp furfural) = ~40 Dornath and Fan (2014)

Fructose 130 ˚C na 5 h H-Beta zeolite Sn-Beta

zeolite H-Beta zeolite

filtrated

HMF levulinic acid glucose Van Donk et al (2003)

Fructose 130 ˚C na 5 h H-Beta zeolite zeolite

filtrate of Beta zeolite

Mordenite and zeolite Y

HMF levulinic acid glucose Kruger et al (2014)

DHA GLA 125 ˚C na 24 h Sn-Beta Zr-Beta Ti-Beta

Al-Beta Si-Beta

Y (lactic acid) = ~90 Taarning et al (2009)

Note S = selectivity Y = yield na = not available but assumed to be saturated vapour pressure HMF = 5-hydroxymethylfurfural DHA =

dihydroxyacetone GLA = glyceraldehyde LHSV = Liquid hourly space velocity

76

Dornath and Fan (2014) investigated the hydrothermal dehydration of fructose over H-

Beta zeolite at 120 150 165 ordmC autogenous pressure 05-2 h The yield of HMF the main

product depended mainly on its subsequent conversion to formic acid and levulinic acid see

Figure 22 To increase the yield of HMF a carbon black (BP2000) was used to selectively

adsorb the HMF and furfural to prevent them to react further thus increasing their selectivity

from 27 mol to 44 mol equivalent to the total yield of 41 mol The catalytic effect of

dissolved aqueous zeolites species was studied by Kruger et al (2013) (2014) who investigated

aqueous phase dehydration of fructose using H-Beta zeolite finding the zeolite to be acting as

a source of aqueous aluminosilicate species adversely affecting the selectivity to the desired

products 1 to 3 wt of the total zeolite used dissolved at water-to-zeolite mass ratio ~27 at

130 degC However it should be noted that the researchers cooled down the mother liqueur to

laboratory temperature prior to analysis possibly affecting the equilibrium concentration of

aqueous species due to precipitation The dehydration of fructose was also carried out in

solutions previously equilibrated at 85 degC with zeolites of various framework types and

SiO2Al2O3 ratios (Kruger et al 2014) The solubility of zeolites decreased with increasing the

SiAl ratio H-BEA-18gt H-BEA-38gt H-BEA-360 where the number indicates the SiO2Al2O3

ratio The solubility was also affected by the framework type (i) H-BEA-18gt H-MOR-20 (ii)

H-FAU-Y-30gt H-BEA-30

Figure 22 Dehydration of fructose to HMF (adapted from Dornath and Fan (2014))

77

The zeolites modified to exhibit increased Lewis acidity exhibited promising activity

in converting of biomass into chemicals For instance Kato and Sekine (2013) studied the

hydrothermal conversion of cellulose at 150 170 and 190 ordmC for 1 3 and 5 h in the presence

of M-doped γ-Al2O3 and M-doped H-zeolite with various SiO2Al2O3 ratios where (i) M = Pt

Pd Co Cu Ni or Fe and (ii) H-zeolite = H-Beta zeolite H-USY H-MOR H-ZSM-5 or H-

FER The metal-doped catalysts were prepared by impregnation and liquid ion exchange (LIE)

with various target metal loadings In the presence of γ-Al2O3 and H-zeolites the liquid

products detected were furfural HMF and levulinic acid On the other hand the use of metal-

doped catalysts also provided gases including C1 to C5+ hydrocarbons The 19 wt Pt

supported on H-Beta zeolite (SiO2Al2O3 = 25) prepared by LIE provided the highest

conversion of cellulose and selectivity to valuable C3 and C4 hydrocarbons

Gonzalez-Rivera et al (2014) reported that the microwave-assisted hydrothermolysis

(210 degC autogenous pressure) of microcrystalline cellulose catalysed by H-Beta zeolite

resulted in several organic compounds such as glucose 5-HMF levulinic acid acetic acid and

lactic acid Zn-Beta zeolite favoured the glucose formation and performed better than Sn-Beta

and K-Beta zeolites however none of them achieved the performance of H-Beta zeolite

possibly due to lower concentration of Broslashnsted acid sites On the other hand Lewis-acidic Sn-

Beta zeolites were reported to have high activities and selectivities in the isomerization of

trioses to lactic acid 90 mol yield of lactic acid from hydrothermolysis of DHA at 125 degC

was obtained (Taarning et al 2009)

In spite of the promising catalytic activities and low prices of transition metals as

compared to precious metals no study reported the use of zeolites doped with these types of

Lewis acidic metals in the hydrothermal conversion of glycerol The present study focuses on

78

the use of transition metals-doped ZSM-5 and Beta zeolites as catalysts for the hydrothermal

transformations of glycerol Both zeolites were selected for their high Broslashnsted acidity and ion

exchange capacity (Weitkamp 2000) The metals selected for doping of the zeolites in this

work included Sn2+ and Zn2+ due to their high catalytic properties in the hydrothermal

transformations of polyols (Taarning et al 2009 Cho et al 2014 Gonzalez-Rivera et al

2014) Other investigated metals were Cu2+ Ce3+ and La3+ The Cu2+ Ce3+ and La3+-doped

zeolites have never been reported in the hydrothermal conversion of polyols but these high

Lewis acidic metals were used in other forms showing promising activity For instance Cu2+

was used for the hydrothermolysis of glycerol in sub-CW as CuOAl2O3 at high pH providing

a 98 mol conversion with a high selectivity to lactic acid (~79) at 240 degC after 6 h (Roy et

al 2011) Similarly the hydrothermal conversion of cellulose at 250 degC catalysed by 30 micromol

LaCl3 provided 80 conversion in 180 s with HMF as the main product (Seri et al 2002)

Ce3+ was selected as another representative of lanthanides because among all the lanthanides

it is most abundant and reactive

234 Preparation of Lewis acidic zeolite catalysts

The modification of zeolites through the ion exchange reactions is often carried out in

liquid phase with a high yield of ion exchanged zeolite However the method may have several

disadvantages (Kinger et al 2000)

i The steric constraints may exist due to the formation of bulky hydration shells of

the cations to be exchanged meaning that the diffusion of the cations into the zeolite

pores is limited

ii The solubility of the cation precursor may be low limiting the amount of cations

available in solution

79

iii The extent of exchange is limited by the thermodynamic equilibrium The exchange

process may need to be repeated several times to achieve high ion exchange degree

resulting in the need for large volumes of solution generating waste

The above limitations may be avoided by using an alternative method known as solid-

state ion exchange (SSIE) involving (i) mechanical grinding of powder zeolite with a salt of

desired cations and (ii) calcining the mixture at high temperature SSIE of zeolite is an efficient

process and its main advantage over liquid ion exchange is that a high degree of exchange may

be achieved in a single-step treatment (Kinger et al 2000) Also the metal containing zeolites

prepared by SSIE and conventional liquid ion exchange showed comparable activity and

selectivity in a number of reactions such as NiH-MFI and NiH-BEA in the n-nonane

hydroconversion (Kinger et al 2000) Ce-ZSM-5 in the selective catalytic reduction of NOx

(van Kooten et al 1999)

The metal-doped zeolites prepared by the ion exchange of the balancing cation exhibit

weak or moderate Lewis acidity because many of the exchangeable cations have a low

electronegativity (eg alkali or alkali earth elements) or have a relatively large atomic diameter

eg La3+ Also the balancing metals may be leached out of the frameworks These issues may

be alleviated by incorporating a desired metal into the frameworks replacing the aluminium

atoms Metal-incorporated zeolites are typically obtained by direct incorporation of the desired

metals into the frameworks during hydrothermal synthesis This process however has several

drawbacks (Hammond et al 2012) such as

i) the formation of metal oxide particles which are significantly less active than the

metal ions in the zeolite framework

ii) long synthesis times with unfavourably large crystals formation and

iii) the need for dangerous additives such as hydrogen fluoride

80

Several research groups have developed a convenient post-synthetic method for the

incorporation of different Lewis acid metals into the framework without changing the

crystalline structure of zeolite (Corma et al 1998 Hammond et al 2012) The method

involves the dealumination of zeolites by strong inorganic acid without collapsing the zeolite

structures and filling of vacated tetrahedral sites with metal atoms by a SSIE reaction This is

done by contacting the dealuminated zeolite with a desired metal salt at high temperature (ge500

degC) The method not only eliminates the long synthesis times required in the conventional

hydrothermal synthesis routes but also yields smaller crystals than previously possible through

the direct synthesis The metal-doped zeolites were demonstrated to have a high catalytic

performance in various reactions Cu-Beta zeolites in the selective catalytic reduction (SCR)

of NOx (Corma et al 1997) Sn-Beta zeolite Sn-MCM-41 Ga-MCM-41 catalysed

isomerisation of triose sugars (Taarning et al 2009 Li et al 2011) Sn-deAl-Beta zeolite in

the BaeyerndashVilliger oxidation of cyclohexanone (Hammond et al 2012) However to the best

of our knowledge they have not been exploited for the hydrothermal conversion of glycerol

235 Immobilisation and shaping of powder zeolite catalysts

Powdered zeolites are unsuitable for a direct use in a continuous flow reactor due to

their nano-sized particles having a tendency to get washed out It is therefore necessary to

immobilise them on a larger particle support or agglomerate the powdered zeolites into

macroscopic forms such as pellets or extrudates prior to administration

2351 Immobilisation of zeolites on inorganic membrane (zeolite membrane)

Immobilisation of zeolites on an inorganic membrane consisting of a zeolite top layer

on a mesoporous ceramic or metal support has been developed over the last two decades (Caro

81

et al 2000 Caro and Noack 2008 Gascon et al 2012) as an alternative to polymer composite

membranes widely used in separation operations but their applications are limited due to their

poor thermal and chemical resistance poor durability and catalytic deactivation (Shelekhin et

al 1992 Ulbricht 2006 Yampolskii 2012) In contrast zeolite membranes are relatively

robust offering the possibility of continuous operation without recurring regeneration and thus

reducing the process downtimes NaA zeolite membrane has been used in a plant with 530

Lmiddoth-1 production capacity of solvents at less than 02 wt of water from the solvents initially

contained 10 wt H2O at 120 ordmC (Morigami et al 2001) The use of zeolite membranes in

catalytic reactions was investigated by (McLeary et al 2006 Van Den Bergh et al 2010)

The zeolite membranes may be viewed as a single unit molecular reactors acting as

both catalysts and separators (McLeary et al 2006) High conversion and selectivity were

reported for several types of reactions Hasegawa et al (2001) reported nearly complete

oxidation of CO in H2-rich mixtures using Pt-loaded Y-type zeolite membrane supported on

porous α-Al2O3 tube at 200-250 ordmC demonstrating the potential application of zeolite

membranes for fuel cells Barbieri et al (2002) investigated the potential of zeolite membrane

reactors as alternatives to a fixed bed tubular reactor for the hydrogenation of CO2 to CH3OH

Both the organophilic membrane (such as a silicalite-1 membrane) and hydrophilic membrane

(such as the MORZSM-5chabazite membrane) can operate at lower pressure and higher

temperature as compared to a fixed bed tubular reactor providing higher conversion (40-50)

and selectivity (almost 100) The higher performance of the membrane reactors possibly

because of the selective product removal shifts the reaction equilibrium towards the products

Despite high performance zeolite membrane reactors possess low packing density

(130-800 m2m3) (ie membrane separation areamodule volume ratio) (Xu et al 2004) To

overcome this issue the immobilisation of zeolites on ceramic hollow fibre membranes has

been investigated Ceramic hollow fibre membranes made of Al2O3 have a micro-tubular

82

configuration (outside diameter lt2 mm) and very high packing density (1000-9000 m2m3) (Xu

et al 2004 Tan and Li 2011) see Figure 24

Figure 24 SEM micrographs of ceramic hollow fibre membranes (taken from Gbenedio et al

(2010))

The high temperature resistance as well as high chemical and mechanical stability make

the ceramic hollow membranes an attractive choice for the reactions andor processes operating

in harsh environments (Kingsbury and Li 2009) such as filtration of corrosive fluids (Weber

et al 2003) water desalination (Fang et al 2012) solid oxide fuel cells (SOFCs) (Wei and

Li 2008) membrane contactors (Koonaphapdeelert and Li 2006) membrane supports (Julbe

et al 2001) and high temperature membrane reactors (Galuszka et al 1998 Neomagus et al

2000 Keuler and Lorenzen 2002 Gbenedio et al 2010 Garciacutea-Garciacutea et al 2012)

Immobilised zeolites on ceramic hollow membranes were successfully prepared and

used in several gas and liquid separations Alshebani et al (2008) grown the MFI zeolite into

the ceramic hollow fibres displaying the separation factors close to 10 for the CO2H2 mix The

mixes tested by other researchers include for instance a mix of n-butaneH2 (Li et al 2008)

83

and xylene isomers (Daramola et al 2009) Xu et al (2004) deposited a considerable amount

of NaA zeolite on a ceramic hollow fibre which could be used in gas separations However to

the best of our knowledge zeolites on ceramic hollow membranes has not been reported for

liquid phase reactions

2352 Shaping of zeolite powder

A majority of industrial heterogeneous catalysts are usually employed in their

macroscopic forms such as pellets granules and extrudates (Kraushaar-Czarnetzki and Peter

Muumlller 2009) The most common industrial shaping methods include (Mitchell et al 2013)

spray drying - used to prepare micrometre-sized agglomerates

pelletisation extrusion or granulation - used to prepare millimetre- or centimetre -sized

agglomerates

Depending on the method used a mixture of powdered zeolite and additives such as binders

peptisers and plasticiser may be processed differently (i) dry mixes may be pelletised while

(ii) wet mixes may be extruded granulated or spray dried (Mitchell et al 2013)

Although it may be possible to press powdered zeolites into pellets without any additive

(Mikkola et al 2014) the cohesion of zeolites alone cannot provide sufficient strength for the

catalysts to be used in industrial practice Binders are the materials usually added to improve

mechanical stability and attrition resistance of the catalysts upon hardening (usually achieved

by thermal treatment) of the shaped bodies (Sntamaaria et al 2002 Bauer et al 2014) Silica

alumina and natural clays such as bentonite are among the most commonly used binders for

zeolites see Table 15 Other additives may also be used for instance a peptiser for dispersing

particles to improve the feed homogeneity prior toduring shaping and plasticiser for decreasing

the viscosity of pre-mixtures to facilitate the processing (Mitchell et al 2013)

84

Table 15 Examples of zeolite-based catalysts agglomerated with commonly used binders and additives The reactions catalysed by the catalysts

prepared are also presented

Zeolite Binder Other additives Tested reactionreaction conditions Ref

Honeycomb H-ZSM-5 colloidal silica methyl cellulose

(plasticiser)

oxidation of 12-dichloroethane

at 200-450 degC gas phase flow reactor

Aranzabal et al (2010)

Pt-Pd supported on Beta zeolite

(SiAl = 125 or 25)

γ-Al2O3 HNO3

(peptiser)

hydroisomerization of long-chain n-paraffins

at 205-230 degC pH2 = 50 bar 1198991198672119899ℎ119910119889119903119900119888119886119903119887119900119899 =

7501 liquid hourly space velocity (LHSV) of 05 hminus1

Bauer et al (2014)

H-Beta zeolite Al2O3 acetic acid

(peptiser)

isopropylation of benzene

at 21 degC WHSV 25 h-1 feed (benzeneisopropyl

alcohol) 651

Kasture et al (2007)

H-Gallosilicate (MFI) zeolite Al2O3 kaolin - propane aromatization

at 550 degC gas phase continuous flow reactor time-on-

stream about 6 h

Choudhary et al (1997)

Ti-SBA-15 bentonite methyl cellulose

(plasticiser)

liquid phase olefin epoxidation

at 110 degC 2 h in batch at 110120 degC in a flow reactor

Melero et al (2008)

85

The formulation and the particle shape may affect the performance and mechanical

strength of the agglomerated zeolites Kasture et al (2007) studied the isopropylation of

benzene using Beta zeolite with different amounts of alumina binder The Beta zeolite was

prepared from the fly ash while the binder was added to the acidic forms of the prepared zeolite

at the dry weight ratio of sample to binder of 9010 8020 7030 6040 and 5050 The final

composite material was pressed into self-bonded pellets as well as extruded Among all the

catalysts prepared the 40 wt alumina binder was found to be the most active catalyst with

respect to the benzene conversion and the selectivity to isopropylbenzene an intermediate for

the production of phenol ~19 conversion with ~94 selectivity was obtained using the

pelletized catalyst while the reactions with the extrudates provided ~18 conversion with 92

selectivity

Melero et al (2008) extruded Ti-SBA-15 with bentonite clay and examined its

performance on the liquid phase olefin epoxidation The bentonite content of the extrudates

varied from 10-40 wt with 30 wt being optimal with respect to the particle resistance and

the Ti content Larger amounts of bentonite did not increase the particle mechanical resistance

but decreased the activity of the final material due to the dilution of the Ti-SBA-15 catalyst

A binder typically accounts for 50-90 wt of agglomerated zeolite catalysts However

certain binders may chemically interact with zeolites and act as catalysts (Choudhary et al

1997) As a consequence the overall activity selectivity and stability of the zeolite may be

influenced by the binder-zeolite interactions (Choudhary et al 1997 Zhang et al 2006 Zhao

et al 2013) For instance Choudhary et al (1997) investigated the influence of alumina and

kaolin on the acidity and performance of a commercial H-Gallosilicate (MFI) zeolite (H-

GaMFI zeolite) on the propane aromatization The zeolite was mechanically mixed with a

binder pressed and crushed into ~02-03 mm particles prior to the calcination at 600 degC The

total concentration of strong acid sites of the agglomerated H-GaMFI zeolite determined by

86

chemisorption of pyridine at 400 degC was reduced significantly when kaolin binder was used

while alumina binder did not significantly affect the total acidity The content of binder tested

at 10-50 wt had a negligible effect on the concentration of the acid sites The conversion of

propane and the selectivity to aromatics in the reactions catalysed by the catalyst agglomerated

with kaolin were decreased whereas no change was observed when alumina binder was used

2353 Agglomeration of zeolite powder

The low intracrystalline diffusion coefficient of zeolites (ranging from 10-8 to10-18 m2s)

(Landau et al 1994) usually results in coke formation and rapid catalyst deactivation making

the process optimization difficult (Bonardet et al 1999 Argyle and Bartholomew 2015) A

possible solution to overcome this mass transport limitation is to decrease the zeolite crystallite

size to nanoscale leading to higher surface area to micropore volume ratio and shorter diffusion

path length (Yamamura et al 1994) However the direct use of nano-sized zeolites may cause

high pressure drops in packed-bed reactors up-flow clogging of equipment as well as health

and environmental issues (Waller et al 2004) Therefore nano-sized zeolites need to be

agglomerated or dispersed on a porous support

Typically zeolites are mixed with a binder and subsequently extruded or compressed

into beads or pellets (Kraushaar-Czarnetzki and Peter Muumlller 2009) However binders are

usually not designed and structured for optimal mass transport in terms of high specific surface

areas and pore geometry (Choudhary et al 1997 Ramos et al 2008 Hargreaves and

Munnoch 2013) Generally zeolites agglomerated with a binder possess macro- meso- and

micropores with total BET surface areas of only around 300 m2middotg-1 (Waller et al 2004)

An alternative approach investigated by a number of researchers is to synthesize

zeolites inside the pores of mesoporous supports (Landau et al 1994 Madsen et al 1999)

87

Embedding of zeolite nanocrystals into a mesoporous inorganic matrix such as MCM-

n and TUD-1 has gained increasing interest as a method for agglomerating zeolites (Jansen et

al 2001 Waller et al 2004 Xia and Mokaya 2004 Mavrodinova et al 2005 Petkov et al

2005 Wang et al 2007 Wang et al 2008 Wang et al 2009 Xu et al 2009 Lima et al

2010) The high surface areas and uniform mesoporosity of the support allow the composites

to benefit from the high zeolite catalytic activity and high diffusion rate Wang et al (2007)

(2008) (2009) developed a one-pot synthesis method to obtain a ZSM-5 zeolitemeso-matrix

composite with tunable mesoporosity and high BET surface area (~600 m2g) Xu et al (2009)

synthesized BetaMCM-41 composite exhibiting high BET surface area (~830 m2g) and high

hydrothermal stability its mesoporous structure was preserved even after 336 h in boiling

water Waller et al (2004) prepared Beta zeolite nanocrystals inside mesoporous TUD-1

exhibiting a higher activity per gram of zeolite than pure nanosized Beta zeolite for n-hexane

cracking The nature of the acid sites in the nanozeolite was partially modified due to the

interactions with the TUD-1 Lima et al (2010) selected TUD-1 as a matrix to agglomerate

with H-Beta zeolite The Beta zeoliteTUD-1 composite was used in the cyclodehydration of

xylose to furfural in a H2O-toluene mixture achieving at 170 ordmC the xylose conversions of

~98 higher furfural yield (74) as compared to that obtained on bulk H-Beta zeolite (54)

Several other zeoliteTUD-1 composites were also reported for instance zeolite

YTUPD-1 composite prepared for benzylation reactions (Hamdy and Mul 2013) and ZSM-

5TUD-1 composite used in aldol condensation (Zhou et al 2010)

88

Table 16 Applications of zeoliteTUD-1 composites reported in literature

Reaction Conditions Composite Results Reference

Cracking of n-

hexane

538 ordmC Beta

zeoliteTUD-1

k = 025 while 011

for pure Beta zeolite

Waller et al

(2004)

aldol condensation

of benzaldehyde

and n-amyl

alcohol

80 ordmC ZSM-5TUD-1 X = 31 while 12

for our ZSM-5

Zhou et al

(2010)

cyclodehydration

of xylose

H2O-toluene

mixture 170

ordmC

H-BetaTUD-1 X = 98 furfural

yield = 74 while X

= 94 and furfural

yield = 58 for a

mixture of Beta and

TUD-1

Lima et al

(2010)

Friedel-Crafts

benzylation

80 ordmC H-YTUPD-1 k = 24 while 18 for

pure H-Y zeolite

Hamdy and

Mul (2013)

Pseudo-first-order reaction rate constant in gzeolite-1middotmin-1middotL first-order rate constant in h-1middotmg-1 X

conversion

89

3 Aim of study

31 Aim

The surplus of crude glycerol from the biodiesel industry has resulted in a significant

drop in its price making it an interesting feedstock for the production of value-added chemicals

Finding new uses of crude glycerol would lead to (i) a more efficient biodiesel production

process by reusing its current waste product and ultimately (ii) to a more competitive biodiesel

fuel economy The aim of this thesis is to improve our understanding of the hydrothermal

conversion of glycerol facilitated by the zeolite-based catalysts with respect to

(i) their activity in the hydrothermal transformations of glycerol and

(ii) their potential to affect the distribution of reaction products in favour of liquid

conversion products of glycerol

The hydrothermal environment was adopted for its ability to provide rapid reaction

rates and the high water content of crude glycerol (Peterson et al 2008) ZSM-5 and Beta

zeolites were selected for their high Broslashnsted acidity and ion exchange capacity (Weitkamp

2000) The metal ions selected for doping of the zeolites included Ce3+ Cu2+ La3+ Sn2+ and

Zn2+ due to their promising activity in the hydrothermal transformations of polyols see Chapter

233

In order to achieve the aim of the project the following five objectives are specifically

addressed

90

32 Objectives

Objective I The effect of key reaction parameters on selectivity and yield

This study initially focuses on the effect of high temperaturepressure water on the

decomposition of glycerol in a binary system glycerol-water Also the presence of zeolite with

and without the presence of H2O2 as an oxidation agent is taken into account The individual

systems studied in the initial phase (batch mode) of current work are as follows

(i) Glycerol - water

(ii) Glycerol - water - non-modified commercial catalyst (H-Beta zeolite H-ZSM-5)

(iii) Glycerol - water - H2O2

(iv) Glycerol - water - H2O2 - non-modified commercial catalyst

The ranges of key parameters used

(i) Reaction time 1-300 min

(ii) Pressure 23-186 bar

(iii) Temperature 105-360 degC

The selection of suitable reaction pressure temperature and time is essential since for

instance a short reaction time may lead to a low conversion while an excessively long reaction

time may lead to a high conversion lowering the yield of liquid products due to degradation of

primary products to gases The reaction time and temperature will be varied and the

composition of reaction products will be determined by quantitative and qualitative chemical

analysis 1H-NMR 13C-NMR 2D-NMR HPLC GC-FID and MS (for gaseous products) The

data collected will allow the determination of optimum reaction temperature and time leading

91

to a maximum conversion to liquid decomposition products of glycerol Such reaction

conditions will be used as a base line in further trials

Objective II Preparation and characterisation of metal-doped zeolites

The composition of glycerol conversion products not only depends on the temperature

pressure and reaction time but also on the type of catalyst(s) used This work focusses on the

use of heterogeneous zeolite catalysts exhibiting high Broslashnsted acidity and adjustable

BroslashnstedLewis acidity ratio (Almutairi 2013) The Broslashnsted acid sites of two selected

zeolites ie H-ZMS-5 and H-Beta zeolite will be transformed into Lewis acid sites by

replacing the balancing H+ with Ce3+ La3+ Sn2+ Zn2+ and Cu2+ using the solid state ion-

exchange technique (SSIE) In the case of H-Beta zeolite the transformation of Broslashnsted acid

sites into Lewis acid sites will also be carried out by replacing the Al atoms inside the

framework with Ce3+ La3+ Sn2+ Zn2+ See Table 22 23 and 24 for the zeolites and modified

zeolites prepared

The prepared catalysts will be characterised by several analytical techniques X-ray

powder diffraction spectroscopy (XRD) will be used to qualitatively identify crystalline

mineral phases in the samples while the content of Si and Al will be quantified by X-ray

fluorescence spectroscopy (XRF) The transmission and scanning electron microscopies (TEM

and SEM respectively) will be employed to image the catalystsrsquo morphology as well as to

study their elemental composition using energy dispersive X-ray spectroscopy analysis (EDS)

The catalysts surface area and pore volume will be determined by BrunauerndashEmmettndashTeller

analysis (BET) while the concentration of acidic active sites will be analysed by temperature

programed desorption of NH3 (TPD-NH3)

92

Objective III Investigation into the catalytic effect of zeolites and metal-

doped zeolites

The specific issues to be addressed in this objective are

The effect of metal-substitution of zeolites on hydrothermal transformations of glycerol

The potential of metal-doped zeolite catalysts prepared in this work to control the

distribution of conversion products of glycerol in favour of liquid products

An investigation into the catalytic effect of H-Beta zeolite H-ZSM-5 and metal-doped

zeolite catalysts will be carried out by varying the following reaction parameters temperature

reaction time and type of catalysts The performance of the catalysts will be evaluated by the

glycerol conversion rate selectivity to the major product as well as the stability of the catalysts

Due to the finely powdered nature of zeolite-based catalysts the initial experiments will

be performed in a batch mode with the 6 ml volume tubular bomb reactors as it is a rapid and

convenient method providing the desired information while eliminating the issues associated

with the use of continuous flow reactors such as the catalyst pellets disintegration and the

instrument maintenance

H2O2 will be used as a source of oxygen when required since it is an easy to use and a

powerful oxidant decomposing to oxygen and water eliminating the possibility of

contamination of the systems studied by foreign ions

Objective IV Design and modification of a continuous flow system

The selected reactions will be repeated using a continuous flow system equipped with

a packed bed reactor (PBR) also called plug flow reactor (PFR) In this type of reactors all the

93

substrates present at any given tube cross-section have identical residence time and so equal

opportunity for reaction Additionally in the continuous flow system the reaction parameters

such as temperature and pressure can be accurately measured and controlled All these features

allow the reactions to be performed more effectively at shorter residence times as compared to

a non-stirred batch process making it a more effective operating process for scaling up and

increasing the production capacity The finely powdered catalysts which are not suitable to be

used directly in the continuous flow system will be immobilised on a support pelletized or

extruded prior to administration

A bench-top continuous flow system will be designed and modified for the

hydrothermal transformations of glycerol

Objective V Kinetic study of glycerol transformation

A kinetic study on glycerol conversion under the conditions optimum for high

conversion degree and selectivity to liquid products will be carried out The reaction kinetics

reaction order reaction rate constant and the reaction activation energies will be determined

The data collected will allow the optimisation of the reaction conditions as well as improve the

understanding of the system

94

4 Experimental protocols and methodology

This chapter describes the experimental procedures used in this work together with

some theoretical background

41 Characterisation of solid samples

411 BrunauerndashEmmettndashTeller (BET) analysis

BET analysis is an instrumental technique used to determine the specific surface area

of solid materials by measuring of physical adsorption of a gas on the surface of a solid

substrate as a function of equilibrium pressure This technique is commonly used to determine

the specific surface area of zeolites and other microporous solid catalysts or catalyst supports

such as alumina and clay (Wenman 1995)

Theoretical background

The experimentally obtained adsorption isotherms ie the variation of adsorption with

pressure at a constant temperature are mathematically treated using a theory developed by

Stephen Brunauer Paul Emmett and Edward Teller (Brunauer et al 1938) The so-called

ldquoBET theoryrdquo is the most widely used theory to describe the phenomenon of multilayer

adsorption as opposed to Langmuirrsquos theory (Langmuir 1916) who introduced one of the first

physically plausible models explaining the adsorption The limitation of Langmuirrsquos model

constrain its use to the cases where there are negligible intermolecular interactions between

adsorbed particles ie a monolayer adsorption

95

In BET analysis the adsorption isotherms are treated using the Equation 5 The specific

surface area is found indirectly from the size and the volume of gas molecules needed to form

a monolayer on the surface of the sample (119881119898)

Equation 5 BET adsorption isotherm equation

1

[119881119886 (1198750

119875 minus 1 )]=

119862 minus 1

119881119898119862 times

119875

1198750+

1

119881119898119862

Where

119875 partial vapour pressure of adsorbate gas in equilibrium with the surface at -1958

degC (the boiling point of liquid nitrogen) Pa

1198750 saturated pressure of adsorbate gas at the temperature of adsorption Pa

119881119886 volume of gas adsorbed at standard temperature and pressure (STP) [0 degC and

atmospheric pressure of 1013 x 105 Pa] ml

119881119898 volume of gas adsorbed at STP to produce an apparent monolayer on the sample

surface ml

119862 dimensionless constant that is related to the enthalpy of adsorption of the

adsorbate gas on the powder sample

By plotting the BET value 1

[119881119886(1198750119875

minus 1)] against

119875

1198750 a straight line (usually in the

approximate relative pressure range from 005 to 03) is obtained From the resulting linear plot

the slope ( 119862minus1

119881119898119862 ) and the intercept (

1

119881119898119862 ) are obtained from the linear regression analysis Thus

96

the BET constant (C) Vm and the BET specific surface area (SBET) are calculated according to

Equation 6 7 and 8 respectively

Equation 6 The formula for the BET constant C

119862 = [119878119897119900119901119890

119868119899119905119890119903119888119890119901119905] + 1

Equation 7 The formula for the monolayer adsorbed gas quantity Vm (ml)

119881119898 = 1

119862 119868119899119905119890119903119888119890119901119905 119874119903

1

(119878119897119900119901119890 + 119868119899119905119890119903119888119890119901119905)

Equation 8 The formula for BET specific surface area SBET (m2gndash1)

119878119861119864119879 = (119881119898 119873 119886)

119898 22400

Where

N Avogadro number (6022 times 1023 molminus1)

Vm monolayer adsorbed gas quantity (ml)

a effective cross-sectional area of one adsorbate molecule m2 (0162 nm2

for N2)

m mass of adsorbent or solid sample g

22400 molar volume of adsorbate gas at STP ml

97

Experimental procedures

In present work the BET adsorption isotherms of samples were determined by using

nitrogen gas as a molecular probe at ndash1958degC and relative pressure (PP0) of 00 to 10 using

a TriStar 3000 (Micromeritics) analyser In a typical measurement approx 100 mg sample was

degassed in a flowing nitrogen gas at 200 degC for 4 h using a Flow prep 060 instrument

(Micromeritics) followed by evacuating and cooling to -1958 degC by liquid nitrogen Nitrogen

gas was dosed to the solid adsorbent in controlled increments After each dose of the gas the

pressure was allowed to equilibrate and measured The quantity of adsorbate ie the nitrogen

gas adsorbed on the adsorbent ie the solid sample was determined and plotted against the

equilibrium gas pressure The data were used to determine the quantity of gas required to

saturate the sample surface with a monolayer and the BET specific surface area (SBET) was

calculated using the quantity of the gas The micropore surface area and micropore volume

were calculated by the t-plot method

412 X-ray Fluorescence (XRF) spectroscopy

X-ray fluorescence spectroscopy is an analytical technique used for quantitative

elemental analysis of materials using an X-ray induced excitation of electrons


When the X-rays collide with atoms or molecules their energy may be absorbed by core

electron resulting in either (i) its excitation to higher energy levels or (ii) ejection from the atom

leaving the atom in an excited state with a vacancy in the inner shell Outer shell electrons then

fill the vacancy emitting waves with energy equal to the energy difference between the two

energy states Since each element has a unique set of energy levels each element emits a pattern

98

of X-rays characteristic of the element termed ldquocharacteristic X-raysrdquo (Atkins and Paula

2006) see Figure 23 The intensity of the X-rays increases with the concentration of the

corresponding element The phenomenon is widely used for elemental analysis of solid

materials

Figure 23 The processes that contribute to the generation of X-rays An incoming electron

collides with an electron (in the K shell) and ejects it Another electron (from the L shell in

this illustration) falls into the vacancy and emits its excess energy as an X-ray photon The

figure was taken from Atkins and Paula (2006)


XRF analysis was carried out in a Bruker XRF Explorer-S4 analyser All samples were

subjected to the heating at 110 degC for 5 h in air atmosphere followed by 1000 degC for 5 h prior

to the X-ray fluorescence analysis The weight loss was recorded for both temperatures The

weight loss at 110 degC indicates the moisture content while the weight loss at 1000 degC also

99

referred to as the Loss On Ignition (LOI) may result from the presence of -OH groups andor

other volatiles eg S C and N compounds The calcined powder sample was placed into a

sample holder and analysed without further treatment

413 Powder X-ray diffraction (XRD) spectroscopy

Powder X-ray diffraction spectroscopy has been a principal instrumental technique

used for characterization of crystalline zeolite materials This non-destructive analytical

technique has invariably been the first choice for the identification of zeolites since it is rapid

and provides information on unit cell dimensions (Fultz and Howe 2013)


X-ray diffraction analysis is based on the theory that crystalline materials with their

repeating structures can diffract radiation with a wavelength similar to the distances of lattice

planes in their structure (~1Aring) When the crystalline material is exposed to monochromatic x-

rays the incident beam is diffracted at specific angles to the lattice planes and can be detected

as a diffraction pattern characteristic of the material X-ray diffraction is at its best when dealing

with crystalline materials ie those with long range order

Braggrsquos law governs the conditions for diffraction (Atkins and Paula 2006) see

Equation 9

Equation 9 Braggs law

119899120582 = 2119889 sin 120579

100

where n is an integer

λ is the wavelength of the incident X-ray radiation

d is the distance between atomic layers in a crystal (d-spacing) and

120579 is the angle of incidence between the X-ray beam and the diffraction planes

Experimental procedure

X-ray powder diffraction (XRD) analysis was used for qualitative identification of

crystalline mineral phases in the samples The XRD spectra of samples were obtained on a

XPert PRO Diffractometer (PANalytical) using CuKα radiation (α = 15404 Adeg) and an

XCelerator detector with Nickel filter and Soller slit system All measurements were carried

out at laboratory temperature (22 degC) NaCl was used as an internal standard if required The

mass ratio of zeolite to NaCl was kept constant at 267 for all samples Unless otherwise stated

the angular scan was between 2θ = 5-75deg with a step size of 003deg 2θ and a count time of 38 s

per step

Phase identification was carried out using the PANalytical XPert High Score Plus

software The degree of crystallinity was determined based on the intensity of the characteristic

peak at around 2θ = 226deg (d302) for Beta zeolite and 2θ = 2303deg (d501) for ZSM-5 The

crystallite size of powder samples was determined by Scherrerrsquos equation see Equation 10

The instrument broadening of standard Si (111) at 2θ = 2844deg with CuKα1 radiation used was

015

101

Equation 10 Scherrer equation

119905 = 119870120582

119861 cos 120579

Where t is the particle size

K is the Scherrer constant typically ranging from 09 to 10 (~ 09 in this work)

λ is the x-ray wavelength (α = 154 Adeg)

Bstructural is the instrument broadening described by the full width at half

maximum (FWHM in radians) of the relevant peaks Bstructural = Bobserved -

Bstandard Bobserved is the observed peak width while Bstandard is the peak width of

a crystalline standard the instrument broadening of standard Si (111) at 2θ =

2844deg with CuKα1 radiation used was 015 (Demuynck et al 2010) FWHM

obtained from the machine is in degree it is therefore must be changed into

radian by multiplication by 120587180

120579 (theta) is half of the Bragg angle (in radians) The angle of diffraction obtained

is in degree and needs to be converted into radian by multiplication by 120587180

414 Electron microscopy

The microstructure of zeolites and supporting materials may be investigated effectively

by electron microscopy It provides information on the composition and morphology of

specimens

102


Electron microscopy takes advantage of the interactions between a coherent beam of

electrons and a solid specimen The electron source is commonly a tungsten filament heated to

around 1700 degC at which point it emits copious electrons These electrons are accelerated across

a potential of several tens of keV to give them the required energy the beam is focused and

collimated by a sequence of electromagnetic lenses and apertures When the high energy beam

of electrons strikes the target specimens several interactions occur simultaneously The

incident electrons striking the target either (i) remain undeviated or (ii) are scattered and then

absorbed reflected (scanning electron microscopy) or transmitted (transmission electron

microscopy) Such interactions have led to the development of various electron microscopy

techniques including transmission secondary and backscattered electron microscopy all of

which are used to study the microstructure of materials Transmission electron microscopy and

Scanning electron microscopy were used to study the microstructure of catalysts in this work

Transmission electron microscopy (TEM)


A JEOL 2000-FX 200KV microscope equipped with an Energy-dispersive X-ray

spectrometer (TEM-EDX) was used A small amount of the powder samples were dispersed in

ethanol prior to depositing onto Holey carbon films on 300 mesh copper grids (Agar Scientific)

placed in sample holders

Energy-dispersive X-ray spectroscopy (EDX or EDS) is a spectroscopy technique used

in conjunction with SEM or TEM It detects the characteristic X-rays emitted by a sample

during bombardment with an electron beam An EDX spectrometer detector measures the

103

relative abundance of emitted x-rays versus their energy The spectrum of X-ray energy versus

counts was evaluated to determine the elemental composition of the samples

Scanning electron microscopy (SEM)


SEM was used to examine the crystallinity morphology and elemental composition of

powdered specimens using JEOL SEMEDX JSM-6010LA microscope The solid sample was

mounted in a silver sample holder on double-sided ldquoadhesive carbon taperdquo (Agar Scientific)

and gold coated

415 Temperature programed desorption of ammonia (TPD-NH3)

Temperature-programmed desorption (TPD) is an analytical technique used to measure

the gas adsorption capacity of a solid sample as a function of temperature TPD of basic

molecules such as NH3 (TPD-NH3) is one of the most commonly used methods for studying

the surface acidity of zeolites clays and mesoporous silica (Katada et al 1997 Niwa and

Katada 1997 Trombetta et al 2000 Flessner et al 2001 Rodrıguez-Castelloacuten et al 2003

Rodriacuteguez-Gonzaacutelez et al 2008) It was used to determine the number and strength of acid

sites of the catalysts tested in this work

TPD-NH3 is widely used for its simplicity and relatively low cost (Corma 1997)

However TPD-NH3 cannot distinguish between Broslashnsted and Lewis acid sites Such sites may

only be distinguished by Fourier Transform Infrared Spectroscopy coupled with pyridine

104

thermodesorption (FTIR-pyridine) However this may not suitable for samples with open

cavities or channels smaller than the molecules of pyridine


Figure 24 A schematic diagram of the system used for the TPD-NH3 analysis Note MFC =

mass flow controller

Approx 50 mg of a sample was transferred into a quartz tube reactor and placed into

an electrically heated furnace coupled with a temperature controller (Newtronic MICRO 96

TP10+) The sample was exposed to a helium flow (9999 BOC 50 mlmin) at 550 degC for 1

h and then cooled to 100degC (with liquid nitrogen) the temperature at which the composition of

the gas stream was adjusted to contain 10 wt of NH3 (9998 NH3 BOC) in He ie 100000

ppm NH3 The sample was exposed to the gas flow for 30 minutes and then rinsed with pure

105

He at the same temperature for 1 h in order to eliminate the species physically adsorbed on the

catalyst surface The desorption of ammonia was then started by increasing the temperature to

600 degC at a heating rate of 5 degCmin in a helium gas flow The amount of desorbed-NH3

detected by a mass spectrometer corresponds to the concentration of the acid sites while the

temperature at which ammonia desorbs correlates with the acid sitesrsquo strength The TPD plot

was logged using an in-line data acquisition system

The gas flow was measured and controlled by a mass flow controller (Brooks

Instrument 0152 Flow Control) Liquid nitrogen was supplied in a cryogenic vessel

(Statebourne Cryogenics Cryostor 60) The starting desorption temperature of 100 degC was used

based on the results reported by Hegde et al (1989) who carried out the TPD-NH3 analysis of

H-Beta zeolite starting at room temperature detecting large quantities of physisorbed NH3

molecules ie weakly NH3 bonded molecules not attached to the acid sites The TPD of NH3

starting at ge100 degC was adopted by several researchers (Katada et al 1997 Camiloti et al

1999 Rodriacuteguez-Gonzaacutelez et al 2008)

The concentration of acid sites was determined from the NH3 desorption profiles in

which the areas under the concentration against time curves were deconvoluted using the

OriginPro 86 (OriginLabreg) software of which the Gauss function was used for fitting multi-

peaks The absolute number of zeolite acid sites was determined by multiplying the area under

the peak by the total gas flow rate and the acidity was expressed in micromol g-1 of the catalyst

used

106

416 Thermogravimetric analysis (TGA) and Differential scanning

calorimetry (DSC)

Thermal analysis is a technique to measure specific physical properties of a substance

under controlled conditions of heating or cooling In practice thermal analysis is the heating

(or cooling) of a sample and benchmarking change with respect to an inert reference sample in

an identical thermal regime and recording any change of enthalpy

When a sample is heated any chemical change (eg decomposition) or physical change

(eg melting phase transition) is accompanied by exo- or endothermic peaks These are

recorded as differential thermal analysis (DTA) The DTA signal is the temperature difference

between sample and reference typically plotted versus temperature If mass changes also

occur these are recorded by thermogravimetry (TG) or differential thermogravimetry (DTG)

Similarly to DTA DSC is a technique measuring the amount of heat required to raise the

temperature of a sample and reference as a function of temperature In addition to temperature

it also measures the heat energy (eg heat of fusion) that is consumed by the sample

Thermogravimetric analysis data were measured using a TA Instruments TGA Q500

thermal analyser with the maximum operating temperature of 1000 degC Approx 15 mg sample

was placed in a flowing gas of N2 (400 mlmin) and air (600 mlmin) and heated up to 600 degC

at a rate of 10 degCmin This technique provided mainly information on the water content of the

sample and decomposition of salts DSC analysis was performed on a Differential Scanning

Calorimeter (DSC Q2000 V2410 Build 122) Approx 3 mg sample was placed in a flowing

gas of N2 (500 mlmin) and He (500 mlmin) and heated up to 500 degC at a rate of 10 degCmin

107

42 Characterisation of liquid and gaseous samples

Gas products were first collected through a valve cap of the tubular batch reactors using

a gas syringe and analysed by a mass spectrometer The liquids discharged from the reactor

were separated from solids by filtration using a syringe filter (Millex-MP 022 microm filter unit)

before being subjected to chemical analysis The identification and quantification of liquid

reaction products were performed by 1H-NMR utilising an internal standard (potassium

hydrogen phthalate KHP) of known-concentration added into each NMR sample using D2O

as a solvent The formula for conversion (mol) yield (C-mol) and selectivity (C-mol)

are given in Chapter 45 The 13C-NMR and correlation spectroscopy (COSY) were also used

to identify the reaction products A high-performance liquid chromatograph (HPLC) equipped

with an ion exchange column was employed to confirm the results using an external standard

method The quantitative analysis was performed after the construction of calibration curve(s)

Details of the equipment and analytical procedures used for the characterisation of gas and

liquid samples are described in Chapter 421 to 424

421 Nuclear magnetic resonance (NMR) spectroscopy


The principle of NMR is based on the fact that nuclei of atoms have magnetic

properties and subatomic particles (ie protons electrons and neutrons) behave like magnetic

bars and spin (precession) around the nuclei (Skoog et al 2007) Quantum subatomic particles

(ie protons electrons and neutrons) have spin However in some atoms (such as 12C 16O 2H)

these spins are paired and cancel each other out so that the nucleus of the atom has no overall

spin

108

The nuclear magnetic resonance phenomenon occurs when the nuclei which initially

have their spins (for example +12 in the case of 1H) in parallel with the external (applied)

magnetic field are induced to absorb energy and subsequently excited into a higher energy

level at which their spins are anti-parallel (-12 in the case of 1H) (Skoog et al 2007) Once

application of the external magnetic field is stopped the nuclei emit energy and return to their

normal state This up and down movement of the nuclei is called ldquoresonancerdquo However in

order to allow the nuclei to resonate the energy (magnetic field having radio-frequency)

applied has to have the same frequency as the frequency spins of the nuclei The energy emitted

by the nuclei is detected by a radio frequency detector


In this work the NMR spectra were recorded on Bruker DRX-400 (1H 4001 MHz

13C 1006 MHz) and AV-400 (1H 4003 MHz 13C 1007 MHz) spectrometers at 298 degK

unless otherwise stated The NMR spectra were processed using MestreNova software 1H and

13C chemical shifts were reported as δ (in ppm) and referenced to the residual proton signal and

to the 13C signal of the deuterated solvent (1H D2O δ 470) respectively The following

abbreviations have been used for multiplicities s (singlet) d (doublet) t (triplet) m (unresolved

multiplet)

4211 Identification of liquid products

A typical 1H-NMR spectrum of liquid products of reactions performed under the

hydrothermal conditions studied (see Chapter 6 and 7) are shown in Figure 25 The peaks in

the 1H-NMR spectra were identified according to the chemical shifts listed in Table 17

109

Liquid products typically identified include acrolein acetol acetic acid lactic acid

ethanol methanol and acetaldehyde which exists in two different forms acetaldehyde and

acetaldehyde hydrate (11-dihydroxyethane) (Ahrens and Strehlow 1965) Traces of formic

acid were also detected but only in the reactions at either low temperature or short reaction

time

The quantification of liquid products was performed mainly by 1H-NMR due to

extensive overlapping of glycerol and lactic acid peaks by HPLC due to the

insufficient separation possibly due to the column

MeOH and EtOH were not detectable with the variable wavelength detector

(VWD) used and

inaccurate quantification of acetaldehyde hydrate with HPLC due to low R-

squared value of the calibration curve (constructed using acetaldehyde aqueous

solution)

110

Figure 25 1H-NMR spectrum of the reaction products detected after the glycerol dehydration

in the presence of 48 CeH-Beta at 330degC 1297 bars for 1 h Reaction conditions 01 M

glycerol (03 mmol) the weight ratio of glycerolcat = 1 the mole ratio of glycerol to acid sites

of the catalyst = 115

111

Table 17 The list of chemical shifts of reaction products detected by 1H-NMR after the

hydrothermal dehydration of 01 M glycerol (03 mmol) in the presence of 48 CeH-Beta at

330 degC 1297 bars for 1 h The weight ratio of glycerolcat = 1 the mole ratio of glycerol to

acid sites of the catalyst = 115

Products 1H NMR data (400 MHz D2O) ppm

acetic acid δ = 195 (1H s CH3COOH)

acetaldehyde δ = 954 (1H q CH3COH) 211 (3H d CH3COH)

acetaldehyde

hydrate

δ = 513 (1H q CH3CH(OH)2) 125 (3H d CH3CH(OH)2)

acetol δ = 203 (2H s CH3COCH2OH) 425 (3H s CH3COCH2OH)

acrolein δ = 936 (1H d CH2CHCOH) 656 (1H d CH2CHCOH) 642 (1H

d CH2CHCOH) 630 (1H m CH2CHCOH)

dihydroxyacetone δ= 430 (4H s (HOCH2)2CO)

ethanol δ = 104 (3H t CH3CH2OH) 350-356 (2H q CH3CH2OH)

formic acid δ = 822 (1H s HCOOH)

glycerol δ =344-358 (4H dd OHCH2CH(OH)CH2OH) 366-370 (1H m

OHCH2CH(OH)CH2OH)

glycolic acid δ = 403 (2H s HOCOCH2OH)

lactic acid δ = 130 (3H d CH3CH(OH)COOH) 423 (1H q

CH3CH(OH)COOH)

methanol δ= 323 (3H s CH3OH)

pyruvaldehyde δ= 125 (3H s CH(OH)2COCH3) 218 (CH(OH)2COCH3)

water δ= 471 (2H s H2O)

112

4212 Quantitative 1H-NMR analysis

The concentrations of feed glycerol and its liquid reaction products were determined by

quantitative 1H-NMR analysis and used for calculating the conversion (mol) of the feed

selectivity (C-mol) to and yield (C-mol) of liquid products The protocol consisted of the

following steps (i) to (iii)

(i) The NMR sample preparation

Each sample contained

150 μl of the reaction sample

150 μl of the internal standard solution (005 M or 01 M)

150 μl of deuterium dioxide (D2O)

Potassium hydrogen phthalate (KHP) was used as an internal standard for 1H-NMR

analysis throughout this work because it is solid non-hygroscopic and air-stable making it

easy to weigh accurately

A known amount of KHP was added into every 1H-NMR sample where its carboxylic

protons deprotonate in aqueous environment see Figure 26 so that only four aromatic protons

corresponding to the resonances at around 7-8 ppm appear in the spectra Although the signals

of the reaction products might also appear in this region only trace amounts were detected

113

Figure 26 Potassium hydrogen phthalate (KHP)

(ii) Quantitative analysis

The relative compound concentration was calculated from the area under its peak in 1H-

NMR spectra using the Equation 11 (Popor and Hallenga 1991)

Equation 11 The relationship between the concentration of a compound peak intensity and

the numbers of equivalent nuclei given the signals in 1H-NMR

CA

CB

= IA

IB

timesnB

nA

Where CA is the concentration of A

CB is the concentration of B

IA is the integrated intensity of A

IB is the integrated intensity of B

nA and nB are the numbers of equivalent nuclei given the signals

114

Example Calculation the concentration of lactic acid

The 1H-NMR spectra of lactic acid shows two peaks a doublet at 128 ppm and a

quartet at 423 ppm However only the doublet was used to evaluate the yield as it was not

overlapped by other peaks The two peaks of the internal standard were integrated calibrated

as 1 and then the area under the doublet found by integration was used for calculating the

relative concentration of lactic acid see Equation 12

Equation 12 The formula used for the calculation of relative concentration of lactic acid

Clactic acid= Ilactic acid

Istandard

times 2

3 timesCstandard

Clactic acid is the concentration of lactic acid produced

I lactic acid is the integrate intensity of the doublet peak of lactic acid

I standard is the integrate intensity of the internal standard

Cstandard is the concentration of the internal standard

nB is 2

nA is 3

each signal of the internal standard corresponds to 2 protons of the aromatic ring

the doublet of the lactic acid peaks correspond to 3 protons of the methyl group

(iii) Quantification calculation

The conversion yield (carbon basis) and selectivity (carbon basis) are defined in

Equation 13 14 and 15 respectively (Bicker et al 2005)

115

Equation 13 The formula used to find the conversion

where C0 is the initial and C1 the final concentration of the starting material (M)

Equation 14 The formula used to find the yield (mol - carbon basis)

Equation 15 The formula used to find the selectivity (mol - carbon basis)

4213 Validation of KHP

Ca(lactate)2 was used as a source of lactate to validate the concentration of the internal

standard KHP because it is solid air-stable non-hygroscopic making it easy to weigh

accurately Validation of KHP was performed by plotting the concentration of lactate obtained

from 1H-NMR against the theoretical values (see Figure 27) The linear regression equation

obtained indicates that the KHP is a suitable standard

116

Figure 27 Validation of KHP the internal standard for 1H-NMR

422 High-performance liquid chromatography (HPLC)


HPLC is an analytical technique in which dissolved chemical species are separated due

to their different movement rates through a porous solid resin (known as a stationary phase)

inside a column A mixture of compounds is carried through the column by a mobile phase (a

solvent or a mixture of solvents) pumped through the column at high pressure and a fixed flow

rate Species with weak attraction to the stationary phase are eluted from the column first and

subsequently detected by a detector The UV absorption intensity of chemical species is

recorded against the retention time allowing both qualitative and quantitative analysis HPLC

y = 1155x + 04549

Rsup2 = 09953

0

2

4

6

8

10

12

14

16

18

0 2 4 6 8 10 12 14 16

[lact

ate

] exp

erim

en

t (m

M)

[lactate]theoritical (mM)

117

technique is suitable for low volatile- or high molecular weight organic compounds High

pressure makes the separation much faster than simple column chromatography


HPLC analyses were carried out using a complete Hewlett Packard 1050 HPLC system

equipped with a variable wavelength detector (VWD) and an ion exchange column (Aminex

HPX-87H 30cm x 78mm ID Bio-rad) The system was controlled by the computer software

HP Chemstation The VWD wavelength (λ) used 190 nm the column temperature 60 degC the

mobile phase 3 mM H2SO4 flow rate 05 mlmin

HPLC analysis was employed to confirm the analysis results obtained by NMR A

typical HPLC chromatogram of liquid samples of the reactions performed under the

hydrothermal conditions studied (see Chapter 6 and 7) is shown in Figure 113 in the Appendix

The calibration curves for glycerol and its reaction products were constructed using

commercial analytical standards The concentrations of unknown samples were determined

using a linear regression equation The retention times of the standards are listed in Table 18

while the calibration curves are provided in Figure 114 115 and 116 (in the Appendix)

Table 18 The retention times of compounds detected by Aminex 87H conditions 3mM

H2SO4 VWD 190 nm column temperature 60 degC flow rate 05mlmin

Retention time

(min)

Compounds

Retention time

(min)

Compounds

13548 pyruvaldehyde 17665 acetic acid

14233 glycolic acid 20322 acetol

14597 lactic acid 20846 acetaldehyde1

15264 glycerol 22276 acetaldehyde hydrate

15590 DHA 26502 acetaldehyde 2

16114 formic acid 30760 acrolein

118

4221 Quantitative analysis of results from HPLC vs 1H-NMR

The results from HPLC were close to those obtained from 1H-NMR (see Table 19) with

a difference of 6 However as the HPLC analysis was performed at a later date as compared

to 1H-NMR there is a possibility that some compounds degraded contributing to the difference

Several peaks in the HPLC chromatogram (especially at 42335 and 66766 min) remained

unidentified The GC-MS analysis was performed on selected samples where necessary

Table 19 Summary of residual glycerol concentrations quantified by 1H-NMR and HPLC The

sample was obtained from hydrothermolysis of glycerol in the presence of H-Beta zeolite at

270 degC 55 bar 3 h the glycerolzeolite weight ratio = 1 the mole ratio of glycerol to acid sites

of H-Beta zeolite = 451

Concentration of Glycerol determined by 1H-NMR Concentration of Glycerol determined by HPLC

00302 mM 00284 mM

423 Inductively Coupled Plasma - Optical Emission Spectrometry

(ICP-OES)


ICP-OES is an analytical technique used for the detection of a broad range of elements

It is a type of emission spectroscopy that uses the inductively coupled plasma at high

temperature up to 9727 degC to produce excited or ionized atoms that emit electromagnetic

radiation at wavelengths characteristic of a particular element upon returning to ground state

119

(Skoog et al 2007) The emitted waves are measured by an optical spectrometer A detector

converts light energy (photons) from analyte emissions generated in the plasma into an

electrical signal that can be quantified A schematic of an ICP-OES is depicted in Figure 28

Figure 28 Schematic of an ICP-OES The figure was taken from (Verheijen 2012)


The liquids recovered from the reactors were filtered using a 02 microm syringe filter

diluted twenty times with 20 M HNO3 and analysed for aqueous Al Si and Cu using ICP-OES

(Optima 2000DV Perkin Elmer) The standard solutions (1000 ppm) were purchased from

MBH and Sigma Aldrich

424 Mass spectrometry (MS)

Mass spectrometry is a versatile analytical technique widely used for both qualitative

and quantitative chemical analysis of species present in a sample by measuring the mass-to-

charge ratio and abundance of gas-phase ions

120


A mass spectrometric analysis involves the following steps (Skoog et al 2007) (1)

ionisation of the atom or molecule to form a positively charged ion (2) acceleration of the ions

to the same kinetic energy (3) deflection of the ions in a magnetic field based on their mass-

to-charge ratio (mz) where m is the mass number of the ion in atomic mass units and z is the

number of fundamental charges that it bears and (4) the detection of ions A mass spectrum is

a plot of the ion signal intensity as a function of the mass-to-charge ratio

Gaseous samples were analysed using a mass spectrometer (European Spectrometry

System II)

425 UV-VIS spectrophotometry

UV-VIS spectrophotometry was used to quantify the final H2O2 concentration of the

mother liqueurs recovered after the oxidative hydrothermolysis of glycerol using H2O2 This

method makes use of a chemical reaction between TiOSO4 and H2O2 producing yellow colour

pertitanic acid (Equation 16) stable for at least 6 h (Eisenberg 1943) see Figure 29 allowing

the spectrophotometry to be carried out at later time Moreover TiOSO4 selectively reacts with

H2O2 and is neither affected by other oxidizing agents nor by air (Amin and Olson 1967)

Equation 16 Reaction between TiOSO4 and H2O2 in water producing H2TiO4 (pertitanic acid)

1198791198944+ + 11986721198742 + 21198672119874 rarr 11986721198791198941198744 + 4119867+

121

Figure 29 Calibration solutions with increasing H2O2 concentrations after the reaction with

TiOSO4

Beckman Coulter DU-640 UV-VIS spectrophotometer was used for the measurements

The wavelength for pertitanic acid determination was 409 nm H2O2 calibration solutions were

prepared from 03 M (300000 μmolL) H2O2 stock solution A nearly linear calibration curve

was obtained in the range of H2O2 concentrations from 100 μmolL to 2000 μmolL The

concentrations of H2O2 in the samples were determined using a linear regression equation

122

Figure 30 A calibration curve of H2O2 solutions obtained using the titanium method

(Eisenberg 1943) the formed pertitanic acid was determined by UVVis spectrophotometry at

409 nm

4251 Preparation of TiOSO4 solution

TiOSO4 solution was prepared using a method adapted from Eisenberg (1943) 25 g

TiOSO4 (29 Ti as TiO2) was dissolved in 1 L of a 20 M H2SO4 solution continuously cooled

in an ice-water bath The solution was then stored in a fridge for up to three months The final

concentration of Ti (as TiO2) in the solution was ge 7480 ppm

4252 Preparation of H2O2 stock solution

Each H2O2 calibration solution was prepared by the dilution of 03 M H2O2 stock

solution the H2O2 concentration of which was determined by redox titration with KMnO4

y = 00005x - 00158

Rsup2 = 09995

0

02

04

06

08

1

12

0 500 1000 1500 2000 2500

Ab

sro

ba

nce

H2O2 (micromolL)

123

03 M H2O2 aqueous solution was prepared as follows 34015 g (003 mol) of 30 wt H2O2

solution was transferred into a 100 ml volumetric flask and the volume was adjusted to 100 ml

with DI water The solution was standardized with 00644 M KMnO4 solution (10230 g of

995 KMnO4 in 100 ml DI water) In a typical redox titration 3 g of conc H2SO4 (95) was

added slowly into 20 ml of 03 M H2O2 The acidified solution was then titrated with the 00644

M KMnO4 standard solution The balanced chemical equation for the overall reaction between

H2O2 and permanganate (1198721198991198744minus) is shown in Equation 17

Equation 17 The reaction between H2O2 and KMnO4 in an acidic solution (Jeffery et al 1989)

511986721198742 + 21198701198721198991198744 + 311986721198781198744 rarr 21198721198991198781198744 + 11987021198781198744 + 81198672119874 + 51198742

H2O2 which is a strong oxidant becomes a reducing agent in the presence of an even

stronger oxidizing agent such as permanganate H2O2 reduces permanganate (Mn7+) which is

intense purple in colour to a colourless product of manganese salt (Mn2+) The reaction occurs

in an H2SO4 solution as protons are required to form water

124

43 Chemicals and materials

Unless otherwise stated all chemicals used were of standard reagent grade and were

used without further purification Table 20 lists all the chemicals and materials used in present

work

Table 20 The list of chemicals and materials used in the present work

Chemical reagents Supplier

Ce(NO3)36H2O 99999 trace metals basis Sigma Aldrich

CeO2 999 trace metals basis Sigma Aldrich

Cu(NO3)23H2O analytical reagents 99-104 Sigma Aldrich

CuO powder 990 Sigma Aldrich

LaCl37H2O ACS reagent 645-700 Sigma Aldrich

La(NO3)3middotH2O analytical reagents ge990 (titration) Sigma Aldrich

SnCl22H2O ACS reagent ge98 Sigma Aldrich

Zn(SO4)27H2O ReagentPlusreg ge990 Sigma Aldrich

triethanolamine (TEA) (97 wt) ACROS Organicstrade

triethylammoniumhydroxide (TEAOH) (40wt) Sigma Aldrich

tetraethylorthosilicate (TEOS) (999) reagent Sigma Aldrich

sodium aluminate anhydrous (NaAlO2) technical Sigma Aldrich

bentonite clay (montmorillonite Al2O3middot4SiO2middotH2O) Sigma Aldrich

methyl cellulose (viscosity 4000cP 2 in H2O) Sigma Aldrich

γ-alumina 9997 trace metals basis Alfa Aesar

NH4-ZSM-5 (CBV2314) Zeolyst International USA

NH4-Beta zeolite (CP814E) Zeolyst International USA

13-propanediol 98 wt Sigma Aldrich

glycerol gt 99 wt Sigma Aldrich

12-propanediol ACS reagent ge995 Sigma Aldrich

glyceraldehyde ge90 (GC) Sigma Aldrich

pyruvaldehyde 40 wt in H2O Sigma Aldrich

lactic acid 88-92 Sigma Aldrich

CeCl37H2O 99999 trace metals basis Sigma Aldrich

ZnCl2 99999 trace metals basis Sigma Aldrich

125

Table 20 (continued)


formic acid 98 Sigma Aldrich

acetic acid glacial ge9985 Sigma Aldrich

acetaldehyde 995 Sigma Aldrich

acrolein 95 Sigma Aldrich

methanol 99 VWR

ethanol absolute 9998 VWR

potassium hydrogenphthalate (KHP) BioXtra ge9995 Sigma Aldrich

deuterium oxide (D2O) 999 atom D Sigma Aldrich

ICP multi-element standard solution IV Merck

MBH analytical Multi-element plasma standard 3 Element

Custom Multi

MBH

Cu (1000mgL) ICP standard solution TraceCERTreg Sigma Aldrich

Al (1000mgL) ICP standard solution TraceCERTreg Sigma Aldrich

H2O2 (30 wv) VWR

H2SO4 95 VWR

HNO3 68 VWR

KMnO4 995 BDH Analar

titanium oxysulfate (TiOSO4 ge29 TiO2) technical Sigma Aldrich

silica beads (particle size ~1 mm) Assistant Germany

carborundum powder (silicon carbide) (60 Grit) T N Lawrence Art Supplies

acetol 90 wt Sigma Aldrich

pyruvic acid 98 wt Sigma Aldrich

Sn(CH3COO)2 Sigma Aldrich

Zn(CH3COO)2 Sigma Aldrich

glycolic acid ReagentPlusreg 99 Sigma Aldrich

13-dihydroxyacetone dimer 97 Sigma Aldrich

Amberlitereg IR120 hydrogen form Sigma Aldrich

126

44 Catalyst preparation

A series of catalysts based on commercial NH4-Beta zeolite or NH4-ZSM-5 was

prepared following the steps outlined in Figure 31 All metal-doped zeolites prepared using

solid state ion exchange reaction (SSIE) with metal salts at 550 degC are listed in Table 21 and

22 The list of sample names of powdered zeolite prepared and tested as catalysts in tubular

batch reactors is given in Table 23 The names are composed of the weight percentage of metal

relative to the weight of zeolite For instance 48 CeH-Beta zeolite stands for 48 wt Ce

content relative to H-Beta zeolite

127

Figure 31 The catalysts preparation based on NH4-Beta zeolite deAl-Beta refers to

dealuminated H-Beta zeolite Identical steps except for the extrusion and the preparation of

metal-doped deAl-ZSM-5 were used for the catalyst preparation based on NH4-ZSM-5 Metal

salts used as the source of corresponding metal ions included Ce(NO3)3middot6H2O La(NO3)3middotH2O

Sn(CH3COO)2 Zn(CH3COO)2 Cu(NO3)23H2O

128

Table 21 A summary of all metal-doped zeolites based on commercial Beta zeolite prepared

in this work The solid state ion exchange (SSIE) technique was used utilizing metal nitrates

as the source of metal ions The metal-doped zeolites were used for trials with tubular batch

reactors

Zeolite

wt of metal content relative to the zeolite

- Ce Ce La Sn Zn Cu

0 25 48 48 48 48 48

NH4-Beta

H-Beta

deAl-Beta

deAl-Beta refers to dealuminated H-Beta zeolite

Table 22 A summary of all metal-doped zeolites based on commercial ZSM-5 zeolite

prepared in this work The solid state ion exchange (SSIE) technique was used utilizing metal

nitrates as the source of metal ions The metal-doped zeolites were used for trials with tubular

batch reactors

Zeolite


- Ce Ce La Sn Zn Cu

0 25 48 48 48 48 48

NH4-ZSM-5

H-ZSM-5

deAl-ZSM-5

deAl-ZSM-5 refers to dealuminated H-ZSM-5

129

Table 23 The list of sample names of powdered zeolite catalysts prepared and tested as catalyst

in tubular batch reactors

Catalyst Catalyst

NH4-Beta NH4-ZSM-5

H-Beta zeolite H-ZSM-5

48 CeNH4-Beta 48 CeNH4-ZSM-5

48 LaNH4-Beta 48 LaNH4-ZSM-5

48 SnNH4-Beta 48 SnNH4-ZSM-5

48 ZnNH4-Beta 48 ZnNH4-ZSM-5

48 CeH-Beta 48 CeH-ZSM-5

48 LaH-Beta 48 LaH-ZSM-5

48 SnH-Beta 48 SnH-ZSM-5

48 ZnH-Beta 48 ZnH-ZSM-5

48 CuH-Beta Dealuminated H-ZSM-5 (deAl-ZSM-5)

Dealuminated H-Beta zeolite (deAl-Beta)

1 CedeAl-HBetaII4h

2 CedeAl-HBetaII4h

3 CedeAl-HBetaII4h

48 CedeAl-BetaII4h

48 CudeAl-BetaII4h

48 SndeAl-BetaII4h

48 ZndeAl-BetaII4h

the Roman and Arabic numerals indicate the number of grams of H-Beta zeolite dealuminated

in 20 ml of 13 M HNO3 and the reaction time in hour (ie 4 h) respectively

The finely powdered zeolites prepared (Table 21 and 22) were tested as catalysts in tubular

batch reactors However they were unsuitable for use in a continuous flow reactor due to their

tendency to get washed out The issue was addressed by attempts to immobilise the zeolites by

the following means

(i) synthesis of CeH-Beta zeolites on hollow fibre ceramic membranes

130

(ii) incorporation of Beta zeolite-based catalysts into mesoporous silica matrix

followed by pelletization

(iii) extrusion of Beta zeolite-based catalysts with clay (bentonite) or γ-alumina

See Table 24 for a summary of all zeolite-based catalysts prepared for the trials with a

continuous flow reactor in the present work Experimental protocols for the preparation of all

the catalysts are presented in Chapter 441 to 446

Table 24 A summary of all zeolite-based catalysts used for the trials with a continuous flow

reactor in the present work

Production method Catalyst

H-Beta 48 CuH-Beta 48 CeH-Beta

Synthesis on ceramic membrane support

Incorporation into mesoporous silica matrix

(TUD-1)

Extrusion with clay

Extrusion with alumina

441 Preparation of H-Beta zeolite and H-ZSM-5

20 g of NH4-Beta zeolite (SiO2Al2O3 = 25) or NH4-ZSM-5 (SiO2Al2O3 = 23) were

activated by calcination at 550 degC for 5 h in air atmosphere in a muffle furnace (Elite Thermal

Systems Limited) at a heatingcooling rate of 100 degCh to form the acidic form of zeolites (H-

zeolites) see Equation 18 The products were characterised by XRD BET-N2 and TPD-NH3

See Chapter 51 for the results

131

Equation 18 Calcination of NH4-zeolites to form H-zeolites

442 Preparation of metal-exchanged NH4-Beta H-Beta NH4-

ZSM-5 and H-ZSM-5 zeolites

The metal-doped zeolite catalysts were prepared via a solid state ion exchange (SSIE)

reaction between (i) the as received zeolites (NH4-ZSM-5 or NH4-Beta zeolite) or activated

zeolites (H-ZSM-5 or H-Beta zeolite) prepared according to the experimental protocol

described in Chapter 441 and (ii) a desired metal salt Ce(NO3)3middot6H2O La(NO3)3middotH2O

Sn(CH3COO)2 Zn(CH3COO)2 Cu(NO3)23H2O The zeolite doped with 48 wt of metal was

prepared as follows 2 g of NH4- or H- Beta zeolite (or NH4- or H- ZSM-5) were mixed with a

required amount of metal salt and manually ground in a ceramic mortar for 15 min at ambient

conditions The mixture was then transferred into an alumina crucible and calcined at 550 degC

for 3 h in air atmosphere using a heatingcooling rate of 100 degCh The calcined samples were

labelled as ldquo48 MH-zeoliterdquo or ldquo48 MNH4-zeoliterdquo where the ldquo48rdquo indicates the

weight percentage of metal relative to the weight of zeolite and the letter ldquoMrdquo denotes the type

of metal ion used The samples were characterised by XRD TPD-NH3 TEM and SEM See

Chapter 52 for the results

132

443 Preparation of metal-exchanged dealuminated H-Beta zeolite

The preparation of metal-doped dealuminated H-zeolite (H-Beta or H-ZSM-5) method

consists of three steps

1 Preparation of H-zeolite

2 Dealumination of H-zeolite

3 Doping of dealuminated H-zeolite with host metal ions

The H-zeolite was prepared following the description in Chapter 441 The

dealumination of the sample was then performed using the method reported by Hammond et

al (2012) This method is capable of removing Al atoms without collapsing the crystalline

structure of the zeolite

The dealumination was carried out as follows 125 g of H-zeolite was dispersed in 25

ml of 13 M HNO3 (20 mlg zeolite) sealed in a 50 ml Teflon lined stainless steel autoclave

reactor and heated at 100 degC for 1 4 or 20 h in a thermostatically controlled air recirculating

oven (GC oven HP Hewlett Packard 5890) The reactor was subsequently cooled down to

room temperature (RT) the reaction liquid was decanted and the solid re-suspended in 100 ml

of deionised water The sample was then centrifuged at 3000 rpm (Heraeus-Megafuge 40R

Centrifuge Thermo Scientific) for 20 min and decanted with the cycle repeating three times

after when the pH of the sample reached ~7 The recovered solid was then oven-dried for 12 h

at 110 degC and stored in a sealed container at RT (Lami et al 1993) The prepared solids were

characterised by XRD TEM XRF and NH3-TPD

The desired metal ions were then incorporated into a dealuminated zeolite by SSIE

method according to the protocol in Chapter 442 The metal salts used as precursors included

Ce(NO3)3middot6H2O La(NO3)3middotH2O Sn(CH3COO)2 Zn(CH3COO)2 CeCl37H2O SnCl22H2O

133

and ZnCl2 The two reaction steps of the dealumination of H-zeolites followed by SSIE is

shown in Equation 19

Equation 19 Preparation of metal-doped dealuminated H-zeolites A treatment with conc

HNO3 creates vacant sites (in the zeolite framework) which were subsequently filled with host

metal atoms supplied by a metal salt

444 Preparation of CeH-Beta zeolite on ceramic hollow fibre

membranes

The CeH-Beta zeolite on a ceramic hollow fibre membrane (CHFM) support was

prepared using a method adapted from Kantam et al (2005) Yadav et al (2009) and Yang et

al (2010) The procedure consisted of the following steps

1 sol-gel synthesis of Na-Beta zeolite on CHFM

2 conversion of Na-Beta zeolite on CHFM to NH4-Beta zeolite

3 conversion of NH4-Beta zeolite on CHFM to H-Beta zeolite

4 conversion of H-Beta zeolite on CHFM to CeH-Beta zeolite

134

1 Sol-gel synthesis of Na-Beta zeolite on CHFM

Solution A Water (27891 g) was added slowly into TEOS (45355 g 2177 mmol) and stirred

for 30 min

Solution B Water (2 g) was added into TEAOH (48195 g 1310 mmol) followed by slow

addition of NaAlO2 (00419 g 050 mmol) The solution mixture was stirred for 30 min

The CHFM were provided by Dr Zhentao Wu of the department of Chemical

Engineering Imperial College London (Kingsbury et al 2010) The alumina hollow fibre

precursors received were cut into approx 5 mm long pellets and calcined in a muffle furnace

(Eurotherm 2116 Elite Thermal Systems Ltd) to yield CHFM The temperature was increased

from room temperature (RT) to 600 degC at 2 degCmin and held for 2 h and then to 1450 degC at 5

degCmin and held for 4 h The temperature was then reduced to RT at a rate of 3 degCmin

Figure 32 Alumina hollow fibre precursors of ceramic hollow fibre membranes used as a

support for CeH-Beta zeolite in the present work

135

Na-Beta zeolite on CHFM was synthesized as follows 2 g of CHFM pre-dried in a

vacuum oven for 1 h at RT was added into solution A and stirred for 30 min at 500 rpm The

solution B was then added dropwise into the stirred mixture producing a white precipitate The

mixture was stirred for another 2 h The product was then sealed in a 50 ml Teflon-lined

autoclave reactor placed in a thermostatically controlled air recirculating oven (HP Hewlett

Packard 5890) at 160 degC for 48 h and subsequently cooled down by an ice-water bath The

mother liquor was decanted and the solid dispersed in 100 ml DI water and centrifuged at 3000

rpm for 20 min at RT The cycle was repeated three times The recovered solid containing a

mix of zeolite and CHFM pellets was oven-dried at 110 degC for 12 h

2 Conversion of Na-Beta zeolite on CHFM to NH4-Beta zeolite

NH4-Beta zeolite on CHFM was prepared by liquid ion exchange reaction of the Na-

Beta zeolite on CHFM obtained in step 1 with 2 M aqueous solution of NH4Cl 2 g of the mix

of Na-Beta zeolite and CHFM was stirred with 120 ml of 2 M NH4Cl(aq) at 80 degC for 6 h The

suspension was filtered on stainless steel mesh with 05 mm aperture diameter and washed

three times with 50 ml of DI water prior to drying at 110 degC for 12 h The recovered filtrate

was diluted with 100 ml DI water and centrifuged at 3000 rpm for 20 min to recover the

suspended zeolite The solid was dried at 110 degC for 12 h and stored at RT To ensure a

complete ion exchange the whole cycle of the liquid ion exchange was repeated three times

3 Conversion of NH4-Beta zeolite on CHFM to H-Beta zeolite

NH4-Beta zeolite on CHFM prepared in step 2 was transformed into H-Beta zeolite by

calcination at 550 degC for 5 h at a heatingcooling rate of 100 degCh The NH4-Beta zeolite

136

recovered from the filtrate in step 2 was converted into its H-Beta form using identical

procedure and used as a control sample

4 Conversion of H-Beta zeolite on CHFM to CeH-Beta zeolite

The samples of (i) H-Beta zeolite on CHFM and (ii) control H-Beta zeolite powder

were transformed into their CeH-Beta form by a liquid ion exchange reaction with soluble

cerium salt 2 g of sample was stirred with 120 ml of 2 M Ce(NO3)3 at 80 degC for 6 h The work-

up procedure is identical to that described in step 2 The obtained CeH-Beta zeolite powder

and CeH-Beta zeolite on CHFM were characterised by XRD and SEM see Chapter 551

445 Preparation of H-Beta and metal-dopedH-Beta zeolites on

TUD-1 matrix

To agglomerate the fine particles of zeolite catalyst the H-Beta zeolite (or 48 CeH-

Beta or 48CuH-Beta) was incorporated into the pores of mesoporous silica matrix TUD-1

using a method based on the work of Lima et al (2010) Using this procedure the final product

consisted of 40 wt of the metal-doped Beta zeolite and 60 wt TUD-1

1587 g (1032 mmol) of TEA was mixed with 12 g of DI water at RT for 15 min 4 g

of H-Beta zeolite (or 48 CeH-Beta or 48 CuH-Beta) was then slowly admixed and the

mixture was stirred for 30 min to ensure complete dispersion 2136 g (1024 mmol) of TEOS

was then added dropwise into the mixture to allow the aggregation of silica particles to occur

gradually The mixture was stirred for 2 h after which 120752 g (328mmol) of TEAOH was

added dropwise and the solution was stirred for another 2 h The resulting light-brown colour

137

gel was left to age under static conditions for 24 h at RT It was dried at 100 degC for 24 h and

then transferred into a 50 ml Teflon line autoclave reactor heated at 180 degC for 8 h followed

by rapid cooling in an ice-water bath The brown colour gel was calcined at 600 degC for 10 h at

a heating rate of 1 degCmin The resulting white powder containing a mixture of TUD-1 and

zeolite was analysed by XRD and BET-N2 see Chapter 552 The powder sample was pressed

into a pellet using a force of 50kN for 10 min crushed using a pestle and mortar and sieved

The particles with sizes ranging from 250-450 μm were used in a packed bed reactor

446 Preparation of extruded zeolite catalysts

The extrusion of H-Beta zeolite and 48 CuH-Beta was performed using two types

of binders bentonite clay and γ-Al2O3

Extrusion with bentonite binder The experimental protocol for the preparation of extruded

zeolite catalysts using bentonite as a binder was adapted from Melero et al (2012) 65 g H-

Beta zeolite 3 g bentonite and 05 g methyl cellulose (MC) were manually mixed together 20

g of DI water was then added and mixed until all the material became a paste The material

was then transferred into a 10 ml plastic syringe used as an extruder The extruded catalyst rods

were left to air dry for 15 min and cut into approx 2 mm long pellets see Figure 33A To

slowly dry the material the pellets were transferred on a metal sieve placed above the water

level inside a 25 L crystallization dish and covered with a lid (see Figure 33B) prior to leaving

it at 20 degC for 24 h The pellets were left to dry at 20degC on the work bench for another 24 h

followed by the calcination at 550degC using a heating rate of 03degCmin

138

Figure 33 The extruded catalyst rods were cut into approx 2 mm long pellets (A) which were

then dried slowly in humid environment at RT (B)

Extrusion with γ-Al2O3 binder The experimental protocol for the extrusion of 48 CuH-

Beta zeolite using γ-Al2O3 (lt106 microm) as a binder was adapted from Sntamaaria et al (2002)

Ramiacuterez et al (2005) and Kasture et al (2007) To prepare a paste of 6040 weight ratio of

zeolite to binder 24 g of 48 CuH-Beta zeolite and 16 g of γ-Al2O3 were manually mixed

together in a 100 ml plastic beaker 5 ml of 3 wt acetic acid aqueous solution was then added

and mixed until the material became a homogeneous paste The paste was then transferred into

a 10 ml plastic syringe used as an extruder The extruded catalyst rods were left to air dry for

5 min and cut into approx 2 mm long pellets The prepared pellets were stored in open

atmosphere at RT overnight followed by drying at 40 degC for 2 h and then 2 h at 120 degC Finally

the pellets were calcined at 550 degC for 4 h at a heating rate of 5 degCmin

The original method used by Sntamaaria et al (2002) Ramiacuterez et al (2005) and

Kasture et al (2007) was modified by the addition of MC in order to improve the consistency

139

of the extruded paste (Mitchell et al 2013) The paste consisted of 575 wt H-Beta zeolite

(or 575 wt of 48 CuH-Beta zeolite) 375 wt γ-Al2O3 and 5 wt MC where the

numbers indicate the weight percentage of each component relative to the total weight of the

mixture 65 ml of 3 wt acetic acid aqueous solution was required to prepare the paste of H-

Beta zeolites while the paste of 48 CuH-Beta zeolite needed 55 ml The extrusion protocol

was identical to that for the preparation of extruded zeolite catalysts using alumina as a binder

140

45 Hydrothermal dehydration of glycerol

451 Dehydration of glycerol

Hydrothermal transformations of glycerol was investigated using tubular batch reactors

heated in a thermostatically controlled air recirculating oven (HP Hewlett Packard 5890) see

Figure 34 The cylindrical tube reactors were made of stainless steel (SS316 Ham-Let Let-

Lokreg dimension internal diameter (id) ~085 cm length ~1063 cm volume ~60 cm3) and

capped at both ends where one end was a valve cap A control reactor was fitted with a K-type

thermocouple placed inside the reactor at ~5 cm length and connected to a digital thermometer

(Comark KM340)

The empty reactors were weighted filled with 3 ml of 01 M stock solution of glycerol

(09209 g (001 mol) of glycerol (gt99 wt) in 100 g DI water) and a pre-determined amount

of a catalyst if required The reactors were purged with N2 gas for 5 min and sealed and the

final weight of the reactors were recorded Each reactor was then placed in an oven at RT and

heated to 270 degC 300degC or 330 degC for the desired period of time The time required for heating

up the reactors to an operating temperature ranged between 8-15 min and was not included in

the recorded reaction times The reactors were subsequently transferred into an ice-water bath

to stop the reactions dried with acetone and then reweighed to check for possible leakage

Multiple reactors were often heated simultaneously and withdrawn individually at regular time

intervals Finally gaseous products were collected through a valve cap of the reactor and the

reactor contents were left to settle The solution was then filtered using a 022 microm nylon syringe

filter while the recovered solids were dried in an oven at 65 degC for 16 h The solid samples

were analysed by XRD spectroscopy while the liquid samples were analysed by 1H-NMR

HPLC and ICP-OES Gaseous products were analysed by mass spectrometry The operating

141

pressures were calculated as a sum of partial pressures of saturated vapour pressures of glycerol

and water at the operating temperatures using the Aspen plus V84 software The calculated

pressures were verified using a separate batch reactor equiped with a thermocouple and

pressure gague

Figure 34 The thermostatically controlled air recirculating oven (GC HP Hewlett Packard

5890) containing a set of bomb reactors

452 Dissolution of H-Beta zeolite in hot liquid water

The dissolution of H-Beta zeolite in hot liquid water (HLW) was investigated using the

equipment listed in Chapter 451 The reactors of known initial weights were filled with 30

mg of H-Beta zeolite and 3 ml of DI water purged with N2 gas for 5 min sealed and the final

weights were recorded Each reactor was placed in an oven at RT and heated to 150 200 and

250 degC for 1 3 5 and 20 h The reactors were subsequently transferred into an ice-water bath

to stop the reactions dried with acetone and reweighed to check for possible leakage Finally

142

the reactor contents were left to settle at RT decanted and filtered using a 022 microm nylon

syringe filter The recovered solids were dried in an oven at 65 degC for 16 h and analysed by

XRD The liquids were analysed by ICP-OES The dissolution of H-Beta zeolite in water at 20

degC (RT) for 1 24 and 48 h was performed in a closed vial without stirring 30 mg of H-Beta

zeolite and 3 ml of DI water were added in a 5 ml glass vial they were then hand shaken for

one minute and left at RT The solutions were filtered after 1 24 and 48 h and analysed by the

same manner as the samples prepared at 150 200 and 250 degC but analysis of solids was not

carried out

453 Effect of dissolved Al and Si on the dehydration of glycerol

To evaluate the effect of aqueous Al and Si species on the hydrothermal dehydration of

glycerol in this work a two-step experiment was carried out

Step 1 ndash Preparation of dissolved aqueous Si and Al species

The experiment was performed using the equipment listed in Chapter 451 The

reactors of known initial weights were filled with

3 ml of DI water and

30 mg H-Beta zeolite or 30 mg dealuminated Beta zeolite (deAl-BetaI20h)

The reactors were purged with N2 gas for 5 min sealed and the final weights were

recorded Each reactor was placed in an oven at RT and heated at 330 degC under autogenic

pressure for 5 10 15 30 45 and 60 min The reactors were subsequently transferred into an

ice-water bath to stop the reactions dried with acetone and reweighed to check for possible

143

leakage Finally the resulting solutions were filtered at RT using a 022 microm nylon syringe filter

and then analysed by ICP-OES

Step 2 - Hydrothermal dehydration of glycerol in zeolite filtrates

The experiment was performed using the equipment described in Chapter 451 3 ml

of the filtered solutions obtained in Step 1 further referred to as zeolite filtrates were

transferred into a tube reactor together with 30 mg of 99 glycerol purged with N2 for 5 min

sealed and heated at 330 degC for 5 10 15 30 45 or 60 min The holding time used was identical

to that used for preparing the zeolite filtrate for instance the 5 min dehydration of glycerol

was performed in the zeolite filtrate prepared with the holding time of 5 min Once the required

times were reached the reactors were cooled down in an ice-water bath the liquids were

filtered analysed by ICP-OES and 1H-NMR

46 Hydrothermal oxidation of glycerol

461 Batch process

The initial work focused on finding of the suitable reaction conditions for the

hydrothermal oxidation of glycerol using tubular batch reactors for the simplicity of use The

equipment and the experimental procedure used are described in Chapter 451 However the

feed stock solution catalysts and reaction conditions used for the oxidation were different and

are provided in this chapter

The empty reactors were weighted filled with 3 ml of a mixture of 02 M aqueous

solution of glycerol and 02 M H2O2 and a pre-determined amount of a catalyst if required

The reactors were purged with N2 gas for 5 min sealed and the final weight of the reactors

144

were recorded Each reactor was then placed in an oven at RT and heated to 125 150 and 175

degC under autogenic pressure (water and H2O2) for the desired period of time The reactors were

subsequently transferred into an ice-water bath to stop the reactions dried with acetone and

reweighed to check for possible leakage Finally the reaction solution was left to settle at RT

the solution was decanted and filtered using a 022 microm nylon syringe filter The recovered

solids were dried in an oven at 65 degC for 16 h The solids were analysed by XRD while the

liquids by 1H-NMR HPLC ICP-OES and UV-VIS

The feed stock solution used was a mixture of 02 M aqueous solution of glycerol and

02 M H2O2 prepared as follows 18418 g (002 mol) of glycerol (gt99 wt) and 22676 g (002

mol) of H2O2 (30 wv) were transferred into a 100 ml volumetric flask and the volume was

adjusted to 100 ml with DI water

462 Continuous flow process

A continuous flow system assembled according to the diagram in Figure 35 was used

to investigate the hydrothermal oxidation of glycerol in subcritical water A photo of the

apparatus is shown in Figure 36

145

Figure 35 A schematic of the high pressure continuous flow system apparatus used for glycerol oxidation under sub-CW conditions

146

Figure 36 The high pressure continuous flow system apparatus used for investigation of

glycerol oxidation under sub-CW conditions A HPLC pump no 1 for preheated water a DI

water reservoir B HPLC pump no 2 for feed solution b feed reservoir C preheater D

tubular reactor E digital thermometer ersquo K-type thermocouple inside the reactor erdquo K-type

thermocouple inside the copper block F electrical furnace G furnace temperature controller

H digital thermometer at the joining point between the feed solution and pre-heated water I

cooling coiled tube in an ice-water bath J stainless steel in-line filter K pressure relief valve

L digital pressure gauge M back pressure regulator N gas-liquid separator O liquid sample

P low pressure gas tube leading to a fume extractor

I High pressure continuous flow system apparatus

Two cylindrical stainless steel tubes (SS316 Ham-Let Let-Lokreg) were fabricated to

the following specifications and used as

147

(i) a flow through water preheater - id ~165 mm length ~500 mm volume ~11 cm3 and

(ii) a plug flow or packed bed reactor - id ~437 mm length ~500 mm volume ~75 cm3

Both the reactor [D] and preheater [C] are housed within a copper block (length 40 cm)

placed in a vertical tube furnace [F] (vertical length 40 cm) with the maximum operating

temperature of 1100 degC see Figure 35 and 36 The temperature of the furnace is controlled by

a digital furnace controller [G] The copper block is fitted with a K-type thermocouple [ersquorsquo]

placed inside at ~200 mm length

The reactor where the conversion of glycerol takes place is also fitted with a K-type

thermocouple [ersquo] placed inside the reactor at length of ~250 mm (or at the top of the reactor

when it is packed with a catalyst) enabling the temperature inside the reactor to be measured

by a digital thermometer It is fed with a mixture of (i) preheated DI water and (ii) the aqueous

glycerol solution A K-type thermocouple connected to a thermometer [H] is installed at the

meeting point of these two solutions to monitor the mixture temperature at ~10 cm before the

inlet of the reactor The two solutions are supplied from two separate reservoirs [a] and [b]

and fed into the reactor [D] in a water to feed ratio of 21 which is achieved by adjusting the

flow rate of the HPLC pumps [A] and [B] The area as well as the connections around the top

and bottom of the furnace is covered with glass wool and then wrapped with aluminium foil to

prevent heat loss The details of all equipment used are provided in Table 25

148

Table 25 Details of equipment used in the continuous flow apparatus

Equipment Model or brand

digital thermometer [EH] Comark KM340

electrical ceramic furnace [F] Elite Thermal Systems Limited model TCV12

digital furnace controller [G] Elite Thermal Systems Limited model Eurotherm 2116

HPLC pump [A B] Gilson 305

back pressure regulator [M] Go Regulator model BP-66 max 689 bar

digital pressure gauge [L] Omega max 689 bar

pressure relief valve [K] Ham-let model H900HPSSL14G

II Preparation of feed solution

The feed solution used in this experiment was a combined 06 M aqueous solution of

glycerol and 06 M H2O2 It was prepared by introducing of 5525 g of gt99 wt glycerol (06

mol) and 6803 g of 30 wv H2O2 (06 mol) into a 1000 ml volumetric flask and adjusting the

volume to 1000 ml with DI water

III Preparation of a fixed-bed reactor

When a solid catalyst was used the reactor was loaded with 1 g of a desired zeolite-

based catalyst which was pelletized or extruded prior to administration in order to prevent the

zeolite from being washed out from the reactor The preparation method for pelletized and

extruded catalysts is provided in Chapter 445 and 446 The order of packing of the fixed bed

reactor with the catalyst shown in Figure 37 was arranged as follows The agglomerated

catalyst was placed between two layers of silicon carbide granules (~254 μm) quartz wool and

silica beads (average particle size ~1 mm) acting as an inert filler before being closed off by

149

another layer of quartz wool and metal mesh (200 mesh count per inch) on either ends keeping

the beads in place The temperature gradient inside the reactor shown in Figure 38 was

measured at 125 ordmC at the water flow rate of 243 mlmiddotmin-1 at the reactor depths of 40 30 20

and 10 cm from the top while the temperature of copper block was recorded at a fixed position

ie at 20 cm

Figure 37 The reactor and a K-type thermocouple (left) and the reactor packing scheme (right)

(adapted from Mikkola et al (2014))

150

Figure 38 The temperature gradient inside the reactor

IV Standard operating procedure

The operating procedure of the continuous flow system shown in Figure 35 and 36 is

as follows The HPLC pumps 1 and 2 are turned on pumping the DI water through the system

at a flow rate of 2 mlmin and gradually pressurising the system by closing the back pressure

regulator [M] before heating the furnace up Such order of actions ie the pressurisation at

laboratory temperature followed by increasing of temperature prevented the formation of

steam which is difficult to control The variable back pressure regulator [M] installed on the

system to attain the desired pressure inside the reactor is monitored by a digital pressure gauge

[L] The pressure relief valve [K] is installed to limit the maximum pressure of the system to

200 bar The DI water [a] and feed solution [b] are fed into the preheater [C] and reactor [D]

respectively by high pressure HPLC pumps [A] and [B] at a constant flow rate of 2 mlmin

151

DI water is initially contained in the reservoir [b] before switching to the glycerol feed solution

(a mix of 06 M glycerol and 06 M H2O2) when the desired temperature and pressure are

attained The concentration of glycerol and H2O2 after the mixing point is 02 M

When passing through the heated reactor the feed solution reacts and the fluid then exits

through a coiled tube cooled by an ice-water bath [I] in order to terminate the reactions An in-

line filter [J] made of stainless steel with pore size of 05 μm is used to filter the product solution

before it is passed through the back pressure regulator [M] and a gas-liquid separator [N] When

the samples pass the back pressure regulator they are under atmospheric pressure The liquid

samples are collected at the bottom exit tube [O] while the gaseous products are released at the

top exit through a plastic tube [P] connected to a fume extractor

The samples were collected when the temperature and pressure of the reactor stabilised

at around the set point (plusmn1 degC and plusmn1 bar respectively) and approx 100 ml of the eluted liquid

was collected to ensure consistency To measure the decomposition of H2O2 500 microl of the

liquid samples were immediately mixed with 1000 microl of the titanium sulphate solution and the

UV-VIS spectrophotometry analysis was carried out in 1-5 h The samples for 1H-NMR

analysis were also prepared promptly and analysed 1-5 h later ~5ml of liquid samples were

stored in a fridge for ICP analysis

V Residence time and voidage calculation

The residence times of the feed solution in the reactor were calculated using the water

densities at operating temperature and pressure using Equation 20 and were varied by changing

the flow rate of the pumps

152

Equation 20 Formula calculation of residence time (120591) based on the water densities at

operating temperature and pressure (Bicker et al 2005)

τ =VR 120576 ρR

V ρSTP

Where VR is the reactor volume cm3

120576 is the void fraction of the bed (which is 1 for the empty-tube experiment)

ρR is the fluid density at process pressure and temperature gcm3

ρSTP is fluid density at standard temperature and pressure (0 and 101325Pa) gcm3

V is the volume flow cm3

The fluid density is assumed to be of pure water in this study because of the low concentration

of glycerol

When a reactor is packed with catalyst the reacting fluid may channel through void

fraction Consequently the molecules do not spend as much time in the reactor as those in a

flow through reactor (Fogler 2008)

Voidage ie the bed volume fraction unoccupied by solid material was determined

experimentally by the displacement method using water The packed bed reactor was weighted

connected to an HPLC pump filling the reactor with water and reweighed The weight

difference (4283 g) was then subtracted by the amount of water in the catalyst pores

(0111135cm3g) determined by a BET N2 analysis see Equation 21

153

Equation 21 Determination of packed bed reactor voidage 120576 containing 1g of catalyst

ε =119881119900119897119906119898119890 119900119891 119908119886119905119890119903 119894119899119904119894119889119890 119905ℎ119890 119903119890119886119888119905119900119903 minus 119898119894119888119903119900119901119900119903119890 119907119900119897119906119898119890 119900119891 119905ℎ119890 119888119886119905119886119897119910119904119905

119879119900119905119886119897 119907119900119897119906119898119890 119900119891 119905ℎ119890 119903119890119886119888119905119900119903

Therefore

ε =4283 g divide 0999 gcm3 minus 1g times 0111135 cm3g

74993 cm3= 0556

The fluid density dependence on temperature and pressure may be expressed by Equation 22

Equation 22 Formula for calculation of fluid density at various temperature and pressure

(wwwengineeringtoolboxcom)

ρR =ρSTP

[1 + β(T1 minus T0)] ∙ [1 minus (P1 minus P0)E]

Where


ρSTP is the fluid density at Standard Temperature and Pressure (0 and 101325Pa) gcm3

β is the volumetric temperature expansion coefficient m3m3

T1 is the final temperature

T0 is the initial temperature (standard temperature)

P1 is the final pressure Pa

P0 is the initial pressure (standard pressure) Pa

E is the bulk modulus fluid elasticity Pa

154

The water density at different processing pressures and temperatures as well as the total

volume flow rate at different resident times as a function of temperature are provided in Table

56 in the Appendix

155

5 Catalyst characterisation

This chapter presents the results of catalyst characterisation The techniques used and

the experimental procedures are detailed in Chapter 41 and 44 respectively

51 H-Beta zeolite and H-ZSM-5

The successful preparation of H-zeolites by calcination of NH4-zeolites at the

temperatures between 500-550 degC was reported by a number of studies (Kerr 1969 Bagnasco

1996 Kuumlhl 1999 Barthos et al 2000 Lenarda et al 2003) H-Beta zeolite and H-ZSM-5

were prepared by calcining the corresponding commercially available NH4-Beta zeolite

(SiO2Al2O3 = 25) and NH4-ZSM-5 (SiO2Al2O3 = 23) at 550 degC for 5 h in air atmosphere at a

heatingcooling rate of 100 degCh The resulting samples were characterized by XRD XRF

SEM-EDS and TPD-NH3

511 Powder X-ray diffraction

The XRD spectra of NH4-ZSM-5 and NH4-Beta zeolite before and after the calcination

at 550 degC for 5 h are shown in Figure 39 The XRD patterns of the zeolites before and after the

thermal treatment are nearly identical and do not reveal the presence of other distinct phases

which is in accordance with the observation made by other researchers (Trombetta et al 2000

Roberge et al 2002 Lenarda et al 2003 Drake et al 2006) However the intensities of the

main diffraction peaks of the calcined NH4-Beta zeolite (Figure 39C) at around 2θ = 78deg and

2θ = 226deg are ~28 and ~5 higher than those of non-calcined NH4-Beta zeolite (Figure

39D) respectively indicating an increase in crystallinity as a result of thermal treatment An

increase in the crystallinity of the treated samples may possibly be explained by the removal

156

of amorphous phase present in the untreated sample andor reduced distortion of the zeolite

framework (Ravenelle et al 2010) Additionally the SEM micrograph of NH4-Beta zeolite

after calcination shows as opposed to that before calcination individual particles with

possibly-increased crystallinity see Figure 40

An increase in the crystallinity of the treated samples is in contrary to the observation

reported by Lenarda et al (2003) who reported no changes in crystallinity after the calcination

of NH4-Beta zeolite in air for 16 h at 500 600 650 and 750 degC at an un-specified heating rate

The crystallographic data reported do not allow the changes in peak intensities if any to be

confirmed The chemical composition of NH4-Beta zeolite used was identical to that used in

the present work

In general the changes in the peak intensity of the calcined NH4-Beta zeolite may be

induced by (i) the nature of balancing cations andor (ii) the in-channel contents of zeolites

(Medrud 1999) The H+ form of zeolite has a lower X-ray radiation absorption coefficient than

its NH4+ form resulting in higher intensities of diffraction peaks (Hubbell and Seltzer 1995)

The low angle diffraction peaks of zeolites are known to be the most sensitive to the changes

in channel content (Medrud 1999) hence an increase in the intensity of the peak at 2θ = 78deg

is likely to be associated with the decrease of zeolite water content during calcination at 550

degC see Figure 118 (in the Appendix) for the thermogravimetric analysis of NH4-Beta zeolite

The calcination of NH4-ZSM-5 as opposed to NH4-Beta zeolite at 550 degC for 5 h did

not result in a significant change in crystallinity as the intensity of its main characteristic peak

at around 2θ = 2303deg increased only by 1 (see Figure 39A amp B) possibly due to the fact that

the structure of ZSM-5 is more rigid than that of Beta zeolite (Gonzalez et al 2011)

157

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

+ ++

+

NH4-Beta zeolite as received (D)

++

+

NH4-Beta zeolite after calcination (C)

+

++

NH4-ZSM-5 as received (B)

++

+ NaCl

+ NaCl

2 [degree]

2 [degree]

+

+

NH4-ZSM-5 after calcination (A)

Inte

nsi

ty [

co

un

ts]

Inte

nsi

ty [

co

un

ts]

Figure 39 The XRD spectra of (A) NH4-ZSM-5 after calcination (B) NH4-ZSM-5 as received

(C) NH4-Beta zeolite after calcination and (D) NH4-Beta zeolite as received The calcination

was performed at 550 degC for 5 h at a heating rate of 100 degCh NaCl used as an internal standard

at the zeolite to NaCl mass ratio of 267 was added to the samples prior to analysis Symbol +

= NaCl

158

Figure 40 SEM micrographs of NH4-Beta zeolite before (left) and after (right) calcination at

550 ordmC for 5 h

Table 26 summarises the XRD analysis results obtained on NH4-Beta zeolite and NH4-

ZSM-5 before and after calcination The positions of the main diffraction peaks are also listed

A small but detectable shift of the main diffraction peaks of calcined NH4-ZSM-5 and calcined

NH4-Beta zeolite towards higher and lower angles respectively relative to the parent NH4-

zeolites was noted This may be due to the replacement of NH4+ in the zeolite cavity by a

smaller size H+ (Peter et al 2010 Sethia et al 2015) The un-changed position of NaCl peaks

confirms that the shift is not an instrumental artifact

159

Table 26 The XRD analysis results of NH4-Beta zeolite and NH4-ZSM-5 before and after

calcination at 550 degC for 5 h at a heating rate of 100 degCh

Sample Crystallite sizea

[nm]

XRD relative

crystallinityb []

Position of the main

peak (2θ)c [degree]

NH4-ZSM-5 as received 320 100 230

NH4-ZSM-5 after calcination 388 101 231

NH4-Beta zeolite as received 159 100 226

NH4-Beta zeolite after calcination 151 105 225

a Calculated using Scherrerrsquos equation b The intensities of main diffraction peaks of zeolites

relative to the as received NH4-Beta zeolite or NH4-ZSM-5 The error is in the range of 1-5

c The main diffraction peak of Beta zeolite and ZSM-5 is at 2θ = 226deg and 2303deg respectively

corresponding to the major peak of 302 and 501 crystal surfaces

The diffraction peaks of Beta zeolite see Figure 39 are generally broader than those of

ZSM-5 The phenomenon is related to the smaller average crystallite size of Beta zeolite (~12-

16 nm) as compared to ZSM-5 (~31-39 nm) see Table 26 Other factors known to be

contributing to the peak broadening are the crystal lattice imperfections andor the crystal

strains (Camblor et al 1998)

The XRD spectra of NH4-Beta zeolite as well as NH4-ZSM-5 before calcination as

compared to those of after calcination are nearly identical although small detectable changes

in peak positions and peak intensities were noted The differences however do not allow

distinguishing between the NH4+ and H+ forms The samples were further examined for

changes in their physical surface properties using BET analysis see Chapter 512 The

formation of H-zeolites may be evidenced by the changed surface acidity of the samples which

was measured by TPD-NH3 see Chapter 513

160

512 BET N2 analysis

The specific surface area (SSA) of zeolites used in the present work was determined by

BET N2 analysis The BET N2 adsorption and desorption isotherms of (i) as received and

calcined NH4-ZSM-5 and (ii) as received and calcined NH4-Beta zeolites are shown in Figure

41 and 42 respectively The shapes of the adsorption and desorption isotherms of the samples

resemble the type IV isotherm according to the classification by the IUPAC Commission on

Colloid and Surface Chemistry (Balbuena and Gubbins 1993) A steep increase of adsorption

at lower pressure region of the graphs is followed by a plateau indicating the saturation of the

zeolite surface by a gas monolayer The adsorption then continues to increase at higher relative

pressure region indicating a multilayer adsorption The hysteresis loop ie the deviation of the

desorption isotherm from the adsorption isotherm at higher relative pressures is a phenomenon

typically observed on zeolites and is caused by the capillary condensation of adsorbates in

meso- and micropores (Balbuena and Gubbins 1993) The capillary condensation occurs when

the gases accumulated on the walls of the tiny capillary pores of adsorbent condense When the

pressure is reduced during desorption the molecules do not tend to leave their place so higher

pressure drop is required to pull the adsorbed molecules out of their sites Hence the same

molecules desorb at lower pressure creating a gap between the equilibrium adsorption and

desorption pressures this gap is also known as hysteresis

161

00 01 02 03 04 05 06 07 08 09 10

0

80

100

120

140

160

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]

Relative Pressure (PPo)

adsorption_calcined NH4-ZSM-5

desorption_calcined NH4-ZSM-5

adsorption_as received NH4-ZSM-5

desorption_as received NH4-ZSM-5

Figure 41 BET N2 adsorptiondesorption isotherms of NH4-ZSM-5 before and after

calcination The data presented is from a single measurement

162

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]


adsorption_calcined NH4-Beta zeolite

desorption_calcined NH4-Beta zeolite

adsorption_as received NH4-Beta zeolite

desorption_as received NH4-Beta zeolite

Figure 42 BET N2 adsorptiondesorption isotherms of NH4-Beta zeolite before and after


The surface areas of NH4-Beta zeolite and NH4-ZSM-5 before and after calcination

determined by BET N2 analysis are summarised in Table 27 The BET N2 surface area of NH4-

Beta zeolites after the calcination increased by ~4 while that of calcined NH4-ZSM-5

increased by 21 possibly due to the removal of bulky NH3 allowing higher accessibility of

the internal surface by the N2 molecules The surface area of the material is also related to its

primary crystallite size The Beta zeolites having primary crystallite sizes of ~12-16 nm have

the BET N2 surface area of ~575-600 m2middotg-1 while that of ZSM-5 with the crystallite size of

~31-39 nm is ~300-360 m2middotg-1

163

Table 27 BET N2 surface analysis results of NH4-Beta zeolite and NH4-ZSM-5 before and

after the calcination

Sample BET N2

surface area

[msup2middotg-1]

Micropore

volume

[cmsup3middotg-1]

Micropore

area

[msup2middotg-1]

External

surface area

[msup2middotg-1]

NH4-ZSM-5 as received 299 013 257 42

NH4-ZSM-5 after calcination 363 012 258 105

NH4-Beta zeolite as received 575 017 358 217

NH4-Beta zeolite after calcination 598 017 367 231

513 TPD-NH3

In TPD-NH3 analysis the temperature at which NH3 desorbs correlates with the

strength of the acid sites (see Figure 43 and 44) while the amount of desorbed NH3 reflected

in the area under the concentration of NH3 against time curves is directly proportional to the

total number of acid sites in the catalyst (see Figure 45) In this work the individual desorption

peaks were deconvoluted using Gaussian model and the areas under the peaks were determined

by integration within the time range from 0-6000 s corresponding to the desorption

temperature of 100-600 degC It should be noted that a small but negligible desorption was

detected at le 100 degC thus introducing a negligible experimental error lt1 The absolute

number of zeolite acid sites was determined by multiplying the area under the peak by the total

gas flow rate used

The TPD-NH3 profiles of the calcined NH4-ZSM-5 and calcined NH4-Beta zeolite

compared to the as received NH4-forms are shown in Figure 43 and 44 respectively See Table

28 for the interpretation of NH3 desorption peaks identified in the TPD-NH3 profiles of NH4-

ZSM-5 and NH4-Beta zeolite before and after calcination Figure 45 shows the peaks labelled

164

as α β and γ deconvoluted from the desorption curves plotted as a function of time and used

for integration The solid curves denote the TPD-NH3 original data while the dashed curves

denote the peaks deconvoluted using the OriginPro 86 graphing software The total amount of

desorbed NH3 and the maximum desorption temperatures (Tmax) of the zeolites are summarised

in Table 29

100 200 300 400 500 600

0

100

200

300

0 1200 2400 3600 4800 6000

Co

ncen

tra

tio

n o

f N

H3 i

n g

as

flo

w [

pp

m]

Temperature [oC]

calcined NH4-ZSM-5 (H-ZSM-5)

NH4-ZSM-5

Time [s]

Figure 43 TPD-NH3 profiles of the as received NH4-ZSM-5 and calcined NH4-ZSM-5 ie

H-ZSM-5

165

100 200 300 400 500 600

0

50

100

150

200

250

300

0 1200 2400 3600 4800 6000

Co

ncen

tra

tio

n o

f N

H3 i

n g

as

flo

w [

pp

m]

Temperature [oC]

calcined NH4-Beta zeolite

(H-Beta zeolite)

NH4-Beta zeolite

Time [s]

Figure 44 TPD-NH3 profiles of the as received NH4-Beta zeolite and calcined NH4-Beta

zeolite (or H-Beta zeolite)

Table 28 The interpretation of NH3 desorption peaks identified in the TPD-NH3 profiles of

NH4-ZMS-5 and NH4-Beta zeolite before and after calcination

Desorption peak Temperature range Interpretation

Low temperature peak 1

(LT-peak 1 or α peak)

lt150 degC The desorption peak of physically adsorbed

NH3 (Hegde et al 1989)


(LT-peak 2 or β peak)

150-260 degC This peak is associated with weakly bonded

NH3 possibly adsorbed on Lewis acid sites

(Topsoslashe et al 1981 Bagnasco 1996

Brandenberger et al 2009) Often part of the

desorbed NH3 is weakly held or physically

adsorbed on sites such as silanol groups and it

is therefore not related to the acid sites (Hegde

et al 1989 Niwa and Katada 1997)

High temperature peak

(HT-peak or γ peak)

260-577 degC The desorption peak of NH3 adsorbed on acid

sites (Niwa and Katada 1997)

166

0 1000 2000 3000 4000 5000 6000

0

50

100

Experimental data

Gaussian deconvolution

Co

nce

ntr

ati

on

of

NH

3 i

n g

as

flo

w [

pp

m]

Time [s]

(A) NH4-ZSM-5

0 1000 2000 3000 4000 5000 6000

0

50

100

150

200

250

300

Experimental data


Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Time [s]

(B) H-ZSM-5

0 1000 2000 3000 4000 5000 6000

0

50

100

150

200

250

300

Experimental data


Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Time [s]

(C) NH4-Beta zeolite

0 1000 2000 3000 4000 5000 6000

0

50

100

150

200

250

Experimental data


Co

ncen

tra

tio

n o

f N

H3 i

n g

as

flo

w [

pp

m]

Time [s]

(D) H-Beta zeolite

Figure 45 TPD-NH3 profiles of (A) NH4-ZSM-5 (B) H-ZSM-5 (C) NH4-Beta zeolite and (D) H-Beta zeolite plotted as a function of time The

black solid lines denote the TPD-NH3 original data while the red dotted lines denote the deconvoluted data

167

Table 29 Total amount of desorbed NH3 and the maximum desorption temperatures (Tmax) of NH4-Beta zeolite H-Beta zeolite NH4-ZSM-5 and

H-ZSM-5 The data presented is from a single measurement unless stated otherwise

Catalyst

α-peak β-peak γ-peak NH3

desorbed

[micromolmiddotg-1]

Ref Tmax

[degC]

NH3

[micromolmiddotg-1]

Tmax

[degC]

NH3

[micromolmiddotg-1]

Tmax

[degC]

NH3

[micromolmiddotg-1]

NH4-ZSM-5 145 4 200 69 420 67 140 This work

H-ZSM-5 145 8 187 242 385 269a 520 This work

150 - 388 - - Long and Yang (2001)

NH4-Beta 127 38 162 amp 250 109 amp 298 - - 445 This work

- - - - 630 Alotaibi et al (2014)

H-Beta 124 2 176 105 300 236a 344 This work

277 - 377 - 750 Lenarda et al (2003)

197 653 363 209 862 Talebi et al (2008)

LT-peak = low temperature peak HT= high temperature peak a The error is in the range of 5-10

168

I ZSM-5

The NH3-desorption profile of the as received NH4-ZSM-5 shows at least two

overlapping peaks with the maximums at ~145 and 200 degC (low temperature peak LT-peak)

and another peak at 420 degC (high temperature peak HT-peak) see Figure 43 These

overlapping peaks were deconvoluted into α- β- and γ peaks respectively (see Figure 45A)

Similarly two major desorption peaks are observed for calcined NH4-ZSM-5 an LT-peak at

187 degC and an HT-peak at 385 degC see Figure 43 and 45B The LT-peak also exhibits a shoulder

highly likely due to overlapping of the α and β peaks that otherwise would have appeared at

around 145 and 200 degC as in the TPD curve of the as received NH4-ZSM-5 The extensive

overlapping of the α and β peaks is usually observed in TPD of NH3 adsorbed at low

temperature ie at 20-30 degC (Topsoslashe et al 1981 Hegde et al 1989 Hunger et al 1990

Brandenberger et al 2009) hence the overlapping was not expected in the present work as the

NH3 adsorption step was performed at 100 degC The phenomenon may be explained by the

insufficient time used ie 1 h for the removal of excess of NH3 before desorption

Different NH3 desorption peaks are attributed to acidic centres of different strengths

According to Brandenberger et al (2009) who studied the surface acidity of H-ZSM-5 (SiAl

~10) and Fe-exchanged ZSM-5 using TPD-NH3 and FTIR spectroscopy the LT-peaks at 140

and 230 degC are associated with weakly adsorbed NH3 on Lewis acid sites while the HT-peak

at 490 degC is related to NH4+ ions with three hydrogen atoms bonded to three oxygen ions of

AlO4 tetrahedra (3H structure) on Broslashnsted acid sites see Figure 46 for a schematic illustration

of NH3 adsorbed on different zeolite sites

169

Figure 46 Schematic illustration of NH3 adsorbed on different Broslashnsted acidic centres (adapted

from Rodriacuteguez-Gonzaacutelez et al (2008))

The above interpretation is in agreement with that previously reported by Topsoslashe et al

(1981) Bagnasco (1996) and Rodriacuteguez-Gonzaacutelez et al (2008) Similarly Niwa and Katada

(1997) identified the HT-peak (277-577 degC) as the desorption peak of NH3 adsorbed on the

acid sites but the LT-peak (127-277 degC) was assigned to NH3 weakly held or physically

170

adsorbed on the zeolite and it is therefore not ascribable to the acid sites See Table 28 for a

summary of NH3 desorption peaks identified in the present work

The presence of LT-peaks in the NH3-desorption profile of the as received NH4-ZSM-

5 is observed in this work but it was not reported by Long and Yang (2001) possibly due to

different removal degrees of physically adsorbed NH3 as a result of different zeolite weight to

flow rate of carrier gas ratio (WF) (Niwa and Katada 1997) In fact a direct comparison is

impossible since the peak shapes and positions not only depend on experimental conditions

such as the sample weight gas flow and heating rate but also on the mechanisms controlling

the desorption such as the re-adsorption andor diffusion (Niwa and Katada 1997 Rodriacuteguez-

Gonzaacutelez et al 2008) The appearance of the HT-peak may be related to the formation of H-

form of the zeolite during the sample degassing in He flow at 550 degC for 1 h

Due to the extensive-overlapping of the two LT-peaks (α and β peaks) as well as the

uncertainty about the interpretation of the β-peak (Hunger et al 1990 Bagnasco 1996 Niwa

and Katada 1997 Rodriacuteguez-Gonzaacutelez et al 2008 Brandenberger et al 2009) only the HT-

peak is used for quantitative determination of the zeolite acid sites Hence the concentration

of the Broslashnsted acid sites of NH4-ZSM-5 before and after the calcination determined was 67

and 269 micromolmiddotg-1 respectively This may be considered as the key evidence indicating that the

as received NH4-ZSM-5 was successfully transformed into its protonic form ie H-ZSM-5

II Beta zeolite

The desorption profile of the as received NH4-Beta zeolite see Figure 44 shows only

three overlapping LT-peaks ie α- β1- and β2- peaks at 128 165 and 250 degC respectively see

Figure 45C for the deconvolution of the overlapped peaks These peaks are highly likely to be

171

associated with NH3 adsorbed on structural defect sites present in significant quantity in Beta

zeolite (Camiloti et al 1999) The high intensities of the α- and β1- peaks indicate that part of

the desorbed NH3 may also be weakly held or physically adsorbed on zeolite sites such as

silanol groups (Hegde et al 1989) According to Niwa and Katada (1997) the concentration

of weak acid sites corresponding to the β-peak was found to be of no catalytic relevance

explaining the low conversion of glycerol observed in the current work see Figure 83 (page

258) The interpretation of the NH3 desorption peaks is summarised in Table 28

Two broad peaks including a β-peak with a small shoulder at 176 degC and a γ-peak at

300 degC are observed in the NH3 desorption curve of the calcined NH4-Beta zeolite (see Figure

44 and 45D) as opposed to the observation of Lenarda et al (2003) who reported two

desorption peaks at ~277 degC and ~377 degC The difference in the peak position may be related

to the WF ratio andor the re-adsorption of NH3 (Niwa and Katada 1997)

Similar to the case of ZSM-5 the extensive-overlapping of the two LT-peaks (α and β

peaks) and the different interpretation of the β peak means that only the HT-peak can be used

in calculating the concentration of acid sites While the concentration of acid sites of the as

received NH4-Beta zeolite could not be determined that of the calcined NH4-Beta zeolite was

~233 micromolmiddotg-1 indicating successful transformation of NH4-Beta zeolite to H-Beta zeolite

Thus the calcined NH4-Beta zeolite is referred to as H-Beta zeolite hereafter in this report

The TPD-NH3 profiles of Beta zeolite and ZSM-5 are similar to those reported in

literature however a different desorption rate and the maximum desorption temperatures (Tmax)

were reported (Long and Yang 2001 Lenarda et al 2003 Talebi et al 2008) In general the

extent of NH3 desorption determined on both NH4-Beta zeolite and NH4-ZMS-5 before and

after calcination was found lower than previously reported (Lenarda et al 2003 Talebi et al

172

2008) possibly due to different experimental conditions and the peak assignation to acid sites

It should be noted that the quantification of NH3 in the present work was based on the peak of

me=17 in the mass spectra to which the fragmented water is known to contribute (Akah et al

2005) Hence the intensity of NH3 in mass spectra obtained was reduced by 20 to account

for the contribution of water

52 Metal-exchanged zeolites

The preparation of transition metal-exchanged zeolites by an ion exchange reaction is

typically carried out using the zeolites in their H-form as the preferred starting materials as

opposed to the NH4-form known to exhibit lower catalytic potential (Naccache and Taarit

1984 Kucherov and Slinkin 1998 Baek et al 2004 Marakatti et al 2014) However several

recent studies reported using the NH4-form of zeolites in the preparation of metal-exchanged

zeolites achieving a high degree of ion exchange (Mihaacutelyi et al 1997 Li and Armor 1999

Mavrodinova et al 2001 Habib et al 2014) The possibility of avoiding an energy intensive

calcination step associated with preparation of H-form of zeolite is attractive To investigate

whether the use of H- and NH4-forms in the preparation of metal-exchanged zeolites would

result in final products with identical or competitive properties both forms of Beta zeolite and

ZSM-5 were used in the present work The 48 wt metal-exchanged Beta zeolite and ZSM-5

catalysts were prepared by solid state ion exchange (SSIE) using various metal salt precursors

including Ce(NO3)3middot6H2O La(NO3)3middotH2O Sn(CH3COO)2 and Zn(CH3COO)2 according to the

experimental protocol described in Chapter 442 The resulting samples were characterized by

XRD XRF TEM-EDS and TPD-NH3 The preparation of metal-exchanged zeolites containing

48 wt of metal relative to zeolite in the initial mixture before the calcination was chosen

173

based on the work of De La Torre et al (2012) Due to the different molar weights of used

metals only a partial ion exchange is expected


The XRD spectra of (i) H-Beta zeolite and (ii) H-ZSM-5 before and after SSIE reaction

with various metal salts ie 48 wt MH-Beta zeolite and 48 wt MH-ZSM-5 where M =

Ce La Sn and Zn are shown correspondingly in Figure 47 and 48 The XRD spectra of NH4-

Beta zeolite NH4-ZSM-5 and their MNH4-forms are provided in the Appendix in Figure 119

and 120 respectively

The XRD patterns of 48 wt MH-zeolites (Figure 47 and 48) and 48 wt MNH4-

zeolites (Figure 119 and 120) are nearly identical except for the slightly higher intensities of

the main diffraction peaks of MH-zeolites (2θ = 226deg for Beta zeolite 2θ = 2303deg for ZSM-

5) as compared to MNH4-zeolites The XRD patterns of all metal-exchanged zeolites studied

except for 48 wt Lazeolites show the traces of corresponding metal oxides ie ZnO SnO2

and CeO2 La2O3 was detected neither in 48 wt LaBeta zeolite nor 48 wt LaZSM-5 This

may be possibly explained by incomplete thermal decomposition of La(NO3)3middotH2O to

La3O4NO3 at 550 degC (Mentus et al 2007) No other phases were detected

The intensities of the diffraction peaks of the parent zeolites ie NH4-Beta zeolite H-

Beta zeolite NH4-ZSM-5 and H-ZSM-5 show a tendency to decrease considerably after the

SSIE reaction with metal salts For instance the intensity of the main diffraction peak of 48

wt CeNH4-Beta zeolite decreased to 55 as compared to NH4-Beta zeolite see Table 30

Such phenomenon is usually observed when metal ions enter the zeolites structure due to

(Medrud 1999 Rauscher et al 1999)

174

i their higher absorption coefficient of the X-ray radiation and

ii the lower relative zeolite content in the samples due to the addition of the metal salts

In addition to a decrease in the intensity the main diffraction peaks of the parent zeolites

(2θ = 226deg for Beta zeolite 2θ = 2303deg for ZSM-5) are observed to shift after the SSIE This

may be due to the replacement of H+ or NH4+ in the zeolite cavity by a different size ion (Peter

et al 2010 Sethia et al 2015) The shift does not show a consistent trend (see Table 30) In

general the SSIE of the zeolites caused their main diffraction peaks to shift to higher angles

for Beta zeolite but towards lower angles for ZSM-5 with respect to their H-forms Although

the un-changed position of NaCl peaks indicates that the shift of the main diffraction peaks of

the zeolite samples is unlikely to be an instrumental artifact the extents of the shifts are

considered as insignificant due to being about the same as the 2θ angle step size used for the

XRD measurement ie ~0033deg The positions of the main diffraction peaks crystallite sizes

and the relative crystallinities of Beta zeolite and ZSM-5 after SSIE compared to their

corresponding parent NH4- and H-forms are summarised in Table 30

175

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

+x

x

+

+

xx

CeO2

48 wt CeH-Beta

+++

+

48 wt LaH-Beta

O

++

OOO

48 wt SnH-Beta

ZnO

O

++

+

+

x

SnO2

48 wt ZnH-Beta

+

+

+

Inte

nsi

ty [

co

un

ts]

2 [degree]

+ NaCl

H-Beta

+

Figure 47 The XRD patterns of H-Beta zeolite and 48 wt MH-Beta zeolite where M = Ce

La Sn and Zn prepared by SSIE using corresponding metal salt as a precursor at 550 degC for

3 h at a heating rate of 100 degCh NaCl used as an internal standard at the zeolite to NaCl mass

ratio of 267 was added to the samples prior to analysis Symbol + = NaCl ZnO ο = SnO2

x = CeO2

176

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

+X+

+

+

X

X

2 (degree)

48 wt CeH-ZSM5

X

+ ++

+

OOO

48 wt LaH-ZSM5

+

+

O

48 wt SnH-ZSM5

O

+++

+

48 wt ZnH-ZSM5

Inte

nsi

ty [

cou

nts

]

+ NaCl ZnO O SnO2

x CeO2

+ +

+

H-ZSM5

+

Figure 48 The XRD patterns of H-ZSM-5 and 48 wt MH-ZSM-5 where M = Ce La Sn

and Zn prepared by SSIE using corresponding metal salt as a precursor at 550 degC for 3 h at a

heating rate of 100 degCh NaCl used as an internal standard at the zeolite to NaCl mass ratio of

267 was added to the samples prior to analysis Symbol + = NaCl ZnO ο = SnO2 x = CeO2

177

Table 30 The positions of the main diffraction peaks the crystallite sizes and the relative

crystallinities of NH4-Beta zeolite H-Beta zeolite NH4-ZSM-5 H-ZSM-5 before and after the

SSIE using various metals salts as precursors The percentages reported are in wt indicating

the metal content relative to zeolite

Sample Crystallite

sizea [nm]

XRD relative

crystallinityb

[]

Position of the

main peakc

(2θ) [degree]

Shift in 2θ of

the main peakc

[degree]

NH4-Beta 159 100 226 +009

H-Beta 151 105 225 000

48 CeNH4-Beta 145 55 225 +007

48 LaNH4-Beta 141 64 225 +003

48 SnNH4-Beta 144 47 225 +002

48 ZnNH4-Beta 121 76 225 -001

48 CeH-Beta 146 64 225 +007

48 LaH-Beta 137 68 226 +008

48 SnH-Beta 139 63 225 +004

48 ZnH-Beta 135 83 225 +006

NH4-ZSM-5 320 100 230 -005

H-ZSM-5 388 101 231 000

48 CeNH4-ZSM-5 331 60 230 -005

48 LaNH4-ZSM-5 372 71 231 -003

48 SnNH4-ZSM-5 381 65 231 000

48 ZnNH4-ZSM-5 369 98 231 000

48 CeH-ZSM-5 318 62 231 -003

48 LaH-ZSM-5 345 75 231 -003

48 SnH-ZSM-5 370 69 231 +003

48 ZnH-ZSM-5 351 84 231 -003


relative to the NH4-Beta zeolite or NH4-ZSM-5 The error is in the range of 1-7 c The main

diffraction peak of Beta zeolite and ZSM-5 is at 2θ = 226deg and 2303deg respectively

corresponding to the peak of 302 and 501 crystal surfaces

178

522 BET N2 analysis

Figure 49 shows the BET N2 adsorptiondesorption isotherms of (A) H-Beta zeolite and

48 wt SnH-Beta zeolite and (B) H-ZSM-5 and 48 wt SnH-ZSM-5 zeolite respectively

These isotherms are the representatives of BET N2 adsorptiondesorption isotherms of H-Beta

zeolite and H-ZSM-5 before and after the SSIE reaction with various metal salts including

Ce(NO3)3middot6H2O La(NO3)3middotH2O and Zn(CH3COO)2 Similar to H-Beta zeolite and H-ZSM-5

(see Chapter 512) the BET N2 adsorptiondesorption isotherms of 48 wt Mzeolites

prepared in the present work resemble the type IV adsorption isotherm according to the

classification by the IUPAC Commission on Colloid and Surface Chemistry (Balbuena and

Gubbins 1993) See Chapter 512 for a description of the type IV adsorption isotherm

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

00 01 02 03 04 05 06 07 08 09 10

0

80

100

120

140

160

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]


adsorption_H-Beta zeolite

desorption_H-Beta zeolite

adsorption_48 SnH-Beta zeolite

desorption_48 SnH-Beta zeolite

(A) (B)

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]


adsorption_H-ZSM-5

desorption_H-ZSM-5

adsorption_48 SnH-ZSM-5

desorption_48 SnH-ZSM-5

Figure 49 N2 adsorptiondesorption isotherms of (A) H-Beta zeolite and 48 wt SnH-Beta zeolite

and (B) H-ZSM-5 and 48 wt SnH-ZSM-5 The data presented is from a single measurement

The BET analysis results of all the 48 wt Mzeolites prepared are summarised in

Table 31 The measured BET N2 surface areas of NH4-Beta zeolite H-Beta zeolite NH4-ZSM-

179

5 and H-ZSM-5 considerably decreased after the SSIE possibly due to the blockage of the

zeolite pores by metal aggregates De La Torre et al (2012) also observed a decrease in BET

N2 surface area after incorporation of copper to H-Beta zeolite (SiAl ~25) and H-ZSM-5 (SiAl

~50) by liquid ion exchange and wet impregnation methods

Table 31 BET N2 surface analysis results of NH4-Beta zeolite H-Beta zeolite NH4-ZSM-5

and H-ZSM-5 before and after SSIE reaction with various metal salts The data presented is

from a single measurement

Sample

BET N2

surface area

[msup2g-1]

Micropore

volume

[cmsup3g-1]

Micropore

area

[msup2g-1]

External

surface area

[msup2g-1]

NH4-Beta 575 017 358 218

H-Beta 598 017 367 230

48 CeNH4-Beta 534 015 330 204

48 LaNH4-Beta 591 015 383 208

48 SnNH4-Beta 489 014 303 186

48 ZnNH4-Beta 526 015 326 200

48 CeH-Beta 539 015 333 206

48 LaH-Beta 567 015 371 196

48 SnH-Beta 514 014 301 213

48 ZnH-Beta 528 014 313 215

NH4-ZSM-5 299 013 257 42

H-ZSM-5 363 012 258 104

48 CeNH4-ZSM-5 294 010 213 81

48 LaNH4-ZSM-5 370 011 280 90

48 SnNH4-ZSM-5 323 011 228 95

48 ZnNH4-ZSM-5 336 012 250 86

48 CeH-ZSM-5 340 011 235 104

48 LaH-ZSM-5 359 011 284 76

48 SnH-ZSM-5 304 010 223 80

48 ZnH-ZSM-5 308 011 227 81

180

523 TPD-NH3

The transformation of Broslashnsted acid sites of zeolites into Lewis acid sites was attempted

by an ion-exchange reaction replacing the balancing H+ with metal ions including Ce La Sn

and Zn The degree of ion exchange was quantified by the decrease in concentration of

Broslashnsted acid sites determined by TPD-NH3

The TPD-NH3 profiles of (A) NH4-Beta zeolite (B) H-Beta zeolite (C) NH4-ZSM-5 and

(D) H-ZSM-5 before and after the SSIE reaction with various metal salts are shown in Figure

50 In general the TPD-NH3 profiles of all metal-exchanged zeolites prepared are similar to

the profiles of their parent NH4- or H-zeolites (see 64-165 ) two main desorption peaks

including a low temperature peak (LT-peak) and a high temperature peak (HT-peak)

corresponding to β- and γ-peak respectively are observed See Chapter 513 for the

interpretation of NH3 desorption peaks The LT-peak seems to overlap another smaller peak

appearing as a shoulder at the Tmax = 124-149 degC highly likely resulting from an extensive-

overlapping of the β-peak and another LT-peak referred to as an α-peak appearing at the

temperatures lt150 degC

The TPD-NH3 profiles of all the metal-exchanged zeolites studied exhibited

(i) a shift of the maximum desorption temperatures (Tmax) toward higher

temperatures 1-17 ordmC shift was recorded for all samples except for 48 wt Ce-

La- and ZnH-ZSM-5 which exhibited a shift towards lower temperatures by

about 5 degC

(ii) a lower amount of desorbed NH3

The amount of NH3 desorbed associated with the γ peak and the Tmax of individual peaks in the

TPD-NH3 profiles recorded for all the zeolites tested are summarised in Table 32

181

Figure 50 TPD-NH3 profiles of (A) NH4-Beta zeolite (B) H-Beta zeolite (C) NH4-ZSM-5 and (D) H-ZSM-5 before and after SSIE reaction with

various metal salts at 550 degC 3 h at a heating rate of 100 degCh

100 200 300 400 500 600

0

50

100

150

200

250

300

100 200 300 400 500 600

0

50

100

150

200

250

300

100 200 300 400 500 600

0

50

100

150

200

250

300

100 200 300 400 500 600

0

50

100

150

200

250

300

48 CeNH4-Beta zeolite

48 LaNH4-Beta zeolite

48 ZnNH4-Beta zeolite

Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]

Temperature [oC]

(A)

NH4-Beta zeolite

48 SnNH4-Beta zeolite

(C)

Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]

Temperature [oC]

NH4-ZSM-5

48 SnNH4-ZSM-5

48 ZnNH4-ZSM-5

48 LaNH4-ZSM-5

48 CeNH4-ZSM-5

(B)

Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]

Temperature [oC]

H-Beta zeolite

48 SnH-Beta zeolite

48 ZnH-Beta zeolite

48 LaH-Beta zeolite

48 CeH-Beta zeolite

(D)

Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]Temperature [

oC]

48 CeH-ZSM-5

48 LaH-ZSM-5

48 ZnH-ZSM-5

H-ZSM-5

48 SnH-ZSM-5

182

Table 32 The amount of desorbed NH3 associated with the γ peak and the maximum desorption

temperatures (Tmax) of individual peaks in TPD-NH3 profiles of NH4-Beta zeolite H-Beta

zeolite NH4-ZSM-5 and H-ZSM-5 before and after SSIE with various metal salts The metal

contents are given in wt relative to zeolite

The data presented is from a single measurement unless stated otherwise a The error is in the

range of 5-10 b Determined using the following formula D = (a-b)c where a = the number of

strong Broslashnsted acid site (γ-peak) present in H-Beta zeolite or H-ZSM-5 b = the number of strong

Broslashnsted acid site (γ-peak) in metal-exchanged zeolite c = the number of formal charges of the

incoming metal cation

Catalyst

α-peak β-peak γ-peak

Degree of ion

exchange b Tmax

[degC]

Tmax

[degC]

Tmax

[degC]

NH3

[micromolmiddotg-1]

NH4-Beta 127 165250 - - 0

H-Beta 124 176 300 236 a 0

48 CeNH4-Beta 134 177 306 94 36

48 LaNH4-Beta 138 178 317 107 43

48 SnNH4-Beta 136 171 304 147 22

48 ZnNH4-Beta 148 178 305 114 61

48 CeH-Beta 140 160 305 73 41

48 LaH-Beta 145 176 317 95 47

48 SnH-Beta 141 160 305 45 48

48 ZnH-Beta 149 180 305 103 67

NH4-ZSM-5 145 200 420 67 0

H-ZSM-5 145 187 385 270 a 0

48 CeNH4-ZSM-5 138 190 387 146 31

48 LaNH4-ZSM-5 146 191 400 113 52

48 SnNH4-ZSM-5 133 190 392 39 58

48 ZnNH4-ZSM-5 148 205 386 88 91

48 CeH-ZSM-5 - 187 380 73 49

48 LaH-ZSM-5 144 180 380 98 57

48 SnH-ZSM-5 144 172 391 35 59

48 ZnH-ZSM-5 145 187 380 57 106

183

All the metal-exchanged zeolites analysed by TPD-NH3 show a general trend in a shift

of Tmax towards slightly higher temperatures as compared to H-Beta zeolite and H-ZMS-5 see

Table 32 Due to the extensive-overlapping of the α- and β-peaks as well as the uncertainty

about the origin of desorbed NH3 associated with the β-peak (Hunger et al 1990 Bagnasco

1996 Niwa and Katada 1997 Rodriacuteguez-Gonzaacutelez et al 2008 Brandenberger et al 2009)

only the γ-peak is used for quantitative determination of the zeolite acid sites in this work

Thus only the changes in the γ-peak are discussed herein

The γ-peaks of almost all metal-exchanged NH4- and metal-exchanged H-zeolites shift

towards higher temperatures by 1-17 degC with respect to H-Beta zeolite (Tmax γ = 300 degC) or H-

ZSM-5 (Tmax γ = 385 degC) indicating stronger bonding interaction of NH3 with the Broslashnsted

acid sites This is in contrast to 48 wt Ce- La- and ZnH-ZSM-5 showing an opposite

general trend in the shift of γ-peaks ie a shift by 5 degC towards lower temperature with respect

to the H-ZSM-5

The amount of desorbed NH3 associated with the γ peak is an indicator of the zeolite

surface acidity As expected the surface acidities of the metal-exchanged Beta zeolites are

generally about 50-60 lower than that of H-Beta zeolite except for 48 CeH-Beta zeolite

and 48 SnH-Beta the acidities of which are 70 and 80 lower respectively A significant

decrease in acidity (~60-90) is observed for metal-exchanged ZSM-5 samples In addition to

the ion exchange reaction the decreased surface acidity of the metal-exchanged zeolites is

likely to be associated with the blockage of the zeolite pores by metal aggregates (De La Torre

et al 2012)

The degree of ion exchange was determined by the difference in the number of strong

Broslashnsted acid site (γ-peak) present in the corresponding zeolites before and after ion exchange

divided by the formal charges of the incoming cation (Lugstein et al 1995 Mavrodinova

184

1998) The formal charges of metal cations indicate the number of protons (from SiOHAl

group) required for exchanging with one metal cation Since both the NH4-Beta zeolite and

NH4-ZSM-5 are assumed to transform into their H-forms during the SSIE the term ldquozeolites

before ion exchangerdquo therefore refers to either H-Beta zeolite or H-ZSM-5 The TPD-NH3 data

indicate that the degree of ion exchange between zeolites and metal salts is found to be higher

(2-118 ) when starting from H-zeolites see Table 32 possibly because the NH4-sites get only

partially exchanged and the sites that are not exchanged get deammoniated forming acidic OH

groups (Onyestyak et al 1991 Mavrodinova et al 2001)

The results indicate a higher degree of ion exchange in ZSM-5 (SiAl = 115) samples

than Beta zeolite (SiAl = 125) De La Torre et al (2012) prepared Cu-exchanged Beta zeolite

(SiAl = 25) and ZSM-5 (SiAl = 50) catalysts by liquid ion exchange and found that slightly

higher degrees of ion exchange ranging from 7-25 were achieved in Beta zeolite The

authors speculated that this may be related to the lower SiAl ratios and consequently to the

higher number of sites available for Cu In this work the SiAl ratio of ZSM-5 is slightly lower

than that of Beta zeolite possibly explaining a higher degree of ion exchange in ZSM-5 than

in Beta zeolite

53 Dealuminated H-ZSM-5 and H-Beta zeolite

H-ZSM-5 and H-Beta zeolite were treated with concentrated HNO3 at 80 degC in order to

remove Al atoms from the zeolite frameworks according to the procedure described in Chapter

443 The resulting materials were analysed by XRD XRF and TPD-NH3 The summary of

experimental conditions used for dealumination of H-ZSM-5 and H-Beta zeolite is provided in

Table 33

185

Table 33 The summary of experimental conditions used for dealumination of H-ZSM-5 and

H-Beta zeolite in 20 ml of 13 M HNO3 solution at 100 degC

Starting zeolite Sample label Amount of zeolite used

[g]

Treatment time

[h]

H-ZSM-5 deAl-ZSM-5 1 20

H-Beta deAl-BetaI4hd 1 4

deAl-BetaI6h 1 6

deAl-BetaI20h 1 20

deAl-BetaII4h 2 4

deAl-BetaII6h 2 6

deAl-BetaII20h 2 20

deAl-BetaIII4h 3 4

deAl-BetaII 5min 2 008


531 Dealuminated ZSM-5

Figure 51 shows the XRD patterns of H-ZSM-5 before (top) and after (bottom) the

treatment with 13 M HNO3 at 100 degC for 20 h The spectra do not reveal significant differences

between before and after the treatment indicating that the MFI structure of ZSM-5 remained

preserved

186

0

300

600

900

10 20 30 40 50 60 70

0

300

600

900

H-ZSM-5In

ten

sity

[C

ou

nts

]

acid treated H-ZSM-5

2 [degree]

Figure 51 XRD spectra of H-ZSM-5 before (top) and after (bottom) the treatment with 13 M

HNO3 at 100 degC for 20 h 1 g of zeolite in 20 ml of 13 M HNO3 solution The angular scan was

between 2θ = 5-70deg with a step size of 0017deg 2θ and a count time of 258 s per step

The morphology and the elemental composition of the acid treated samples was

analysed by the TEM-EDS The results showed that the SiAl ratio increased from 115 to ~122

as a result of the acid treatment indicating a relatively small extent (~6 wt) of dealumination

This is in agreement with the study by Muumlller et al (2000) and Gonzalez et al (2011) The

dealumination of ZSM-5 was reported to be challenging using aqueous HBr H2SO4 or HCl

(Kooyman et al 1997) The low extent of dealumination in ZSM-5 means that the replacement

187

of Al atoms inside the zeolite framework would not be possible Based on the results obtained

further work was abandoned

532 Dealuminated Beta zeolite

5321 Physical properties

H-Beta zeolite was treated with 13 M HNO3 solution at 100 degC for 4 6 and 20 h at the

ratios of 1 2 and 3 g of zeolite in 20 ml of 13 M HNO3 Typical XRD patterns of H-Beta zeolite

before (top) and after (bottom four) the acid treatment for different times are shown in Figure

52 while the related crystallite sizes relative crystallinities as well as the BET-N2 surface areas

and XRF analysis results are summarised in Table 34

188

0

4000

8000

0

4000

8000

0

4000

8000

10 20 30 40 50 60 70

0

4000

8000

+ +

+

+ NaCl H-Beta zeolite

+

+ ++

+

deAl-BetaII4h+ NaCl

Inte

nsi

ty [

Co

un

ts]

+ +

+

+deAl-BetaII6h+ NaCl

+ +

+

+

deAl-BetaII20h+ NaCl

2 [degree]

Figure 52 X-ray diffraction patterns of H-Beta zeolite before and after the treatment with 13

M HNO3 at 100 degC for 4 6 and 20 h deAl-Beta refers to the dealuminated Beta zeolite the

Roman and Arabic numerals indicate the number of grams of H-Beta zeolite dealuminated in

20 ml of 13 M HNO3 and the dealumination time in hours respectively NaCl used as an

internal standard at the zeolite to NaCl mass ratio of 267 was added to the samples prior to

analysis Symbol + = NaCl

189

Table 34 The summary of BET XRD and XRF analysis results of dealuminated Beta zeolites (deAl-Beta) compared to NH4-Beta and H-Beta

zeolites

Catalyst BET-N2

surface area

[msup2middotg-1]

Crystallite

sizea

[nm]

Relative

crystallinityb

[]

2θ of d302

[degree]

shift of d302

[degree]

d302-spacing

[Aring]

SiAl

(XRF)

Al extractedc

[wt]

NH4-Beta zeolite 575 159 100 226 394 124 0

H-Beta zeolite 598 151 104 225 000 396 124 0

deAl-BetaI4hd 573 133 95 227 +017e 391 533 974

deAl-BetaI6h 572 137 94 227 +024 391 600 978

deAl-BetaI20h 554 141 89 226 +007 394 795 983

deAl-BetaII4h 580 129 100 227 +017 393 688 977

deAl-BetaII6h 551 130 94 227 +017 389 671 980

deAl-BetaII20h 542 154 89 226 +009 392 526 969

deAl-BetaIII4h 585 122 95 227 +017 392 556 974

a The primary crystallite size was calculated by Scherrerrsquos equation b Relative crystallinity was calculated using the intensity of the main diffraction

peak (d302 at 2θ = 226deg) considering the NH4-Beta zeolite as a benchmark ie 100 crystalline c Al extracted (wt) was calculated based on the

amount of Al remaining after the acid treatment compared to the initial amount of Al d deAl-Beta refers to dealuminated Beta zeolite the Roman

and Arabic numerals indicate the number of grams of H-Beta zeolite dealuminated in 20 ml of 13 M HNO3 and the dealumination time in hours

respectively e the ldquo+rdquo (plus symbol) denotes the positive peak shift relative to H-Beta zeolite

190

The XRD pattern of H-Beta zeolite after the treatment with HNO3 (see Figure 52) may

be attributed only to Beta zeolite structure (BEA) indicating that the dealumination did not

significantly affect the BEA structure of the Beta zeolite No other distinct phases were

detected However the intensity of the diffraction peak at (i) 2θ = 78deg (d101) increased after 4

and 6 h (deAl-BetaII4h and deAl-BetaII6h) and then considerably decreased after 20 h (deAl-

BetaII for 20 h) while that of the peak at (ii) around 2θ = 226deg slightly decreased but also

substantially shifted to higher angles (see Figure 53) According to Medrud (1999) the

substitution in the tetrahedral framework may cause a substantial shift in 2θ For instance the

substitution of Al3+ for Si4+ causes the unit cell to expand because the Al3+ is a larger ion than

Si4+ Consequently the diffraction peaks tend to shift to lower angles (Camblor et al 1998

Medrud 1999) This implies that any changes in the tetrahedral frameworks would cause a

shift in the 2θ hence the shift of the d302 peak of deAl-Beta zeolites to higher angle in this work

may be ascribable to the removal of Al3+ from the BEA framework A shift of the d302 peak of

Beta zeolite to higher angle after dealumination with 13 M HNO3 solution was also reported

by Dzwigaj et al (2013)

The change in the position of the main diffraction peak of zeolite samples may be used

to obtain information on the lattice contractionexpansion of the framework since according to

the Braggrsquos law equation (see Equation 9 in Chapter 413) the d302 spacing is calculated using

the corresponding 2θ value (Dzwigaj et al 2013) Under the conditions studied the d302

spacing of H-Beta zeolite decreases after the dealumination Independently to the zeoliteHNO3

ratio the d302 spacing of deAl-Beta zeolites decreased after the dealumination for 4 and 6 h

however a slightly bigger d302 spacing was noticed after 20 h dealumination possibly due to

the re-insertion of Si species (Ho et al 1998 Kunkeler et al 1998) An increasedecrease in

the d-spacing in a given series of samples is generally considered a sufficient evidence of lattice

contractionexpansion in the BEA framework It is commonly used for monitoring of the

191

dealumination progress of Beta zeolite as well as the incorporation of metal ions such as

titanium (Ti) silver (Ag) and vanadium (V) ions into the BEA tetrahedral framework (Camblor

et al 1993 Sudhakar Reddy and Sayari 1995 Dzwigaj et al 1998 Dzwigaj et al 2000

Baran et al 2012 Dzwigaj et al 2013) Table 34 summarises the changes of position of the

main diffraction peaks d-spacing (d302) crystallite size and crystallinity of all deAl-Beta

samples as well as their SiAl ratios obtained from XRF analysis and specific surface area from

BET N2 analysis

The change in the intensity of the main diffraction peaks of H-Beta zeolite treated with

HNO3 for different times indicates a possible change in the relative crystallinity see Figure 53

Considering the crystallinity of NH4-Beta zeolite as a benchmark the relative crystallinity of

deAl-Beta samples decreases with the dealumination time The relative crystallinity was found

to be inversely proportional to the crystallite size of deAl-Beta samples On the other hand no

apparent trend was found between the zeolite to HNO3 solution ratio the crystallinity and the

extent of dealumination According to the XRF analysis 97-98 wt of total Al was extracted

from the zeolite framework after 4 h in all samples and remained unchanged for 20 h

confirming the successful removal of Al atoms from the BEA framework see Figure 54

192

6 8 10 20 22 24

0

2000

4000

6000

8000

H-Beta zeolite

deAl-BetaII4h

deAl-BetaII6h

deAl-BetaII20h

Inte

nsi

ty [

cou

nts

]

2 [degree]

Figure 53 The details of the main X-ray diffraction peaks of H-Beta zeolite before and after

dealumination of 2 g of H-Beta zeolite in 20 ml of 13 M HNO3 solution for 4 6 and 20 h The

error is in the range of 3-5

193

0

25

50

75

100

Al

extr

act

ed [

wt

]

Treatment time [h]

1 g H-Beta in 20 ml NH3 solution



0 4 6 20

Figure 54 The extent of dealumination of H-Beta zeolite with 13 M HNO3 at 100 degC at

different ratios of zeolite to HNO3 solution as a function of treatment time

The results obtained are in accordance with the observation made by Baran et al (2012)

who achieved similar degree of Al extraction from H-Beta zeolite (SiAl = 17) within 2 h and

~100 Al extraction in 4 h using the same concentration of HNO3 (the zeolite to acid solution

ratio not specified) but at 80 degC and under vigorous stirring possibly explaining faster Al

extraction rate and higher degree of dealumination The XRF results also indicate a decrease

in Si content of the dealuminated Beta zeolites This is noticeable on the samples with similar

percentage of Al extracted at relatively low SiAl ratio indicating that Si was possibly extracted

too eg deAl-BetaI6h vs deAl-BetaI20h A decrease in the Si content in conjunction with a

decrease in the BET-N2 surface area of the deAl-Beta zeolites suggest that the BEA structure

may be partially destructed The BET-N2 adsorptiondesorption isotherms of all deAl-Beta

zeolites in this work resemble the type IV adsorption isotherm according to the classification

194

by the IUPAC Commission on Colloid and Surface Chemistry (Balbuena and Gubbins 1993)

See Chapter 512 for a description of the type IV adsorption isotherm

5322 Surface acidity and the degree of Al extraction

TPD-NH3 profiles of H-Beta zeolite before and after the dealumination under the

conditions studied are shown in Figure 55 Almost complete disappearance of the NH3

desorption peaks in the TPD-NH3 profiles of deAl-Beta samples dealuminated from 5 min to

20 h as compared to their parent H-Beta zeolite indicates a significant decrease in acidity

associated with successful removal of Al atoms from the BEA framework The amount of NH3

desorbed from deAl-Beta samples dealuminated for 5 min is significantly lower as compared

to H-Beta zeolite while the profiles of the samples dealuminated for 15 min 4 6 and 20 h are

nearly identical with the amount of NH3 desorbed approaching zero

195

100 200 300 400 500 600

0

50

100

150

200

250

300

deAl-BetaI20h

deAl-BetaII6h

deAl-BetaII4h

deAl-BetaII 15 min

deAl-BetaII 5min

H-Beta zeolite

Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Temperature [C]

Figure 55 TPD-NH3 profiles of H-Beta zeolite before and after the treatment with 13 M HNO3

at 100 degC deAl-Beta refers to dealuminated Beta zeolite the Roman and Arabic numerals

indicate the number of grams of H-Beta zeolite dealuminated in 20 ml of 13 M HNO3 and the

dealumination time in hours or minutes respectively The data presented is from a single

measurement

The XRF analysis results show that the extraction of Al from the H-Beta zeolite

dealuminated for 4-20 h reached 97-98 wt The drop in zeolite Al content determined by

XRF correlates with the decrease of acidity determined by TPD-NH3 for the samples

dealuminated for 4-20 h However only the TPD-NH3 data is available for the samples

dealuminated for 5 and 15 min as opposed to the XRF and TPD-NH3 available for other

samples Based on the correlation of data from XRF and TPD-NH3 established on samples

dealuminated for 4-20 h it is likely that significant degree of dealumination is equally achieved

196

at the reaction times le 15 min Using identical dealumination conditions Baran et al (2012)

reported 94 Al extracted from Beta zeolite providing the SiAl ratio (bulk) of 297 after 5 min

After 2 h the degree of Al extraction reached 98 and the SiAl molar ratio (bulk) increased

from 297 to 947 The high dealumination degree but accompanied by a slow increase in the

SiAl ratio in bulk suggests that the dealumination process comprises two subsequent stages

In the first stage according to Kooyman et al (1997) Al is removed from its tetrahedral

framework position and becomes octahedrally coordinated inside the zeolitic pore structure

resulting in a significant change in the framework SiAl ratio but not the bulk SiAl ratio In

other words Al may have been extracted from the framework but is still present inside the

pores of the zeolite In the second stage the octahedrally coordinated 119860119897(1198672119874)63+ species

diffuse out of the zeolitic pore system into the solution Thus the bulk SiAl ratio decreases

whereas the framework SiAl ratio does not change The SiAl ratio of the samples would

increase after washing out the dissolved Al Therefore the SiAl ratio of dealuminated zeolite

samples may be different depending on the characterisation techniques and the data

presentation The bulk SiAl ratio can be obtained by AAS or XRF spectroscopy while the

framework SiAl ratio may be obtained by MAS NMR spectroscopy (Muumlller et al 2000)

533 Conclusions and discussion

The experiments carried out on the dealumination of H-ZSM-5 under the conditions

studied did not lead to significant Al extraction (~6 wt) On the other hand nearly complete

dealumination (97-98wt) was achieved for H-Beta zeolite samples under identical

experimental conditions ie 1 g zeolite in 20 ml of 13 M HNO3 100 degC 20 h The degree of

Al extraction was found to be much higher for Beta zeolite than ZSM-5 which is consistent

with the observation made by Gonzalez et al (2011) who concluded that the extent of

197

dealumination was a function of the zeolite structure the degree of dealumination decreased in

the following order BEA gt MOR gt MFI

Based on the experimental results the following observation were made

While 97-98 wt Al extraction was achieved in Beta zeolite an insignificant

degree of dealumination for ZSM-5 was attained possibly due to the higher

internal strains within its structure (Cha et al 2013)

The dealumination did not significantly affect the BEA structure of Beta zeolite

Its flexible structure allows it to remain intact without Al

Optimum conditions for dealumination of Beta zeolite were established 2 g

zeolite in 20 ml of 13 M HNO3 solution 100 degC 4 h

A significant decrease in the density of the acid sites of Beta zeolite was

observed even after 5 min of dealumination

54 Metal-exchanged dealuminated Beta zeolites

The deAl-BetaII4h was selected as a starting material for SSIE with the desired metal

ions ie Ce3+ La3+ Sn2+ and Zn2+ due to its high level of dealumination and the highest

relative crystallinity see Table 34 indicating its structure was not adversely affected by the

acid treatment The preparation procedure used is described in Chapter 443 The target metal

contents studied and the analytical techniques used for characterisation are listed in Table 35

The zeolites were doped with various amounts of metals in order to evaluate the effect on the


198

Table 35 The list of metal-exchanged deAl-BetaII4ha prepared by SSIE and the analytical

techniques used for characterisation The metal contents are given in weight relative to the

deAl-BetaII4h

Sample Mole ratio of

metalAlextracted

Weight ratio of

metalzeolite

XRD TPD-NH3 TEM-EDX

NH4-Beta - -

H-Beta - -

deAl-BetaII4h - -

05 CedeAl-BetaII4h 004 05100




10 CedeAl-BetaII4hb 099 115100

10 LadeAl-BetaII4hb 100 115100

88 SndeAl-BetaII4hb 099 97100

5 ZndeAl-BetaII4hb 099 54100

48 CedeAl-BetaII4h (Cl)c 043 5100

48 SndeAl-BetaII4h (Cl)c 052 5100

48 ZndeAl-BetaII4h (Cl)c 094 5100

a deAl-BetaII4h refers to dealuminated Beta zeolite prepared from H-Beta zeolite dealuminated

in 20 ml of 13 M HNO3 at 100 degC for 4 h b The amount of metal equals the number of mole

of Al extracted c The metal precursors used were corresponding chlorides salts instead of

nitrates used for Ce- and La-doped or acetates for Sn- and Zn-doped catalysts


Phase identification

A series of deAl-BetaII4h catalysts containing various amounts of Ce was prepared and

characterised by XRD Figure 56 shows the XRD spectra of H-Beta zeolite and deAl-BetaII4h

compared to those of 05 wt- 07 wt- 1 wt- 6 wt- and 10 wt CedeAl-BetaII4h

199

catalysts The XRD spectra reveal that the BEA structure was preserved in all samples despite

the changes in the peak intensities d302 positions and d302-spacings summarised in Table 37

(page 207) The CeO2 was detected in the 6 wt- and 10 wt CedeAl-BetaII4h catalysts

which also developed a characteristic pale yellow discoloration of CeO2 This observation is in

good agreement with the work of Xue et al (2006) who reported the presence of CeO2 in Ce-

loaded NH4-Y zeolites at CeNH4 mole ratio which is equivalent to the CeAl mole ratio as

used in current work larger than 095 The CeO2 is known to form by thermal decomposition

of Ce(NO3)36H2O (Kamruddin et al 2004)

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

8000

10000

X

XXX

H-Beta zeolite

deAl-BeatII4h

10 CedeAl-BetaII4h

6 CedeAl-BetaII4h

1 CedeAl-BetaII4h

07 wt CedeAl-BetaII4h


Inte

nsi

ty [

cou

nts

]

2 [degree]

X

CeO2

Inte

nsi

ty [

cou

nts

]

2 (degree)

045 to 1 CedeAl-BetaII4

Figure 56 The XRD spectra of H-Beta zeolite compared to those of deAl-BetaII4h and Ce-

incorporated deAl-BetaII4h with the Ce content of 05 wt 07 wt 1 wt 6 wt and 10

wt corresponding to the CeAlextracted molar ratios of 004 006 009 057 and 099

respectively The inset graph details the two main peaks at around 2θ = 78deg (d101) and 2θ =

226deg (d302) Symbol x = CeO2

200

The presence of CeO2 in the 6 wt- and 10 wt CedeAl-BetaII4h catalysts indicates

that the incorporation of Ce into the zeolite structure either exceeded its maximum or was

unsuccessful The TEM micrograph of 10 wt CedeAl-BetaII4h shows significant amount of

CeO2 particles (dark spots) dispersed over the surface of Beta zeolite see Figure 57 The CeO2

was not as expected detected in 05 wt- 07 wt- 1 wt CedeAl-BetaII4h catalysts likely

because it was below the detection limit of XRD spectroscopy (typically ~3wt for a two

phase mixture (Toney 1992) and crystalline grain size roughly about 30Aring (Malin 2015))

Figure 57 The TEM micrograph of 10 wt CedeAl-BetaII4h ie the molar ratio of

CeAlextracted ~1 The dark spots are assumed to be CeO2

The presence of metal oxides was observed not only in CedeAl-BetaII4h with high

metal ion loadings ie the molar ratios of CeAlextracted ~057 and ~1 but also in Sn- and

ZndeAl-BetaII4h Figure 58 shows the XRD spectra of deAl-BetaII4h before and after the

SSIE with salts of various metals ie Ce3+ La3+ Sn2+ and Zn2+ at the molar ratio of metal ion

201

to Alextracted of ~1 corresponding to 10 wt Ce- 10 wt La- 88 wt Sn- and 5 wt ZndeAl-

BetaII4h The XRD patterns of all samples except for 10 wt LadeAl-BetaII4h show not

only the diffraction peaks of the parent BEA structure but also the traces of corresponding

metal oxides ie ZnO SnO2 and CeO2 see Table 36 for a summary of phases identified The

formation of metal oxides was also observed in 48 wt metal-exchanged samples using H-

and NH4-forms of both Beta zeolite and ZSM-5 as starting materials see Chapter 52 La2O3

was not detected in 10 wt LadeAl-BetaII4h which may be possibly explained by incomplete

thermal decomposition of La(NO3)3middotH2O to poorly-crystalline La3O4NO3 at 550 degC (Gobichon

et al 1996 Mentus et al 2007)

202

0

3000

6000

0

3000

6000

0

3000

6000

0

3000

6000

10 20 30 40 50 60 70

0

3000

6000

+ = NaCl

= ZnO

(D)

5 ZndeAl-BetaII4h

2 [degree]

+

+ = NaCl

O = SnO2

(C)

ooo+

88 SndeAl-BetaII4h

Inte

nsi

ty [

Co

un

ts]

+

+

+

o

+ = NaCl

(B)

++

+

10 LadeAl-BetaII4h

+ = NaCl

x = CeO2

xxx +

10 CedeAl-BetaII4h

+x

(A)

+ = NaCl

(E)

++

+

deAl-BetaII4h

Figure 58 XRD spectra of deAl-Beta zeolite before and after SSIE with salts of Ce3+ La3+

Sn2+ and Zn2+ The initial molar ratio of metal ion to Alextracted in all samples is ~1 corresponding

to 10 wt Ce- 10 wt La- 88 wt Sn- and 5 wt ZndeAl-BetaII4h NaCl used as an

internal standard was added to the samples prior to analysis Symbol + = NaCl = ZnO

ο = SnO2 x = CeO2

203

Table 36 A summary of phases identified in the XRD spectra of various metal-incorporated

deAl-BetaII4ha catalysts


metalAlextracted

Phases identified

NH4-Beta - Beta zeolite

H-Beta - Beta zeolite

deAl-BetaII4h - Beta zeolite

05 wt CedeAl-BetaII4h 004 Beta zeolite



6 wt CedeAl-BetaII4h 057 Beta zeolite CeO2

10 wt CedeAl-BetaII4hb 099 Beta zeolite CeO2

10 wt LadeAl-BetaII4hb 100 Beta zeolite

88 wt SndeAl-BetaII4hb 099 Beta zeolite SnO2

5 wt ZndeAl-BetaII4hb 099 Beta zeolite ZnO

48 wt CedeAl-BetaII4h (Cl)c 043 Beta zeolite CeO2

48 wt SndeAl-BetaII4h (Cl)c 052 Beta zeolite SnO2

48 wt ZndeAl-BetaII4h (Cl)c 094 Beta zeolite 2 unidentified peaks a deAl-BetaII4h refers to dealuminated Beta zeolite prepared from H-Beta zeolite dealuminated


of Al extracted c The metal precursors used were corresponding metal chlorides instead of


The Si-O(H)-Al groups (bridging hydroxyl groups) in zeolite structure are relatively

highly acidic (Hunger 1997 Kazansky et al 2003) allowing a rapid ion exchange with a metal

cation On the other hand the Si-OH (silanol) groups formed inside the zeolite framework

after the Al removal see Equation 19 are only slightly acidic (Kazansky et al 2003) possibly

resulting in slow metal exchange rate The thermal decomposition of metal salts to metal oxides

may then be considered as a competing reaction The use of strong acid cerium salt such as

CeCl3 instead of weaker acid cerium salt such as Ce(NO3)3 may promote the ion-exchange

204

due to the higher acidity of the salt To examine the effect of chloride-based salts 48 wt

Ce- Sn- and ZndeAl-BetaII4h catalysts were prepared using corresponding metal chloride as

a precursor The XRD spectra of the three catalysts see Figure 59 reveal the presence of metal

oxides in 48 wt Ce- and 48 wt SndeAl-BetaII4h samples despite lower metal ion loadings

as compared to those prepared from metal nitrate and acetate ie 10 wt Ce- and 88 wt Sn-

deAl-BetaII4h respectively On the other hand ZnO was not detected in 48 wt ZndeAl-

BetaII4h prepared from ZnCl2 although the Zn2+ loading was similar to that prepared from

Zn(acetate)2 ie 5 wt Zn2+ relative to zeolite and two unidentified peaks at 2θ = 565deg and

691deg were detected in its XRD spectra The results indicate that the nature of metal salt

precursors does not affect the extent of metal oxide formation

205

0

3000

6000

9000

0

3000

6000

0

3000

6000

10 20 30 40 50 60 70

0

3000

6000

5 wt ZndeAl-BetaII4h

48 wt ZndeAl-BetaII4h (Cl)

2 [degree]

+

(D)

(B)

(C)

88 wt SndeAl-BetaII4h

48 wt SndeAl-BetaII4h (Cl)

ooo+

Inte

nsi

ty [

Cou

nts

]

+

+

+

o


48 wt CedeAl-BetaII4h (Cl)

+

x

x + x x

(A)

++

+

deAl-BetaII4h

Figure 59 XRD spectra of (D) deAl-BetaII4h before and after SSIE with salts of (A) Ce3+ (B)

Sn2+ and (C) Zn2+ The black colour denotes catalysts prepared using the nitrate or acetate-

based salts while the blue colour denotes the sample prepared using the metal chloride In the

former the molar ratio of metal ion to Alextracted in all samples is ~1 NaCl used as an internal

standard was added to the samples prior to analysis Symbol + = NaCl = ZnO ο = SnO2 x

= CeO2

206

Changes in XRD spectra

Independently of the type of metal and the metal content the BEA structure of all

catalysts prepared was preserved after the SSIE however the changes in the peak intensities

d302 position and d302-spacing were noted and tabulated See Figure 60 below Figure 121 and

122 in the Appendix for the XRD spectra of 10 wt La- 88 wt Sn- and 5 wt ZndeAl-

BetaII4h catalysts respectively compared to those of H-Beta zeolite and deAl-BetaII4h Table

37 summarises the shifts of the main diffraction peaks (d302) the changes of d-spacing (d302)

and the relative crystallinities of deAl-BetaII4h before and after the SSIE reaction with metal

salts under study

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

++

+ NaCl

H-Beta zeolite

deAl-BetaII4h

10wt LadeAl-BetaII4h

Inte

nsi

ty [

co

un

ts]

2 [degree]

+

Inte

nsi

ty [

cou

nts

]

2 [degree]

Figure 60 The XRD spectra of H-Beta zeolite compared to those of deAl-BetaII4h and 10

LadeAl-BetaII4h The inset graph details the two main peaks at around 2θ = 78deg (d101) and 2θ

= 226deg (d302) NaCl used as an internal standard at the zeolite to NaCl mass ratio of 267 was

added to the samples prior to analysis Symbol + = NaCl

207

Table 37 Summary of the main diffraction peaks positions d-spacing (d302) (2θ = 225ordm) and

the relative crystallinity of NH4-Beta and H-Beta zeolites as well as deAl-BetaII4h zeolite

before and after the SSIE reaction with various metal salts

Sample Δd302

position

[degree]a

Crystallite

sizeb

[nm]

d302-

spacing

[Aring]

Δd302 [Aring]c

Relative

crystallinityd

NH4-Beta +009 159 394 100

H-Beta 000 151 396 000 105

deAl-BetaII4he +019 129 392 -004 100

045 CedeAl-BetaII4h +022 118 392 -004 82

07 CedeAl-BetaII4h +019 131 392 -004 79

1 CedeAl-BetaII4h +019 117 392 -004 78

6 CedeAl-BetaII4h +012 127 393 -002 64

10 CedeAl-BetaII4hf +038 110 389 -007 58

10 LadeAl-BetaII4h +016 110 393 -003 63

88 SndeAl-BetaII4h +012 135 393 -002 68

5 ZndeAl-BetaII4h +003 146 395 -001 92

48 CedeAl-BetaII4h (Cl)g +012 127 393 -002 64

48 SndeAl-BetaII4h (Cl)g +012 135 393 -002 68

48 ZndeAl-BetaII4h (Cl)g +003 146 395 -001 92

a Changes of the position of the main diffraction peak 2θ = 2247deg (d302 ) relative to H-Beta zeolite the

ldquo+rdquo (plus symbol) denotes the positive peak shift relative to parent H-Beta zeolite b The primary

crystalline size was calculated by Scherrerrsquos equation c Changes of the d-spacing (d302) relative to H-

Beta zeolite the ldquo-rdquo (minus symbol) denotes a negative d-spacing change d The crystallinity of the

samples relative to NH4-Beta zeolite based on the intensity of its main diffraction peak (2θ = 226deg) in

the XRD spectra e deAl-BetaII4h was prepared using 2 g of H-Beta zeolite in 20 ml of 13 M HNO3

100 degC 4 h f The amount of Ce introduced equals the number of mol of Alextracted g corresponding metal

chloride was used as a precursor The error is in the range of 3-5

208

The SSIE of deAl-BetaII4h with salts of Ce3+ La3+ Sn2+ and Zn2+ resulted in

(i) a decrease in the relative crystallinity of parent zeolite

(ii) significant changes in the position of the main diffraction peak at 2θ = 226deg

(d302) and

(iii) changes in d302-spacing (also known as interplanar distance)

The incorporation of a cation may induce significant changes of the diffracted peak

intensities due to different X-ray radiation absorption coefficient of individual ion (Medrud

1999) The changes of the position of the d302 peak at 2θ = 226deg are associated with the changes

in the interplanar distance (d302-spacing) (see Braggrsquos law Equation 9 in Chapter 413) within

the crystal lattice indicating a contracting or expanding BEA framework For instance a

decrease from 3956 Aring (H-Beta zeolite with 2θ of 22470deg) to 3921 Aring (deAl-BetaII4h with

2θ of 22662deg) is consistent with the removal of aluminium atoms while an increase from 3921

Aring (deAl-BetaII4h) to 3948 Aring at 22501 (5 wt ZndeAl-BetaII4h) indicates the incorporation

of Zn ions inside the framework may be successful (Dzwigaj et al 2013) However the XRD

patterns of 5 wt ZndeAl-BetaII4h also reveal the presence of ZnO indicating that Zn at least

partially co-exists as a separate phase

To conclude whether or not the incorporation of metal ions into the BEA framework

was successful a combination of several characterisation techniques such as pyridine

adsorption by FTIR and MAS NMR would be required (Kazansky et al 2003 Tang et al

2014) Both techniques can be used to determine the existence and concentration of Lewis acid

sites associated with the presence of metals as well as to identify the environment of each

element in each preparation steps For instance the presence of silanol groups in the

dealuminated zeolite before and after the SSIE see Equation 19 (page 133)

209

542 Surface acidity

Figure 61 shows the TPD-NH3 profiles of the H-Beta zeolite before and after the

treatment with 13 M HNO3 at 100 degC for 4 h (deAl-BetaII4h) compared to those of 10 wt

Ce- 10 wt La- and 88 wt Sn-incorporated deAl-BetaII4h samples see Chapter 513 and

532 for a full discussion on the surface acidity of H-Beta zeolite and deAl-Beta zeolites

respectively The TPD-NH3 profiles show that the dealumination of H-Beta zeolite resulted in

a complete disappearance of its NH3 desorption peaks indicating a successful removal of Al

atoms from the BEA framework (see the TPD-NH3 curves of H-Beta zeolite vs deAl-BetaII4h)

After the SSIE the TPD-NH3 profile of the deAl-BetaII4h shows extensively overlapping

peaks resulting in a long plateau from (i) 150 to 250 degC (ii) 125 to 200 degC and (iii) 150 to 200

degC for Ce- La- and Sn- incorporated deAl-BetaII4h samples respectively This may be due to

the metals creating new Lewis acid sites (Jentys et al 1997)

210

100 200 300 400 500 600

0

50

100

150

200

250

300


10 wt LadeAl-BetaII4h


deAl-BetaII4h

H-Beta zeolite

Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Temperature [C]


2 g zeolite in 20 ml HNO3 (aq) 100 degC 4 h (deAl-BetaII4h) compared to those of metal-

incorporated deAl-BetaII4h The percentages reported are in wt indicating the metal content

relative to zeolite

55 Immobilisation and agglomeration of Beta zeolite-

based catalysts

Zeolite powders are unsuitable for a direct use in a continuous flow reactor due to the

tendency to get washed out It is therefore necessary to shape the powder into a macroscopic

form or immobilise it on a larger particles prior to administration Several techniques were

used to process the powders into a more suitable form

211

Ceramic hollow fibre membranes (CHFM) were used to support the CeH-Beta zeolite

for its high temperature resistance and chemical mechanical stability The use of CHFM may

also alleviate reactor pressure drop usually found in packed bed reactors However only

insignificant amounts of catalysts were successfully deposited into the pores of the membrane

and the zeolite particles were washed out from the continuous flow reactors after a few hours

use See Chapter 551

The incorporation of Beta zeolite-based catalysts into the pores of mesoporous silica

matrix TUD-1 was then carried out The pellets of the Beta zeolite-TUD-1 composite

disintegrated and leached out from the reactor See Chapter 552

The extrusion of Beta zeolite-based catalysts was performed using bentonite clay binder

but the extruded catalysts partially disintegrated The Beta zeolite-based catalysts was then

extruded with γ-Al2O3 binder and methyl cellulose plasticiser in order to improve the

consistency of the extruded paste See Chapter 553

551 CeH-Beta zeolite on ceramic hollow fibre membranes

The Ce-exchanged H-Beta zeolite (CeH-Beta) was introduced into the pores of the

ceramic hollow fibre membranes (CHFM) according to the 4-step procedure described in

Chapter 444 In the final step the CeH-Beta recovered from the filtrate as well as the CeH-

Beta deposited on the CHFM were characterized by SEM-EDS and XRD

Figure 62 shows the XRD spectra of (A) H-Beta zeolite prepared by calcining of

commercial NH4-Beta at 550 degC 5 h (B) synthesized CeH-Beta powder recovered from the

filtrate and (C) CeH-Beta deposited on CHFM support and the CHFM support The XRD

pattern of the solid recovered from the filtrate collected after the synthesis confirmed the

212

presence of Beta zeolite see Figure 62A and B However the XRD spectra of the CeH-Beta

zeolite on CHFM support shows only the diffraction peaks of Al2O3 the main component of

the CHFM see Figure 62C possibly indicating that the amount of CeH-Beta zeolite

introduced is below the detection limit ie lt3wt

213

0

1000

2000

0

1000

2000

10 20 30 40 50 60 70

0

1000

2000

Inte

nsi

ty [

Co

un

ts]

(B) Synthesized zeolite (powder)

2 [degree]

(A) H-Beta zeolite

2= 7776

2= 22630

2= 25456

2= 27158

2= 43971 2= 55980

2 = 7643

2= 22557

2 = 25356

2 = 26958

2 = 439670

(C) CHFM support

after the zeolite synthesis

before the zeolite synthesis

Figure 62 XRD spectra of (A) commercial H-Beta zeolite (CP814E SiO2Al2O3 = 25) (B)

CeH-Beta recovered from the filtrate and (C) ceramic hollow fibre membrane (CHFM)

support and CeH-beta deposited on CHFM support

214

The SEM micrographs of CeH-Beta particles deposited on the CHFM are shown in

Figure 63 The zeolite particles appear to reside inside the CHFM pores

Figure 63 SEM micrographs of CeH-Beta particles on the ceramic hollow fibre membranes

The effect of the catalyst on the hydrothermal oxidation of glycerol was studied in a

continuous flow reactor according to the experimental procedures in Chapter 462 The reactor

was packed with 24 g CeH-Beta on CHFM and fitted with metal mesh at both ends The

reaction was performed at 175 degC 35 bar and a residence time of 180 and 240 s using 02 M

glycerol with the molar glycerolH2O2 ratio = 1 The results are shown in Table 38 A moderate

degree of conversion (23-25 mol) and high selectivity to liquid products (54-103 mol) were

obtained Several liquid products were detected Formic acid the main product was obtained

with the highest selectivity of 542 mol and yield of 134 mol

215

Table 38 The products of hydrothermal oxidation of 02 M glycerol with H2O2 using 24 g CeH-Beta on ceramic hollow fibre membranes as

catalyst Reaction conditions 175 degC 35 bar and a residence time of 180 and 240 s the molar glycerolH2O2 = 1

Temperature

[degC]

Residence time

[s]

Conversion

[mol]

Selectivity to liquid products [C-mol] Total

[C-mol] AA LA FA DHA GCA PVA

175 180 251 plusmn 12 153 plusmn 11 50 plusmn 07 542 plusmn 16 131 plusmn 11 114 plusmn 08 32 plusmn 04 1025 plusmn 35


Yield of liquid products [C-mol] Total




Note AA= acetic acid LA = lactic acid FA = formic acid DHA = dihydroxyacetone GCA = glycolic acid and PVA = pyruvaldehyde The

numbers presented are an averaged plusmn standard error of means (119878119864)

216

Despite the promising results the CeH-Beta particles deposited on the CHFM were

unsuitable for use in the continuous flow reactor as the zeolites particles washed out after 4 h

see Figure 64 Further work was abandoned

Figure 64 SEM micrograph of the CeH-Beta on CHFM after the 4 h use in the hydrothermal

oxidation of 02 M glycerol with H2O2 at 175 degC 35 bar and a residence time of 180 s the

molar glycerolH2O2 of 1 and 24 g of the catalyst

552 H-Beta and metal-dopedH-Beta zeolites embedded in TUD-1

matrix

Mesoporous silica matrix TUD-1 was used for the agglomeration of Beta zeolite

catalysts for its easy preparation and low cost (Jansen et al 2001) The key characteristics of

this matrix include well-defined pores high thermal and hydrothermal stability (Jansen et al

217

2001) It also has high surface area and three-dimensional porosity which may be beneficial

for internal mass transfer (Lima et al 2010)

Three zeolite-based catalysts ie H-Beta 48 CeH-Beta and 48 CuH-Beta were

prepared by SSIE and incorporated into the pores of TUD-1 according to the procedure

described in Chapter 445 Cu is known as an effective catalyst for oxidation and hence it was

also used The agglomerated catalysts were characterised by XRD and BET-N2 analysis

Figure 65 shows the XRD spectra of (B) H-Beta (C) 48 wt CeH-Beta and (D) 48

wt CuH-Beta before and after incorporating into the TUD-1 matrix at the zeoliteTUD-1

weight ratio set constant to 4060 The XRD patterns of the H-Beta and the H-Beta in TUD-1

(Figure 65A amp B) do now show significant differences with the characteristic diffraction peaks

of BEA structure of Beta zeolite as the single phase identified The apparent broadening of low

angle peaks may be explained by an intergrowth of different polymorphs of the Beta zeolite

(mainly A and B) in the crystals (Lima et al 2010) The apparent decrease in intensity of

agglomerated H-Beta in TUD-1 matrix may be explained by lower zeolite content relative to

pure H-Beta zeolite see Figure 65B The characteristic diffraction peaks of Beta zeolite as well

as the low angle peaks broadening are also observed for the 48 wt CeH-Beta and 48 wt

CeH-Beta in TUD-1 with CeO2 as an additional phase present detected in both spectra On the

other hand no line broadening was observed for the 48 wt CuH-Beta in TUD-1 (Figure

65D) with Beta zeolite and CuO being the only phases identified

The formation of amorphous silica matrix TUD-1 may be confirmed by XRD analysis

but only at lower scanning angles (1deg to 5deg) (Antunes et al 2012)

218

10 20 30 40 50 60 70

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

(D)

= CuO

Inte

nsi

ty [

Cou

nts

]

2 [degree]

48 CuH-Beta in TUD-1

48 wt CuH-Beta

(C)

xxx

x = CeO2

48 CeH-Beta in TUD-1

48 CeH-Beta

x

(B)

H-Beta in TUD-1

H-Beta

(A)

H-Beta

Figure 65 The XRD spectra of Beta zeolite-based catalysts in mesoporous silica matrix TUD-

1 (B) H-Beta in TUD-1 (C) 48 wt CeH-Beta in TUD-1 and (D) 48 wt CuH-Beta in

TUD-1 The XRD spectra of all the catalysts before incorporating into the TUD-1 are given for

comparison The Beta zeolite content is set constant to 40 wt zeolite relative to TUD-1

Symbols x = CeO2 = CuO

219

The BET-N2 adsorption and desorption isotherms of (i) H-Beta vs H-Beta in TUD-1

and (ii) H-Beta 48 wt CuH-Beta and 48 wt CuH-Beta in TUD-1 are shown in Figure

123 and 124 (in the Appendix) respectively Similar to H-Beta zeolite (see Figure 42 page

162) the BET-N2 adsorptiondesorption isotherms resemble the type IV adsorption isotherm

which is typical for mesoporous materials (Balbuena and Gubbins 1993) See Chapter 512

for a description of the type IV adsorption isotherm

The incorporation of the H-Beta zeolite and 48 wt CuH-Beta zeolite catalysts into

the TUD-1 matrix leads to an increase in their BET-N2 surface areas see Table 39 An increase

in the surface area of the TUD-1 incorporated samples may be due to multilayer adsorption on

the external surface of the nanocrystallites

Table 39 BET-N2 analysis results of H-Beta zeolite and 48 wt CuH-Beta zeolite before and

after the incorporation into the mesoporous silica matrix TUD-1 The data presented is from a

single measurement

Sample Micropore

volume

[cmsup3middotg-1]

Micropore

area

[msup2middotg-1]

External

surface area

[msup2middotg-1]

BET surface

area

[msup2middotg-1]

H-Beta zeolite 017 367 231 598

H-Beta zeolite in TUD-1 009 195 428 624

48 wt CuH-Beta 015 330 200 530

48 wt CuH-Beta in TUD-1 012 278 348 627

The protocol used in this work was previously reported by Lima et al (2010) to provide

the H-Beta zeolite incorporated in the TUD-1 silica matrix The characterisation techniques

220

used in this work do not allow to confirm conclusively that the incorporation of Beta zeolite-

based catalysts into TUD-1 matrix was achieved

The H-BetaTUD-1 composite material was pelletized and tested for the hydrothermal

oxidation of 02 M glycerol with H2O2 at 175 degC 35 bar 180 s using the molar glycerolH2O2

ratio of 1 The experiment procedure is provided in Chapter 462 The pellets disintegrated and

leached out from the reactor after a few hours The chemical analysis of reaction products was

not performed

553 Extruded catalysts

5531 Starting zeolite-based catalysts

Extrusion is another technique used to shape the zeolite powders into macroscopic

forms more suitable for administration in a continuous flow reactor Three zeolite-based

catalysts ie

H-Beta

25wt CuH-Beta and

48wt CuH-Beta

were prepared mixed with either bentonite or γ-Al2O3 binders according to the procedure

described in Chapter 446 and then extruded into 3-5 mm long 2 mm diameter rods The rods

were calcined at 550 degC prior to the instrumental analysis H-Beta zeolite was prepared by the

calcination of NH4-Beta zeolite (see Chapter 441) while the 25wt and 48wt CuH-Beta

zeolite catalysts were prepared by SSIE according to the procedure described in Chapter 442

221

The 25wt CuH-Beta zeolite was used as the results obtained on the 48wt CuH-Beta

zeolite indicated that lowering the Cu loading may increase the yield of liquid products

Figure 66 presents the XRD spectra of H-Beta zeolite 25 wt CuH-Beta and 48 wt

CuH-Beta The XRD pattern of H-Beta zeolite shows the characteristic peaks of the BEA

structure with the main diffraction peaks at 2θ = 75-8deg and 226deg The XRD patterns of H-Beta

zeolite after the SSIE with nitrate salt of Cu2+ ie 25 wt- and 48 wt CuH-Beta catalysts

show that the BEA structure of Beta zeolite remained preserved but the CuO was identified as

an additional phase in both samples The XRD spectrum of 25 wt CuH-Beta is almost

identical to that of 48 wt CuH-Beta but exhibits lower intensity of the diffraction peaks of

CuO

10 20 30 40 50 60 70

0

1000

2000

3000

4000

5000

6000

2 [degree]

= CuO

H-Beta

25 wt CuH-Beta

48 wt CuH-Beta

Inte

nsi

ty [

cou

nts

]

Figure 66 The XRD spectra of H-Beta zeolite 25 wt CuH-Beta zeolite and 48 wt CuH-

Beta zeolite Symbol = CuO

222

5532 Beta zeolite-based catalysts extruded with bentonite clay

I Powder X-ray diffraction

The XRD spectra of the H-Beta zeolite and 48 wt CuH-Beta zeolite catalysts before

and after the extrusion with bentonite clay are shown in Figure 67 The decreased intensities

of the extruded zeolites relative to pure zeolites may be explained by the dilution with the

bentonite as the zeolite catalyst content in the extruded form was 68 wt However the

diffraction peaks of bentonite and methylcellulose see Figure 125 in the Appendix are absent

in the XRD spectra of the extruded catalysts calcined at 550 degC which may be explained by the

poor crystallinity of bentonite and the thermal instability at 550 degC for methylcellulose

223

10 20 30 40 50 60 70

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

= CuO

Inte

nsi

ty [

Cou

nts

]

2 [degree]

(D) extruded 48 wt CuH-Betabentonite

(C) 48 wt CuH-Beta

(B) extruded H-Betabentonite

(A) H-Beta

Figure 67 The XRD spectra of (A) amp (B) H-Beta zeolite and (C) amp (D) 48 wt CuH-Beta

zeolite before and after the extrusion with bentonite clay The Cu content is given in weight

relative to H-Beta zeolite The content of ldquo48 wt CuH-Betardquo is 68 wt relative to bentonite

224

II BET N2 and SEM analysis

The BET N2 adsorptiondesorption isotherms of extruded H-Beta and 48 wt CuH-

Beta see Figure 126 (in the Appendix) resemble the type IV isotherms featuring the H1

hysteresis loops typical for mesostructured materials with pore sizes larger than 40 Aring (Balbuena

and Gubbins 1993 Melero et al 2008) The extrusion of H-Beta zeolite and 48 wt CuH-

Beta zeolite with bentonite resulted in a decrease of 11 in their BET surface area mainly due

to a decrease in the total pore volume and external surface area see Table 40 This may be

explained by the dilution of the mesostructured material with the low-surface area bentonite

clay The SEM micrographs of H-Beta and 48 wt CuH-Beta before and after extrusion with

bentonite see Figure 68 show that after the extrusion most zeolite particles are encapsulated

within the clay body

Table 40 BET N2 surface area analysis results for H-Beta zeolite and 48wt CuH-Beta

zeolite before and after the extrusion with clay (bentonite) The metal contents are given in

weight percentage (wt) relative to H-Beta zeolite The weight percentage of H-Beta zeolite

or ldquo48 wt CuH-Betardquo is 68wt relative to bentonite The data presented is from a single

measurement

Sample Micropore

volume

[cmsup3middotg-1]

Micropore

area

[msup2middotg-1]

External

surface area

[msup2middotg-1]

BET N2

surface area

[msup2middotg-1]


extruded H-Betabentonite 012 269 154 423

48 CuH-Beta 015 330 200 530

extruded 48 CuH-Betabentonite 011 247 141 388

bentonite 001a - - 94a

a reported by Grisdanurak et al (2012)

225

Figure 68 SEM micrographs of (A) H-Beta (B) H-Beta extruded with bentonite (C) 48 wt

CuH-Beta and (D) 48 wt CuH-Beta extruded with bentonite The metal contents are given

in weight percentage (wt) relative to H-Beta zeolite The weight percentage of H-Beta zeolite

or ldquo48 wt CuH-Betardquo is 68 wt relative to bentonite

5533 Beta zeolite-based catalysts extruded with γ-Al2O3

The procedure used for preparation of extruded catalysts is described in Chapter 446

All extruded catalyst samples discussed in the chapters below were calcined at 550 degC prior to

the instrumental analysis


The XRD spectra of H-Beta zeolite 48 wt- and 25 wt CuH-Beta before and after

extrusion with γ-Al2O3 are shown in Figure 69 70 and 71 respectively The XRD patterns of

all three samples show that the BEA structure remained preserved after the extrusion with γ-

226

Al2O3 followed by calcination at 550 degC despite the reduction in the intensity of the diffraction

peaks possibly caused by the relatively lower zeolite content in the extruded samples The

reduction in the peak intensity of zeolite-based catalysts extruded with γ-Al2O3 is however

not as high as in the case of bentonite clay (see Figure 67 Chapter 5532) In addition to the

characteristic diffraction peaks of Beta zeolite the XRD patterns of the catalysts show the

presence of the following phases

(i) CuO in 25 wt- and 48 wt CuH-Beta both before and after extrusion with

γ-Al2O3 followed by calcination at 550 degC

(ii) γ-Al2O3 in all extruded catalysts see Figure 130 (in the Appendix) for the XRD

patterns of supporting extrusion materials ie γ-Al2O3 and methyl cellulose

(MC)

The addition of MC 5 wt relative to zeolite + γ-Al2O3 into the pastes of (i) H-Beta

zeolite or (ii) 48 wt CuH-Beta zeolite increased the homogeneity facilitating the material

processing The XRD spectra of both H-Betaγ-Al2O3 and 48 wt CuH-Betaγ-Al2O3

extruded with and without MC show no significant differences see Figure 69(B) vs (C) and

Figure 70(B) vs C likely due to the fact that MC decomposed during the calcination at 550

degC However a reduction in the intensity of the main diffraction peak appearing at 2θ = 226deg

(d302) was noted for the extruded catalysts prepared from the paste with MC see Table 41 for

a summary of composition of extruded catalysts

A slight shift of the main diffraction peak was also observed for all the samples after

the extrusion but the cause of the shift is uncertain as an internal standard such as NaCl was

not used

The reduction in the diffraction peak intensity of the zeolite catalysts resulted in a

decrease in their XRD relative crystallinity Table 42 For instance the relative crystallinity of

227

H-Beta zeolite after the extrusion with γ-Al2O3 with and without MC decreases from 105 to

49 and 38 with respect to NH4-Beta The changes in the intensity and position of the main

diffraction peaks as well as the BET N2 analysis results are summarised in Table 42

10 20 30 40 50 60 70

red circle-Al2O

3

(C) extruded H-Beta-Al2O

3

(B) extruded H-Beta-Al2O

3(MC)

(A) H-Beta

Inte

nsi

ty [

arb

un

its]

2 [degree]

Figure 69 The XRD spectra of H-Beta zeolite before and after the extrusion with γ-Al2O3

binder with or without methyl cellulose (MC) acting as a plasticiser The weight percentage of

zeolite relative to binder in the extrusion paste was 60 (without MC) and 575 (with MC)

Symbol red circle = γ-Al2O3

228

10 20 30 40 50 60 70

= CuO red circle-Al2O

3

(C) extruded 48 wt CuH-Beta-Al2O

3

(B) extruded 48 wt CuH-Beta-Al2O

3(MC)

Inte

nsi

ty [

arb

un

its]

2 [degree]

(A) 48 wt CuH-Beta

Figure 70 The XRD spectra of 48 wt CuH-Beta zeolite before and after the extrusion with

γ-Al2O3 binder with or without methyl cellulose (MC) plasticiser The metal content is 48 wt

Cu relative to H-Beta zeolite The composition of the extrusion paste was 575 wt zeolite

catalyst 375 wt γ-Al2O3 and 5wt MC (B) and 60 wt zeolite catalyst 40 wt γ-Al2O3

(C) Symbol = CuO red circle = γ-Al2O3

229

10 20 30 40 50 60 70


3

(A) extruded 25 wt CuH-Beta-Al2O

3 (MC)

Inte

nsi

ty [

arb

un

its]

2 [degree]

(B) 25 wt CuH-Beta

Figure 71 The XRD spectra of 25 wt CuH-Beta zeolite before and after extrusion with γ-

Al2O3 binder using methyl cellulose (MC) plasticiser The metal content is 25 wt Cu relative

to H-Beta zeolite The composition of the extrusion paste was 575 wt zeolite catalyst 375

wt γ-Al2O3 and 5wt MC Symbol = CuO red circle = γ-Al2O3

Table 41 Composition of extrusion paste for the extrusion of H-Beta zeolite and 48 wt

CuH-Beta with γ-Al2O3 The metal content is 48 wt Cu relative to H-Beta zeolite

Catalysts

Composition [wt] Normalized

wt of zeolite

catalyst relative

to γ-Al2O3

H-Beta or

48 CuH-Beta γ-Al2O3 MC

extruded H-Betaγ-Al2O3 60 40 - 6040

extruded H-Betaγ-Al2O3 (MC) 575 375 5 605395

extruded 48 CuH-Beta γ-Al2O3 60 400 - 6040

extruded 48 CuH-Beta γ-Al2O3 (MC) 575 375 5 605395

230

Table 42 Physical properties of Beta zeolite-based catalysts extruded with bentonite clay or γ-

Al2O3 The weight percentage assigned in CuH-Beta indicates the metal content relative to H-

Beta zeolite The weight percentage of H-Beta and CuH-Beta catalysts relative to bentonite in

the extrusion paste is 60 (without MC) and 575 (with MC) Note MC = methyl cellulose

Catalyst BET N2

surface area

[m2middotg-1]

Micropore

Volume

[cmsup3middotg-1]

XRD relative

crystallinitya

[]

Post of d302

[degree 2θ]

TEM-EDS

SiO2Al2O3

mol ratio

NH4-Beta 575 017 100 226 25b

H-Beta 598 017 105 225 25 b

25 wt CuH-Beta 573 016 nad 226

48 wt CuH-Beta 534 015 83 227

H-Betaγ-Al2O3c - - 49 226

H-Betaγ-Al2O3 (MC)c 423 010 38 228 54

25 wt CuH-Betaγ-

Al2O3 (MC)c 419 009 nad 226 24

48 wt CuH-Betaγ-

Al2O3c

- - 56 227 44

48 wt CuH-Betaγ-

Al2O3 (MC)c 446 010 62 227 45

a Relative crystallinity of the samples using the main peak intensity from XRD patterns (2θ = 22563deg d302) and considering

the crystallinity of NH4-Beta zeolite as 100 b manufacture specification c in an extruded form d not applicable as

different sample holder was used

II BET N2 and TEM-EDS analysis

Figure 127 128 and 129 (in the Appendix) show the BET N2 adsorptiondesorption

isotherms of H-Beta 25 wt CuH-Beta and 48 wt CuH-Beta zeolites before and after the

extrusion with γ-Al2O3 and calcination at 550 degC Similar to H-Beta zeolite (see Chapter 512)

the BET N2 adsorptiondesorption isotherms of extruded H-Betaγ-Al2O3 as well as 25 wt

CuH-Beta and 48 wt CuH-Beta catalysts before and after the extrusion with γ-Al2O3

resemble the type IV adsorption isotherm according to the IUPAC classification (Balbuena

231

and Gubbins 1993) featured with H1 hysteresis loops See Chapter 512 for a description of

the type IV adsorption isotherm

The 48 wt CuH-Beta catalyst prepared via SSIE reaction between H-Beta zeolite

and Cu2+ nitrate exhibits ~11 lower BET N2 surface area and micropore volume as compared

to its parent H-Beta zeolite see Table 42 The extrusion of the catalyst with γ-Al2O3 leads to a

further decrease of 16 in its surface area and 34 in the pore volume relative to 48 wt

CuH-Beta The decrease in the BET N2 surface area and micropore volume may possibly be

due to the blockage of the zeolite pores by metal aggregates andor by γ-Al2O3 Similarly H-

Beta and 25 wt CuH-Beta after the extrusion exhibit (i) 29 and 27 respectively lower

surface area and (ii) 42 and 45 respectively lower pore volume

TEM micrographs of extruded H-Betaγ-Al2O3 (MC) 25 wt CuH-Betaγ-Al2O3

(MC) and 48 wt CuH-Betaγ-Al2O3 (MC) are shown in Figure 72 while the results of TEM-

EDS analysis are provided in Table 42

Figure 72 TEM micrographs of (A) H-Betaγ-Al2O3 (MC) (B) 25 wt CuH-Betaγ-Al2O3

(MC) and (C) 48 wt CuH-Betaγ-Al2O3 (MC)

232


Dehydration is one of the most intensively investigated reactions for glycerol The

results of study on hydrothermal dehydration of glycerol with and without a zeolite-based

catalyst carried out in batch reactors are presented in this chapter The details of experimental

procedures are provided in Chapter 45

61 Non catalysed hydrothermal dehydration of glycerol

An experimental study on the hydrothermal decomposition of glycerol without a

catalyst at varying temperature and reaction time was carried out The data obtained was used

as a benchmark to evaluate the activity of various zeolite-based catalysts

A summary of experimental conditions studied and the detected reaction products are

provided in Figure 73 and Table 43 In general the glycerol conversions obtained were rather

low but gradually increased with increasing temperature and reaction time giving a maximum

of ~59 mol at 330 degC 128 bar (saturated vapour pressure) after 300 min Lowering the

temperature from 330 to 300 degC 86 bar resulted in 306 mol conversion and only 53 mol

at 270 degC 55 bar Under identical conditions (ie 300 degC saturated vapour pressure 60 min)

similar glycerol conversion of 49 mol was previously reported by Watanabe et al (2007)

On the other hand at the same temperature of 300 degC a complete conversion of 089 M glycerol

solution was achieved within 40 min when the reactions were performed at 2955 bar

(Qadariyah et al 2011) This may be attributed to the higher pressure applied indicating that

at a given temperature the pressure higher than the saturated vapour pressure increases the

conversion rate

233

0 60 120 180 240 3000

20

40

60

80

100

0 60 120 180 240 3000

10

20

30

40

50

270 C

300 C

330 C

Gly

cero

l co

nv

ersi

on

[m

ol

]

Reaction time [min]

270 C

300 C

330 C

Sel

ecti

vit

y t

o a

ll l

iqu

id p

rod

uct

s [C

-mo

l]

Reaction time [min]

Figure 73 Glycerol conversion and selectivity to all liquid products as a function of reaction time obtained in the hydrothermal dehydration of 01 M glycerol

(03 mmol) at various temperatures under saturated vapour pressure (55-186 bar) The error bars show the standard error of mean (119878119864)

234

Table 43 The summary of experimental conditions studied for the non-catalysed hydrothermal conversion of 01 M glycerol (03 mmol) and the corresponding

compositions of liquid products compared to previously reported data The selectivity and yield are reported on carbon basis in current work while on molar

basis in the literature Note MeOH = methanol AA = acetic acid LA = lactic acid AC = acetaldehyde amp acetaldehyde hydrate EtOH = ethanol

a The numbers plusmn 119878119864 (standard error of mean) b total yield of liquid products (yield is the product of conversion and selectivity) c other products detected were

allyl alcohol and formaldehyde with the selectivity of 2 and 33 respectively

Temp

[degC]

Press

[bar]

Time

[min]

Conversion

[mol]a

Selectivity [C-mol] Total yield

[C-mol]b References

MeOH AA LA AC EtOH acrolein acetol

300 86 60 49 204 ˃100 39 70 Watanabe et al (2007)c

300 2955 60 100 005 0002 Qadariyah et al (2011)

270 55 240 26 plusmn 04 - - 137 183 - - - 08

300 53 plusmn 04 - - 96 127 - - - 11

300 86 60 49 plusmn 20 17 35 104 120 - - - 08

120 143 plusmn 15 25 07 11 158 - 32 - 36

180 206 plusmn 14 19 05 22 123 - 23 08 41

240 229 plusmn 23 18 04 33 165 - 20 07 62

300 306 plusmn 09 14 07 14 149 - 17 06 64

330 128 60 121 plusmn 19 29 08 46 215 - 53 21 45

120 241 plusmn 15 31 05 43 244 10 43 14 94

180 333 plusmn 56 45 08 38 287 11 40 07 145

240 441 plusmn 51 51 07 21 286 16 38 05 187

300 586 plusmn 65 50 06 18 281 22 36 00 241

235

Despite the absence of a catalyst a number of liquid degradation products of glycerol

were identified The presence of acetaldehyde acetol acrolein ethanol methanol is in good

agreement with the findings by Watanabe et al (2007) who reported acrolein as the main

product Qadariyah et al (2011) detected acrolein at the temperature as low as 250 degC 2955

bar with the highest yield of ~02 mol at 300 degC 2955 bar 60 min In current study traces

of acrolein (~05 mol) were observed only at ge 300 degC 120 min with acetaldehyde (referred

to as both acetaldehyde and acetaldehyde hydrate) as the main liquid product albeit at low yield

(~16 mol) due to the low glycerol conversion see Table 43 Traces of lactic acid acetic acid

and formic acid as well as gases including CO2 and H2 were also detected The potential

applications and the market values of some of the products found in the present work are

provided in Table 8 (page 44)

The variety of liquid decomposition products detected indicates a range of

decomposition reactions taking place simultaneously Acetaldehyde the main reaction product

may be formed via homolytic cleavage of 2-hydroxypropanal the intermediate from which

acrolein is formed by dehydration see Figure 74 (Antal et al 1985)

236

Figure 74 The reaction mechanism of glycerol dehydration to 2-hydroxypropanal which may

then convert to (i) acrolein via Pathway I andor (ii) acetaldehyde via Pathway II The

mechanism was adapted from Antal et al (1985) and Haider et al (2015)

The role of water in the hydrothermal conversion of glycerol is not clear According to

Buumlhler et al (2002) and Ott et al (2006) the formation of acrolein in sub-CW (T le 374 degC P

le 221 bar) follows an ionic mechanism Pathway I in Figure 74 which may be promoted by

the higher ionic product of water (Kw) ie the higher concentration of hydronium (H3O+) and

hydroxide (OH-) ions (see Figure 6 page 14) At a given temperature the ionic product of

water increases with increasing pressure (Bandura and Lvov 2005) possibly explaining the

faster acrolein rate of formation observed by Qadariyah et al (2011) as compared to that

237

observed in the present work The formation of lactic acid a base-catalysed conversion product

of glycerol (see Figure 17 page 58 for the proposed mechanism) found as a product at ge 270

degC 240 min (see Table 43) may be promoted by the increased ionic product of water

supporting the role of sub-CW in the ionic mechanism of glycerol conversion On the other

hand Ramirez-Lopez et al (2010) who investigated the alkaline hydrothermal conversion of

glycerol at 250-290 degC 35-70 bar (autogenous pressure) suggested that the sub-CW plays no

role in the base-catalysed conversion of glycerol to lactic acid because

(i) the experimental conditions used were not close to the critical point of water

(374 degC and 2206 bar) and

(ii) according to the experimental results in the work of Kishida et al (2005) almost

no lactic acid was formed during the conversion of 033 M glycerol in the

absence of NaOH at 300 degC autogenous pressure 10-60 min

The degree of glycerol conversion and the nature of other reaction products formed in this non-

catalysed reaction were however not reported by Kishida et al (2005) Ramirez-Lopez et al

(2010) also believe that high temperatures are required in the alkaline hydrothermal conversion

of glycerol to lactic acid to overcome the energetic barrier of some intermediate step(s) and the

corresponding high pressures are only needed to keep the water in its liquid state (Ramirez-

Lopez et al 2010)

238

62 H-ZSM-5 and H-Beta zeolite catalysed hydrothermal

dehydration of glycerol

The effect of H-ZSM-5 and H-Beta zeolite on the conversion of glycerol was

investigated at 270 300 and 330 degC saturated vapour pressure reaction time of 60 120 180

240 and 300 min The experimental procedure used is described in Chapter 451 An additional

set of experiments was performed at 360 degC in the presence of H-Beta zeolite

621 Conversion degree and selectivity to liquid products

Figure 75 shows the effect of temperature on the conversion of glycerol and the

selectivity to liquid products in the presence of H-ZSM-5 and H-Beta zeolite at different

reaction times

The glycerol conversion catalysed by H-ZSM-5 at 270 degC increased with longer

reaction time peaking at 79 mol in 300 min see Figure 75(A) The selectivity to liquid

products maintained at ~18-23 mol at 60-300 min see Figure 75(B) An increase in

temperature increased the glycerol conversion rate ~83 and ~98 mol were obtained within 1

h at 300 and 330 degC respectively The total selectivity to liquid products at 300 and 330 degC

was higher than at 270 degC but only at the reaction time of 60 min after which it tended to

decrease This may be a consequence of further degradation of the primary liquid products into

gases

In the presence of H-Beta zeolite the conversion ranged from 16-99 mol depending

on the operating temperature and reaction time see Figure 75(C) The higher the temperature

the faster the reaction rate at 330 degC the conversion was almost 85 mol within 60 min as

239

compared to only 47 mol conversion at 270 degC in 300 min The increase of temperature from

270 to 300 degC increased the conversion from 47 to 76 mol at 300 min As for the selectivity

to liquid products the effect of temperature generally followed the same trend as that for the

conversion see Figure 75(D) but increasing the temperature from 270 to 300 degC did not result

in a considerable change in selectivity to liquid products despite the considerable difference

in the conversion degrees At 330 degC the selectivity increases with the reaction time but only

up to 180 min after which it tends to decrease An additional set of experiments was carried

out at 360 degC to see whether the selectivity to liquid products can be further increased It was

found that the selectivity to liquid products had a maximum at 330 degC (~34 mol in 180 min)

while at 360 degC (water is in its vapour phase at saturated vapour pressure) it was lower and

tended to decrease with longer reaction time

240

0 60 120 180 240 300

0

20

40

60

80

100

0 60 120 180 240 300

0

10

20

30

40

50

0 60 120 180 240 300

0

20

40

60

80

100

0 60 120 180 240 300

0

10

20

30

40

50

270 oC

300 oC

330 oC

(A) H-ZSM-5

270 oC

300 oC

330 oC

(B) H-ZSM-5

60 120 180 240 300

Temp [degC]

270 4plusmn14 8plusmn25 11plusmn23 11plusmn74 12plusmn33



360 29plusmn22 30plusmn09 29plusmn09 26plusmn24

Reaction time [min]

Total yield [C-mol]

Gly

cerol

con

versi

on

[m

ol

]

270 oC

300 oC

330 oC

360 oC

Gly

cerol

con

versi

on

[m

ol

]

Reaction time [min]

(C) H-Beta

Sele

cti

vit

y t

o a

ll l

iqu

id p

rod

ucts

[C

-mol

]

270 oC

300 oC

330 oC

360 o

C

Sele

cti

vit

y t

o a

ll l

iqu

id p

rod

ucts

[C

-mol

]

Reaction time [min]

(D) H-Beta

60 120 180 240 300

Temp [degC]




Reaction time [min]

Total yield [C-mol]

Figure 75 Glycerol conversion yield and selectivity to all liquid products as a function of reaction time at various temperatures in the presence of H-ZSM-5

(A B) and H-Beta zeolite (C D) Conditions 01 M glycerol (03 mmol) 55-186 bar glycerolcatalyst weight ratio = 1 the mole ratio of glycerol to acid sites

of H-Beta zeolite = 451 while that for H-ZSM-5 = 401 The error bars show standard error of mean (119878119864) The numbers plusmn 119878119864

241

It was concluded that the addition of H-zeolites increased the glycerol conversion

independently of the reaction temperatures and times Additionally the conversion rate of

glycerol was found to be higher on H-ZSM-5 than on H-Beta zeolite possibly due to the higher

concentration of Broslashnsted acid sites of the former 269 micromolmiddotg-1 for H-ZSM-5 as compared to

~236 micromolmiddotg-1 for H-Beta zeolite see Table 29 page 167 for the TPD-NH3 analysis results

The H-ZSM-5 exhibits higher activity than H-Beta zeolite despite having smaller average pore

size The possible explanations as suggested by our later findings in Chapter 64 (page 263)

are

i A significant portion of the zeolite catalysts ie 1-18 wt Al and 17 wt Si for

H-Beta zeolite 06-23 wt Al and 14-16 wt Si for H-ZSM-5 dissolves in HLW

under the conditions studied with the dissolved Al and Si aqueous species acting as

homogeneous catalysts see Figure 76 for the ICP analysis results of the reaction

solution

ii The framework structures of H-ZSM-5 and H-Beta zeolite collapse under

hydrothermal conditions reducing the role of pores in the conversion of glycerol in

the present work The XRD data obtained in the present work see Figure 77 and

other works (Lutz et al 2005) are in agreement with this speculation

The destruction of the BEA framework of H-Beta zeolite in HLW was previously reported to

be clearly visible at 130 degC and at 240 degC more than half of its structure collapsed (Lutz et al

2005) In contrast the ZSM-5 was stable for up to 72 h under identical conditions The high

degree of dissolution and structural damage showed by both H-zeolites under the conditions

studied (270-330 degC autogenous pressure) are not a surprise The hydrothermal stability of

zeolites is discussed in Chapter 64

242

0

1

2

3

4

5

6

7

8

0

450

500

550

600

650

0

1

2

3

0

13

14

15

16

17

18

H-Beta

H-ZSM-5

Time [h]

Con

cen

trati

on

of

Al

[pp

m]

Time [h]

0 008 017 025 05 075 1

H-Beta

H-ZSM-5

Con

cen

trati

on

of

Si

[pp

m]

0 008 017 025 05 075 10 008 017 025 05 075 1

H-Beta

H-ZSM-5

Time [h]

Am

ou

nt

of

Al

[wt

]

Time [h]

0 008 017 025 05 075 1

H-Beta

H-ZSM-5

Am

ou

nt

of

Si

[wt

]

Figure 76 The aqueous Al and Si concentrations of the mother liquor recovered from the dehydration of glycerol catalysed by H-Beta zeolite and

H-ZSM-5 at different reaction times The numbers presented are average from at least two experiments The error is in the range of 5-15

Reaction conditions 3 ml of 01 M glycerol (03 mmol) aqueous solution weight ratio of glycerol to zeolite = 1

243

10 20 30 40 50 60 70

0

1000

2000

3000

Inte

nsi

ty [

Co

un

ts]

2 [degree]

H-Beta zeolite

H-Beta zeolite after reaction at 330 C 60 min


H-Beta zeolite after reaction at 150 C 24 h

Figure 77 Powder XRD spectra of H-Beta zeolite kept in water at 150 degC for 24 h and at 330

deg C saturated vapour pressure for 5 min and 60 min

The catalytic activity of H-ZSM-5 and H-Beta zeolite arises mainly from their Broslashnsted

acidity as evidenced by the lower conversion degree on the H-Beta zeolite after removing Al

atoms the source of protons from its framework Figure 78 shows the results obtained on the

hydrothermal dehydration of glycerol catalysed by dealuminated Beta zeolite (deAl-BetaII4h)

ie H-Beta zeolite after removing Al atoms with either no or only a small number of acid sites

See Chapter 443 and 532 for the preparation and characterisation of deAl-BetaII4h

respectively Despite providing lower glycerol conversion as compared to the unmodified H-

Beta zeolite see Figure 78 vs Figure 75(C) and (D) deAl-BetaII4h provided almost the same

total yield of liquid products This result suggests that the catalyst acidity positively influences

244

the catalytic activity but the high concentration of Broslashnsted acid sites resulted in rapid

degradation of liquid reaction products of glycerol and thus high selectivity towards gaseous

products

245

0 60 120 180 240 300

0

20

40

60

80

100

0 60 120 180 240 300

0

20

40

60

80

100

Gly

cero

l con

ver

sion

[m

ol

]

270 oC

300 oC

330 oC

Reaction time [min]

Sel

ecti

vit

y t

o a

ll l

iqu

id p

rod

uct

s [C

-mol

]

270 oC

300 oC

330 oC

Reaction time [min]

60 120 180 240 300

Temp [degC]

270 7 10 13 14 22

300 10 14 17 19 19

330 7 20 24 28 26

Reaction time [min]

Total yield [C-mol]

Figure 78 Glycerol conversion (top) and selectivity to and yield of all liquid products (bottom)

as a function of reaction time at various temperatures in the presence of dealuminated Beta

zeolite (deAlBetaII4h SiO2Al2O3 = 1376) prepared by leaching of 1 g of H-Beta zeolite in 20

ml of 13 M HNO3 at 100 degC for 20 h Conditions of glycerol dehydration 01 M glycerol (03

mmol) 55-186 bar glycerolzeolite weight ratio = 1 The data presented is from a single

experiment

246

622 Composition of liquid products

The use of protonic-zeolites ie H-ZSM-5 and H-Beta zeolite in the hydrothermal

conversion of glycerol had a positive effect on glycerol conversion degree rate and selectivity

to liquid products (see Figure 79) The highest selectivity towards acrolein was found to be

within the first 5 min at 330 degC ie ~38 mol on H-Beta zeolite and ~27 mol on H-ZSM-5

after which it decreased at a faster rate for H-ZSM-5 than H-Beta zeolite suggesting that the

selectivity to acrolein could be higher at the reaction time le 5 min At the same time the

selectivity towards acetaldehyde which represents both acetaldehyde and its hydrate form

gradually increased with longer reaction time reaching its maximum of ~20 mol in 10 min

for H-ZSM-5 and ~26 mol in 30 min for H-Beta zeolite The high selectivity towards acrolein

obtained at short reaction time such as 5 min was mainly because of the selective catalytic

activity of the protonic zeolites on the dehydration of glycerol while an increase in the

selectivity to acetaldehyde at longer reaction time possibly due to higher conversion of

glycerol

247

0

25

50

75

1000

25

50

75

100

gases amp char

acetol

acrolein

EtOH

acetaldehyde

lactic acid

acetic acid

MeOH

(A) H-Beta

Reaction Time [min]

(B) H-ZSM-5

0 5 10 15 30 45 60

Conversion

Co

nv

ersi

on

[m

ol

] o

r S

elec

tiv

ity

[C

-mo

l]

Figure 79 Glycerol conversion and selectivity to all liquid products at 330 degC in the presence

of (A) H-Beta zeolite and (B) H-ZSM-5 Conditions 01 M glycerol (03 mmol) 12970 bar

glycerolzeolite weight ratio = 1 the mole ratio of glycerol to acid sites of H-Beta zeolite =

451 while that for H-ZSM-5 = 401 The error bars show the standard error of mean (119878119864)

Akizuki et al (2013) proposed that the hydrothermal conversion of glycerol (400 degC

250-410 bar) in the presence of solid acidic WO3TiO2 occurs through three main reactions as

248

shown in Figure 80 C-C bond cleavage dehydration and dehydrogenation The dehydration

yields (i) acrolein and (ii) acetol subsequently converting to lactic acid in the presence of TiO2

at 400 degC 330 bar Lactic acid may also be formed directly from glycerol through

dehydrogenation catalysed by metal oxide catalysts In the present work traces of lactic acid

were detected in both non-catalysed and H-zeolite-catalysed reactions despite the absence of

metal oxides The reaction route from glycerol to lactic acid is unclear Nonetheless in the case

of zeolite-catalysed reaction lactic acid may form through the dehydrogenation catalysed by

Al(OH)3 generated by the dissolution of the zeolites see Figure 20 and 21 (page 72) for a

schematic diagram of stepwise decomposition of zeolites Lewis acidic Al(OH)3 and other

forms of extra framework aluminium (EFAl) such as Al(OH)2+ Al(OH)2+ AlO(OH) and

Al2O3 were previously reported to exhibit good activity in the formation of lactic acid and

alkyl lactate from trioses such as dihydroxyacetone and pyruvaldehyde (Taarning et al 2009

West et al 2010) Lactic acid formed under the conditions studied was hydrothermally

unstable as it was not detected after 45 and 15 min on H-Beta zeolite and H-ZSM-5

respectively

249

Figure 80 The main reaction pathways of glycerol reaction under hydrothermal conditions in

the presence of solid acidic catalysts (Katryniok et al 2011 Akizuki and Oshima 2012) The

compounds detected in this work are highlighted in red

623 Reaction kinetic analysis

The kinetic analysis of hydrothermal glycerol conversion was conducted using the

methodology adopted by Qadariyah et al (2011) The data collected on the non-catalysed H-

ZSM-5 H-Beta and deAlBetaII4h catalysed reactions at 270-330 degC saturated vapour

pressure 60-300 min were used to determine the kinetics of the process see Table 57-60 in the

Appendix for the summary of the data used The kinetic analysis of glycerol conversion

250

reactions is complicated by the presence of by-products however the reactions may be

simplified and expressed as follows

119892119897119910119888119890119903119900119897 1198961rarr 119886119888119890119905119886119897119889119890ℎ119910119889119890 Equation 23

119886119888119890119905119886119897119889119890ℎ119910119889119890 1198962rarr 119901119903119900119889119906119888119905119904 Equation 24

119892119897119910119888119890119903119900119897 1198963rarr 119901119903119900119889119906119888119905119904 Equation 25

The reaction of glycerol to acetaldehyde is described by Equation 23 The further

degradation of acetaldehyde to other products as indicated by the experimental data collected

in current work is described by Equation 24 Equation 25 describes the glycerol reacting via

an alternative reaction pathway to produce other liquid products

The distribution of liquid conversion products of glycerol varies depending on the

reaction conditions For instance in the H-zeolite catalysed reactions acrolein was the main

product at short reaction times up to 5 or 10 min while acetaldehyde was the main product at

longer reaction time see Chapter 622 Due to the low glycerol conversion at short reaction

time in the non-catalysed- and deAl-BetaII4h-catalysed reactions only the data collected at 60-

300 min ie the conditions under which acetaldehyde was the main product were used in

kinetic analysis

The data collected in current work indicate that the order of reaction with respect to

the rate of glycerol consumption and acetaldehyde formation is of first order examples of the

reaction order determination and the raw data used for the analysis are provided respectively

in Figure 131 and Table 60 in the Appendix The equations 23 24 and 25 may then be expressed

as follows

251

119889[119892119897119910119888119890119903119900119897]

119889119905= minus(1198961 + 1198963)[119892119897119910119888119890119903119900119897] Equation 26

119889[119886119888119890119905119886119897119889119890ℎ119910119889119890]

119889119905= 1198961[119892119897119910119888119890119903119900119897] minus 1198962[119886119888119890119905119886119897119889119890ℎ119910119889119890] Equation 27

Berkeley Madonna Software was used to determine the reaction rate constants k1 k2

and k3 using the experimental data on glycerol and acetaldehyde concentrations see Table 60

The best curve fit for the data was obtained simultaneously solving the differential equations

for the glycerol consumption and acetaldehyde formation An example result calculated at 300

degC for the H-Beta zeolite catalysed system is shown in Figure 81

0 3600 7200 10800 14400 18000

000

002

004

006

008

010

012

Con

cen

trati

on

[M

]

Time [s]

glycerol_H-Beta_300 C

acetaldehyde_H-Beta_300 C

curve fit_glycerol

curve fit_acetaldehyde

k1 = 27787e

-5

k2 = 171056e

-6

k3 = 781408e

-5

Initial [glycerol] = 01126 M

Figure 81 The concentration of glycerol (G) and acetaldehyde (AC) as a function of time at 300 degC

saturated vapour pressure (128 bar) using H-Beta catalyst at the glycerol to catalyst weight ratio of 1

The reaction rate constants (k1 k2 and k3) were calculated using Berkeley Madonna software Square

circle data points = experimentally determined concentrations of G and AC lines = the best fit curves

252

The reaction rate constants found for the reactions at different temperatures for each

catalysts investigated ie no catalyst H-ZSM-5 H-Beta zeolite and deAlBetaII4h are

summarised in Table 44

Table 44 Reaction rate constants of equations 23 24 and 25 at different temperatures for

different catalysts Reaction conditions 01 M glycerol (03 mmol) glycerol to catalyst mass

ratio = 1 saturated vapour pressure 60-300 min

Catalyst Temperature 119948120783 [119956minus120783] 119948120784 [119956minus120783] 119948120785 [119956minus120783]

No catalyst 270degC 396E-7 753E-11 152E-6

300degC 462E-5 273E-4 247E-5

330degC 174E-5 488E-13 257E-5

H-Beta Zeolite 270degC 880E-6 375E-10 306E-5

300degC 278E-5 171E-6 780E-5

330degC 141E-4 266E-12 297E-4

360degC 319E-4 360E-6 574E-4

H-ZSM-5 270degC 174E-5 161E-6 101E-4

300degC 108E-4 766E-6 362E-4

330degC 309E-4 376E-5 807E-4

deAlBetaII4h 270degC 271E-5 373E-5 190E-5

300degC 155E-5 287E-11 282E-5

330degC 432E-5 300E-5 427e-5

dealuminated Beta zeolite prepared by leaching of 2 g of H-Beta zeolite in 20 ml of 13 M

HNO3 at 100 degC for 4 h Raw data used for the analysis is provided in Table 60 in the Appendix

The non-catalysed reactions provided high selectivities to acetaldehyde see Table 43

(page 234) possibly because the reaction rate constant k2 (acetaldehyde degradation) was very

small in comparison to k1 (glycerol to acetaldehyde) at 330 ordmC see Table 44 The reaction rate

253

constants of the zeolite catalysed reactions are higher than those of non-catalysed reactions and

decrease in the following order H-ZSM-5 gt H-Beta gt deAlBetaII4h gt no catalyst

The higher reaction rate constants obtained in the catalysed reactions are likely to be

related to the Broslashnsted acidity of the zeolite catalysts The concentration of the Broslashnsted acid

sites of H-ZSM-5 and H-Beta zeolite are 269 and 236 micromolmiddotg-1 respectively while that of

deAlBetaII4h is very close to zero see Table 29 (page 167) for the summary of the density of

Broslashnsted acid sites of H-zeolites determined by TPD-NH3 analysis and see Figure 55 (page

195) for that of deAlBetaII4h zeolite

The conversion of glycerol using H-Beta zeolites at 330 degC was selected for further

experiments as the reaction rate constant k1 (glycerol to acetaldehyde) is high whereas the k2

(conversion of acetaldehyde to other products) is significantly lower However the reaction

rate constant k3 (glycerol to other liquid products) is also high reducing the selectivity towards

acetaldehyde A shorter reaction time ie 5-60 min was therefore used to maximise the

acetaldehyde yield see Figure 79 (page 247)

The reaction rate constants give an indication of how fast a reaction is proceeding On

the other hand to compare the ease at which the glycerol to acetaldehyde reaction takes place

for different catalysts the activation energies required were determined using the Arrhenius

equation see Equation 28

119896 = 119860119890minus119864119886119877119879 Equation 28

where k is the reaction rate constant in s-1 A is the pre-exponential factor in s-1 Ea is

the activation energy in Jmol-1 R is the gas constant in Jmol-1K-1 and T is the reaction

temperature in K

254

In order to find Ea and A the Arrhenius rate expression shown in Equation 28 was

linearized as shown in Equation 29 and a graph of ln k vs 1T was plotted The gradient of the

graph may be used to find Ea of the glycerol to acetaldehyde reaction and the intercept of the

graph may be used to find A The summary of Ea and A for different catalysts is presented in

Table 45

ln 119896 = ln 119860 minus119864119886

119877(

1

119879) Equation 29

Figure 82 ln k vs 1T for the non-catalysed and H-ZSM-5 H-Beta zeolites and deAl-BetaII4h

catalysed reactions Only k1 (reaction rate constants of glycerol to acetaldehyde reaction) was

analysed

y = -15767x + 18168

Rsup2 = 09847

y = -2393x - 6364

Rsup2 = 01825

y = -17817x + 20981

Rsup2 = 09314

y = -26229x + 33953

Rsup2 = 09138

-15

-14

-13

-12

-11

-10

-9

-8160E-03 165E-03 170E-03 175E-03 180E-03 185E-03 190E-03

ln k

1T [K-1]

H-ZSM-5 deAl-BetaII4h H-Beta zeolite No Catalyst

Linear (H-ZSM-5) Linear (deAl-BetaII4h) Linear (H-Beta zeolite) Linear (No Catalyst)

255

Table 45 Summary of reaction activation energies (Ea) and the pre-exponential factors (A) for

different catalysts in the glycerol to aldehyde reaction (k1) see Equation 23

Catalyst Ea [kJmol-1] A [s-1]

No Catalyst 218 56E+14

H-Beta Zeolite 148 13E+09

H-ZSM-5 131 78E+07

deAl-BetaII4h 20 17E-03

The activation energy is the minimum energy which must be available to result in a

chemical reaction while the A factor indicates the frequency of effective molecular collisions

(Brucat 2013) The activation energy of the non-catalysed glycerol to acetaldehyde reaction at

55-186 bar determined in this work is 218 kJmol-1 see Table 45 The H-Beta zeolite and H-

ZSM-5 catalysed reactions required 32 and 40 lower activation energy as compared to non-

catalysed reactions The A factors in the first two systems are higher indicating a higher number

of effective molecular collisions The combination of lower activation energy and higher

frequency of effective molecular collisions explains as to why the H-Beta zeolite and H-ZSM-

5 provided higher glycerol conversions

The use of the deAl-BetaII4h as a catalyst lowered the activation energy by 91

indicating that the reaction proceed more rapidly than a non-catalysed and H-zeolites catalysed

reactions However deAl-BetaII4h provided low conversions likely due to the absence of the

Broslashnsted acid sites on the catalyst resulting in the low pre-exponential factor as compared to

the H-Beta zeolite and H-ZSM-5 catalysed reactions and the low reaction rate In other words

a low activation energy is advantageous as the reaction may proceed with ease but there must

be available active sites on a catalyst for a reaction to occur

256

63 Effect of lanthanide and transition metal doping

The presence of Broslashnsted acid sites on H-ZSM-5 and H-Beta zeolites was shown to

promote the conversion of glycerol in this work but also a degradation of primary liquid

products To examine whether Lewis acidic zeolites could be used to increase the selectivity to

liquid products of the hydrothermal conversion of glycerol the NH4-ZSM-5 H-ZSM-5 NH4-

Beta zeolite and H-Beta zeolite were doped with metal ions and used as catalysts at 330 degC

autogenous pressure and reaction time of 1 h The metal ions investigated were Ce3+ La3+ Sn2+

and Zn2+ The procedure used to prepare the meta-doped zeolites also referred to as metal-

exchanged zeolites is described in Chapter 442 The chemical characterisation of all the

catalysts used in this section is provided in Chapter 51-54

Figure 83 and Table 46 compare the results of the hydrothermal conversion of glycerol

in the presence of non-doped ie NH4-Beta zeolite H-Beta zeolite NH4-ZSM-5 and H-ZSM-

5 and metal-doped zeolites (Mzeolites) The hydrothermal conversion of glycerol catalysed

by metal-doped zeolite catalysts resulted in varying degrees of conversion and selectivity to its

liquid degradation products Generally Mzeolites provided lower conversion but higher

selectivity to liquid products as compared to the corresponding H-zeolites highly likely due

to the lower densities of their Broslashnsted acid sites see Figure 83 (right Y axis) and Table 32

(page 182) for the NH3-TPD analysis of the catalysts It was found that the conversion of

glycerol has a clear relation to the density of Broslashnsted acid sites which decreases in the

following order H-zeolites gt Mzeolites gt NH4-zeolites However the activities of the

catalysts did not show a clear trend between MNH4-zeolites and MH-zeolites as not all

catalysts in the former group exhibited higher activities despite their higher density of Broslashnsted

acid sites Thus a possible factor contributing to the overall activity of the catalysts might be

not only the Broslashnsted acidity of zeolites but also the metal ions

257

In general MNH4-Beta zeolites display higher conversion than MH-Beta zeolites but

only 48 wt CeNH4-Beta and 48 wt LaNH4-Beta zeolites yields were competitive to that

of H-Beta zeolite ie ~28-29 mol while other catalysts provided lower yields ~20-25 mol

see Table 46 and Figure 84 As compared to MBeta zeolite catalysts MZSM-5 catalysts

generally provide higher glycerol conversion and hence higher yield of liquid products despite

lower selectivity The MNH4-ZSM-5 or MH-ZSM-5 catalysed hydrothermolysis of glycerol

led to similar or slightly higher yields (26-33 mol) relative to their parent zeolites 48 wt

ZnNH4-ZSM-5 and 48 wt LaH-ZSM-5 display the highest liquid yields of ~33 mol see

Table 46 and Figure 85

258

No

cata

lyst

NH

4-Bet

a

H-B

eta

48

Ce

NH

4-Bet

a

48

La

NH

4-Bet

a

48

SnN

H4-

Bet

a

48

ZnN

H4-

Bet

a

48

Ce

H-B

eta

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

NH

4-ZSM

-5

H-Z

SM-5

48

Ce

NH

4-ZSM

-5

48

La

NH

4-ZSM

-5

48

SnN

H4-

ZSM

-5

48

ZnN

H4-

ZSM

-5

48

Ce

H-Z

SM-5

48

La

H-Z

SM-5

48

SnH

-ZSM

-5

48

ZnH

-ZSM

-5

0

25

50

75

100

[]

Conversion [mol]

Total selectivity to liquid products [C-mol]

Total yield of liquid products [C-mol]

0

50

100

150

200

250

300

amount of desorbed NH3 [molg-1

]

Am

ou

nt

of

des

orb

ed N

H3 [

mo

lg

-1]

Figure 83 The conversion degree selectivity and total yield of liquid products obtained in the hydrothermal dehydration of 01 M glycerol (03

mmol) catalysed by various zeolite-based catalysts at 330 degC 128 bar ( saturated vapour pressure) 1 h glycerolcatalyst weight ratio = 1 The

percentages reported are in wt indicating the metal content relative to zeolite Amount of desorbed NH3 on the corresponding catalysts is

presented in the right Y axis The error bar indicates standard error of mean (119878119864)

259

Table 46 A summary of hydrothermal transformation of 01 M glycerol (03 mmol) at 330 degC 128 bar (autogenic pressure) reaction time of 1 h

glycerolcatalyst weight ratio = 1 The percentages reported are in wt indicating the metal content relative to zeolite

Catalyst Conversion

[mol]

Selectivity to liquid products [C-mol] Total Sa

[C-mol]

Total Yb

[C-mol] MeOH AA LA MeCHO EtOH acrolein acetol

NH4-Beta 345 plusmn 28 24 07 39 346 07 33 11 468 161

H-Beta 839 plusmn 24 14 06 04 246 12 44 09 335 plusmn 28 282 plusmn 32

48 CeNH4-Beta 628 plusmn 18 23 plusmn 01 06 plusmn 01 32 plusmn 14 298 plusmn 04 13 plusmn 02 77 plusmn 05 07 plusmn 02 455 plusmn 17 286 plusmn 12

48 LaNH4-Beta 560 plusmn 15 29 09 17 356 14 81 14 519 291

48 SnNH4-Beta 552 plusmn 06 21 05 38 290 09 82 07 451 249

48 ZnNH4-Beta 481 plusmn 02 22 05 59 244 08 83 12 433 208

48 CeH-Beta 591 plusmn 32 16 plusmn 01 08 plusmn 00 24 plusmn 01 232 plusmn 02 08 plusmn 00 56 plusmn 03 06 plusmn 00 350 plusmn 05 207 plusmn 04

48 LaH-Beta 556 plusmn 16 21 plusmn 00 05 plusmn 01 26 plusmn 01 262 plusmn 12 08 plusmn 00 72 plusmn 02 06 plusmn 00 400 plusmn 14 223 plusmn 12

48 SnH-Beta 737 plusmn 36 10 06 19 222 08 42 10 318 235

48 ZnH-Beta 556 plusmn 35 23 04 29 253 08 76 06 400 222

NH4-ZSM-5 583 plusmn 45 17 08 12 281 12 36 09 375 219

H-ZSM-5 980 plusmn 096 10 30 00 192 14 15 06 268 262

48 CeNH4-ZSM-5 938 plusmn 348 11 20 06 200 08 22 03 271 254

48 LaNH4-ZSM-5 836 plusmn 49 13 12 08 224 13 38 08 316 264

48 SnNH4-ZSM-5 832 plusmn 10 11 33 00 217 11 41 09 323 269

48 ZnNH4-ZSM-5 748 plusmn 47 20 07 13 302 10 76 10 439 328

48 CeH-ZSM-5 927 plusmn 42 12 23 11 206 11 23 05 289 268

48 LaH-ZSM-5 986 plusmn 081 12 29 11 229 09 34 04 328 324

48 SnH-ZSM-5 927 plusmn 34 10 plusmn 00 34 plusmn 01 00 plusmn 00 207 plusmn 06 12 plusmn 01 32 plusmn 11 07 plusmn 01 301 plusmn 18 278 plusmn 10

48 ZnH-ZSM-5 811 plusmn 28 16 plusmn 01 10 plusmn 01 08 plusmn 03 257 plusmn 07 13 plusmn 01 58 plusmn 06 04 plusmn 00 366 plusmn 16 296 plusmn 08

Note MeOH = methanol AA = acetic acid LA = lactic acid MeCHO = acetaldehyde amp acetaldehyde hydrate EtOH = ethanol a Total selectivity

to liquid products b total yield of liquid products The numbers plusmn 119878119864

260

NH

4-Bet

a

H-B

eta

48

Ce

NH

4-Bet

a

48

La

NH

4-Bet

a

48

SnN

H4-

Bet

a

48

ZnN

H4-

Bet

a

48

Ce

H-B

eta

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

0

25

50

75

100Y= 222 Y= 235 Y= 208

Co

nv

ersi

on

[m

ol

]Y= 223 Y= 207 Y= 291 Y= 286 Y= 282 Y= 161

Y= 249 Conversion

MeOH

acetic acid

lactic acid

acetaldehyde

EtOH

acrolein

0

10

20

30

40

Sel

ecti

vit

y [

C-m

ol

]

Figure 84 The results of the hydrothermal dehydration of 01 M glycerol (03 mmol) using NH4- Beta H-Beta 48 wt MH-Beta and 48 wt

MNH4-Beta zeolites where Mzeolite = metal exchanged zeolite Reaction conditions 330 degC 128 bar (saturated vapour pressure) 1 h

glycerolcatalyst weight ratio = 1 Note The error bar indicates 119878119864 Y = yield of liquid products [C-mol]

261

NH

4-ZSM

-5

H-Z

SM-5

48

Ce

NH

4-ZSM

-5

48

La

NH

4-ZSM

-5

48

SnN

H4-

ZSM

-5

48

ZnN

H4-

ZSM

-5

48

Ce

H-Z

SM-5

48

La

H-Z

SM-5

48

SnH

-ZSM

-5

48

ZnH

-ZSM

-5

0

25

50

75

100

Y = 296 Y = 278 Y = 324 Y = 268 Y = 328 Y = 269 Y = 264 Y = 254 Y = 262 C

on

ver

sio

n [

mo

l]

or

sele

ctiv

ity

[C

-mo

l] ConversionY = 219

0

10

20

30

40

MeOH

acetic acid

lactic acid

acetaldehyde

EtOH

acrolein

Sel

ecti

vit

y [

C-m

ol

]

Figure 85 The results of the hydrothermal dehydration of 01 M glycerol (03 mmol) using NH4- ZSM-5 H-ZSM-5 48 wt MH-ZSM-5 and

48 wt MNH4-ZSM-5 where Mzeolite = metal exchanged zeolite Reaction conditions 330 degC 128 bar (saturated vapour pressure) 1 h


262

The liquid products detected in the hydrothermal dehydration of glycerol catalysed by

Mzeolites included methanol acetic acid lactic acid acetaldehyde ethanol and acrolein

Acetaldehyde was the major products on all catalysts see Table 46 Figure 84 and 85 It should

be noted that acrolein was the main product in H-Beta zeolite and H-ZSM-5 catalysed system

under identical conditions but at shorter reaction times see Chapter 622

The Lewis acidic metal-exchanged zeolites (Mzeolites) prepared by SSIE were used

in the hydrothermal conversion of glycerol at 330 degC saturated vapour pressure 1 h

Hydrothermolysis is an acid-catalysed reaction hence the lower densities of Broslashnsted acid site

on the Mzeolites resulted in lower conversion However the Mzeolites increased the

selectivity to liquid products possibly by forming complexes with glycerol or its reaction

products retarding their transformationdecomposition Glycerol is known to readily form a

five-membered ring complex with metals (Chaminand et al 2004 Liu et al 2013) The

activities of the Mzeolites vary with different metals Among the metal ions investigated La3+

and Zn2+ were found to be the least active in terms of glycerol conversion degree but

advantageously they provided the highest yield of liquid products MdeAl-Beta zeolite did

not show better activity than Mzeolites (data not presented)

263

64 Hydrothermal stability of H-Beta zeolite

641 Dissolution of H-Beta zeolite

Several research studies showed that zeolites have low stability in HLW (Ravenelle et

al 2010 Ennaert et al 2014 Kruger et al 2014 Zhang et al 2015) see Chapter 232 for a

complete literature survey In the present work the stability of H-Beta zeolite in water as a

function of time at 20 150 200 and 250 degC autogenic pressure was evaluated by XRD

analysis The aqueous Si and Al concentrations of mother liqueurs were analysed by ICP-OES

The experimental protocol is described in Chapter 452

Figure 86 87 and 88 show the XRD spectra of H-Beta zeolite kept in water at 150 200

and 250 degC respectively for various times Table 47 summarises the XRD relative crystallinity

of H-Beta zeolite before and after the treatment

264

10 20 30 40 50 60 70

0

1500

3000

5 6 7 8 9 16 18 20 22 240

1500

3000 H-Beta zeolite

150 C 1 h

150 C 20 h

Inte

nsi

ty [

cou

nts

]

2 [degree]

Figure 86 Powder XRD spectra of H-Beta zeolite kept in water at 150 degC (saturated vapour

pressure) for 1 h and 20 h

10 20 30 40 50 60 70

0

1500

3000

5 6 7 8 9 16 18 20 22 240

1500

3000

Inte

nsi

ty [

cou

nts

]

2 [degree]

H-Beta zeolite

200 C 1 h

200 C 3 h

200 C 5 h

200 C 20 h

Figure 87 Powder XRD spectra of H-Beta zeolite kept in water at 200 degC saturated vapour

pressure for 1 3 5 and 20 h

265

10 20 30 40 50 60 70

0

1500

3000

5 6 7 8 9 16 18 20 22 240

1500

3000 H-Beta zeolite

250 C 1 h

250 C 20 h

Inte

nsi

ty [

co

un

ts]

2 [degree]


pressure for 1 and 20 h

Table 47 The relative crystallinity of H-Beta zeolite in water at different temperatures as a

function of time saturated vapour pressure Conditions 30 mg H-Beta zeolite in 3 ml of DI

water The relative crystallinities are based on the main diffraction 2θ=225deg (d302) The data

presented is an average of triple experiments

Temperature

[degC]

Time

[h]

XRD relative

crystallinity

20 0 100 plusmn 00

150 1 132 plusmn 38

20 105 plusmn 22

200 1 110 plusmn 39

3 108 plusmn 61

5 100 plusmn 53

20 76 plusmn 17

250 1 74 plusmn 45

20 40 plusmn 72

266

The XRD patterns of fresh H-Beta zeolite and the H-Beta zeolite held at 150 degC for 1 h

and 20 h show the characteristic peaks of the BEA structure of Beta zeolite with no significant

changes except for an increase in the intensity of the diffraction peaks ie an increase in the

crystallinity by 32 and 5 respectively An increase in the crystallinity of the treated

samples may possibly be due to the removal of an amorphous phase present in the untreated

sample andor a reduced distortion of the zeolite framework (Ravenelle et al 2010) The

differences in relative crystallinities of the zeolite with time may be explained by the

dissolution At 200 degC the intensity of XRD spectra of H-Beta zeolite decreased significantly

(24) after 20 h several peaks are no longer detected indicating significant changes took place

in the BEA structure These changes likely to be related to the structural degradation of the

zeolite are clearly observed at 250 degC after only 1 h Similarly at 330 degC the BEA structure of

Beta zeolite as indicated by its XRD patterns in Figure 77 (page 243) collapsed and

transformed into an X-ray amorphous solid within 5 min The transformation is known to be

accompanied by collapsing of the micropore structure resulting in an increase in mesoporous

volume (Ravenelle et al 2010 Ennaert et al 2014 Zhang et al 2015)

Figure 89 shows the amount of dissolved Si and Al in the mother liquor recovered after

cooling of the following two systems previously kept at several temperatures for different

times

(i) H-Beta zeolite - water at 20 150 200 and 250 degC and

(ii) H-Beta zeolite (or H-ZSM-5) - water - glycerol at 330 degC

The data collected indicate that the extent of H-Beta zeolite dissolution in water increased with

time and temperature The dissolution was low at 20 degC only about 02 wt and 03 wt of

total Al and Si dissolved after 20 h respectively The highest extent of dissolution ie 3 wt

267

Al and 13 wt Si was detected at 250 degC after 20 h when the crystal structure of H-Beta zeolite

was significantly affected by the temperature see Figure 88

High amount of dissolved Al (18 wt) and Si (17 wt) were detected within the first

5 min at 330 degC in the H-Beta zeolite ndash glycerol ndash water system but the amount of dissolved Al

decreased with increasing reaction time possibly due to precipitation Lower quantities of Al

(~13-54 ppm or ~06-23 wt) and Si (~499-570 ppm or 14-16 wt) were detected in the H-

ZSM-5 - glycerol - water system at 330 degC Increasing the temperature to 360 degC did not result

in a significant increase in dissolved Al or Si ie ~034-114 wt Al and ~14 wt Si The

tabulated data is shown in Table 61 in the Appendix The dissolution of H-Beta zeolite was

higher than H-ZSM-5 possibly due to the higher density of its Si-OH terminated defects (Zhang

et al 2015) However it should be noted that the aqueous concentration of Si and Al is likely

to be significantly higher at the operating temperature as the solubility of SiO2 in water at RT

is generally low but gradually increases with temperature and pressure up to the neighbourhood

of the critical temperature of water where the solubility changes significantly at relatively low

pressures with increasing temperature the solubility is very low Brunner (2009) see Figure

91 (page 272) for the solubility of SiO2 in water at different temperatures and pressures

268

0

1

2

3

4

5

6

7

8

0

100

200

300

400

500

600

0

1

2

3

0

5

10

15

0 008 017 025 05 075 1 3 5 20 48

0 008 017 025 05 075 1 3 5 20 48

20 C

150 C

200 C

250 C

330 C

330 C_H-ZSM-5

Time [h]

Co

nce

ntr

ati

on

of

Al

[pp

m]

Time [h]

0 008 017 025 05 075 1 3 5 20 48

20 C

150 C

200 C

250 C

330 C

330 C_H-ZSM-5

Co

nce

ntr

ati

on

of

Si

[pp

m]

20 C

150 C

200 C

250 C

330 C

330 C_ H-ZSM-5

Time [h]

Am

ou

nt

of

Al

[wt

]

Time [h]

0 008 017 025 05 075 1 3 5 20 48

20 C

150 C

200 C

250 C

330 C

330 C_ H-ZSM-5

Am

ou

nt

of

Si

[wt

]

Figure 89 The ICP-OES analysis of aqueous Al and Si concentrations of mother solutions recovered from various hydrothermal systems containing H-Beta

zeolite (and H-ZSM-5 where specified) Experimental conditions 20 150 200 and 250 degC 30 mg H-Beta zeolite in 3 ml DI water at 330 degC 3 ml of 01 M

glycerol (03 mmol) aqueous solution weight ratio of glycerol to zeolite = 1 All experiments were performed under saturated vapour pressure The error bars

show standard error of mean (119878119864)

269

642 Effect of dissolved Si and Al on the dehydration of glycerol

The aqueous Al and Si species originating from dissolved H-Beta zeolite have been

reported to adversely affect the selectivity to the desired product of aqueous phase dehydration

of fructose ie 5-hydroxymethyl furfural (HMF) at 130 degC (Kruger et al 2013 Kruger et al

2014) To evaluate the effect of aqueous Al and Si species on the hydrothermal dehydration of

glycerol in this work a two-step experiment described in Chapter 453 was carried out

In the first step zeolite filtrates containing dissolved aqueous Si and Al species were

prepared by treating H-Beta zeolite or dealuminated Beta zeolite (deAl-BetaI20h) in water at

330 degC under autogenic pressure for 5 10 15 30 45 and 60 min The resulting solutions were

filtered at RT and analysed by ICP-OES see Table 48 The filtration performed at RT is also

referred to as ldquocold filtrationrdquo in the current work

In the second step the filtered solutions obtained in step 1 further referred to as zeolite

filtrates were subsequently transferred into a tube reactor together with 30 mg of 99 glycerol

purged with N2 for 5 min sealed and heated at 330 degC for various reaction times to evaluate

the effect of the zeolite filtrates on hydrothermal dehydration of glycerol The holding times

corresponded to the holding time used for preparing the zeolite filtrate The reaction solutions

were analysed by ICP-OES and 1H-NMR and the results are summarised in Table 48 and Figure

90

I Glycerol - H-Beta zeolite filtrate

The XRD spectra reveal that the H-Beta zeolite treated in water at 330 degC transforms

into an X-ray amorphous material within 5 min see Figure 77 (page 243) The aqueous Al and

Si concentrations as well as the glycerol decomposition products are shown in Table 48 and

270

Figure 90 respectively The conversion of glycerol (X) selectivity (S) and yield of liquid

products (Y) in the glycerol - H-Beta zeolite filtrate system is significantly lower than in

glycerol - H-Beta - DI water under identical conditions see Figure 90 and 93 and Table 49 At

the reaction time of 1 h H-Beta zeolite filtrate provided significantly higher conversion and

selectivity to liquid products than in a non-catalysed system ie glycerol - DI water system

Table 48 The ICP-OES analysis of dissolved Si and Al in the H-Beta zeolite filtrate before

and after its use in the hydrothermal dehydration of glycerol The experiments were performed

at 330 degC under saturated vapour pressure

aqueous ion concentration

[ppm]

Holding time [min]

5 10 15 30 45 60

(i) H-Beta zeolite - water

Al 444 393 374 356 298 332

Si 6005 5886 6034 6195 620 6215

(ii) H-Beta zeolite filtrate - glycerol

Al 266 191 236 229 228 163

Si 4581 4758 5108 4773 484 4789

the solution obtained in (i) The numbers are averaged results of duplicate experiments The


271

0

25

50

75

100

Y= 498 mol

Y= 572 mol

Y= 423 mol

Y= 359 mol

Y= 141 mol

gases amp char

acetol

acrolein

acetaldehyde

acetic acid

MeOH

Y= 044 mol

Conversion

Co

nv

ersi

on

[m

ol

] o

r S

elec

tiv

ity

[C

-mo

l]

Reaction Time [min]

5 10 15 30 45 60

Figure 90 The conversion degree selectivity and total yield (symbol Y in the text box) of

liquid products obtained in the hydrothermal dehydration of 03 mmol glycerol in 3 ml H-Beta

zeolite filtrate at 330 degC autogenic pressure 5-60 min The error bars show the standard error

of mean (119878119864)

The conversion of glycerol in H-Beta zeolite filtrate solution increases with the reaction

time reaching its maximum of 28 mol see Figure 90 and 93 The selectivity and yield of

liquid products also increases with reaction time but only up to 45 min after which it starts to

decrease possibly due to degradation of primary liquid products The Al and Si concentrations

in the zeolite filtrate do not change significantly with time 3-4 ppm Al and ~589-622 ppm Si

see Table 48 making the reaction time a likely explanation for the increasing trend in glycerol

conversion degree selectivity and yield of liquid products It should be noted that the

preparation of the zeolite filtrate involved cooling down of the mix of H-Beta zeolite and water

to laboratory temperature prior to filtration and ICP-OES analysis The cooling step may have

affected the temperature-pressure dependent equilibrium concentration of Al and Si species

272

inducing their partial precipitation limiting our insight into the role of Al and Si See Figure 91

and 92 for the solubility of correspondingly SiO2 and Al2O3 in water at different temperatures

and pressures

Figure 91 The solubility of SiO2 in water at different temperatures and pressures (taken from

Brunner (2009)) Solid line = solubility at different pressures in MPa (megapascal) dashed line

= specific volume (cm3middotg-1)

273

Figure 92 The solubility of Al2O3 in water at different temperatures and pressures (taken from

Ziemniak (1995)) Psat = saturated vapour pressure kb = kilobar

The liquid products detected in the H-Beta zeolite filtrate system included acetol

acrolein acetaldehyde acetic acid and methanol The distribution of the liquid products is

similar to that in solid H-Beta zeolite system except that for H-Beta zeolite filtrate system

acetaldehyde was the main product under all conditions studied and no ethanol and lactic acid

was detected

274

Table 49 A summary of results obtained in the hydrothermal dehydration of glycerol using (i)

no catalyst (ii) H-Beta zeolite (iii) H-Beta zeolite filtrate and (iv) deAl-BetaI20h filtrate The

reaction conditions 3 ml DI water (or zeolite filtrate) 03 mmol glycerol (with 28 mg H-Beta

zeolite when needed) at 330 degC autogenic pressure 5 to 60 min

Catalysts Reaction time

[min]

Conversion

[mol]

Selectivity to liquid

products [C-mol]

Yield

[C-mol]

No 60 121 plusmn 19 372 45

H-Beta zeolite 5 332 plusmn 32 556 176

10 610 plusmn 22 497 300

15 633 plusmn 46 512 315

30 732 plusmn 54 420 300

45 769 plusmn 21 408 311

60 839 plusmn 24 335 282

H-Beta zeolite filtrate 5 101 plusmn 03 44 04

10 145 plusmn 09 100 14

15 163 plusmn 07 218 36

30 242 plusmn 26 177 42

45 264 plusmn 03 217 57

60 283 plusmn 12 174 50

deAl-BetaI20h

zeolite filtrate 5 54 plusmn 10 142 07

10 59 plusmn 00 125 07

15 111 plusmn 08 98 11

30 160 plusmn 17 130 21

45 1758 plusmn 25 123 21

60 174 plusmn 05 142 25

275

0 10 20 30 40 50 60

0

20

40

60

80

100

0 10 20 30 40 50 60

0

10

20

30

40

50

60

70 deAl-BetaI20h filtrate

H-Beta zeolite filtrate

H-Beta zeolite

No catalyst

deAl-BetaI20h filtrate


H-Beta zeolite

No catalyst

Gly

cero

l co

nver

sion

[m

ol

]

Reaction time [min]Reaction time [min]

Sel

ecti

vit

y t

o a

ll l

iqu

id p

rod

uct

s [C

-mol

]

Figure 93 The conversion degree and selectivity to liquid products obtained in the hydrothermal dehydration of glycerol using (i) no catalyst (ii)

H-Beta zeolite (iii) H-Beta zeolite filtrate and (iv) deAl-BetaI20h filtrate The conditions of dehydration 3 ml DI water (or zeolite filtrate) 03

mmol glycerol (with 28 mg H-Beta zeolite when needed) at 330 degC autogenic pressure 5-60 min The error bars show 119878119864

276

II Glycerol - deAl-BetaI20h filtrate

The hydrothermal dehydration of glycerol was carried out using the zeolite filtrate

solution prepared from deAl-BetaI20h in which 98 wt Al was extracted by dealumination

with HNO3 to investigate the effect of different AlSi ratio of the zeolite filtrate solution

Identical preparation technique was used as for the H-Beta zeolite filtrate see Chapter 453

The ICP-OES analysis of the filtrate showed 1-25 ppm (~05-11 wt) Al equivalent to 36-

66 decrease in the Al content with respect to H-Beta zeolite filtrate while the Si (215-225

ppm) decreased by 35-38 see Table 50 It should be noted that the low Al concentration

detected were close to the ICP-OES (01 ppm) detection limit increasing the experimental error

The XRD analysis of deAl-BetaI20h confirms that its BEA structure was still intact and

its XRD relative crystallinity is only 15 lower than that of H-Beta zeolite see Chapter 532

for a full characterisation of deAl-BetaI20h In addition the amount of SiO2 in H-Beta zeolite

and deAl-BetaI20h determined by XRF analysis is 74 wt and 81 wt respectively indicating

that the relatively low amount of dissolved Si detected in deAl-BetaI20h filtrate was not due to

lower amount of Si present in the sample The lower Si concentration in deAl-BetaI20h filtrate

as compared to H-Beta zeolite filtrate may possibly be explained by the lower HLW

susceptibility of the framework after the dealumination The dealumination is a process

commonly used to increase the hydrothermal stability of zeolites in a gas phase and steam The

increased hydrothermal stability may be due to the presence of the extra-framework aluminium

(EFAl) species formed from the Al atoms removed from the framework during the

dealumination (Klinowski 1984 Ennaert et al 2014) The EFAl species may either reside

separately outside of the zeolite crystal (Sanz et al 1988 Stockenhuber and Lercher 1995

Ennaert et al 2014) or be present as isolated charge-compensating cations in the zeolite cages

(Stockenhuber and Lercher 1995 Beyerlein et al 1997) Owing to their low water-solubility

the EFAl species located outside of the zeolite crystal surface prevent solubilization of the

277

zeolite framework increasing the stability of zeolites not only in steam but in the case of

(US)Y zeolites also in HLW (Ennaert et al 2014)

Table 50 The ICP-OES analysis of dissolved Si and Al in the dAl-BetaI20h filtrate before




[ppm]

Holding time [min]

5 10 15 30 45 60

(i) deAl-BetaI20h - water

Al 193 184 248 216 153 12

Si 2152 2253 2186 2167 2158 217

(ii) deAl-BetaI20h filtrate - glycerol

Al 04 036 029 024 034 024

Si 1838 18991 18861 19957 19424 19816

dAl-BetaI20h (dealuminated Beta zeolite with SiO2Al2O3 = ~1590) the solution obtained

in (i) The numbers are averaged of duplicate experiments

278

0

25

50

75

100

gases amp char

acetaldehyde

acetic acid

MeOH

Y= 248 mol

Y= 211 mol

Y= 205 mol

Y= 108 mol

Y= 074 mol

Y= 073 mol

Conversion

Con

ver

sion

[m

ol

] o

r S

elec

tiv

ity

[C

-mol

]

Reaction Time [min]

5 10 15 30 45 60


liquid products obtained in the hydrothermal dehydration of glycerol Reaction conditions 03

mmol glycerol in 3 ml of deAl-BetaI20h filtrate at 330 degC autogenic pressure 5-60 min The

error bars show 119878119864

The results of the hydrothermal dehydration of glycerol performed in deAl-BetaI20h

filtrate are shown in Figure 94 also see Figure 93 and Table 49 for the data comparison of

various systems At the reaction time of 60 min the conversion of glycerol obtained in the

deAl-BetaI20h filtrate system (~17 mol) was higher than that in non-catalysed reaction (~12

mol) but the selectivity to liquid products in the former was only ~14 mol as compared to

~37 mol indicating that the aqueous Al and Si species present in the deAl-BetaI20h filtrate

may adversely affect the liquid product formation

The conversion of glycerol selectivity and yield of liquid products obtained in the

deAl-BetaI20h filtrate system were lower than in H-Beta zeolite filtrate system see Figure 93

279

and Table 49 Only three liquid products were detected in the former system acetaldehyde

acetic acid and MeOH whereas as opposed to the non-catalysed and solid H-Beta zeolite

systems acrolein and acetol were not found

The lower yield of liquid products in the deAl-BetaI20h filtrate system (max 25 mol)

as compared to the H-Beta filtrate system (max 57 mol) may be related to the lower Al and

Si concentrations in the former On the other hand the lower yield of liquid products in the

deAl-BetaI20h filtrate system as compared to the non-catalysed system (max 45 mol) may

be attributed to the presence of Si which may have facilitated the decomposition of the primary

liquid products such as acrolein and acetol This speculation was raised when the hydrothermal

dehydration of glycerol performed in the presence of H2SO4 resulted in similar liquid products

found in H-Beta zeolite and non-catalysed systems ie acrolein and acetol were also detected

see Figure 95 H2SO4 was used as an alternative to H4SiO4 which was not commercially

available and difficult to prepare

280

0

25

50

75

100

gases amp char

acetol

acrolein

EtOH

acetaldehyde

acetic acid

MeOH

Conversion

Co

nv

ersi

on

[m

ol

] o

r S

elec

tiv

ity

[C

-mo

l]

Reaction Time [min]

5 10 15 30 45 60

Figure 95 Hydrothermolysis of glycerol in the presence of 66 micromol H2SO4 (the equivalent

amount of the acid sites in 28 mg H-Beta zeolite) at 330degC under autogenous pressure and

reaction time of 5 to 60 min The error bars show 119878119864

643 Conclusion

It has been demonstrated that the H-Beta zeolite and H-ZSM-5 are unsuitable

heterogeneous catalysts for hydrothermolysis of glycerol at ge200 degC for Beta zeolite or 250 degC

for ZSM-5 due to their low hydrothermal stability However the catalytic effect of dissolved

zeolite aluminosilicate species on the hydrothermal conversion of glycerol was taken into

account and studied at 330 degC 5-60 min ie at the conditions considered optimum with respect

to conversion degree and selectivity to liquid products see Chapter 642

281

7 Hydrothermal oxidation of glycerol with H2O2

Oxidation of glycerol usually results in a variety of high market-value chemicals such

as dihydroxyacetone glycolic acid lactic acid and formic acid (Katryniok et al 2011) A

number of studies on oxidation of glycerol were carried out at the temperature range of 20-80

degC using O2 or H2O2 as an oxidant (McMorn et al 1999 Brett et al 2011 Zhou et al 2011

Wu et al 2013) In these works the conversion rates however were slow even in the presence

of a catalyst This may be overcome by the use of hydrothermal conditions In this chapter the

results of the hydrothermal oxidation of glycerol catalysed by zeolite-based catalysts in both

batch and continuous flow modes are presented

71 Batch process

The initial work on the hydrothermal oxidation of glycerol focussed on finding suitable

temperature(s) and catalyst(s) Several trials were carried out in a batch mode using tubular

reactors for the simplicity as compared to the more complex continuous mode

711 Non-catalysed oxidation

A series of experiments on the hydrothermal oxidation of glycerol with H2O2 was

performed in sub-CW at 125 150 175 and 200 degC autogenic pressure 30 60 120 and 180

min H2O2 was used as a source of oxygen since it is a powerful and inexpensive oxidant

(Martin and Garrone 2003) In addition the final decomposition products of H2O2 are

environmentally friendly O2 and H2O (Lin and Smith 1990) The details of experimental

282

procedures are provided in Chapter 461 The glycerol to H2O2 mole ratio used was ~1

providing sufficient amount of H2O2 for oxidation of a single hydroxyl group of glycerol

(McMorn et al 1999) see Equation 30

Equation 30 Oxidation of glycerol with 1 equivalent H2O2 and its ideal oxidation products

The data obtained was used as a benchmark for evaluation of the performance of

various zeolite-based catalysts The summary of the reaction conditions and analysis results are

summarised in Figure 96 as well as in Table 51

283

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

Y = 164 06 Y = 178 03 Y = 211 00

Reaction time [min]

Y = 248 09

Con

ver

sion

[m

ol

] or

Sel

ecti

vit

y [

C-m

ol

]

125 C

30 60 120 180

150 C

Reaction time [min]

30 60 120 180

Y = 156 08 Y = 153 11 Y = 126 08

Con

ver

sion

[m

ol

] or

Sel

ecti

vit

y [

C-m

ol

]

Y = 148 05

Y = 131 19 Y = 1309 07 Y = 135 03

200 C175 C

Reaction time [min]

30 60 120

gases amp char

pyruvaldehyde

acetol

acrolein

glycolic acid

DHA

formic acid

acetaldehyde

acetic acid

Reaction time [min]

30 60 120 180

Y = 148 06

Conversion

Con

ver

sion

[m

ol

] o

r S

elec

tivit

y [

C-m

ol

]

Con

ver

sio

n [

mol

] or

Sel

ecti

vit

y [

C-m

ol

]

200 C

Y = 106 15 Y = 137 13 Y = 124 02

Figure 96 A summary of results on the oxidation of 02 M glycerol (06 mmol) with H2O2 in sub-CW at different temperatures (autogenic pressure) and reaction

times Molar ratio of glycerol to H2O2 = 1 The error bars show the standard error of mean (119878119864) Note DHA = dihydroxyacetone Y = total yield of liquid

products [C-mol]

284

Table 51 A summary of results on the oxidation of 02 M glycerol (06 mmol) with H2O2 in

sub-CW at different temperatures (autogenic pressure) and reaction times batch mode Molar

ratio of glycerol to H2O2 = 1

Temperature

[degC]

Reaction time

[min]

Conversion

[mol]

Selectivity to liquids

[C-mol]

Yield of liquids

[C-mol]

125 30 248 plusmn 13 1006 plusmn 55 248 plusmn 09

60 436 plusmn 08 484 plusmn 09 211plusmn 00

120 455 plusmn 30 395 plusmn 26 178 plusmn 03












120 557 plusmn 49 198plusmn 42 106 plusmn 15

The numbers plusmn standard error of mean (119878119864)

At 150 degC no glycerol converted after the hydrothermolysis for 24 h see Figure 132 in

the Appendix illustrating the crucial role of H2O2 In the presence of H2O2 the conversion of

glycerol at 125 degC was increasing with the reaction time reaching ~48 mol at 180 min At

150 175 and 200 degC the conversion of glycerol reached ~48-50 mol within 30 min and then

maintained at ~50-55 mol up to 180 min see Figure 96 indicating a possibility that H2O2

was completely consumed or decomposed within the first 30 min

On the other hand the highest yield of liquid products (~25 mol) was obtained at 125

degC after 30 min but it decreased with reaction time to ~16 mol after 180 min possibly due to

285

further degradation of primary liquid products The total yield also decreased with temperature

~15 mol at 30 min at 150 and 175 degC while only 12 mol at 200 degC These yields gradually

decreased with increasing reaction time The selectivity to liquid products as a function of time

and temperature follows the same trend as that of the yield see Figure 96 the highest selectivity

of ~100 mol was obtained at 125 degC 30 min and the selectivity decreased with temperature

and reaction time reaching ~35 mol after 180 min

The liquid products detected included formic acid dihydroxyacetone (DHA) glycolic

acid acetic acid acetol acetaldehyde (including acetaldehyde hydrate) and several

unidentified compounds see Figure 133 in the Appendix for a typical 1H-NMR spectrum of

liquid samples recovered from the oxidation of glycerol under conditions studied The main

products were formic acid and DHA with the selectivity range between 135-59 mol and 13-

29 mol respectively see Figure 96

286

The formation of numerous reaction products is highly likely a result of complex

reaction pathways of glycerol as shown in Figure 97

Figure 97 The products obtained from the oxidation of glycerol (adapted from by (Katryniok

et al 2011))

The results obtained show that the oxidation of glycerol with H2O2 under hydrothermal

conditions leads to rapid conversion of glycerol and subsequent decomposition of its liquid

conversion products into gasses This is likely due to the presence of highly reactive hydroxyl

287

radicals (HObull or HO2bull) the decomposition products of H2O2 (Lin and Smith 1990) As opposed

to the conversion of glycerol the selectivity to and yield of liquid products decreased with

temperature and reaction time The degrees of glycerol conversion at 175 and 200 degC were

almost identical but the yields were lower at 200 degC Hence the operating temperature of 200

degC was not further investigated in a continuous flow system

712 Zeolite-catalysed hydrothermal oxidation of glycerol

The literature survey reveals that only a few catalysts have been reported to be tested

for the hydrothermal oxidation of glycerol see Table 12 (page 63) The catalysts reported

include NaOH (Zhang et al 2013 Zhang(a) et al 2014) Ru(OH)4 on reduced graphite oxide

(Xu et al 2014) and vanadium-substituted phosphomolybdic acids (H3+nPVnMo12-nO40)

(Zhang(b) et al 2014 Zhang 2015) In these studies the main liquid product is formic acid

with the highest yield of ~60 mol (carbon basis) obtained on the Ru(OH)4 on reduced graphite

oxide The performance of several zeolite-based catalysts in glycerol oxidation was

investigated in this work


The hydrothermal oxidation of glycerol with H2O2 in the presence of H-Beta zeolite

and H-ZSM-5 was studied at 150 degC under autogenic pressure at 30 60 120 and 180 min the

molar ratio glycerolH2O2 = 1 the weight ratio glycerolzeolite = 3 the weight ratio

glycerolwater = 00184 Analysis of the reaction solution revealed the presence of several

products with formic acid as the main product see Figure 98 The addition of H-Beta zeolite

did not improve the conversion of glycerol (~51 mol) but slightly decreased the total

288

selectivity to its liquid oxidation products (~28 mol) as compared to the non-catalysed

oxidation possibly due to the Broslashnsted acidity of H-Beta zeolite which tends to promote the

decomposition of the primary liquid products It was also speculated that H-Beta zeolite may

have increased the conversion rate and the glycerol conversion reached the 51 mol earlier

than 30 min

In contrast to H-Beta zeolite the reaction catalysed by H-ZSM-5 possessing higher

density of Broslashnsted acid sites than H-Beta zeolite provided lower glycerol conversion than the

non-catalysed reaction but higher selectivity to liquid products see Table 29 (page 167) for a

summary of the Broslashnsted acid site density of H-Beta zeolite and H-ZSM-5 The lower

conversion on H-ZSM-5 as compared to H-Beta zeolite is likely to be caused by its smaller

pores ie H-ZSM-5 051x055 053x056 nm while H-Beta zeolite 066x067 056x056 nm

(McCusker et al 2007) limiting the reactant diffusion and hence increasing the adsorption of

the liquid reactants andor products on the zeolite surface

Despite providing different degrees of conversion and selectivity to liquid products

both H-Beta zeolite and H-ZSM-5 provided traces of pyruvaldehyde and lactic acid not

previously detected in the absence of the zeolites All other liquid products found in the non-

catalysed reaction except for acetaldehyde were also present in the oxidation catalysed by the

H-ZSM-5 and H-Beta zeolite

289

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

gases amp char

lactic acid

pyruvaldehyde

acetol

glycolic acid

dihydroxyacetone (DHA)

formic acid

acetaldehyde

acetic acid

(C) H-ZSM-5

Reaction time [min]

30 60 120 180

(A) No catalyst

Conversion

Con

versi

on

[m

ol

] or S

ele

cti

vit

y [

C-m

ol

]

(B) H-Beta

30 60 120 18030 60 120 180

Reaction time [min]

30 60 120 18030 60 120 180

Con

versi

on

[m

ol

] or S

ele

cti

vit

y [

C-m

ol

]Reaction time [min]

30 60 120 180

Con

versi

on

[m

ol

] or S

ele

cti

vit

y [

C-m

ol

]

Figure 98 The results of the hydrothermal oxidation of glycerol with H2O2 in the presence of (A) no catalyst (B) H-Beta zeolite and (C) H-ZSM-

5 Reaction conditions 3 ml of 02 M glycerol (06 mmol) at 150 degC under autogenic pressure and the reaction time of 30 60 120 and 180 min

Molar ratio of glycerol to H2O2 = 1 The error bars show 119878119864

290

The conversion degree of glycerol in the presence of no catalyst H-Beta zeolite and H-

ZSM-5 reached 51 mol 48 mol and 36 mol respectively within 30 min and remained

almost unchanged up to 180 min see Figure 98(A) (B) and (C) The lower conversion degrees

of the catalysed reactions may possibly be explained by the decomposition of H2O2 to O2 and

H2O instead of H- and highly reactive OHbull in the presence of the zeolites with Fe and Cu

impurities see Table 62 in the Appendix for the elemental composition of the zeolites

determined by ICP-OES

The presence of both pyruvaldehyde including its hydrate form and lactic acid was

confirmed by 1H-NMR HPLC and GC-FID see Figure 134-136 in the Appendix for examples

of spectra and chromatograms The pyruvaldehyde hydrate is commonly present in aqueous

diluted solutions of pyruvaldehyde (Kobayashi and Takahashi 1979 Scheithauer et al 2015)

Lactic acid may be formed through oxidation pathways having pyruvaldehyde as an

intermediate see Figure 99 while the most likely precursor of pyruvaldehyde is DHA The

conversion of DHA to lactic acid via pyruvaldehyde is a known reaction pathway for instance

in the conversion of sugars to lactic acid (Jin et al 2006) While the DHA and pyruvaldehyde

were present only at early reaction times of up to 60 min the yield of lactic acid tended to

increase with time

291

Figure 99 The suggested conversion of glucose to lactic acid in subcritical water (adapted from

Jin et al (2006))

7122 Metal-exchanged Beta zeolite

The results obtained in Chapter 711 and 7121 showed that the hydrothermal

oxidation of glycerol at below 200 degC is affected by H2O2 while the addition of Broslashnsted acidic

zeolites may promote the transformation of DHA to pyruvaldehyde and subsequently to lactic

acid Also the conversion of glycerol and the total selectivity to its liquid oxidation products

almost reached the maximum within 30 min at 150 degC Further experimental work on catalyst

screening for a continuous flow system was therefore carried out at 150 degC autogenic pressure

and a reaction time of only 5 min H-Beta zeolite was chosen to be used in a continuous flow

process not only for its high Broslashnsted acidity but also for its larger average pore size as

compared to H-ZSM-5 hence the degree andor the rate of deactivation may be minimal In

this chapter the catalysts tested included 48 wt metal-doped Beta zeolites further referred

to as MBeta zeolites where M is Ce3+ Cu2+ La3+ Sn2+ and Zn2+ which were prepared by SSIE

according to the experimental protocol described in Chapter 442 A full characterisation of

the catalysts is provided in Chapter 52 The results of the hydrothermal oxidation of glycerol

using the catalysts are summarised in Figure 100 and Table 52

292

No

cata

lyst

48

Ce

H-B

eta

48

CuH

-Bet

a

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

0

20

40

60

80

100 conversion

acetic acid

lactic acid

formic acid


glycolic acid

acetol

pyruvaldehyde

acetaldehyde

Co

nv

ersi

on

[m

ol

]

0

5

10

15

20

25

Sel

ecti

vit

y [

C-m

ol

]

Figure 100 The results of the hydrothermal oxidation of glycerol with H2O2 in the presence of various zeolite catalysts Reaction conditions 3 ml

of 02 M glycerol (06 mmol) 18 mg catalyst at 150 degC under autogenic pressure and the reaction time of 5 min Molar ratio of glycerol to H2O2

= 1 The error bar indicates the standard error of mean (119878119864)

293

The non-catalysed oxidation of glycerol resulted in ~36 mol conversion and 48 mol

selectivity to all the liquid products Formic acid was the main liquid product with 22 mol

selectivity Other liquids detected included DHA glycolic acid acetic acid acetol

acetaldehyde and traces of pyruvaldehyde The addition of all MBeta zeolites except for 48

wt CeH-Beta zeolite generally increased the conversion of glycerol but had an adverse

effect on the selectivity to liquid products as compared to the non-catalysed reactions see

Figure 100 On the other hand 48 wt CeH-Beta zeolite the least active catalyst in the

oxidation of glycerol provided ~28 mol conversion and ~45 mol selectivity to liquid

products Despite this the glycerol oxidation catalysed by 48 wt CeH-Beta zeolite resulted

in an increase by 60 45 and 28 in the selectivity to acetic acid DHA and glycolic acid

respectively as compared to the non-catalysed reaction The possible explanations are (i) the

Cezeolite catalysed the decomposition of H2O2 to O2 and H2O instead of H- and highly

reactive OHbull (Golchoubian and Babaei 2010) or (ii) the Cezeolite was an inactive catalyst of

the H2O2 decomposition

Only the 48 wt CuH-Beta catalyst provided high conversion of glycerol with DHA

as the main liquid product with the highest selectivity of ~173 mol A positive influence of

the catalyst on the stability of DHA may explain the high selectivity to DHA although its

transformation products such as pyruvaldehyde and lactic acid with the selectivity of 2 mol

and 06 mol respectively were also detected

The stability of oxidation products of glycerol was examined further by increasing the

reaction time from 5 min to 180 min see Table 52 and Figure 101 The longer reaction time

did not significantly affect the degree of glycerol conversion Almost no DHA was present but

lactic acid was detected in all reactions independently of the catalyst used except for the non-

catalysed reaction Formic acid was the main liquid product in the non-catalysed and La- Zn-

294

and SnH-Beta zeolite catalysed reactions while lactic acid in Ce- and CuH-Beta zeolite

catalysed reactions with the highest concentration when CeH-Beta zeolite was used

295

Table 52 A summary of results obtained on the hydrothermal oxidation of glycerol with H2O2 in the presence of various zeolite catalysts Reaction

conditions 3 ml of 02 M glycerol (06 mmol) 18 mg catalyst at 150 degC under autogenic pressure and the reaction time of 5 and 180 min Molar


Time

[min] Catalyst

Conversion

[mol]


[C-mol]

Total liquid yield

[C-mol] AA LA FA DHA GCA acetol PVA AC

5 No catalyst 356 plusmn 13 15 00 223 103 46 51 11 27 476 169

48 CeH-Beta 277 plusmn 08 24 00 198 149 59 15 00 00 445 123

48 CuH-Beta 418 plusmn 07 00 06 126 173 21 01 20 01 348 137

48 LaH-Beta 488 plusmn 04 10 00 103 48 27 20 01 03 213 104

48 SnH-Beta 415 plusmn 62 09 00 95 51 28 15 00 02 200 83

48 ZnH-Beta 507 plusmn 30 07 01 110 59 24 25 03 04 235 119


48 CeH-Beta 329 plusmn 16 30 148 141 00 24 04 02 04 353 116

48 CuH-Beta 430 plusmn 09 11 126 99 08 52 08 13 00 316 136

48 LaH-Beta 501 plusmn 00 24 68 199 00 56 36 00 08 382 191

48 SnH-Beta 396 plusmn 26 08 05 28 12 22 05 02 01 74 29

48 ZnH-Beta 467 plusmn 02 28 61 215 00 27 00 00 11 332 155

Note The number plusmn standard error of mean (119878119864) AA = acetic acid LA = lactic acid FA = formic acid DHA= dihydroxyacetone GCA = glycolic

acid PVA = pyruvaldehyde AC = acetaldehyde

296

No

cata

lyst

48

Ce

H-B

eta

48

CuH

-Bet

a

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

0

20

40

60

80

100 conversion

acetic acid

lactic acid

formic acid


glycolic acid

acetol

pyruvaldehyde

acetaldehyde

Con

ver

sion

[m

ol

]

0

5

10

15

20

25

Sel

ecti

vit

y [

C-m

ol

]


of 02 M glycerol (06 mmol) 18 mg catalyst at 150 degC under autogenic pressure and the reaction time of 3 h Molar ratio of glycerol to H2O2 =

1 The error bar indicates standard error of mean (119878119864)

297

The CuH-Beta zeolite provided the best balance between the conversion and selectivity

to liquid products within 5 min which is a practical residence time in a continuous flow system

In addition the DHA initially present at 5 min converted into lactic acid at 180 min in the

CuH-Beta zeolite catalysed system as opposed to the non-catalysed system where the DHA

likely converted to gaseous products Other catalysts ie La- Sn- and ZnH-Beta zeolites

displayed high selectivity toward formic acid while CeH-Beta zeolite although providing high

selectivity to lactic acid at 180 min was the least active catalyst for the oxidation of glycerol


Batch processing mode as opposed to a continuous processing mode was used as a

convenient method for rapid evaluation of the performance of catalysts The method allowed

rapid identification of trends in glycerol conversion and selectivity to liquid reaction products

under a broad range of reaction conditions tested However batch operating mode might suffer

from two issues

(i) mass transfer limitations due to the catalyst settling at the bottom of the non-agitated

tubular bomb reactor resulting in a limited contact of glycerol with the catalyst

(ii) rapid decomposition of primary oxidation products of glycerol resulting in high

selectivity towards gases even at 5 min

Mass transfer between the glycerol and the catalyst possibly present in the non-stirred

batch reactors may be improved by using a reactor equipped with a stirrer (Engineers 2013)

Alternatively the reactions may be performed using a plug flow reactor (PFR) eg a tubular

reactor containing an immobilised solid catalyst The fluids would then flow through a reactor

298

as a plug ideally at the same velocity and parallel to the reactor axis with little or no back-

mixing (Davis and Davis 2003) All the substrates present at any given tube cross-section have

identical residence time and so equal opportunity for reaction The advantages of continuous

flow mode over batch operation mode are that the former allows a short residence time (usually

on a timescale of seconds) and the reaction pressure to be precisely measured and controlled

The hydrothermal oxidation of glycerol performed in a continuous packed bed reactor was

therefore investigated


The hydrothermal oxidation of glycerol with H2O2 was studied in a bench top

continuous flow system at 125 150 and 175 degC 35 bar with residence times of 60 120 180

240 and 300 s The equipment and experimental procedure used are described in Chapter 462

The reaction conditions studied as well as the results are summarised in Figure 102 and Table

53

Similarly to the reactions in the batch mode no conversion was detected in the

subcritical water ndash glycerol system at 125 150 and 175 degC 35 bar and residence times of 60 -

300 s (data not presented) In the presence of H2O2 the conversion of glycerol occurred within

60 s independently of the temperature applied see Figure 102 and Table 53 The conversion of

glycerol clearly correlated with the H2O2 consumption the initial amount of which was kept

constant for all samples The degree of glycerol conversion in the presence of H2O2 was also

significantly affected by temperature and residence time 49 mol 48 mol and 55 mol

conversion was recorded at 125 150 and 175 degC respectively at 300 s In general the higher

temperatures promoted the conversion degree and the reaction rate the temperature increase

from 125 to 150 degC increased the conversion degree by 15-242 while an increase from 150

299

to 175 degC increased the conversion by 3-67 The effect of temperature tended to be more

significant at shorter residence time

The yield of liquid products was lt 2 mol The total selectivity to liquid products was

generally low (~1-23 mol) independently of temperature with a tendency to decrease with

the residence time The selectivities and yields of individual products are lower than in the

batch operation mode in which similar glycerol conversion (approx 50 mol) was obtained

using the same concentration of glycerol glycerolH2O2 molar ratio and the temperature of

125 150 and 175 degC 30-180 min the selectivity obtained was between 20-100 mol while

the yield was 11-25 mol The low selectivity and yield obtained in the continuous flow

system at 120-300 s may be the result of degradation of the primary products This may be

possibly caused by the presence of highly reactive HObull radicals see Table 53 for the H2O2

consumption at various temperatures and residence times

300

0

15

30

45

60

0

15

30

45

60

0

15

30

45

60

0

5

10

15

acetic acid

formic acid


glycolic acid

Residence time [sec]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Conversion

Con

ver

sion

[m

ol

]

(A) No catalyst_125 C

0

5

10

15


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]

(B) No catalyst_150 C

0

5

10

15


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]

(C) No catalyst_175 C

Figure 102 The results of the hydrothermal oxidation of 02 M glycerol using H2O2 in a continuous flow reactor at 125 150 and 175 degC 35 bar

at a residence time of 60-300 s the molar ratio of glycerol to H2O2 = 1 The data presented is from a single experiment

301

Table 53 A summary of results obtained in the hydrothermal oxidation of 02 M glycerol using H2O2 in a continuous flow reactor at 125 150 and

175 degC 35 bar at a residence time of 60-300 s the molar ratio of glycerol to H2O2 = 1 The data presented is from a single experiment

Temp

[degC]

Residence Time

[s]

Conversion

[mol]

Selectivity to liquid products [C-mol] Total selectivity

[C-mol]

Total yield

[C-mol]

H2O2 consumption

[] AA FA DHA GCA PVA

125 60 39 - 86 146 0 - 232 090 237

120 180 - 23 32 0 - 55 099 643

180 286 - 15 2 03 - 38 107 847

240 389 - 09 1 02 - 21 08 948

300 491 - 0 08 0 - 08 038 991

150 60 65 traces 10 108 22 - 231 149 737

120 213 traces 3 23 03 - 57 120 939

180 319 traces 16 12 02 traces 30 095 1000

240 399 traces 16 05 02 traces 23 093 999

300 480 traces 12 07 02 traces 20 097 1000

175 60 222 04 39 34 07 - 84 186 947

120 374 01 21 14 04 02 43 159 1000

180 458 01 2 08 05 03 38 172 1000

240 475 01 21 07 05 02 35 166 1000

300 550 0 17 - - traces 17 093 1000

liquid products AA = acetic acid FA = formic acid DHA = dihydroxyacetone GCA = glycolic acid PVA = pyruvaldehyde

302

73 Catalytic oxidation of glycerol

731 Effect of temperature on the catalytic oxidation of glycerol in

subcritical water using H-Betaγ-Al2O3 (MC) catalyst

The effect of temperature on the catalytic oxidation of glycerol in sub-CW using H-

Betaγ-Al2O3 (MC) as a catalyst was studied at 125 150 and 175 degC 35 bar at the residence

time of 60-300 s The preparation procedure and characterisation of the H-Betaγ-Al2O3 (MC)

are provided in Chapter 446 and 5533 respectively The experimental conditions and the

results compared to those obtained in the non-catalysed oxidation are presented in Table 54

and Figure 103

As expected the degree of hydrothermal conversion oxidation of glycerol in the

presence of H2O2 and H-Betaγ-Al2O3 (MC) increased with increasing temperature and

residence time A maximum degree of conversion was attained after 60 s at 125 degC after when

it remained constant up to 300 s At 150 and 170 degC the conversion degree gradually increased

up to 300 s however in general it did not reach the extent observed in the non-catalysed system

(max ~55) Despite the higher conversion rate the H-Betaγ-Al2O3 (MC) catalysed system

provided lower conversion degrees (max ~46 mol) as compared to the non-catalysed

oxidation (max ~55 mol) For instance at 125 degC the degrees of glycerol conversion in the

H-Betaγ-Al2O3 (MC) catalysed system were lower by 32 49 and 62 at 180 240 and 300

s respectively A possible reason for the lower conversion degrees may be the decomposition

of H2O2 into O2 and H2O instead of highly reactive OHbull in the presence of the zeolites with

Fe and Cu impurities see Table 62 in the Appendix for the elemental composition of the

zeolites determined by ICP-OES

303

Table 54 A summary of the results obtained in the hydrothermal oxidation of 02 M glycerol in the presence of (i) no catalyst and (ii) H-Betaγ-

Al2O3 (MC) at 125 150 and 175 degC 35 bar and a residence time of 60-300 s the molar glycerolH2O2 ratio = 1 1 g of extruded H-Betaγ-Al2O3

(MC) The data presented is from a single experiment

Temp

[degC]

Residence Time

[s]

No catalyst H-Betaγ-Al2O3 (MC)

Conversion

[mol]


[C-mol]

Yield to liquids

[C-mol]

Conversion

[mol]


[C-mol]

Yield to liquids

[C-mol]

125 60 39 232 09 202 118 24

120 180 55 10 176 191 34

180 286 38 11 195 184 36

240 389 21 08 198 154 31

300 491 08 04 188 135 25

150 60 65 231 15 178 372 66

120 213 57 12 263 486 128

180 319 30 10 375 399 149

240 399 23 09 382 385 147

300 480 20 10 407 385 157

175 60 222 84 19 273 907 239

120 374 43 16 347 647 214

180 458 38 17 345 659 219

240 475 35 17 439 506 217

300 550 170 09 461 424 191

304

0

15

30

45

0

15

30

45

0

15

30

45

0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mo

l]

60 120 180 240 300

Conversion

Co

nv

ersi

on

[m

ol

]

(A) H-Beta-Al2O3 (MC)_125 C

0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mo

l]

60 120 180 240 300

Co

nv

ersi

on

[m

ol

]

(B) H-Beta-Al2O3 (MC)_150 C

0

10

20

30

acetic acid

formic acid


glycolic acid

pyruvaldehyde

lactic acid

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mo

l]

60 120 180 240 300

Co

nv

ersi

on

[m

ol

]

(C) H-Beta-Al2O3 (MC)_175 C

Note traces of pyrvaldehyde and lactic acid were also detected at 150 C

traces of acetol and acetaldehyde were also detected at 150 C and 175 C

Figure 103 The degree of conversion and selectivity to liquid products obtained in the hydrothermal oxidation of 02 M glycerol in the presence

of H-Betaγ-Al2O3 (MC) at (A) 125 degC (B) 150 degC and (C) 175 degC 35 bar at the residence time of 60-300 s the molar glycerolH2O2 ratio = 1 1

g of extruded H-Betaγ-Al2O3 (MC) The data presented is from a single experiment The raw data is tabulated in Table 64 in the Appendix

305

The selectivity to and the yield of all liquid products are considerably higher in the

presence of a catalyst as compared to the non-catalysed system independently of the

temperature see Table 54 and Figure 103 The factors contributing to such phenomenon may

include

i the higher availability of O2 as compared to the non-catalysed systembull

ii the adsorption of glycerol andor its reaction products on the catalyst surface

resulting in their decreased availability for the reaction with H2O2 andor O2

andor HObull

The highest selectivity of ~91 mol was obtained in the H-Betaγ-Al2O3 (MC) catalysed

system at 175 degC 60 s but it decreased steadily to ~42 mol at 300 s On the other hand there

was no significant change in the selectivity at 125 degC (~11-19 mol) and 150 degC (~37-49

mol) between 60 and 300 s

The distribution of liquid products in the H-Betaγ-Al2O3 (MC) catalysed system is

shown in Figure 103 Four main products including acetic acid formic acid DHA and glycolic

acid were detected at 125 degC and 150 degC Interestingly at 175 degC pyruvaldehyde and lactic

acid known to be the transformation products of DHA (see Figure 104) were also found The

traces of pyruvaldehyde and lactic acid were also detected at 150 degC while acetol and

aceldehyde were detected at both 150 and 175 degC

At 125 and 150 degC the operating pressure of 35 bar DHA was the major liquid product

at all the residence times studied except for at 150 degC 300 s The selectivity to DHA (~21

mol) peaked at 150 degC 120 s with the glycerol conversion of ~26 mol and hence the DHA

yield of 54 mol At 175 degC the main product was formic acid (~20-33 mol selectivity) at

60-120 s At longer residence times the lactic acid was predominant (max 225 mol

306

selectivity) The selectivity to formic acid was highest at 175 degC irrespectively of the residence

time

Figure 104 The proposed reaction pathways for the oxidation of glycerol over the PtSn-MFI

catalyst (Cho Chang amp Fan 2014b)

732 Effect of residence time on the catalytic oxidation of glycerol

in subcritical water using H-Betaγ-Al2O3 (MC) catalyst

The temperature not only affects the degree and the rate of glycerol conversion but also

the conversion of the primary liquid products Therefore it is important to find the residence

time at which the selectivity to liquid products is high

The conversion of glycerol increased with increasing residence time and temperature

see Table 54 (page 303) and Figure 103 (page 304) On the other hand while the selectivity to

liquid products in the non-catalysed reaction decreased with time the selectivity in the H-

307

Betaγ-Al2O3 (MC) catalysed system at 125 and 150 degC increased up to 120 s and then

decreased possibly due to further degradation of the liquid products At 175 degC the selectivity

to liquid products (~91 mol) was highest at 60 s possibly due to the high reaction rate at

early reaction time ie le 60 s As the residence time increases the liquid products may be

consumed in the side reactions resulting in lower selectivity at longer residence times

733 Effect of Cu-doped H-Betaγ-Al2O3 (MC) on the catalytic

oxidation of glycerol in subcritical water

The effect of Cu-doped H-Betaγ-Al2O3 (MC) on the oxidation of glycerol with H2O2

in sub-CW was evaluated using two Cu-loadings 25 wt- and 48 wt CuH-Betaγ-Al2O3

(MC) The preparation procedure and the characterisation results of the catalysts are provided

in Chapter 446 and 5533 respectively The experimental conditions and the results obtained

are shown in Table 55 The selectivities to the liquid products of the reactions catalysed by H-

Betaγ-Al2O3 25 wt- and 48 wt CuH-Betaγ-Al2O3 (MC) are shown in Figure 103 (page

304) 105 and 106 respectively

308

Table 55 A summary of results of the hydrothermal oxidation of glycerol with H2O2 in a continuous flow reactor catalysed by (i) H-Betaγ-Al2O3

(MC) (ii) 25 wt CuH-Betaγ-Al2O3 (MC) and (iii) 48 wt CuH-Betaγ-Al2O3 at 125 150 and 175 degC 35 bar and a residence time of 60-300

s Reaction conditions 02 M glycerol solution the molar ratio of glycerolH2O2 = 1 1 g of the catalyst

Temp

[degC]

Residence time

[s]

H-Betaγ-Al2O3 (MC) 25 wt CuH-Betaγ-Al2O3 (MC) 48 wt CuH-Betaγ-Al2O3 (MC)

Conversion

[mol]

Selectivitya

[C-mol]

Yieldb

[C-mol]

Conversion

[mol]

Selectivitya

[C-mol]

Yieldb

[C-mol]

Conversion

[mol]

Selectivitya

[C-mol]

Yieldb

[C-mol]

125 60 202 118 24 130 51 07 na na na

120 176 191 34 125 85 11 76 593 45

180 195 184 36 153 167 26 118 620 73

240 198 154 31 164 212 35 166 396 65

300 188 135 25 159 233 37 259 231 60

150 60 178 372 66 155 224 35 251 403 95

120 263 486 128 266 306 82 278 630 165

180 375 399 150 374 209 78 334 601 190

240 382 385 147 384 231 89 397 480 183

300 407 385 157 408 205 82 432 464 192

175 60 273 907 239 364 420 143 450 170 70

120 347 647 214 377 552 197 434 294 119

180 345 659 219 401 554 212 371 493 175

240 439 506 217 393 604 233 463 456 206

300 461 424 191 382 567 212 473 361 168

a Selectivity to all liquid products b yield of all liquid products na = not available as the experiment failed The results were obtained by performing

a single experiment

309

0

15

30

45

0

15

30

45

0

15

30

45

0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Conversion

Con

ver

sion

[m

ol

]

(A) 25 CuH-Beta-Al2O3 (MC)_125 C

0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]

(B) 25 CuH-Beta-Al2O3 (MC)_150 C

0

10

20

30

acetic acid

formic acid


glycolic acid

pyruvaldehyde

lactic acid

Residence time [s]S

elec

tivit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]

(C) 25 CuH-Beta-Al2O3 (MC)_175 C

Note traces of acetol were detected at 150 C and 175 C

traces of acetaldehyde were detected at 175 C

Figure 105 The conversion degree and selectivity to liquid products obtained in the hydrothermal oxidation of 02 M glycerol in the presence of

25 wt CuH-Betaγ-Al2O3 (MC) at (A) 125 degC (B) 150 degC and (C) 175 degC 35 bar and a residence time of 60-300 s the molar glycerolH2O2

ratio = 1 1 g of the catalyst The results were obtained by performing a single experiment

310

0

15

30

45

0

15

30

45

0

15

30

45

0

10

20

30

40


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Conversion

Con

ver

sion

[m

ol

]


0

10

20

30

40


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]


0

10

20

30

40

acetic acid

formic acid


glycolic acid

pyruvaldehyde

lactic acid


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]60 120 180 240 300

Con

ver

sion

[m

ol

]


Note traces of acetol and acetaldehyde were detected

at 150 C and 175 C




311

The conversion of glycerol catalysed by 25 wt CuH-Betaγ-Al2O3 (MC) increased

with temperature and residence time reaching a maximum of ~40 mol in 300 s at 150 degC or

180 s at 175 oC see Table 55 The conversion rate of glycerol in the presence of 25 wt CuH-

Betaγ-Al2O3 (MC) at 150 and 175 degC were higher than in the presence of H-Betaγ-Al2O3 (MC)

but the degrees of conversion were lower The higher conversion of glycerol in the H-Betaγ-

Al2O3 (MC) catalysed system was possibly be due to the higher density of Broslashnsted acid sites

of H-Beta zeolite which was found to promote the conversion of glycerol but adversely affect

the selectivity and the yield of liquid products see Figure 75 (page 240) In contrast to the

reactions at 150 and 175 degC the conversion degree rate of glycerol in the presence of 25 wt

CuH-Betaγ-Al2O3 (MC) at 125 degC was relatively low showing the crucial role of temperature

Increasing the amount of Cu loading to 48 wt increased the conversion rate especially at

150 and 175 degC but did not affect the degree of conversion

The hydrothermal oxidation of glycerol catalysed by H-Betaγ-Al2O3 25 wt- and 48

wt CuH-Betaγ-Al2O3 (MC) led to the formation of several liquid products including acetic

acid formic acid DHA glycolic acid pyruvaldehyde and lactic acid as well as traces of acetol

and acetaldehyde The distribution of these products varies depending on the temperature

residence time and catalysts see Table 55 for a summary of the conversion of glycerol

selectivity to and yield of liquid products obtained in all catalysed systems Based on the

selectivity the top-three liquid products obtained were DHA formic acid and lactic acid

DHA was dominant in every reaction at 125 and 150 degC irrespectively of the catalyst

used see Figure 103 (page 304) 105 and 106 except for the 48 wt CuH-Betaγ-Al2O3 (MC)

catalysed system at 150 degC in which the DHA was predominant only at 60 s The selectivity to

DHA varies depending mainly on the catalyst used In the H-Betaγ-Al2O3 (MC) catalysed

reaction the DHA selectivity was higher at 150 degC (11-21 mol) than at 125 degC (6-10 mol)

and 175 degC (05-18 mol) The selectivity to DHA generally increased with the residence time

312

but only up to 120 s when it started to decrease The decrease was faster at 175 degC the

selectivity started to decrease from 18 mol after 60 s to 05 mol at 300 s resulting in lower

selectivity to DHA than at 125 degC On the other hand the selectivity to DHA obtained in the

25 wt CuH-Betaγ-Al2O3 (MC) catalysed system at 125 degC increased with residence time

peaking at 22 mol after 300 s At 150 degC the selectivity maintained at 14-16 mol throughout

the run while at 175 degC the selectivity started to decrease from 16 mol after 60 s to 2 after

300 s In the presence of 48 wt CuH-Betaγ-Al2O3 (MC) the selectivity of 42 mol to DHA

was achieved at 125 degC at 60 s and then started to decrease Similar trend in the selectivity was

observed at 150 degC and 175 degC The results indicate that in addition to the temperature and the

residence time the presence of Cu also plays an important role in the formationtransformation

of DHA

The decrease in the selectivity of the DHA observed independently of the reaction

temperature residence time and the catalyst is likely to be caused by its transformation into

lactic acid showing an opposite trend The high selectivity to DHA did not lead to high yield

due to low conversion The highest yield of DHA (~8 mol) was achieved in the 48 wt

CuH-Betaγ-Al2O3 (MC) catalysed system at 150 degC 60 s see Figure 107A B and C

Formic acid was present independently of the residence time and temperature in the

presence of H-Betaγ-Al2O3 (MC) with the highest selectivity of ~24 mol (equivalent to ~9

mol yield) at 175 degC 60 s (see Figure 103 (page 304) 105 106 and 107) In contrast the

reactions catalysed by 25 wt CuH-Betaγ-Al2O3 (MC) did not result in a detectable amount

of formic acid at 125 degC Formic acid was detected at 150 degC only up to 120 s but it was found

at 175 degC independently of the residence time Increasing the Cu-loading from 25 wt to 48

wt led to the faster formation of formic acid as it was detected even at 125 degC

313

0

2

4

6

8

10

0

2

4

6

8

10

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2

4

6

8

10

0

2

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10

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DH

A y

ield

[C

-mo

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Residence time [s]

(A) 125 C

60 120 180 240 300

Residence time [s]

(B) 150 C

DH

A y

ield

[C

-mo

l]

Residence time [s]

(C) 175 C

60 120 180 240 300

60 120 180 240 300

48 wt CuH-Beta-Al2O3 (MC)


H-Beta-Al2O3 (MC)

Fo

rmic

aci

d y

ield

[C

-mo

l]

Residence time [s]

(D) 125 C

60 120 180 240 300

Residence time [s]

(E) 150 C

Fo

rmic

aci

d y

ield

[C

-mo

l]

Residence time [s]

(F) 175 C

60 120 180 240 300

Figure 107 The yield of dihydroxyacetone (DHA) (top) and formic acid (bottom) as a function of residence time obtained in the hydrothermal oxidation of 02

M glycerol at 125 150 and 175 degC 35 bar in the presence of H-Betaγ-Al2O3 25 wt- and 48 wt CuH-Betaγ-Al2O3 (MC) The molar glycerolH2O2 ratio

= 1 1 g of the catalyst The data presented is from a single experiment

314

Lactic acid the main precursor of which is DHA was only present at 175 degC in the

reaction catalysed by H-Betaγ-Al2O3 (MC) and 25wt CuH-Betaγ-Al2O3 (MC) see Figure

103 (page 304) and 105 In the latter case the highest selectivity to lactic acid of 28 mol was

attained after 240 s On the other hand 18-19 mol selectivity to lactic acid was obtained even

at 150 degC when 48 wt CuH-Betaγ-Al2O3 (MC) was used see Figure 106 With this catalyst

the highest yield of lactic acid (115 mol) was achieved at 175 degC 240 s see Figure 108

where the selectivity was ~25 mol Independently of the catalysts used the yield of lactic

acid at 175 degC increased with increasing residence time up to 240 s when it started to decrease

possibly due to further decomposition

0

4

8

12



H-Beta-Al2O3 (MC)

La

cti

c a

cid

yie

ld [

C-m

ol

]

Residence time [s]

at 175 C

60 120 180 240 300

Figure 108 The lactic acid yield as a function of residence time obtained in the hydrothermal

oxidation of 02 M glycerol with H2O2 at 175 degC 35 bar in the presence of various Beta-zeolite

based catalysts Molar glycerol H2O2 = 1 1 g catalyst was used

315

The decomposition of DHA may include several reaction pathways Glycolic acid and

formic acid are known to be the oxidation products of DHA (Li et al 2014) while

pyruvaldehyde is its dehydration product see Figure 104 (Cho Chang amp Fan 2014b) While

the dehydration might be catalysed by Broslashnsted acid sites of the Beta zeolite-based catalysts

the oxidation may be promoted by the Cu ion catalysed H2O2 On the other hand the Cu ions

may also play a crucial role in the formation of DHA as well as in its transformation to lactic

acid as the metal ions such as Zn2+ were reported to favour this transformation by forming a

complex with pyruvaldehyde which is the final intermediate before lactic acid is formed

(Bicker et al 2005 Kong et al 2008) see Figure 109 In fact the hydration of pyruvaldehyde

to lactic acid is a Lewis acid catalysed reaction hence any Lewis acid catalyst could promote

such reaction

Figure 109 The proposed action of Zn2+ in the formation of lactic acid from pyruvaldehyde

(adapted from from Bicker et al (2005)

7331 Conclusion

The presence of catalysts ie H-Betaγ-Al2O3 (MC) 25wt- and 48wt CuH-

Betaγ-Al2O3 (MC) increased the conversion rate of glycerol as well as the selectivity to liquid

products The three catalysts provided identical liquid products but the distribution varied with

316

the temperature residence time and the catalysts The addition of H-Betaγ-Al2O3 (MC) led to

the highest yield of formic acid while the presence of 25wt- and 48wt CuH-Betaγ-Al2O3

(MC) resulted in the highest amount of either DHA or lactic acid It should be noted that the

former is known to be the main precursor of the latter The results suggest that the CuH-Betaγ-

Al2O3 (MC) exhibiting Lewis acidity may play an important role in the formation of DHA

and its transformation into lactic acid Without the Cu2+ less DHA and lactic acid were formed

but formic acid which is a relatively low market-value was detected in a significant amount

However the use of 48 wt CuH-Betaγ-Al2O3 (MC) also led to faster degradation of

primary liquid products as compared to 25 wt CuH-Betaγ-Al2O3 (MC) resulting in lower

yield of the liquid products This may be related to the high loading of Cu ions The degradation

of primary liquid products may be alleviated by lowering the Cu loading as well as by

optimising the operating temperature and residence time

734 Stability of extruded Betaγ-Al2O3 (MC) catalysts

The shape and white colour of the H-Betaγ-Al2O3 (MC) extrudates before and after the

use in the hydrothermal oxidation of glycerol at 125 degC were preserved see Figure 110A for

the photos of the catalysts indicating the catalyst was stable under the conditions studied In

contrast the H-Betaγ-Al2O3 (MC) catalyst used at 150 and 175 degC turned light brown possibly

due to the burnt carbon materials Some of the extrudates broke into smaller pieces especially

at 175 degC The changes were also observed for 25 wt- and 48 wt CuH-Betaγ-Al2O3 (MC)

extrudates as the light blue discolouration faded away after the reaction only at 125 degC see

Figure 110B and C indicating that the Cu ions may have leached out from the extrudates during

the continuous run The extruded 25 wt CuH-Betaγ-Al2O3 (MC) catalyst turned light brown

317

colour at 175 degC as opposed to the extruded 48 wt CuH-Betaγ-Al2O3 (MC) catalyst which

turned light brown at 150 degC but then turned white at 175 degC

Figure 110 The photos of H-Betaγ-Al2O3 (MC) (A) 25 wt CuH-Betaγ-Al2O3 (MC) (B)

and 48 wt CuH-Betaγ-Al2O3 (MC) (C) before and after the use in the hydrothermal

oxidation of 02 M glycerol with H2O2 at 125 150 and 175 degC 35 bar 5-300 s Molar ratio of

glycerol H2O2 = 1 1 g catalyst was used

318

The XRD patterns of the spent H-Betaγ-Al2O3 (MC) catalysts show the characteristic

diffraction peaks of BEA structure and the γ-Al2O3 binder but the intensity of the diffraction

peaks decreased by 10 and 20 after the hydrothermal oxidation of glycerol at 125 degC and

150 degC respectively see Figure 138 in the Appendix Similarly the X-ray patterns of 25 wt

CuH-Betaγ-Al2O3 (MC) used at 125 150 and 175 degC show that both the BEA structure of

Beta zeolite and the γ-Al2O3 binder were preserved see Figure 111 However no CuO presents

in the XRD spectra of the spent catalysts irrespectively of the temperature used indicating

leaching of the metal ions see Figure 139 in the Appendix for the solubility of CuO in sub-

CW Identical changes were observed in the XRD spectra of the spent 48 wt CuH-Betaγ-

Al2O3 (MC) hence its XRD spectra are not shown due to their similarity to those of 25 wt

CuH-Betaγ-Al2O3 (MC) see Figure 111

319

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

32 36 400

1000

2000

3000

4000

6 8 10 20 22 240

2000

4000

6000

8000

10000

Inte

nsi

ty [

Co

un

ts]

2 [degree]

25 wt CuH-Beta-Al2O

3 MC

after 125 C

after 150 C

after 175 C

(A)

Red circle = -Al2O

3

(C)

Inte

nsi

ty [

Cou

nts

]

2 [degree]

CuO

(B)

Inte

nsi

ty [

Co

un

ts]

Figure 111 The overlay of the XRD patterns of 25 wt CuH-Betaγ-Al2O3 (MC) catalysts

before and after the hydrothermal oxidation of glycerol with H2O2 at 125 150 and 175 degC 35

bar The graphs (B) and (C) detail the graph (A) at 2θ = 5-25deg and 2θ = 29-43deg respectively

The leaching of the catalysts observed from their appearances and XRD patterns was

confirmed by ICP analysis of the reaction solution recovered from the oxidation of glycerol in

sub-CW (at 125 150 and 175 oC 35 bar 60-300 s) using H-Betaγ-Al2O3 (MC) 25wt- and

48wt CuH-Betaγ-Al2O3 (MC) The results are provided in Figure 112

320

60 120 180 240 300

0

20

40

60

80

100

60 120 180 240 300

0

100

200

300

400

60 120 180 240 300

0

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60 120 180 240 300

0

100

200

300

400

60 120 180 240 300

0

20

40

60

80

125 C

150 C

175 C

(G) Al_48 wt CuH-Beta-Al2O

3 (MC)

Co

nce

ntr

ati

on

of

Al

[pp

m]

Residence Time [s]

(H) Si_48 wt CuH-Beta-Al2O

3 (MC)

Co

nce

ntr

ati

on

of

Si

[pp

m]

Residence Time [s]

(I) Cu_48 wt CuH-Beta-Al2O

3 (MC)

Co

nce

ntr

ati

on

of

Cu

[p

pm

]

Residence Time [s]

(D) Al_25 wt CuH-Beta-Al2O

3 (MC)

125 C

150 C

175 C

Co

nce

ntr

ati

on

of

Al

[pp

m]

Residence Time [s]

(E) Si_25 wt CuH-Beta-Al2O

3 (MC)

Co

nce

ntr

ati

on

of

Si

[pp

m]

Residence Time [s]

(F) Cu_25 wt CuH-Beta-Al2O

3 (MC)

Co

nce

ntr

ati

on

of

Cu

[p

pm

]

Residence Time [s]

Co

nce

ntr

ati

on

of

Al

[pp

m]

Residence Time [s]

125 C

150 C

175 C

(A) Al_H-Beta-Al2O

3 (MC) (B) Si_H-Beta-Al

2O

3 (MC)

Co

nce

ntr

ati

on

of

Si

[pp

m]

Residence Time [s]

(C) Cu_H-Beta-Al2O

3 (MC)

Co

nce

ntr

ati

on

of

Cu

[p

pm

]

Residence Time [s]

Figure 112 The results of the ICP-OES analysis of aqueous Al Si and Cu detected in the reaction solution recovered after the hydrothermal oxidation of 02 M glycerol

with H2O2 in the presence of H-Betaγ-Al2O3 (MC) 25wt- and 48wt CuH-Betaγ-Al2O3 (MC) The total amount of Cu ions in 1 g of the samples used before the

reactions were 0 15 and 29 mg respectively Reaction conditions at 125 150 and 175 degC 35 bar 60-300 s the molar ratio of glycerolH2O2 = 1

321

High amounts of dissolved Al and Si ions were detected in all reaction solutions

indicating the dissolution of the Beta zeolite-based catalysts and possibly the γ-Al2O3 The

solution recovered from the H-Betaγ-Al2O3 (MC) catalysed system contain 06-89 ppm of Al

ions and 10-169 ppm Si ions see Figure 112A and B respectively while the XRD spectra of

the solids show no structural changes in the BEA structure see Figure 111 as well as Figure

138 in the Appendix The concentration of Si increases with the temperature and the residence

time reaching a maximum of 169 ppm at 175 degC 300 s while the concentration of Al remains

unchanged at 125 degC (1 ppm) and 175 degC (5-7 ppm) but increases significantly with time at

150 oC

The concentrations of Si in the reaction solution of 25wt CuH-Betaγ-Al2O3 (MC)

at 125 150 and 175 ordmC are between ~37-442 ppm (equivalent to 35-615) higher than that of

H-Betaγ-Al2O3 (MC) see Figure 112E vs B The concentration of Al in the reaction solution

at 125 and 175 oC is also significantly higher (~43-2679) but at 150 degC the concentration of

Al in the 25wt CuH-Betaγ-Al2O3 (MC) catalysed system is 12-19 lower than in the H-

Betaγ-Al2O3 (MC) catalysed system see Figure 112D vs A

It should be noted that the flow rate of the reaction solution was set to increase with

time As a consequence the reaction solution contacted with the extruded zeolite catalysts for

longer time was sampled as first possibly contributing to the higher amounts of ions detected

at longer residence times In addition it was apparent that the concentration of Si ions tended

to increase with increasing temperature and residence time This is in a good agreement with

the trend of Si concentration observed in the dissolution of H-Beta zeolite in HLW see Figure

89 (page 268) However the concentration of Al and Cu ions in some reaction solutions did

not increase with temperature andor residence time indicating the leaching of extruded Beta

zeolite-based catalysts in a continuous flow reactor may be controlled by a range of factors

such as the temperature residence time flow rate and the shape and strength of the extruded

322

catalysts The complexity of the dissolution of extruded Beta zeolite in a continuous flow

reactor may also attributed to the very low concentrations of Al and Cu ions present in the

catalysts The low ion concentrations resulted in higher experimental error as compared to the

Si

The concentration of Si in the reaction solution of 48wt CuH-Betaγ-Al2O3 (MC)

was 27-72 lower than that of 25 wt CuH-Betaγ-Al2O3 (MC) The concentration of Si

(~27-120 ppm) increased with temperature but it was not significantly affected by the residence

time The development of Al and Cu concentrations did not show a clear trend with varying

temperature 4-19 ppm of Al and 3-68 ppm of Cu (equivalent to 001-018 wt of the total

amount of Cu ions) were detected in the range of temperatures and residence times studied

While the aqueous Al concentration did not considerably change with the residence time the

Cu concentration tended to increase with increasing residence time at 125 and 175 oC but it

showed an opposite trend at 150 oC for 48wt CuH-Betaγ-Al2O3 (MC) These changes

similarly to the case of 25 wt CuH-Betaγ-Al2O3 (MC) may be attributed to the complexity

of the dissolution of the extruded Beta zeolite in a continuous flow reactor

323

8 Summary and Future work

81 Summary

The aim of this thesis was to improve our understanding of the hydrothermal conversion

of glycerol facilitated by ZSM-5 and Beta zeolite based catalysts with respect to (i) their

activity and (ii) their potential to affect the distribution of liquid reaction products The

experimental study addressed the following objectives (i) the preparation and characterisation

of H-zeolites and metal-doped zeolites (ii) the effect of key reaction parameters (iii) the effect

of the prepared catalysts on the selectivity and yield of liquid reaction products of glycerol (iv)

the design and modification of a continuous flow system and (iv) the kinetic study of glycerol

transformations under selected conditions

Objective I The preparation and characterisation of H-zeolites and metal-

doped zeolites

H-ZSM-5 and H-Beta zeolite were successfully prepared by thermal treatment of their

NH4-forms M-doped zeolites (Mzeolites) where M = Ce Cu La Sn Zn and zeolite = NH4-

ZSM-5 H-ZSM-5 NH4-Beta and H-Beta zeolite were prepared by solid state ion exchange

(SSIE) reaction of zeolites and metal salts at 550 degC The XRD analysis of the Mzeolites

revealed that the BEA and MFI frameworks of Beta zeolite and ZSM-5 respectively remained

preserved but corresponding metal oxides were also detected The BET N2 surface areas of

NH4-Beta zeolite H-Beta zeolite NH4-ZSM-5 and H-ZSM-5 considerably decreased after the

SSIE possibly due to the blockage of the zeolite pores by metal aggregates The TPD-NH3

analysis showed that the density of the Broslashnsted acid sites of the Mzeolites were ~50-90

324

lower than that of their H-forms suggesting successful replacement of the balancing H+ or

NH4+ by the metal ions However the decreased surface acidity of the Mzeolites may also be

associated with the blockage of the zeolite pores by metal aggregates

The preparation of metal-doped dealuminated zeolites MdeAl-ZSM-5 and MdeAl-

Beta zeolite was attempted but the work on the former was abandoned due to a low

dealumination degree (~6 wt Al extracted) possibly resulting from rigid framework of ZSM-

5 ~97-98 Al was extracted from Beta zeolite while its BEA framework remained preserved

MdeAl-Beta zeolites were prepared by SSIE Similarly to Mzeolites their XRD spectra show

the presence of corresponding metal oxides It was also found that the prepared catalysts have

no Broslashnsted acid sites and decreased BET surface area as compared to H-Beta zeolite

Objective II The effect of key reaction parameters

Two hydrothermal transformation reactions of glycerol were studied in this work

dehydration and oxidation The dehydration was performed in batch tubular reactors at 270-

360 ordmC saturated vapour pressure (55-186 bar) 5-300 min Acetaldehyde was the main liquid

product under all conditions studied The glycerol conversion was rather low but gradually

increased with increasing temperature and reaction time max conversion ~59 mol (liquid

yield of ~21 C-mol) at 330 degC 128 bar after 300 min

The oxidation of glycerol with H2O2 was performed in both batch and continuous flow

reactors Batch tubular reactors were used for identifying suitable reaction conditions as well

as catalysts The conditions studied were 125-200 ordmC autogenic pressure 5-120 min The

results showed that the liquid reaction products rapidly decomposed into gasses possibly due

to the presence of highly reactive HObull As opposed to the conversion of glycerol the selectivity

325

to and yield of liquid products decreased with temperature and reaction time The high degree

of glycerol oxidative conversion and yield of its liquid products were obtained at le 175 degC le

5 min

The oxidation of glycerol in a continuous flow packed bed reactor was performed at

125-175 ordmC 35 bar 60-300 s The conversion degree increased with temperature and residence

time while the selectivity to and yield of liquid products showed an opposite trend The

maximum conversion of 55 mol was obtained at 175 degC 300 s but the yield of liquid products

(lt2 C-mol) was significantly lower than that obtained in a batch mode (~1-23 C-mol at

max ~56 mol conversion) Dihydroxyacetone (DHA) and formic acid (FA) were the main

liquid products

Objective III The effect of prepared catalysts on the selectivity and yield of

liquid reaction products of glycerol

The effect of the prepared catalysts see Objective I on the hydrothermal dehydration

of glycerol was investigated at 270-360 degC 55-186 bar 5-300 min in batch tubular reactors

Several reaction products with acrolein as the main liquid product with the highest selectivity

of ~38 mol at 330 degC 5 min on H-Beta zeolite were detected At longer reaction times

acrolein decomposed and acetaldehyde became the main product (max selectivity ~26 mol

in 30 min) The addition of Mzeolites did not increase the degree of glycerol conversion but

increased the total selectivity towards the liquid products The possible explanation is that the

metals may form complexes with glycerol or its reaction products retarding their

transformationdecomposition 48 LaNH4-Beta resulted in a 56 mol glycerol conversion

with a 36 mol selectivity towards acetaldehyde MdeAl-Beta zeolite did not show better

activity than Mzeolites

326

The hydrothermal oxidation of glycerol with H2O2 was performed at 125 150 and 175

ordmC 35 bar 60-300 s in the presence of 0 wt 25 wt- and 48 wt CuH-Beta catalysts

extruded with γ-Al2O3 As compared to non-catalysed oxidation the addition of CuH-Beta

zeolites did not increase the conversion degree but promoted the conversion rate of glycerol as

well as the selectivity towards liquid products The liquid products detected included

dihydroxyacetone (DHA) formic acid (FA) acetic acid glycolic acid pyruvaldehyde and

lactic acid (LA) The distribution of these products varied with the temperature residence time

and the type of catalyst The top-three main products obtained were DHA FA and LA The

highest yield of DHA (~8 mol) was achieved with 48 wt CuH-Betaγ-Al2O3 (MC) at 150

degC 60 s The same catalyst also provided LA with the highest yield of 115 mol at 175 degC

240 s FA was detected with the highest yield of ~9 mol at 175 degC 60 s on H-Betaγ-Al2O3

(MC)

Despite the promising activity on the hydrothermal transformations of glycerol ZSM-

5 and Beta zeolite-based catalysts are unstable in HLW dissolving Al and Si participating in

the reactions The dissolution of zeolites varies with temperature and the type of frameworks

Beta zeolite was found to be more susceptible to HLW than ZSM-5


A bench-top continuous flow system was designed and modified for the hydrothermal

conversion of glycerol operating at high temperature pressure

327

Objective V Kinetic study of selected reactions

The kinetic analysis of hydrothermal dehydration of glycerol was conducted using the

data collected on the non-catalysed H-ZSM-5 H-Beta and deAlBetaII4h catalysed reactions

at 270-330 degC saturated vapour pressure 60-300 min

The reaction rate constants of the zeolite catalysed reactions are higher than those of

non-catalysed reactions and decrease in the following order H-ZSM-5 gt H-Beta gt

deAlBetaII4h gt no catalyst The higher reaction rate constants of the catalysed reactions are

likely to be related to the Broslashnsted acidity of the zeolite catalysts The concentration of the

Broslashnsted acid sites of H-ZSM-5 and H-Beta zeolite are 269 and 236 micromolmiddotg-1 respectively

while that of deAlBetaII4h is very close to zero The activation energy of the non-catalysed

glycerol to acetaldehyde reaction at 55-186 bar determined in this work is 2181 kJmol-1 The

H-Beta zeolite and H-ZSM-5 catalysed reactions required 32 and 40 lower activation

energy as compared to non-catalysed reactions

82 Future work

This study demonstrated that the Beta zeolite ZSM-5 and their metal-doped forms

exhibit promising activities in the hydrothermal dehydration or oxidation of diluted glycerol

providing several value-added chemicals However the zeolite catalysts may not be the most

suitable candidates for the processes as they are unstable in hot liquid water (HLW)

Modification of zeolites to increase their stability is therefore necessary The process economy

would also benefit from using concentrated glycerol feed solution as opposed to a diluted

solution

328


The data acquired in this work indicate that the hydrothermal oxidation of glycerol is

more efficient in a continuous flow reactor than in a batch reactor The hydrothermal

dehydration of glycerol was not attempted using a continuous flow reactor which may increase

the process efficiency at lower temperature and pressure

A deeper understanding of the role of solid zeolites and aqueous Al and Si species in

the conversion of glycerol would help to develop a more suitable catalyst


A TPD-NH3 and MAS-NMR analysis of extruded H-Betaγ-Al2O3 (MC) and CuH-

Betaγ-Al2O3 (MC) used to catalyse the hydrothermal oxidation of glycerol with H2O2 would

provide a better insight into the relationship between the Broslashnsted acidity catalytic activity

and zeolite structure

The results presented in this work demonstrated the potential of zeolite-based catalysts

for the hydrothermal oxidation and dehydration of glycerol However more data needs to be

gathered for a kinetic analysis and a further study on the effect of γ-Al2O3 binder reaction

pathways and mechanism is required

329

9 References

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OF CELLULOSE IN SUPERCRITICAL AND SUBCRITICAL WATER Journal of

Chemical Engineering of Japan 26(6) 676-680

Ahrens M L and H Strehlow (1965) Acid catalyzed hydration of acetaldehyde

Discussions of the Faraday Society 39(0) 112-120

Aitani A M (2004) Oil Refining and Products Encyclopedia of Energy C J Cleveland

New York Elsevier 715-729

Akah A C Cundy and A Garforth (2005) The selective catalytic oxidation of NH3 over

Fe-ZSM-5 Applied Catalysis B Environmental 59(3ndash4) 221-226

Akiya N and P E Savage (2002) Roles of water for chemical reactions in high-temperature

water Chemical Reviews 102(8) 2725-2750

Akizuki M and Y Oshima (2012) Kinetics of Glycerol Dehydration with WO3TiO2 in

Supercritical Water Industrial amp Engineering Chemistry Research 51(38) 12253-12257

Akizuki M and Y Oshima (2013) Effects of water density on acid-catalytic properties of

TiO2 and WO3TiO2 in supercritical water The Journal of Supercritical Fluids 84(0) 36-42

Al-zaidi B Y S (2011) The effect of modification techniques on the performance of zeolite-

Y catalysts in hydrocarbon cracking reactions Doctor of Philosophy The University of

Manchester

Almeida J L Faacutevaro and B Quirino (2012) Biodiesel biorefinery opportunities and

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Carrico C S F T Cruz M B Santos H O Pastore H M C Andrade and A J S

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Catalytic and Non-catalytic Supercritical Water Gasification of Microalgae and Glycerol

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Corma A G W Huber L Sauvanauda and P OConnor (2008) Biomass to chemicals

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Datta R and S-P Tsai (1997) Lactic Acid Production and Potential Uses A Technology and

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De La Torre U B Pereda-Ayo and J R Gonzaacutelez-Velasco (2012) Cu-zeolite NH3-SCR

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de Oliveira A S S J S Vasconcelos J R de Sousa F F de Sousa J M Filho and A C

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a platform chemical in the biobased economy the role of chemocatalysis Energy amp

Environmental Science 6(5) 1415-1442

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incorporation of V in β zeolite Journal of Molecular Catalysis A Chemical 155(1ndash2) 169-

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silver atoms into the vacant T-atom sites of the framework of SiBEA Zeolite as mononuclear

Ag(I) evidenced by XRD FTIR NMR DR UV-vis XPS and TPR Journal of Physical

Chemistry C 117(24) 12552-12559

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Encyclopedia of Industrial Chemistry Wiley-VCH Verlag GmbH amp Co KGaA

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Pressure Aqueous Environments 8 Improved Catalysts for Hydrothermal Gasification


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aqueous environments 2 Development of catalysts for gasification Industrial amp Engineering


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Alkaline Hydrothermal Processes ChemSusChem 6(6) 989-992

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acidity of acid-treated montmorillonite clay catalysts Journal of Molecular Catalysis A

Chemical 168(1ndash2) 247-256

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Electron Microscopy and Diffractometry of Materials Springer Berlin Heidelberg 1-57

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Pdalumina hollow fibre membrane reactor for propane dehydrogenation Catalysis Today

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thermogravimetric analysis Solid State Ionics 93(1ndash2) 51-64

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Mn(III) schiff-base complex using hydrogen peroxide as an oxidant Chinese Journal of

Catalysis 31(6) 615-618

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1417-1425

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Biomass Residues To Transportation Fuels With The HTUreg Process

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Catalytic Reduction of NO x of Ship Diesel Engine Exhaust Gas with C3H6 over CuY

Zeolite ACS Catalysis 4(8) 2479-2491

Haider M H N F Dummer D W Knight R L Jenkins M Howard J Moulijn S H

Taylor and G J Hutchings (2015) Efficient green methanol synthesis from glycerol Nat

Chem advance online publication

Hamdy M S and G Mul (2013) TUD‐1‐Encapsulated HY Zeolite A New Hierarchical

MicroporousMesoporous Composite with Extraordinary Performance in Benzylation

Reactions ChemCatChem 5(10) 3156-3163

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active Lewis acidic Sn-Beta Angewandte Chemie-International Edition 51(47) 11736-

11739

Han Y and J Zhang (2015) Methods of making formic acid from glycerol Kingdom of Saudi

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performance of dealuminated HndashY zeolite supported bimetallic nanocatalysts in

Hydroizomerization of n-hexane and n-heptane Egyptian Journal of Petroleum 23(1) 119-

133

340

Hargreaves J S J and A L Munnoch (2013) A survey of the influence of binders in zeolite

catalysis Catalysis Science amp Technology 3(5) 1165-1171

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in hydrogen-rich mixtures by permeation through a platinum-loaded Y-type zeolite

membrane Journal of Membrane Science 190(1) 1-8

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Environmental Solids with Sub- and Supercritical Water Analytical Chemistry 66(18) 2912-

2920

Hayashi H and Y Hakuta (2010) Hydrothermal synthesis of metal oxide nanoparticles in

supercritical water Materials 3(7) 3794-3817

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of zeolite Beta by FTir spectroscopy and tpd of NH3 Zeolites 9(3) 231-237

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J Sherwood S P Binks and A D Curzons (2011) Expanding GSKs solvent selection

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Chemistry 13(4) 854-862

Herrero M A Cifuentes and E Ibanez (2006) Sub-and supercritical fluid extraction of

functional ingredients from different natural sources Plants food-by-products algae and

microalgae A review Food chemistry 98(1) 136-148

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dispersed on dealuminated beta zeolite Journal of Molecular Catalysis A Chemical 136(3)

293-299

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Plants Journal of Agricultural and Food Chemistry 60(23) 5915-5921

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energy-absorption coefficients 1 keV to 20 MeV for elements Z= 1 to 92 and 48 additional

substances of dosimetric interest National Inst of Standards and Technology-PL

Gaithersburg MD (United States) Ionizing Radiation Div

Huber G W J Shabaker and J Dumesic (2003) Raney Ni-Sn catalyst for H2 production

from biomass-derived hydrocarbons Science 300(5628) 2075-2077

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Hunger B J Hoffmann O Heitzsch and M Hunger (1990) Temperature-programmed

desorption (TPD) of ammonia from HZSM-5 zeolites Journal of Thermal Analysis 36(4)

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NMR Spectroscopy Catalysis Reviews 39(4) 345-393

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58

Izumizaki Y K C Park Y Tachibana H Tomiyasu and Y Fujii (2005) Organic

decomposition in supercritical water by an aid of ruthenium (iv) oxide as a catalyst-exploitation

of biomass resources for hydrogen production Progress in Nuclear Energy 47(1-4) 544-552

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3113-3119

Sasaki M Z Fang Y Fukushima T Adschiri and K Arai (2000) Dissolution and

Hydrolysis of Cellulose in Subcritical and Supercritical Water Industrial amp Engineering


Sasaki M M Furukawa K Minami T Adschiri and K Arai (2002) Kinetics and

Mechanism of Cellobiose Hydrolysis and Retro-Aldol Condensation in Subcritical and


Scheithauer A E von Harbou H Hasse T Gruetzner C Rijksen D Zollinger and W R

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354

Shabaker J W and J A Dumesic (2004) Kinetics of Aqueous-Phase Reforming of

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Shabaker J W G W Huber R R Davda R D Cortright and J A Dumesic (2003)

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Letters 88(1-2) 1-8

Shabaker J W G W Huber and J A Dumesic (2004) Aqueous-phase reforming of

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Shabaker J W D A Simonetti R D Cortright and J A Dumesic (2005) Sn-modified Ni

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16(25) 7368-7371

Shen Z F Jin Y Zhang B Wu A Kishita K Tohji and H Kishida (2009) Effect of

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355

Srokol Z A-G Bouche A van Estrik R C J Strik T Maschmeyer and J A Peters (2004)

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Talebi G M Sohrabi R L Keiski M Huuhtanen S J Royaee S Maghsoudi and H

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356

Toney M F (1992) 1 - INTRODUCTION AND SUMMARIES Encyclopedia of Materials

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Trombetta M G Busca M Lenarda L Storaro R Ganzerla L Piovesan A Jimenez Lopez

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357

van Kooten W E J B Liang H C Krijnsen O L Oudshoorn H P A Calis and C M van

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httpwwwinnovationservicesphilipscomsitesdefaultfilesmaterials-analysis-icp-aespdf

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358

Werpy T and G Petersen (2004) Top Value Added Chemicals from Biomass Volume I --

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Xia Y and R Mokaya (2004) On the synthesis and characterization of ZSM-5MCM-48

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Xu H J Guan S Wu and Q Kan (2009) Synthesis of BetaMCM-41 composite molecular

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Xu J Y Zhao H Xu H Zhang B Yu L Hao and Z Liu (2014) Selective oxidation of

glycerol to formic acid catalyzed by Ru(OH)4r-GO in the presence of FeCl3 Applied

Catalysis B Environmental 154ndash155 267-273

Xu X W Yang J Liu L Lin N Stroh and H Brunner (2004) Synthesis of NaA zeolite

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Xue M R Chitrakar K Sakane T Hirotsu K Ooi Y Yoshimura M Toba and Q Feng

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Yadav M K M V Patil and R V Jasra (2009) Acetoxylation and hydration of limonene

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Yamamura M K Chaki T Wakatsuki H Okado and K Fujimoto (1994) Synthesis of

ZSM-5 zeolite with small crystal size and its catalytic performance for ethylene

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359

Yamamura T T Mori K C Park Y Fujii and H Tomiyasu (2009) Ruthenium(IV)

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Yampolskii Y (2012) Polymeric Gas Separation Membranes Macromolecules 45(8)

3298-3311

Yan X F Jin K Tohji A Kishita and H Enomoto (2010) Hydrothermal conversion of

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Yang S-T J Kim and W-S Ahn (2010) CO2 adsorption over ion-exchanged zeolite beta

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90-94

Ye X P and S Ren (2014) Value-added chemicals from glycerol ACS Symp Ser

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Yu Y X Lou and H Wu (2008) Some recent advances in hydrolysis of biomass in hot-

compressed water and its comparisons with other hydrolysis methods Energy and Fuels

22(1) 46-60

Yuksel A H Koga M Sasaki and M Goto (2009) Electrolysis of glycerol in subcritical

water Journal of Renewable and Sustainable Energy 1(3)

Yuksel A H Koga M Sasaki and M Goto (2010) Hydrothermal Electrolysis of Glycerol

Using a Continuous Flow Reactor Industrial amp Engineering Chemistry Research 49(4) 1520-

1525

Zapata P A J Faria M P Ruiz R E Jentoft and D E Resasco (2012) Hydrophobic

zeolites for biofuel upgrading reactions at the liquidndashliquid interface in wateroil emulsions

Journal of the American Chemical Society 134(20) 8570-8578

Zhang J (2015) Biomass Conversion over Heteropoly Acid Catalysts King Abdullah

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Zhang L K Chen B Chen J L White and D E Resasco (2015) Factors that Determine

Zeolite Stability in Hot Liquid Water Journal of the American Chemical Society 137(36)

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Zhang S F Jin J Hu and Z Huo (2011) Improvement of lactic acid production from

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Technology 102(2) 1998-2003

Zhang Y (2010) Hydrothermal liquefaction to convert biomass into crude oil Biofuels

from agricultural wastes and byproducts 201

360

Zhang Y B R Bakshi and E S Demessie (2008) Life cycle assessment of an ionic liquid

versus molecular solvents and their applications Environmental Science and Technology

42(5) 1724-1730

Zhang Y Y Zhou A Qiu Y Wang Y Xu and P Wu (2006) Effect of alumina binder on

catalytic performance of PtSnNaZSM-5 catalyst for propane dehydrogenation Industrial amp

engineering chemistry research 45(7) 2213-2219

Zhang Y l M Zhang Z Shen J f Zhou and X f Zhou (2013) Formation of formic acid

from glycerine using a hydrothermal reaction Journal of Chemical Technology and

Biotechnology 88(5) 829-833

Zhang(a) Y Z Shen X Zhou M Zhang and J Zhou (2014) Process for producing formic

acid by hydrothermal oxidation reaction with glycerol and their equipment Tongii University

Shanghai (CN) US 008772538B2

Zhang(b) J M Sun and Y Han (2014) Selective oxidation of glycerol to formic acid in

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phosphomolybdic acids RSC Adv

Zhao C Y Yu A Jentys and J A Lercher (2013) Understanding the impact of aluminum

oxide binder on NiHZSM-5 for phenol hydrodeoxygenation Applied Catalysis B

Environmental 132 282-292

Zhou C-H J N Beltramini Y-X Fan and G Q Lu (2008) Chemoselective catalytic

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Society Reviews 37(3) 527-549

Zhou C-H J N Beltramini C-X Lin Z-P Xu G Q Lu and A Tanksale (2011) Selective

oxidation of biorenewable glycerol with molecular oxygen over Cu-containing layered double

hydroxide-based catalysts Catalysis Science amp Technology 1(1) 111-122

Zhou J Z Hua J Zhao Z Gao S Zeng and J Shi (2010) A micromesoporous

aluminosilicate key factors affecting framework crystallization during steam-assisted

synthesis and its catalytic property Journal of Materials Chemistry 20(32) 6764-6771

Ziemniak S (1995) Solubility behavior of quartz and corundum in supercritical water A

quantitative thermodynamic interpretation Knolls Atomic Power Lab Schenectady NY

(United States)

Zimmermann F J (1954) Waste disposal Sterling Drug Inc US2665249 A

361

10 Appendix

Figure 113 HPLC chromatogram of reaction solution obtained from the hydrothermal

dehydration of glycerol at 330 degC 1297 bars 1 h in the presence of 48 CeNH4-Beta zeolite

The weight ratio of glycerol cat = 1 to 1 the molar ratio of glycerol to acid sites of the catalyst

used = 711

362

Figure 114 HPLC calibration curves for glycerol acetic acid acetaldehyde lactic acid and

glycolic acid

y = 28146x + 1252

Rsup2 = 09849

y = 49077x - 16235

Rsup2 = 09979

y = 78768x - 12788

Rsup2 = 09838

y = 86171x - 05366

Rsup2 = 09996

y = 9912x + 13915

Rsup2 = 09953

0

100

200

300

400

500

600

700

800

900

1000

0 2 4 6 8 10 12 14

Are

a

Concentration [mM]

glycerol acetic acid acetaldehyde3

lactic acid glycolic acid Linear (glycerol)

Linear (acetic acid) Linear (acetaldehyde3) Linear (lactic acid)

Linear (glycolic acid)

363

Figure 115 HPLC calibration curves for DHA acrolein and acetol

Figure 116 HPLC calibration curves for pyruvaldehyde and formic acid

y = 16711x + 23975

Rsup2 = 09933

y = 19991x + 12406

Rsup2 = 0999

y = 56833x + 24233

Rsup2 = 099590

5000

10000

15000

20000

25000

30000

0 2 4 6 8 10 12 14

Are

a

Concentration [mM]

DHA acroleinacetol Linear (DHA)Linear (acrolein) Linear (acetol)

y = 28396x - 26609

Rsup2 = 09997

y = 64254x - 20459

Rsup2 = 09981

0

200

400

600

800

1000

1200

1400

1600

0 5 10 15 20 25

Are

a

Concentration [mM]

pyruvaldehyde formic acid

Linear (pyruvaldehyde) Linear (formic acid)

364

Table 56 The volume flow rate at different temperatures with different residence times

Temperature

[degC]

Residence time

[s]

Total flow rate

[mlmin]

Feed flow rate

[mlmin]

Water flow rate

[mlmin]

125 60 39286 1310 2619

120 19643 0655 1310

180 13095 0437 0873

240 09822 0327 0655

300 07857 0262 0524

150 60 38465 1282 2564

120 19232 0641 1282

180 12822 0427 0855

240 09616 0321 0641

300 07693 0256 0513

175 60 37662 1255 2511

120 18831 0628 1255

180 12554 0418 0837

240 09416 0314 0628

300 07532 0251 0502

TGA and DSC analysis of NH4-Beta zeolite and NH4-ZSM-5

The water content of NH4-Beta zeolite and NH4-ZSM-5 as well as the decomposition

of their balancing NH4+ were analysed by the thermogravimetric analysis (TGA) and

differential scanning calorimetry (DSC) The TGA dTG and DSC curves of NH4-Beta zeolite

and NH4-ZSM-5 are shown in Figure 117 and 118 respectively

Upon heating the samples from 30 to 150 degC a steep weight loss of ~9 and ~5 is

observed at up to about 100 degC in the TGAdTA thermograms obtained for NH4-Beta zeolite

and NH4-ZSM-5 respectively This weight loss is likely to be due to the loss of physically

adsorbed water (Deepesh et al 2013) corresponding to the sharp endothermic peaks present

in the DSC curves of NH4-Beta zeolite at 146 degC and of NH4-ZSM-5 at 124 and 140 degC The

weight loss observed from 150 to 600 degC may be attributed to desorption of remaining water

365

bounded in the zeolite framework as well as the formation of NH3 from NH4+ ions in the zeolite

pores (Al-zaidi 2011 Hanafi et al 2014) However the weight losses from 150 to 600 degC

recorded for NH4-Beta zeolite and NH4-ZSM-5 are different For NH4 Beta zeolite a steady

weight loss of 28 was observed up to about 186 degC followed by a gradual loss in the weight

adding a further weight loss of 38 at 600 degC Its DSC curve shows an endothermic peak at

217 degC No other peaks were detected in neither DSC nor TGA indicating the material is of

high purity On the other hand the TGA spectra of NH4-ZSM-5 at 150 to 600 degC shows steps

the weight loss of 28 12 and 16 at 207 degC 327 degC and 436 degC respectively The DSC

curve of NH4-ZSM-5 exhibits an endothermic peak at 207 degC prior to deviating from linearity

and steadily increasing at 419 degC Similar to the case of NH4-Beta zeolite the weight loss of

NH4-ZSM-5 at this temperature range may be attributed to desorption of water locatedbound

in zeolite cavities and dissociation of NH3 from NH4+ ions although this occurs in a more

complex manner for NH4-ZSM-5 due to its smaller pore sizes

The obtained results indicate that the thermal treatments of NH4-Beta zeolite and NH4-

ZSM-5 at the temperature range of 30-600 degC lead to the weight loss attributed mainly to the

loss of physically adsorbed water and hydroxyl groups in the zeolite framework The weight

loss was found to be higher for NH4-Beta zeolite than for NH4-ZSM-5 possibly due to its higher

surface area and bigger pore size

366

0 100 200 300 400 500 600

-20

-15

-10

-5

0

278

100 C

379

596 C

TGA

wei

gh

t lo

ss

NH4-Beta zeolite

943

186 C

-03

-02

-01

00

01

02

dTG

Der

iv w

eigh

t [

C

-1]

Temperature [C]

80

82

84

86

88

90

92

94

96

98

100

217 C

146 C

TGA

Wei

gh

t [

]

NH4-Beta zeolite

0 100 200 300 400 500 600

-20000

-15000

-10000

-5000

0

5000

DSC

Temperature [C]

Heat

Flo

w [

mWg

-1]

Figure 117 TGA vs dTG plots (top) and TGA vs DSC plots for NH4-Beta zeolite

367

0 100 200 300 400 500 600

-15

-10

-5

0

502

161

116

30 C

436 C

327C

w

eigh

t lo

ss TGA

100C

207C

280

-010

-005

000

005

dTG

Der

iv w

eigh

t [

C

-1]

Temperature [C]

NH4-ZSM-5

0 100 200 300 400 500 600

-2500

-2000

-1500

-1000

-500

0

500

1000

1500

207 C

140 C

124 C

DSC

Temperature [C]

Hea

t F

low

[m

Wg

-1]

90

95

100

TGA

w

eig

ht

loss

NH4-ZSM-5

Figure 118 TGA vs dTG plots (top) and TGA vs DSC plots for NH4-ZSM-5

368

10 20 30 40 50 60 70

0

7000

0

7000

0

7000

0

7000

0

7000

2 [degree]

48 wt CeNH4-Beta

x CeO2

O ZnO SnO2+ NaCl

xx x

x

48 wt LaNH4-Beta

Inte

nsi

ty [

co

un

ts]

48 wt ZnNH4-Beta

O OO O

+

48 wt SnNH4-Beta

+

NH

4-Beta

+

+ +

+

+ +

+

+ + +

+

+

+ +

+

+

Figure 119 The XRD patterns of NH4-Beta zeolite and 48 wt MNH4-Beta zeolite where

M = Ce La Sn and Zn prepared by SSIE using corresponding metal salt as a precursor at 550

degC for 3 h at a heating rate of 100 degCh NaCl used as an internal standard at the zeolite to

NaCl mass ratio of 267 was added to the samples prior to analysis Symbol + = NaCl ZnO

ο = SnO2 x = CeO2

369

10 20 30 40 50 60 70

0

7500

0

7500

0

7500

0

7500

0

7500

Inte

nsi

ty [

cou

nts

]

2 [degree]

48 wt CeNH4-ZSM5

+XX X

X

+ NaCl ZnO O SnO2

x CeO2

+

48 wt LaNH4-ZSM5

+

48 wt SnNH4-ZSM5

OO

OO

O

+

48 wt ZnNH4-ZSM5

+

NH

4-ZSM5+

+

+

+

+

+

+

++

+

++





370

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

8000

+

+

+ = NaCl

O

OO

O

H-Beta zeolite

deAl-BetaII4h


Inte

nsi

ty [

co

un

ts]

2 [degree]

O

= SnO

+

Inte

nsi

ty [

cou

nts

]

2 (degree)


SndeAl-BetaII4h The inset graph details the two main peaks at around 2θ = 78deg (d101) and 2θ


added to the samples prior to analysis Symbol + = NaCl o = SnO

371

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

8000

++

H-Beta zeolite

deAl-BetaII4h


Inte

nsi

ty [

cou

nts

]

2 [degree]

+ NaCl

+

ZnO

2 [degree]


ZndeAl-BetaII4h The inset graph details the two main peaks at around 2θ = 78deg (d101) and 2θ


added to the samples prior to analysis Symbol + = NaCl ZnO

372

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]

Relative Pressure [PP0]

adsorption_H-Beta

desorption_H-Beta

adsorption_H-Beta in TUD-1

desorption_H-Beta in TUD-1

Figure 123 The BET-N2 adsorptiondesorption isotherms of H-Beta zeolite (black) and H-Beta

in TUD-1 (red)

373

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm

3g

-1]


adsorption_H-Beta

desorption_H-Beta

adsorption_48 CuH-Beta

desorption_48 CuH-Beta

adsorption_48 CuH-Beta in TUD-1

desorption_48 CuH-Beta in TUD-1

Figure 124 The BET-N2 adsorptiondesorption isotherms of 48 wt CuH-Beta and 48 wt

CuH-Beta in TUD-1 (red) The BET N2 adsorptiondesorption isotherms of H-Beta zeolite

(black) are given for comparison

10 20 30 40 50 60 70

0

200

400

600

800

1000

1200

methyl cellulose

Inte

nsi

ty [

co

un

ts]

2 [degree]

10 20 30 40 50 60 70

0

200

400

600

800

1000

1200 bentonite clay

Inte

nsi

ty [

co

un

ts]

2 [degree]

Figure 125 The XRD patterns of supporting materials used to extrude the zeolite-based catalyst

in the present work (left) methyl cellulose used as a plasticiser and (right) bentonite clay used

as a binder

374

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta



adsorption_extruded 48 CuH-Betabentonite

desorption_extruded 48 CuH-Betabentonite

adsorption_extruded H-Betabentonite

desorption_extruded H-Betabentonite

Figure 126 The BET-N2 adsorptiondesorption isotherms of H-beta zeolite and 48 wt CuH-

Beta before and after the extrusion with bentonite clay The Cu content is given in weight

relative to H-Beta zeolite The content of ldquoH-Betardquo and ldquo48 wt CuH-Betardquo is 68 wt

relative to bentonite

375

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta

adsorption_extruded H-Beta-Al2O

3 (MC)

desorption_extruded H-Beta-Al2O

3 (MC)

Figure 127 The BET N2 adsorptiondesorption isotherms of H-Beta zeolite before and after

the extrusion with γ-Al2O3 in the presence of methyl cellulose (MC)

376

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta



adsorption_extruded 25 CuH-Beta-Al2O3 (MC)

desorption_extruded 25 CuH-Beta-Al2O3 (MC)

Figure 128 The BET N2 adsorptiondesorption isotherms of 25 wt CuH-Beta before and

after the extrusion with γ-Al2O3 in the presence of methyl cellulose (MC) The BET N2

adsorptiondesorption isotherms of H-Beta zeolite are shown for comparison

377

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta








378

10 20 30 40 50 60 70

0

200

400

600

800

1000

1200

methyl cellulose

Inte

nsi

ty [

co

un

ts]

2 [degree]

10 20 30 40 50 60 70

0

200

400

600

800

1000

1200

Inte

nsi

ty [

co

un

ts]

2 [degree]

-Al2O3

Figure 130 The X-ray diffractograms of methyl cellulose (MC) and γ-Al2O3 used as a

plasticiser and binder respectively

379

Table 57 A summary of results on the hydrothermal dehydration of 01 M glycerol (03 mmol) in the presence of H-Beta zeolite at different

reaction and temperature (saturated vapour pressure) The mass glycerolH2O2 ratio = 1

Time

[min]

Conversion

[mol]

Yield [C-mol] Total

Selectivity [C- mol] Total

MeOH AA LA AC FA EtOH AL AT MeOH AA LA AC FA EtOH AL AT

60 156 plusmn 01 01 01 02 13 00 00 17 04 36 03 08 10 82 00 00 105 23 231

120 331 plusmn 16 01 02 04 33 00 00 39 04 84 03 06 14 98 00 00 117 11 249

180 441 plusmn 41 02 03 20 54 00 00 32 04 115 05 07 48 125 00 00 74 09 267

240 433 plusmn 74 02 02 08 63 00 00 34 05 115 05 05 19 147 00 00 79 12 267

300 472 plusmn 33 04 04 09 74 00 00 26 04 120 07 08 19 154 00 00 56 08 252

60 431 plusmn 91 02 02 03 56 00 09 25 05 103 04 05 08 140 00 19 74 16 265

120 561plusmn00 04 04 06 102 00 03 15 04 138 07 07 10 181 00 06 27 07 246

180 655 plusmn 98 05 04 09 107 00 03 15 05 149 07 07 13 169 00 06 27 09 240

240 744 plusmn 62 06 05 06 139 00 06 15 04 180 08 07 08 188 00 08 22 05 247

300 760 plusmn 47 07 05 15 147 00 09 10 05 199 09 07 19 195 00 13 14 07 264

60 839 plusmn 24 12 05 04 207 00 10 37 07 282 14 06 04 246 00 12 44 09 335

120 859 plusmn 19 11 05 14 204 02 06 34 03 279 13 06 17 238 02 06 39 03 325

180 898 plusmn 14 16 12 05 238 02 09 19 03 303 17 13 05 266 02 10 21 03 337

240 954 plusmn 25 15 10 02 231 02 14 10 01 283 16 10 02 242 02 15 10 09 306

60 940 plusmn 20 24 11 00 243 00 07 13 02 301 26 12 00 259 00 07 14 02 319

120 975 plusmn 35 11 07 00 219 00 04 40 08 289 12 07 00 225 00 05 41 03 293

180 976 plusmn 07 23 11 00 237 00 09 08 00 288 24 11 00 243 00 09 09 00 295

240 998 plusmn 02 18 11 00 220 00 10 00 00 259 18 11 00 220 00 10 00 00 259

Note MeOH = methanol AA = acetic acid LA = lactic acid AC = acetaldehyde FA = formic acid EtOH = ethanol AL = acrolein AT = acetol

380

Table 58 A summary of results on the hydrothermal dehydration of 01 M glycerol (03 mmol) in the presence of H-ZSM-5 at different reaction

and temperature (saturated vapour pressure) The mass glycerolH2O2 ratio = 1

Time

[min]

Conversion

[mol]

Yield [C-mol] total

Selectivity [C- mol] total


60 449 plusmn 33 01 04 09 30 00 00 26 10 80 03 09 19 67 00 00 59 22 179

120 572 plusmn 43 04 07 11 57 01 02 39 09 130 08 11 20 100 02 03 67 15 227

180 743 plusmn 43 04 09 13 71 03 04 30 06 139 05 11 17 96 04 05 41 08 187

240 773 plusmn 01 04 10 11 80 00 06 43 06 160 06 14 15 103 00 07 55 07 207

300 793 plusmn 01 04 10 14 84 00 05 29 06 151 05 13 18 106 00 06 36 07 191

60 827 plusmn 40 09 17 08 130 00 07 55 11 237 11 20 09 158 00 09 67 13 288

120 937 plusmn 29 07 20 05 133 00 09 15 06 195 08 22 05 142 00 09 16 07 208

180 930 plusmn 00 08 28 03 145 00 13 10 06 256 08 30 03 155 00 14 10 07 275

240 963 plusmn 12 09 30 00 137 00 13 10 05 204 10 31 00 142 00 13 10 05 212

300 990 plusmn 05 08 29 00 138 00 13 00 03 191 08 29 00 139 00 13 00 03 193

60 980 plusmn 17 09 29 00 189 00 14 15 06 262 10 30 00 192 00 14 15 06 268

120 990 plusmn 10 08 28 00 155 00 11 00 00 203 09 29 00 157 00 11 00 00 206

180 1000 plusmn 00 08 35 00 133 00 15 00 00 190 08 35 00 133 00 15 00 00 190

240 1000 plusmn 00 06 44 00 107 00 16 00 00 173 06 44 00 107 00 16 00 00 173

300 1000 plusmn 00 07 49 00 104 00 19 00 00 180 07 49 00 104 00 19 00 00 180


381

Table 59 A summary of results on the hydrothermal dehydration of 01 M glycerol (03 mmol) in the presence of deAl-BetaII4 at different reaction


Time

[min]

Conversion

[mol]

Yield [C-mol] Total

Selectivity [C-mol] Total

MeOH AA AC EtOH AL AT MeOH AA AC EtOH AL AT

60 01 16 02 51 00 27 06 102 48 06 151 00 82 18 305

120 01 05 02 87 00 36 06 136 14 05 236 00 99 16 370

180 01 10 02 125 04 27 03 172 23 05 289 09 63 07 397

240 01 15 02 145 00 27 03 193 35 05 331 00 62 07 439

300 01 12 04 141 00 27 03 188 23 08 268 00 52 06 356

60 204 01 00 35 00 30 07 73 05 00 173 146 32 356

120 280 04 02 70 00 20 03 100 16 08 252 00 71 12 358

180 454 06 02 86 00 30 03 127 12 05 189 00 65 07 278

240 390 09 02 106 00 20 03 140 23 06 271 00 51 08 358

300 335 09 04 161 00 40 03 217 26 13 479 00 118 10 647

60 166 05 04 51 00 09 03 72 30 24 305 00 55 18 433

120 639 17 02 158 00 27 00 205 27 03 247 00 43 00 320

180 597 21 04 172 00 36 03 237 36 07 289 00 61 05 397

240 720 31 06 193 14 27 03 275 44 08 267 20 38 04 381

300 676 31 08 180 14 18 03 255 46 12 267 21 27 04 378

Note MeOH = methanol AA = acetic acid AC = acetaldehyde EtOH = ethanol AL = acrolein AT = acetol

382

Figure 131 The determination of reaction order for the glycerol conversion at 270 300 and

330 degC saturated vapour pressure ((55-186 bar) using H-Beta catalyst at the glycerol to catalyst

weight ratio of 1

y = -3E-05x - 23164

Rsup2 = 09454-3

-28

-26

-24

-22

-2

0 5000 10000 15000 20000

ln[g

ly]

Time [s]

ln[gly] vs time H-beta dehydration at 270 ordmC

y = -8E-05x - 23627

Rsup2 = 09444-4

-38

-36

-34

-32

-3

-28

-26

-24

-22

-2

0 5000 10000 15000 20000

ln[g

ly]

Time [s]

ln[gly] vs time H-Beta dehydration at 300 ordmC

y = -00002x - 27519

Rsup2 = 08891

-62

-57

-52

-47

-42

-37

-32

-27

-220 5000 10000 15000 20000

ln[g

ly]

Time [s]


383

Table 60 The reaction constants (k) of hydrothermal dehydration of glycerol at different temperatures and in the presence of various catalysts

The mass glycerolcatalyst ratio = 1 The k1 k2 and k3 are the rates of the glycerol conversion to acetaldehyde acetaldehyde to its degradation

products and glycerol to other reaction products respectively

Catalyst Temp

[degC] Time

[s]

[ Gly]

M

[AC]

M 119948120783 [119956minus120783] 119948120784 [119956minus120783] 119948120785 [119956minus120783]

No Catalyst 270 0 01024 00000 396E-07 753E-11 152E-06

3600 01024 00000

7200 01024 00000

10800 01024 00000

14400 00997 00007

18000 00969 00010

300degC 0 01143 00000 462E-05 273E-04 247E-05

3600 01087 00120

7200 00956 00158

10800 00886 00123

14400 00862 00165

18000 00773 00149

330degC 0 01020 00000 174E-05 488E-13 257E-05

3600 00882 00039

7200 00761 00088

10800 00669 00144

14400 00561 00190

18000 00415 00247

H-Beta Zeolite 270degC 0 01035 00000 880E-06 375E-10 306E-05

3600 00874 00020

7200 00752 00053

384

10800 00620 00088

14400 00602 00101

18000 00565 00116

300degC 0 01126 00000 278E-05 171E-06 780E-05

3600 00632 00094

7200 00494 00170

10800 00378 00180

14400 00282 00233

18000 00265 00248

330degC 0 01122 00000 141E-04 266E-12 297E-04

3600 00154 00281

7200 00149 00323

10800 00108 00378

14400 00050 00365

18000 00022 00365

360degC 0 01117 00000 319E-04 360E-06 574E-04

3600 00026 00364

7200 00070 00406

10800 00026 00397

14400 00003 00367

H-ZSM-5 270degC 0 01076 00000 174E-05 161E-06 101E-04

3600 00592 00049

7200 00461 00092

10800 00276 00115

14400 00244 00129

18000 00222 00135

300degC 0 00949 00000 108E-04 766E-06 362E-04

3600 00164 00185

7200 00060 00189

385

10800 00066 00206

14400 00035 00195

18000 00009 00196

330degC 0 01065 00000 309E-04 376E-05 807E-04

3600 00020 00278

7200 00011 00204

10800 00000 00212

14400 00000 00170

18000 00000 00166

deAlBetaII4h 270degC 0 01105 00000 271E-05 373E-05 190E-05

3600 00736 00084

7200 00698 00144

10800 00627 00208

14400 00620 00241

18000 00523 00234

300degC 0 01015 00000 155E-05 287E-11 282E-05

3600 00808 00054

7200 00731 00107

10800 00554 00131

14400 00619 00161

18000 00675 00245

330degC 0 01102 00000 432E-05 300E-05 427E-05

3600 00919 00084

7200 00398 00261

10800 00444 00285

14400 00308 00318

18000 00357 00298

Note Gly = glycerol and AC = acetaldehyde

386

Table 61 The ICP-OES analysis results on aqueous Si and Al concentrations of mother solutions recovered from various hydrothermal systems

containing H-Beta zeolite and ZSM-5 The numbers presented are average from at least two experiments

Zeolite Temp

[degC]

Time

[h] Al Si

ppm wt ppm wt

H-Beta zeolite - watera

H-Beta RT 1 051 plusmn 01 326 plusmn 05 013 plusmn 00

20 050 plusmn 01 022 plusmn 00 749 plusmn 05 030 plusmn 00


H-Beta 150 1 165 plusmn 06 072 plusmn 03 16730 plusmn 76 544 plusmn 01









3 426 plusmn 02 186 plusmn 01 42605 plusmn49 1200 plusmn 04



H-Beta zeolite ndash water - glycerolb

H-Beta 330 008 420 183 60050 1692

017 271 118 58860 1658

025 374 163 60340 1700

05 356 155 60350 1700

075 298 130 61950 1745

1 232 101 62150 1751

387

H-ZSM-5 ndash water - glycerolb

H-ZSM-5 330 008 133 058 56978 1605

017 186 081 52511 1479

025 222 097 51823 1460

05 128 056 50890 1434

075 180 079 50150 1413

1 536 234 49880 1405

H-ZSM-5 360 008 163 071 50780 1430

017 106 046 49270 1388

025 095 041 48020 1353

05 077 034 50050 1410

075 142 062 50910 1434

1 262 114 50900 1434

Conditions a 30 mg H-Beta zeolite in 3 ml DI water b 3 ml of 01 M glycerol (03 mmol) aqueous solution weight ratio of glycerol to zeolite =

1 ab saturated vapour pressure

388

Figure 132 1H-NMR spectrum of the mother liquor recovered from the hydrothermal

conversion of 01 M glycerol (03 mmol) at 150 degC 4 bar 24 h

389

Figure 133 1H-NMR spectrum of the reaction products detected after glycerol hydrothermal

oxidation at 125degC for 30 min The molar ratio of glycerol H2O2 = 10 autogenic pressure

CH3COOH δ 197 (1H s) CH3COH δ 955 (1H q) 212 (3H d) CH3CH(OH)2 δ 513 (1H

q) 121 (3H d) CH3COCH2OH δ 203 (2H s) 425 (3H s) (HOCH2)2CO δ 430 (4Hs)

HCOOH δ 818 (1H s) OHCH2CH(OH)CH2OH δ 344-358 (4H dd) 366-370 (1H m)

HOCOCH2OH δ 404 (2H s) H2O δ 471 (2Hs) KHP δ 751 (2H m) 764 (2H m)

Table 62 The elemental composition of the zeolites determined by ICP-OES

Zeolite SiO2Al2O3

(manufacture)

Fe (ppm) Cu

[ppm]

Al

[ppm]

Na

[ppm]

ZSM-5 23 100-150 50-200

26000 500-600

Beta 25 150-200 25000 300-400

390

Figure 134 1H-NMR spectrum (top) and HPLC chromatogram (bottom) of the reaction

products detected after glycerol hydrothermal oxidation at 125degC for 30 min The molar ratio

of glycerol H2O2 = 10 autogenic pressure

391


products detected after glycerol hydrothermal oxidation catalysed by H-ZSM-5 at 150 degC for

30 min The molar ratio of glycerol H2O2 = 10 autogenic pressure

392

Figure 136 GC-FID chromatogram of the reaction products detected after glycerol

hydrothermal oxidation catalysed by H-ZSM-5 at 150 degC for 60 min The details for the

analysis as well as the retention times of compounds detected are provided in Table 63 below

Table 63 The retention times of compounds detected by Stabilwaxreg-DA Columns (fused

silica) Conditions Inlet 220 oC Oven 35 oC hold 5 min 5 oCmin until 90 oC 40 oCmin

until 230 oC holding time = 2 min

Entry Compound Concentration used

[mgL]

BP

[ordmC]

RT

[min] Area

1 Acetaldehyde 1000 202 20 1567

2 Acetol 3704 145 173 991

3 Glyceraldehyde 4504 140-150 67 124

4 Lactic acid 4504 122 ND ND

5 Glycerol 4605 290 ND ND

6 Pyruvaldehyde 3603 72 24 55 62 71

7 Acrolein 2803 53 42 176 866 536

8 MeOH 3204

9 EtOH 7837

Note BP=boiling point ND= Not detected

393

Figure 137 The mass spectrum of gaseous products collected in the hydrothermal oxidation of

glycerol Reaction conditions 03 mmol glycerol (276 mg) glycerol to H2O2 molar ratio =1

28 mg of 48 wt CeH-Beta 150 ordmC 476 bar 1 h

-100E-10

-800E-11

-600E-11

-400E-11

-200E-11

000E+00

200E-11

400E-11

600E-11

800E-11

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49

Ion

cu

rren

t

Mw

SN132-1

28 =N2

32 = O2

40 = Ar

44 = CO2

394

Table 64 The results of the hydrothermal oxidation of 02 M glycerol in the presence of extruded H-Betaγ-Al2O3 (MC) at 125 degC 150 degC and

175 degC 35 bar at the residence time of 60-300 s 1 g of the catalyst was used and the molar glycerolH2O2 ratio = 1

Temp

[degC]

Residence time

[s]

Conversion

[mol]



125 0 00 00 00 00 00 00 00 00 00 00

60 202 09 00 41 61 07 00 00 00 118

120 176 21 00 63 100 08 00 00 00 191

180 195 24 00 64 90 07 00 00 00 184

240 198 19 00 56 73 07 00 00 00 154

300 188 10 00 51 66 07 00 00 00 135

150 0 00 00 00 00 00 00 00 00 00 00

60 178 66 00 98 181 27 00 00 00 372

120 263 105 00 140 205 36 00 00 00 486

180 375 108 00 123 134 34 00 00 00 399

240 382 106 00 121 125 33 00 00 00 385

300 407 117 00 117 111 39 00 00 00 385

175 0 00 00 00 00 00 00 00 00 00 00

60 273 186 98 331 182 62 16 21 10 907

120 347 125 171 200 61 49 12 20 08 647

180 345 104 225 217 31 45 12 16 08 659

240 439 69 203 167 14 32 10 06 04 506

300 461 45 181 147 05 31 06 06 04 424

Note AA = acetic acid LA = lactic acid FA = formic acid DHA = dihydroxyacetone GCA = glycolic acid PVA = pyruvaldehyde AC= acetaldehyde

395

10 20 30 40 50 60 70

0

500

1000

1500In

ten

sity

[C

ou

nts

]

2 [degree]

H-Beta-Al2O

3 MC

after 125 C

after 150 C

Red circle = -Al2O

3

Figure 138 The X-ray patterns of H-Betaγ-Al2O3 (MC) catalysts before and after the use in

the hydrothermal oxidation of 02 M glycerol with H2O2 at 125 degC at 150 degC 35 bar and

residence time of 5-300 s 1 g of the catalyst was used and the molar glycerolH2O2 ratio = 1

396

Figure 139 The solubilities of cupric (CuII) and cuprous (CuI) oxides in water as a function of

temperature at two fixed pH25degC = 90 and 95 (taken from (Palmer et al (2004)))

ii

To my dear mother Nium

and in the memory of my dad Kaewta Srisamai

iii

Declaration






Suna Srisamai

London January 2016

iv






v

Abstract
























vi





vii

Acknowledgments






















viii

Nomenclature









Ɛ void fraction



FA formic acid








spectrometry




LA lactic acid


ix

MC methyl cellulose

MHz megahertz

mM millimolar

MPa megapascal


RT room temperature






TEA triethanolamine








Universiteit Delft







x

Table of Contents

Declaration iii

Abstract v

Acknowledgments vii

Nomenclature viii

Table of Contents x

1 Introduction 1











2211 Biomass 20

2212 Glycerol 23


2221 Biomass 25

2222 Glycerol 26




xi













3 Aim of study 89

31 Aim 89

32 Objectives 90













xii




























xiii


513 TPD-NH3 163




523 TPD-NH3 180






















xiv






643 Conclusion 280
















7331 Conclusion 315



81 Summary 323

82 Future work 327


xv


9 References 329

10 Appendix 361

1

1 Introduction








et al (2014))







2








00

05

10

15

20

25

30

35

Cru

de g

lycerol

[mil

lion

ton

ne]

Year

2004 2005 2006 2007 2008 2009 2010 2012 2014 2015 2023

0

100

200

300

400

500

Pric

e o

f cru

de g

lycerol (8

0

pu

re) [U

S $

ton

ne]






3





















2222



4











5




converting glycerol













6





glycerol 65-85 229-333 ~83


methanol 234-375 86-126 lt1

water 1-3 41-182 ~13

sodium 01-4 16-19 lt5

















7

























8








9

2 Literature review




















10








pressure water















11












12









13





Water

Subcritical

Water

Supercritical

Water

Acetone


Vapour pressure

[bar]

003 (24 degC) 1 (100 degC) to 221

(374 degC)

gt221 024

(20 degC)



bar) 692 (330 degC

300 bar)




7899 (20

degC 11

bar)


(25 degC)

L 277 G123

(101 degC) L504

G 307 (371 degC)

low 330

(25 degC)

Heat capacity Cp

[kJ kg-1K-1]

422 (25 degC) 486 13 (400 degC 250 bar) 218

(20 degC)

Dielectric

constant

785 (25 degC 1

bar)

271 (250 degC 50

bar) 182 (330 degC

300 bar)

59 (400 degC 250 bar)

105 (400 degC 500 bar)

206

(20 degC)


but still a liquid

(at 370 degC)

yes na

-logKw 14 na 21 na








14





(2012))

15











16






















17












information



Solvent MP

[ordmC]

BP

[ordmC]

Waste Environmental

impact

Health Flammability

amp Explosion

Reactivity

Stability

Life cycle

score

Legislation

Flag

EHS

Red Flag

Water 0 100 4 10 10 10 10 10

2-Propanol -88 82 3 9 8 6 8 4

1-Butanol -89 118 5 7 5 8 9 5

Ethanol -114 78 3 8 8 6 9 9

Methanol -98 65 4 9 5 5 10 9

Acetone -95 56 3 9 8 4 9 7

Acetic acid 17 118 4 8 6 8 7 8

Toluene -95 111 6 3 4 4 10 7

Heptane -91 98 6 3 8 3 10 7




18












solvents


treat


cool rapidly

Inexpensive

Non-flammable








19













20





2211 Biomass




21







grass



















22


























23



2212 Glycerol



















24


Equation 1



as














25



2221 Biomass






















26



















2222 Glycerol




27








119862119874 + 1198672119874 harr 1198621198742 + 1198672









28


























29















30










S (H2) = 85




promoters)



CO2 28 CH4






Wen et al (2008)


catalytic activity

Luo et al (2010)




King et al (2010)


phase


[1 wt amp 10wt]

NiCeO2

250 270 autogenous

(375 527)



Manfro et al (2011)

[5-85 wt]

PtAl2O3


at 5-45wt glycerol


31


























32
























33




biomass

















34






chemicals

35




Time


Ref








glucose 300-400 ˚C 250-400 bar

002-2 s




Fructose 300-400 ˚C 250-400 bar

002-2 s


Glucose 250-350 ˚C 276 bar 5

min



001-054 s


D-glucose other

mono-saccharides



124-benzenetriol

Srokol et al (2004)

sucrose hexoses

trioses


Co2+ Cu2+ Ni2+

Zn2+



75-180 s

HCl H2SO4

H3PO4 other

organic acids


(2006)

36

























37















38


39


























40






41




Time




300 s



anhydro-D-glucose


microcrystalline

cellulose

320-400 degC 250 bar 005

to 10 s




Y = 51

Sasaki et al (2000)


solid waste)


acid) = 26

Goto et al (2004)

cherry (hard wood)

cypress (soft wood)




cellulose starch

glucose

270-400 degC auto-

geneous 30-180 s



min

alkali alkaline

earth AlCl3 and

transition metal

chlorides


67

Peng et al (2010)


min

Ni Zn activated

C in NaOH



42


glycerol











43







44


of glycerol


process

Production

[tonnesyr]

Price

US $tonnes




pentaerythritol

crotonaldehyde


carbohydrates




DHA fermentation of

glycerol




(i) Acrolein











45


(2009))







glycerol





46



(ii) Acetaldehyde














47






(iii) Lactic acid


















48















2244 is desirable







studies

49













50





C2H4 C2H6

Antal et al (1985)

flow 349-475 degC 250 350 450 bar

32-165 s



H2



60 min



Watanabe et al

(2007)


acrolein

Qadariyah et al

(2011)


51















52







53



Catalyst Reactor

Type


Ref





H2SO4 flow 300-400 degC 250 300 345 bar

5-83 s



60 s




May et al (2010)


x103 kg-cat sm-3





(005- 8) x103 kg-cat sm-3


lactic acid



Beta Na-MFI


mlmiddoth-1



LHSV = 2 h-1



ZSM-23



54









at 400 degC 345 bar




such as

metal salts

metal oxides and

zeolites

Metal salts




55

Metal oxides











Zeolites











selectivity

56
















57




Time

Conversion

[]

Yield of

LA2 [] [LA]3 gL Ref


NaOH



KOH


25 M glycerol 275 M

NaOH


(2010)

011 M glycerol PtC


Semi-

batchwise



in 01 M H3BO3



045 M NaOH



in 054 M NaOH


033 M glycerol




58














59


























60


























61






Auneau et al (2012)












62













63



Pressure Time


Ref

045 M Crude

glycerol



or O2 or H2O2



was added


et al (2014)


O2 1 h 40 mM FeCl3

Ru(OH)4 on



1-90 wt

glycerol



(H3+nPVnMo12-nO40)



formaldehyde


(2015)


64











al 2014)














65


















66


Almutairi (2013)











and Davis 2013)



67

























68





69



Pressure Time

Note Ref


Mordenite (MOR)-20

Zeolite Y (FAU)-30





Kruger et al (2014)


ZSM-5 (MFI)-15 25 40

150 ˚C 200 ˚C

saturated vapour

pressure 1-6 h





saturated vapour

pressure 72 h


100





metakaolinite


ZSM-5 (MFI)-24 to 918





vapour pressure 72


= 50


decomposed

Lutz et al (2005)

H-Y (FAU)-25

H-USY (FAU)-19 9 3

35 ppm of HCl 190


750 rpm 50 bar H2

24 h




ZSM-5 (MFI)

mordenite (MOR)

Zeolite Beta (BEA)

Zeolite Y (FAU)

200 ˚C saturated


reaction time



Zhang et al (2015)

70


























71


















framework







72




al (2005)

73





















74




chemicals







75




Pressure Time


Ref

Cellulose (150 170 190 ˚C)

na (1 3 5 h)





min microwave-

assisted


Beta zeolite


acid lactic acid


Fructose (120 150 165 ˚C)

autogenous 05-2 h


an adsorbent




filtrated







Al-Beta Si-Beta




76




















77
























78





















pores is limited



79

























80























81


























82




(2010))












83











agglomerates













84





(plasticiser)





(SiAl = 125 or 25)

γ-Al2O3 HNO3

(peptiser)


at 205-230 degC pH2 = 50 bar 1198991198672119899ℎ119910119889119903119900119888119886119903119887119900119899 =


Bauer et al (2014)


(peptiser)



alcohol) 651




stream about 6 h



(plasticiser)



Melero et al (2008)

85











selectivity















86
























87





















88



Cracking of n-

hexane

538 ordmC Beta

zeoliteTUD-1

k = 025 while 011


Waller et al

(2004)

aldol condensation

of benzaldehyde

and n-amyl

alcohol


for our ZSM-5

Zhou et al

(2010)

cyclodehydration

of xylose

H2O-toluene

mixture 170

ordmC


yield = 74 while X

= 94 and furfural

yield = 58 for a

mixture of Beta and

TUD-1

Lima et al

(2010)

Friedel-Crafts

benzylation


pure H-Y zeolite

Hamdy and

Mul (2013)


conversion

89

3 Aim of study

31 Aim















233


addressed

90

32 Objectives





















91













zeolites prepared










92


doped zeolites




















93

















94




















95





1

[119881119886 (1198750

119875 minus 1 )]=

119862 minus 1

119881119898119862 times

119875

1198750+

1

119881119898119862

Where







surface ml




[119881119886(1198750119875

minus 1)] against

119875





1


96




119862 = [119878119897119900119901119890

119868119899119905119890119903119888119890119901119905] + 1


119881119898 = 1

119862 119868119899119905119890119903119888119890119901119905 119874119903

1

(119878119897119900119901119890 + 119868119899119905119890119903119888119890119901119905)


119878119861119864119879 = (119881119898 119873 119886)

119898 22400

Where




for N2)



97























98




materials










99

















Equation 9


119899120582 = 2119889 sin 120579

100













per step






015

101


119905 = 119870120582

119861 cos 120579
















specimens

102























103








and gold coated












104












105




















used

106


calorimetry (DSC)




















107






















spin

108

















multiplet)





109





time





(VWD) used and



solution)

110





111








acetaldehyde

hydrate









OHCH2CH(OH)CH2OH)



CH3CH(OH)COOH)




112


















113







CA

CB

= IA

IB

timesnB

nA






114









Istandard

times 2

3 timesCstandard





nB is 2

nA is 3






115











116











y = 1155x + 04549

Rsup2 = 09953

0

2

4

6

8

10

12

14

16

18

0 2 4 6 8 10 12 14 16

[lact

ate

] exp

erim

en

t (m

M)


117


















Retention time

(min)

Compounds

Retention time

(min)

Compounds







118












00302 mM 00284 mM


(ICP-OES)






119














120









System II)









1198791198944+ + 11986721198742 + 21198672119874 rarr 11986721198791198941198744 + 4119867+

121


TiOSO4






122



409 nm









y = 00005x - 00158

Rsup2 = 09995

0

02

04

06

08

1

12

0 500 1000 1500 2000 2500

Ab

sro

ba

nce

H2O2 (micromolL)

123









511986721198742 + 21198701198721198991198744 + 311986721198781198744 rarr 21198721198991198781198744 + 11987021198781198744 + 81198672119874 + 51198742





124




work




























125







methanol 99 VWR






Custom Multi

MBH



H2O2 (30 wv) VWR

H2SO4 95 VWR

HNO3 68 VWR












126









127






128




reactors

Zeolite


- Ce Ce La Sn Zn Cu

0 25 48 48 48 48 48

NH4-Beta

H-Beta

deAl-Beta





batch reactors

Zeolite


- Ce Ce La Sn Zn Cu

0 25 48 48 48 48 48

NH4-ZSM-5

H-ZSM-5

deAl-ZSM-5


129



Catalyst Catalyst

NH4-Beta NH4-ZSM-5












1 CedeAl-HBetaII4h

2 CedeAl-HBetaII4h

3 CedeAl-HBetaII4h

48 CedeAl-BetaII4h

48 CudeAl-BetaII4h

48 SndeAl-BetaII4h

48 ZndeAl-BetaII4h






the following means


130













(TUD-1)

Extrusion with clay








131

















132
























133







membranes








134



for 30 min











135






















136










TUD-1 matrix











137





















138















139







140









(Comark KM340)















141




pressure gague










142








carried out













143













461 Batch process









144
















145


146













147



















148























149





ie at 20 cm



150













151






















152



τ =VR 120576 ρR

V ρSTP







of glycerol









153


ε =119881119900119897119906119898119890 119900119891 119908119886119905119890119903 119894119899119904119894119889119890 119905ℎ119890 119903119890119886119888119905119900119903 minus 119898119894119888119903119900119901119900119903119890 119907119900119897119906119898119890 119900119891 119905ℎ119890 119888119886119905119886119897119910119904119905

119879119900119905119886119897 119907119900119897119906119898119890 119900119891 119905ℎ119890 119903119890119886119888119905119900119903

Therefore


74993 cm3= 0556




ρR =ρSTP


Where









154



56 in the Appendix

155











SEM-EDS and TPD-NH3











156










the present work













157

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

+ ++

+


++

+


+

++


++

+ NaCl

+ NaCl

2 [degree]

2 [degree]

+

+


Inte

nsi

ty [

co

un

ts]

Inte

nsi

ty [

co

un

ts]





= NaCl

158


550 ordmC for 5 h








159




[nm]

XRD relative

crystallinityb []























160

512 BET N2 analysis


















161

00 01 02 03 04 05 06 07 08 09 10

0

80

100

120

140

160

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]








162

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]















~31-39 nm is ~300-360 m2middotg-1

163



Sample BET N2

surface area

[msup2middotg-1]

Micropore

volume

[cmsup3middotg-1]

Micropore

area

[msup2middotg-1]

External

surface area

[msup2middotg-1]





513 TPD-NH3










gas flow rate used





164





in Table 29

100 200 300 400 500 600

0

100

200

300

0 1200 2400 3600 4800 6000

Co

ncen

tra

tio

n o

f N

H3 i

n g

as

flo

w [

pp

m]

Temperature [oC]


NH4-ZSM-5

Time [s]


H-ZSM-5

165

100 200 300 400 500 600

0

50

100

150

200

250

300

0 1200 2400 3600 4800 6000

Co

ncen

tra

tio

n o

f N

H3 i

n g

as

flo

w [

pp

m]

Temperature [oC]


(H-Beta zeolite)

NH4-Beta zeolite

Time [s]
























166

0 1000 2000 3000 4000 5000 6000

0

50

100

Experimental data


Co

nce

ntr

ati

on

of

NH

3 i

n g

as

flo

w [

pp

m]

Time [s]

(A) NH4-ZSM-5

0 1000 2000 3000 4000 5000 6000

0

50

100

150

200

250

300

Experimental data


Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Time [s]

(B) H-ZSM-5

0 1000 2000 3000 4000 5000 6000

0

50

100

150

200

250

300

Experimental data


Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Time [s]


0 1000 2000 3000 4000 5000 6000

0

50

100

150

200

250

Experimental data


Co

ncen

tra

tio

n o

f N

H3 i

n g

as

flo

w [

pp

m]

Time [s]

(D) H-Beta zeolite



167



Catalyst


desorbed

[micromolmiddotg-1]

Ref Tmax

[degC]

NH3

[micromolmiddotg-1]

Tmax

[degC]

NH3

[micromolmiddotg-1]

Tmax

[degC]

NH3

[micromolmiddotg-1]

NH4-ZSM-5 145 4 200 69 420 67 140 This work

H-ZSM-5 145 8 187 242 385 269a 520 This work

150 - 388 - - Long and Yang (2001)


- - - - 630 Alotaibi et al (2014)

H-Beta 124 2 176 105 300 236a 344 This work

277 - 377 - 750 Lenarda et al (2003)

197 653 363 209 862 Talebi et al (2008)


168

I ZSM-5





















169







170



















II Beta zeolite




171
























172























173























174















175

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

+x

x

+

+

xx

CeO2

48 wt CeH-Beta

+++

+

48 wt LaH-Beta

O

++

OOO

48 wt SnH-Beta

ZnO

O

++

+

+

x

SnO2

48 wt ZnH-Beta

+

+

+

Inte

nsi

ty [

co

un

ts]

2 [degree]

+ NaCl

H-Beta

+





x = CeO2

176

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

+X+

+

+

X

X

2 (degree)

48 wt CeH-ZSM5

X

+ ++

+

OOO

48 wt LaH-ZSM5

+

+

O

48 wt SnH-ZSM5

O

+++

+

48 wt ZnH-ZSM5

Inte

nsi

ty [

cou

nts

]

+ NaCl ZnO O SnO2

x CeO2

+ +

+

H-ZSM5

+





177





Sample Crystallite

sizea [nm]

XRD relative

crystallinityb

[]

Position of the

main peakc

(2θ) [degree]

Shift in 2θ of

the main peakc

[degree]

NH4-Beta 159 100 226 +009

H-Beta 151 105 225 000

48 CeNH4-Beta 145 55 225 +007

48 LaNH4-Beta 141 64 225 +003

48 SnNH4-Beta 144 47 225 +002

48 ZnNH4-Beta 121 76 225 -001

48 CeH-Beta 146 64 225 +007

48 LaH-Beta 137 68 226 +008

48 SnH-Beta 139 63 225 +004

48 ZnH-Beta 135 83 225 +006

NH4-ZSM-5 320 100 230 -005

H-ZSM-5 388 101 231 000

48 CeNH4-ZSM-5 331 60 230 -005

48 LaNH4-ZSM-5 372 71 231 -003

48 SnNH4-ZSM-5 381 65 231 000

48 ZnNH4-ZSM-5 369 98 231 000

48 CeH-ZSM-5 318 62 231 -003

48 LaH-ZSM-5 345 75 231 -003

48 SnH-ZSM-5 370 69 231 +003

48 ZnH-ZSM-5 351 84 231 -003





178

522 BET N2 analysis










00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

00 01 02 03 04 05 06 07 08 09 10

0

80

100

120

140

160

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]






(A) (B)

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]


adsorption_H-ZSM-5

desorption_H-ZSM-5







179








Sample

BET N2

surface area

[msup2g-1]

Micropore

volume

[cmsup3g-1]

Micropore

area

[msup2g-1]

External

surface area

[msup2g-1]

NH4-Beta 575 017 358 218

H-Beta 598 017 367 230

48 CeNH4-Beta 534 015 330 204

48 LaNH4-Beta 591 015 383 208

48 SnNH4-Beta 489 014 303 186

48 ZnNH4-Beta 526 015 326 200

48 CeH-Beta 539 015 333 206

48 LaH-Beta 567 015 371 196

48 SnH-Beta 514 014 301 213

48 ZnH-Beta 528 014 313 215

NH4-ZSM-5 299 013 257 42

H-ZSM-5 363 012 258 104

48 CeNH4-ZSM-5 294 010 213 81

48 LaNH4-ZSM-5 370 011 280 90

48 SnNH4-ZSM-5 323 011 228 95

48 ZnNH4-ZSM-5 336 012 250 86

48 CeH-ZSM-5 340 011 235 104

48 LaH-ZSM-5 359 011 284 76

48 SnH-ZSM-5 304 010 223 80

48 ZnH-ZSM-5 308 011 227 81

180

523 TPD-NH3








the profiles of their parent NH4- or H-zeolites (see Page 164-165 ) two main desorption peaks











about 5 degC




181



100 200 300 400 500 600

0

50

100

150

200

250

300

100 200 300 400 500 600

0

50

100

150

200

250

300

100 200 300 400 500 600

0

50

100

150

200

250

300

100 200 300 400 500 600

0

50

100

150

200

250

300




Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]

Temperature [oC]

(A)

NH4-Beta zeolite


(C)

Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]

Temperature [oC]

NH4-ZSM-5

48 SnNH4-ZSM-5

48 ZnNH4-ZSM-5

48 LaNH4-ZSM-5

48 CeNH4-ZSM-5

(B)

Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]

Temperature [oC]

H-Beta zeolite

48 SnH-Beta zeolite

48 ZnH-Beta zeolite

48 LaH-Beta zeolite

48 CeH-Beta zeolite

(D)

Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]Temperature [

oC]

48 CeH-ZSM-5

48 LaH-ZSM-5

48 ZnH-ZSM-5

H-ZSM-5

48 SnH-ZSM-5

182










Catalyst


Degree of ion

exchange b Tmax

[degC]

Tmax

[degC]

Tmax

[degC]

NH3

[micromolmiddotg-1]

NH4-Beta 127 165250 - - 0

H-Beta 124 176 300 236 a 0

48 CeNH4-Beta 134 177 306 94 36

48 LaNH4-Beta 138 178 317 107 43

48 SnNH4-Beta 136 171 304 147 22

48 ZnNH4-Beta 148 178 305 114 61

48 CeH-Beta 140 160 305 73 41

48 LaH-Beta 145 176 317 95 47

48 SnH-Beta 141 160 305 45 48

48 ZnH-Beta 149 180 305 103 67

NH4-ZSM-5 145 200 420 67 0

H-ZSM-5 145 187 385 270 a 0

48 CeNH4-ZSM-5 138 190 387 146 31

48 LaNH4-ZSM-5 146 191 400 113 52

48 SnNH4-ZSM-5 133 190 392 39 58

48 ZnNH4-ZSM-5 148 205 386 88 91

48 CeH-ZSM-5 - 187 380 73 49

48 LaH-ZSM-5 144 180 380 98 57

48 SnH-ZSM-5 144 172 391 35 59

48 ZnH-ZSM-5 145 187 380 57 106

183













to the H-ZSM-5








et al 2012)




184
















in Beta zeolite






Table 33

185




[g]

Treatment time

[h]



deAl-BetaI6h 1 6

deAl-BetaI20h 1 20

deAl-BetaII4h 2 4

deAl-BetaII6h 2 6

deAl-BetaII20h 2 20

deAl-BetaIII4h 3 4







preserved

186

0

300

600

900

10 20 30 40 50 60 70

0

300

600

900

H-ZSM-5In

ten

sity

[C

ou

nts

]


2 [degree]










187










188

0

4000

8000

0

4000

8000

0

4000

8000

10 20 30 40 50 60 70

0

4000

8000

+ +

+


+

+ ++

+

deAl-BetaII4h+ NaCl

Inte

nsi

ty [

Co

un

ts]

+ +

+


+ +

+

+


2 [degree]







189


zeolites

Catalyst BET-N2

surface area

[msup2middotg-1]

Crystallite

sizea

[nm]

Relative

crystallinityb

[]

2θ of d302

[degree]

shift of d302

[degree]

d302-spacing

[Aring]

SiAl

(XRF)

Al extractedc

[wt]

NH4-Beta zeolite 575 159 100 226 394 124 0

H-Beta zeolite 598 151 104 225 000 396 124 0

deAl-BetaI4hd 573 133 95 227 +017e 391 533 974

deAl-BetaI6h 572 137 94 227 +024 391 600 978

deAl-BetaI20h 554 141 89 226 +007 394 795 983

deAl-BetaII4h 580 129 100 227 +017 393 688 977

deAl-BetaII6h 551 130 94 227 +017 389 671 980

deAl-BetaII20h 542 154 89 226 +009 392 526 969

deAl-BetaIII4h 585 122 95 227 +017 392 556 974






190


























191







BET N2 analysis










192

6 8 10 20 22 24

0

2000

4000

6000

8000

H-Beta zeolite

deAl-BetaII4h

deAl-BetaII6h

deAl-BetaII20h

Inte

nsi

ty [

cou

nts

]

2 [degree]




193

0

25

50

75

100

Al

extr

act

ed [

wt

]

Treatment time [h]




0 4 6 20














194












195

100 200 300 400 500 600

0

50

100

150

200

250

300

deAl-BetaI20h

deAl-BetaII6h

deAl-BetaII4h

deAl-BetaII 15 min

deAl-BetaII 5min

H-Beta zeolite

Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Temperature [C]





measurement








196
























197





















198



deAl-BetaII4h


metalAlextracted

Weight ratio of

metalzeolite

XRD TPD-NH3 TEM-EDX

NH4-Beta - -

H-Beta - -

deAl-BetaII4h - -





















199









10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

8000

10000

X

XXX

H-Beta zeolite

deAl-BeatII4h

10 CedeAl-BetaII4h

6 CedeAl-BetaII4h

1 CedeAl-BetaII4h



Inte

nsi

ty [

cou

nts

]

2 [degree]

X

CeO2

Inte

nsi

ty [

cou

nts

]

2 (degree)







200














201










202

0

3000

6000

0

3000

6000

0

3000

6000

0

3000

6000

10 20 30 40 50 60 70

0

3000

6000

+ = NaCl

= ZnO

(D)

5 ZndeAl-BetaII4h

2 [degree]

+

+ = NaCl

O = SnO2

(C)

ooo+

88 SndeAl-BetaII4h

Inte

nsi

ty [

Co

un

ts]

+

+

+

o

+ = NaCl

(B)

++

+

10 LadeAl-BetaII4h

+ = NaCl

x = CeO2

xxx +

10 CedeAl-BetaII4h

+x

(A)

+ = NaCl

(E)

++

+

deAl-BetaII4h





ο = SnO2 x = CeO2

203




metalAlextracted

Phases identified

























204











205

0

3000

6000

9000

0

3000

6000

0

3000

6000

10 20 30 40 50 60 70

0

3000

6000



2 [degree]

+

(D)

(B)

(C)



ooo+

Inte

nsi

ty [

Cou

nts

]

+

+

+

o



+

x

x + x x

(A)

++

+

deAl-BetaII4h






= CeO2

206









salts under study

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

++

+ NaCl

H-Beta zeolite

deAl-BetaII4h


Inte

nsi

ty [

co

un

ts]

2 [degree]

+

Inte

nsi

ty [

cou

nts

]

2 [degree]





207




Sample Δd302

position

[degree]a

Crystallite

sizeb

[nm]

d302-

spacing

[Aring]

Δd302 [Aring]c

Relative

crystallinityd

NH4-Beta +009 159 394 100

H-Beta 000 151 396 000 105

deAl-BetaII4he +019 129 392 -004 100

045 CedeAl-BetaII4h +022 118 392 -004 82

07 CedeAl-BetaII4h +019 131 392 -004 79

1 CedeAl-BetaII4h +019 117 392 -004 78

6 CedeAl-BetaII4h +012 127 393 -002 64

10 CedeAl-BetaII4hf +038 110 389 -007 58

10 LadeAl-BetaII4h +016 110 393 -003 63

88 SndeAl-BetaII4h +012 135 393 -002 68

5 ZndeAl-BetaII4h +003 146 395 -001 92












208




(d302) and




















209

542 Surface acidity












210

100 200 300 400 500 600

0

50

100

150

200

250

300




deAl-BetaII4h

H-Beta zeolite

Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Temperature [C]




relative to zeolite


based catalysts





211






use See Chapter 551

















212





213

0

1000

2000

0

1000

2000

10 20 30 40 50 60 70

0

1000

2000

Inte

nsi

ty [

Co

un

ts]


2 [degree]

(A) H-Beta zeolite

2= 7776

2= 22630

2= 25456

2= 27158

2= 43971 2= 55980

2 = 7643

2= 22557

2 = 25356

2 = 26958

2 = 439670

(C) CHFM support






214












215



Temperature

[degC]

Residence time

[s]

Conversion

[mol]











216








matrix




217






















218

10 20 30 40 50 60 70

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

(D)

= CuO

Inte

nsi

ty [

Cou

nts

]

2 [degree]


48 wt CuH-Beta

(C)

xxx

x = CeO2


48 CeH-Beta

x

(B)

H-Beta in TUD-1

H-Beta

(A)

H-Beta






219













single measurement

Sample Micropore

volume

[cmsup3middotg-1]

Micropore

area

[msup2middotg-1]

External

surface area

[msup2middotg-1]

BET surface

area

[msup2middotg-1]



48 wt CuH-Beta 015 330 200 530

48 wt CuH-Beta in TUD-1 012 278 348 627



220







not performed





catalysts ie

H-Beta

25wt CuH-Beta and

48wt CuH-Beta






221










CuO

10 20 30 40 50 60 70

0

1000

2000

3000

4000

5000

6000

2 [degree]

= CuO

H-Beta

25 wt CuH-Beta

48 wt CuH-Beta

Inte

nsi

ty [

cou

nts

]



222










223

10 20 30 40 50 60 70

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

= CuO

Inte

nsi

ty [

Cou

nts

]

2 [degree]


(C) 48 wt CuH-Beta


(A) H-Beta




224
















measurement

Sample Micropore

volume

[cmsup3middotg-1]

Micropore

area

[msup2middotg-1]

External

surface area

[msup2middotg-1]

BET N2

surface area

[msup2middotg-1]



48 CuH-Beta 015 330 200 530




225













226











(MC)











not used



227




10 20 30 40 50 60 70

red circle-Al2O

3


3


3(MC)

(A) H-Beta

Inte

nsi

ty [

arb

un

its]

2 [degree]





228

10 20 30 40 50 60 70


3


3


3(MC)

Inte

nsi

ty [

arb

un

its]

2 [degree]

(A) 48 wt CuH-Beta






229

10 20 30 40 50 60 70


3


3 (MC)

Inte

nsi

ty [

arb

un

its]

2 [degree]

(B) 25 wt CuH-Beta







Catalysts


wt of zeolite

catalyst relative

to γ-Al2O3

H-Beta or






230





Catalyst BET N2

surface area

[m2middotg-1]

Micropore

Volume

[cmsup3middotg-1]

XRD relative

crystallinitya

[]

Post of d302

[degree 2θ]

TEM-EDS

SiO2Al2O3

mol ratio

NH4-Beta 575 017 100 226 25b

H-Beta 598 017 105 225 25 b


48 wt CuH-Beta 534 015 83 227


H-Betaγ-Al2O3 (MC)c 423 010 38 228 54

25 wt CuH-Betaγ-

Al2O3 (MC)c 419 009 nad 226 24

48 wt CuH-Betaγ-

Al2O3c

- - 56 227 44

48 wt CuH-Betaγ-

Al2O3 (MC)c 446 010 62 227 45











231
















232





















conversion rate

233

0 60 120 180 240 3000

20

40

60

80

100

0 60 120 180 240 3000

10

20

30

40

50

270 C

300 C

330 C

Gly

cero

l co

nv

ersi

on

[m

ol

]

Reaction time [min]

270 C

300 C

330 C

Sel

ecti

vit

y t

o a

ll l

iqu

id p

rod

uct

s [C

-mo

l]

Reaction time [min]



234






Temp

[degC]

Press

[bar]

Time

[min]

Conversion

[mol]a


[C-mol]b References


300 86 60 49 204 ˃100 39 70 Watanabe et al (2007)c

300 2955 60 100 005 0002 Qadariyah et al (2011)

270 55 240 26 plusmn 04 - - 137 183 - - - 08

300 53 plusmn 04 - - 96 127 - - - 11

300 86 60 49 plusmn 20 17 35 104 120 - - - 08

120 143 plusmn 15 25 07 11 158 - 32 - 36

180 206 plusmn 14 19 05 22 123 - 23 08 41

240 229 plusmn 23 18 04 33 165 - 20 07 62

300 306 plusmn 09 14 07 14 149 - 17 06 64

330 128 60 121 plusmn 19 29 08 46 215 - 53 21 45

120 241 plusmn 15 31 05 43 244 10 43 14 94

180 333 plusmn 56 45 08 38 287 11 40 07 145

240 441 plusmn 51 51 07 21 286 16 38 05 187

300 586 plusmn 65 50 06 18 281 22 36 00 241

235
















236











237


















Lopez et al 2010)

238










reaction times








gases




239












240

0 60 120 180 240 300

0

20

40

60

80

100

0 60 120 180 240 300

0

10

20

30

40

50

0 60 120 180 240 300

0

20

40

60

80

100

0 60 120 180 240 300

0

10

20

30

40

50

270 oC

300 oC

330 oC

(A) H-ZSM-5

270 oC

300 oC

330 oC

(B) H-ZSM-5

60 120 180 240 300

Temp [degC]





Reaction time [min]

Total yield [C-mol]

Gly

cerol

con

versi

on

[m

ol

]

270 oC

300 oC

330 oC

360 oC

Gly

cerol

con

versi

on

[m

ol

]

Reaction time [min]

(C) H-Beta

Sele

cti

vit

y t

o a

ll l

iqu

id p

rod

ucts

[C

-mol

]

270 oC

300 oC

330 oC

360 o

C

Sele

cti

vit

y t

o a

ll l

iqu

id p

rod

ucts

[C

-mol

]

Reaction time [min]

(D) H-Beta

60 120 180 240 300

Temp [degC]




Reaction time [min]

Total yield [C-mol]




241








are





solution











242

0

1

2

3

4

5

6

7

8

0

450

500

550

600

650

0

1

2

3

0

13

14

15

16

17

18

H-Beta

H-ZSM-5

Time [h]

Con

cen

trati

on

of

Al

[pp

m]

Time [h]

0 008 017 025 05 075 1

H-Beta

H-ZSM-5

Con

cen

trati

on

of

Si

[pp

m]

0 008 017 025 05 075 10 008 017 025 05 075 1

H-Beta

H-ZSM-5

Time [h]

Am

ou

nt

of

Al

[wt

]

Time [h]

0 008 017 025 05 075 1

H-Beta

H-ZSM-5

Am

ou

nt

of

Si

[wt

]




243

10 20 30 40 50 60 70

0

1000

2000

3000

Inte

nsi

ty [

Co

un

ts]

2 [degree]

H-Beta zeolite















244



products

245

0 60 120 180 240 300

0

20

40

60

80

100

0 60 120 180 240 300

0

20

40

60

80

100

Gly

cero

l con

ver

sion

[m

ol

]

270 oC

300 oC

330 oC

Reaction time [min]

Sel

ecti

vit

y t

o a

ll l

iqu

id p

rod

uct

s [C

-mol

]

270 oC

300 oC

330 oC

Reaction time [min]

60 120 180 240 300

Temp [degC]

270 7 10 13 14 22

300 10 14 17 19 19

330 7 20 24 28 26

Reaction time [min]

Total yield [C-mol]






experiment

246














glycerol

247

0

25

50

75

1000

25

50

75

100

gases amp char

acetol

acrolein

EtOH

acetaldehyde

lactic acid

acetic acid

MeOH

(A) H-Beta

Reaction Time [min]

(B) H-ZSM-5

0 5 10 15 30 45 60

Conversion

Co

nv

ersi

on

[m

ol

] o

r S

elec

tiv

ity

[C

-mo

l]







248















respectively

249










250



119892119897119910119888119890119903119900119897 1198961rarr 119886119888119890119905119886119897119889119890ℎ119910119889119890 Equation 23

119886119888119890119905119886119897119889119890ℎ119910119889119890 1198962rarr 119901119903119900119889119906119888119905119904 Equation 24

119892119897119910119888119890119903119900119897 1198963rarr 119901119903119900119889119906119888119905119904 Equation 25











kinetic analysis





as follows

251

119889[119892119897119910119888119890119903119900119897]

119889119905= minus(1198961 + 1198963)[119892119897119910119888119890119903119900119897] Equation 26

119889[119886119888119890119905119886119897119889119890ℎ119910119889119890]

119889119905= 1198961[119892119897119910119888119890119903119900119897] minus 1198962[119886119888119890119905119886119897119889119890ℎ119910119889119890] Equation 27






0 3600 7200 10800 14400 18000

000

002

004

006

008

010

012

Con

cen

trati

on

[M

]

Time [s]



curve fit_glycerol


k1 = 27787e

-5

k2 = 171056e

-6

k3 = 781408e

-5






252









300degC 462E-5 273E-4 247E-5

330degC 174E-5 488E-13 257E-5


300degC 278E-5 171E-6 780E-5

330degC 141E-4 266E-12 297E-4

360degC 319E-4 360E-6 574E-4

H-ZSM-5 270degC 174E-5 161E-6 101E-4

300degC 108E-4 766E-6 362E-4

330degC 309E-4 376E-5 807E-4


300degC 155E-5 287E-11 282E-5

330degC 432E-5 300E-5 427e-5






253



















119896 = 119860119890minus119864119886119877119879 Equation 28



temperature in K

254





Table 45

ln 119896 = ln 119860 minus119864119886

119877(

1

119879) Equation 29



analysed

y = -15767x + 18168

Rsup2 = 09847

y = -2393x - 6364

Rsup2 = 01825

y = -17817x + 20981

Rsup2 = 09314

y = -26229x + 33953

Rsup2 = 09138

-15

-14

-13

-12

-11

-10

-9

-8160E-03 165E-03 170E-03 175E-03 180E-03 185E-03 190E-03

ln k

1T [K-1]



255






H-ZSM-5 131 78E+07


















256

























257










258

No

cata

lyst

NH

4-Bet

a

H-B

eta

48

Ce

NH

4-Bet

a

48

La

NH

4-Bet

a

48

SnN

H4-

Bet

a

48

ZnN

H4-

Bet

a

48

Ce

H-B

eta

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

NH

4-ZSM

-5

H-Z

SM-5

48

Ce

NH

4-ZSM

-5

48

La

NH

4-ZSM

-5

48

SnN

H4-

ZSM

-5

48

ZnN

H4-

ZSM

-5

48

Ce

H-Z

SM-5

48

La

H-Z

SM-5

48

SnH

-ZSM

-5

48

ZnH

-ZSM

-5

0

25

50

75

100

[]

Conversion [mol]



0

50

100

150

200

250

300


]

Am

ou

nt

of

des

orb

ed N

H3 [

mo

lg

-1]





259



Catalyst Conversion

[mol]


[C-mol]

Total Yb


NH4-Beta 345 plusmn 28 24 07 39 346 07 33 11 468 161



48 LaNH4-Beta 560 plusmn 15 29 09 17 356 14 81 14 519 291

48 SnNH4-Beta 552 plusmn 06 21 05 38 290 09 82 07 451 249

48 ZnNH4-Beta 481 plusmn 02 22 05 59 244 08 83 12 433 208



48 SnH-Beta 737 plusmn 36 10 06 19 222 08 42 10 318 235

48 ZnH-Beta 556 plusmn 35 23 04 29 253 08 76 06 400 222

NH4-ZSM-5 583 plusmn 45 17 08 12 281 12 36 09 375 219

H-ZSM-5 980 plusmn 096 10 30 00 192 14 15 06 268 262

48 CeNH4-ZSM-5 938 plusmn 348 11 20 06 200 08 22 03 271 254

48 LaNH4-ZSM-5 836 plusmn 49 13 12 08 224 13 38 08 316 264

48 SnNH4-ZSM-5 832 plusmn 10 11 33 00 217 11 41 09 323 269

48 ZnNH4-ZSM-5 748 plusmn 47 20 07 13 302 10 76 10 439 328

48 CeH-ZSM-5 927 plusmn 42 12 23 11 206 11 23 05 289 268

48 LaH-ZSM-5 986 plusmn 081 12 29 11 229 09 34 04 328 324





260

NH

4-Bet

a

H-B

eta

48

Ce

NH

4-Bet

a

48

La

NH

4-Bet

a

48

SnN

H4-

Bet

a

48

ZnN

H4-

Bet

a

48

Ce

H-B

eta

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

0

25

50

75

100Y= 222 Y= 235 Y= 208

Co

nv

ersi

on

[m

ol

]Y= 223 Y= 207 Y= 291 Y= 286 Y= 282 Y= 161

Y= 249 Conversion

MeOH

acetic acid

lactic acid

acetaldehyde

EtOH

acrolein

0

10

20

30

40

Sel

ecti

vit

y [

C-m

ol

]




261

NH

4-ZSM

-5

H-Z

SM-5

48

Ce

NH

4-ZSM

-5

48

La

NH

4-ZSM

-5

48

SnN

H4-

ZSM

-5

48

ZnN

H4-

ZSM

-5

48

Ce

H-Z

SM-5

48

La

H-Z

SM-5

48

SnH

-ZSM

-5

48

ZnH

-ZSM

-5

0

25

50

75

100

Y = 296 Y = 278 Y = 324 Y = 268 Y = 328 Y = 269 Y = 264 Y = 254 Y = 262 C

on

ver

sio

n [

mo

l]

or

sele

ctiv

ity

[C

-mo


0

10

20

30

40

MeOH

acetic acid

lactic acid

acetaldehyde

EtOH

acrolein

Sel

ecti

vit

y [

C-m

ol

]




262

















263












264

10 20 30 40 50 60 70

0

1500

3000

5 6 7 8 9 16 18 20 22 240

1500

3000 H-Beta zeolite

150 C 1 h

150 C 20 h

Inte

nsi

ty [

cou

nts

]

2 [degree]



10 20 30 40 50 60 70

0

1500

3000

5 6 7 8 9 16 18 20 22 240

1500

3000

Inte

nsi

ty [

cou

nts

]

2 [degree]

H-Beta zeolite

200 C 1 h

200 C 3 h

200 C 5 h

200 C 20 h



265

10 20 30 40 50 60 70

0

1500

3000

5 6 7 8 9 16 18 20 22 240

1500

3000 H-Beta zeolite

250 C 1 h

250 C 20 h

Inte

nsi

ty [

co

un

ts]

2 [degree]







Temperature

[degC]

Time

[h]

XRD relative

crystallinity

20 0 100 plusmn 00

150 1 132 plusmn 38

20 105 plusmn 22

200 1 110 plusmn 39

3 108 plusmn 61

5 100 plusmn 53

20 76 plusmn 17

250 1 74 plusmn 45

20 40 plusmn 72

266


















times






267

















268

0

1

2

3

4

5

6

7

8

0

100

200

300

400

500

600

0

1

2

3

0

5

10

15

0 008 017 025 05 075 1 3 5 20 48

0 008 017 025 05 075 1 3 5 20 48

20 C

150 C

200 C

250 C

330 C

330 C_H-ZSM-5

Time [h]

Co

nce

ntr

ati

on

of

Al

[pp

m]

Time [h]

0 008 017 025 05 075 1 3 5 20 48

20 C

150 C

200 C

250 C

330 C

330 C_H-ZSM-5

Co

nce

ntr

ati

on

of

Si

[pp

m]

20 C

150 C

200 C

250 C

330 C

330 C_ H-ZSM-5

Time [h]

Am

ou

nt

of

Al

[wt

]

Time [h]

0 008 017 025 05 075 1 3 5 20 48

20 C

150 C

200 C

250 C

330 C

330 C_ H-ZSM-5

Am

ou

nt

of

Si

[wt

]





269


















90





270










[ppm]

Holding time [min]

5 10 15 30 45 60


Al 444 393 374 356 298 332

Si 6005 5886 6034 6195 620 6215


Al 266 191 236 229 228 163

Si 4581 4758 5108 4773 484 4789



271

0

25

50

75

100

Y= 498 mol

Y= 572 mol

Y= 423 mol

Y= 359 mol

Y= 141 mol

gases amp char

acetol

acrolein

acetaldehyde

acetic acid

MeOH

Y= 044 mol

Conversion

Co

nv

ersi

on

[m

ol

] o

r S

elec

tiv

ity

[C

-mo

l]

Reaction Time [min]

5 10 15 30 45 60




of mean (119878119864)











272



and pressures




273







was detected

274






[min]

Conversion

[mol]


products [C-mol]

Yield

[C-mol]

No 60 121 plusmn 19 372 45


10 610 plusmn 22 497 300

15 633 plusmn 46 512 315

30 732 plusmn 54 420 300

45 769 plusmn 21 408 311

60 839 plusmn 24 335 282


10 145 plusmn 09 100 14

15 163 plusmn 07 218 36

30 242 plusmn 26 177 42

45 264 plusmn 03 217 57

60 283 plusmn 12 174 50

deAl-BetaI20h


10 59 plusmn 00 125 07

15 111 plusmn 08 98 11

30 160 plusmn 17 130 21

45 1758 plusmn 25 123 21

60 174 plusmn 05 142 25

275

0 10 20 30 40 50 60

0

20

40

60

80

100

0 10 20 30 40 50 60

0

10

20

30

40

50

60



H-Beta zeolite

No catalyst



H-Beta zeolite

No catalyst

Gly

cero

l co

nver

sion

[m

ol

]


Sel

ecti

vit

y t

o a

ll l

iqu

id p

rod

uct

s [C

-mol

]




276


























277







[ppm]

Holding time [min]

5 10 15 30 45 60


Al 193 184 248 216 153 12

Si 2152 2253 2186 2167 2158 217


Al 04 036 029 024 034 024

Si 1838 18991 18861 19957 19424 19816



278

0

25

50

75

100

gases amp char

acetaldehyde

acetic acid

MeOH

Y= 248 mol

Y= 211 mol

Y= 205 mol

Y= 108 mol

Y= 074 mol

Y= 073 mol

Conversion

Con

ver

sion

[m

ol

] o

r S

elec

tiv

ity

[C

-mol

]

Reaction Time [min]

5 10 15 30 45 60














279














280

0

25

50

75

100

gases amp char

acetol

acrolein

EtOH

acetaldehyde

acetic acid

MeOH

Conversion

Co

nv

ersi

on

[m

ol

] o

r S

elec

tiv

ity

[C

-mo

l]

Reaction Time [min]

5 10 15 30 45 60




643 Conclusion







281










71 Batch process










282








283

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

Y = 164 06 Y = 178 03 Y = 211 00

Reaction time [min]

Y = 248 09

Con

ver

sion

[m

ol

] or

Sel

ecti

vit

y [

C-m

ol

]

125 C

30 60 120 180

150 C

Reaction time [min]

30 60 120 180

Y = 156 08 Y = 153 11 Y = 126 08

Con

ver

sion

[m

ol

] or

Sel

ecti

vit

y [

C-m

ol

]

Y = 148 05

Y = 131 19 Y = 1309 07 Y = 135 03

200 C175 C

Reaction time [min]

30 60 120

gases amp char

pyruvaldehyde

acetol

acrolein

glycolic acid

DHA

formic acid

acetaldehyde

acetic acid

Reaction time [min]

30 60 120 180

Y = 148 06

Conversion

Con

ver

sion

[m

ol

] o

r S

elec

tivit

y [

C-m

ol

]

Con

ver

sio

n [

mol

] or

Sel

ecti

vit

y [

C-m

ol

]

200 C

Y = 106 15 Y = 137 13 Y = 124 02



products [C-mol]

284




Temperature

[degC]

Reaction time

[min]

Conversion

[mol]


[C-mol]

Yield of liquids

[C-mol]

























285













286




et al 2011))




287






















288





than 30 min














289

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

gases amp char

lactic acid

pyruvaldehyde

acetol

glycolic acid


formic acid

acetaldehyde

acetic acid

(C) H-ZSM-5

Reaction time [min]

30 60 120 180

(A) No catalyst

Conversion

Con

versi

on

[m

ol

] or S

ele

cti

vit

y [

C-m

ol

]

(B) H-Beta

30 60 120 18030 60 120 180

Reaction time [min]

30 60 120 18030 60 120 180

Con

versi

on

[m

ol

] or S

ele

cti

vit

y [

C-m

ol


30 60 120 180

Con

versi

on

[m

ol

] or S

ele

cti

vit

y [

C-m

ol

]




290

















increase with time

291


Jin et al (2006))
















292

No

cata

lyst

48

Ce

H-B

eta

48

CuH

-Bet

a

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

0

20

40

60

80

100 conversion

acetic acid

lactic acid

formic acid


glycolic acid

acetol

pyruvaldehyde

acetaldehyde

Co

nv

ersi

on

[m

ol

]

0

5

10

15

20

25

Sel

ecti

vit

y [

C-m

ol

]




293

























294



295




Time

[min] Catalyst

Conversion

[mol]


[C-mol]

Total liquid yield



48 CeH-Beta 277 plusmn 08 24 00 198 149 59 15 00 00 445 123

48 CuH-Beta 418 plusmn 07 00 06 126 173 21 01 20 01 348 137

48 LaH-Beta 488 plusmn 04 10 00 103 48 27 20 01 03 213 104

48 SnH-Beta 415 plusmn 62 09 00 95 51 28 15 00 02 200 83

48 ZnH-Beta 507 plusmn 30 07 01 110 59 24 25 03 04 235 119


48 CeH-Beta 329 plusmn 16 30 148 141 00 24 04 02 04 353 116

48 CuH-Beta 430 plusmn 09 11 126 99 08 52 08 13 00 316 136

48 LaH-Beta 501 plusmn 00 24 68 199 00 56 36 00 08 382 191

48 SnH-Beta 396 plusmn 26 08 05 28 12 22 05 02 01 74 29

48 ZnH-Beta 467 plusmn 02 28 61 215 00 27 00 00 11 332 155



296

No

cata

lyst

48

Ce

H-B

eta

48

CuH

-Bet

a

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

0

20

40

60

80

100 conversion

acetic acid

lactic acid

formic acid


glycolic acid

acetol

pyruvaldehyde

acetaldehyde

Con

ver

sion

[m

ol

]

0

5

10

15

20

25

Sel

ecti

vit

y [

C-m

ol

]




297













from two issues









298













53











299













300

0

15

30

45

60

0

15

30

45

60

0

15

30

45

60

0

5

10

15

acetic acid

formic acid


glycolic acid


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Conversion

Con

ver

sion

[m

ol

]


0

5

10

15


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]


0

5

10

15


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]




301



Temp

[degC]

Residence Time

[s]

Conversion

[mol]


[C-mol]

Total yield

[C-mol]

H2O2 consumption


125 60 39 - 86 146 0 - 232 090 237

120 180 - 23 32 0 - 55 099 643

180 286 - 15 2 03 - 38 107 847

240 389 - 09 1 02 - 21 08 948

300 491 - 0 08 0 - 08 038 991

150 60 65 traces 10 108 22 - 231 149 737

120 213 traces 3 23 03 - 57 120 939

180 319 traces 16 12 02 traces 30 095 1000

240 399 traces 16 05 02 traces 23 093 999

300 480 traces 12 07 02 traces 20 097 1000

175 60 222 04 39 34 07 - 84 186 947

120 374 01 21 14 04 02 43 159 1000

180 458 01 2 08 05 03 38 172 1000

240 475 01 21 07 05 02 35 166 1000

300 550 0 17 - - traces 17 093 1000


302









and Figure 103














303




Temp

[degC]

Residence Time

[s]


Conversion

[mol]


[C-mol]

Yield to liquids

[C-mol]

Conversion

[mol]


[C-mol]

Yield to liquids

[C-mol]

125 60 39 232 09 202 118 24

120 180 55 10 176 191 34

180 286 38 11 195 184 36

240 389 21 08 198 154 31

300 491 08 04 188 135 25

150 60 65 231 15 178 372 66

120 213 57 12 263 486 128

180 319 30 10 375 399 149

240 399 23 09 382 385 147

300 480 20 10 407 385 157

175 60 222 84 19 273 907 239

120 374 43 16 347 647 214

180 458 38 17 345 659 219

240 475 35 17 439 506 217

300 550 170 09 461 424 191

304

0

15

30

45

0

15

30

45

0

15

30

45

0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mo

l]

60 120 180 240 300

Conversion

Co

nv

ersi

on

[m

ol

]


0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mo

l]

60 120 180 240 300

Co

nv

ersi

on

[m

ol

]


0

10

20

30

acetic acid

formic acid


glycolic acid

pyruvaldehyde

lactic acid

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mo

l]

60 120 180 240 300

Co

nv

ersi

on

[m

ol

]







305




include




andor HObull
















306


time











307















308




Temp

[degC]

Residence time

[s]


Conversion

[mol]

Selectivitya

[C-mol]

Yieldb

[C-mol]

Conversion

[mol]

Selectivitya

[C-mol]

Yieldb

[C-mol]

Conversion

[mol]

Selectivitya

[C-mol]

Yieldb

[C-mol]

125 60 202 118 24 130 51 07 na na na

120 176 191 34 125 85 11 76 593 45

180 195 184 36 153 167 26 118 620 73

240 198 154 31 164 212 35 166 396 65

300 188 135 25 159 233 37 259 231 60

150 60 178 372 66 155 224 35 251 403 95

120 263 486 128 266 306 82 278 630 165

180 375 399 150 374 209 78 334 601 190

240 382 385 147 384 231 89 397 480 183

300 407 385 157 408 205 82 432 464 192

175 60 273 907 239 364 420 143 450 170 70

120 347 647 214 377 552 197 434 294 119

180 345 659 219 401 554 212 371 493 175

240 439 506 217 393 604 233 463 456 206

300 461 424 191 382 567 212 473 361 168


a single experiment

309

0

15

30

45

0

15

30

45

0

15

30

45

0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Conversion

Con

ver

sion

[m

ol

]


0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]


0

10

20

30

acetic acid

formic acid


glycolic acid

pyruvaldehyde

lactic acid

Residence time [s]S

elec

tivit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]







310

0

15

30

45

0

15

30

45

0

15

30

45

0

10

20

30

40


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Conversion

Con

ver

sion

[m

ol

]


0

10

20

30

40


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]


0

10

20

30

40

acetic acid

formic acid


glycolic acid

pyruvaldehyde

lactic acid


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]60 120 180 240 300

Con

ver

sion

[m

ol

]



at 150 C and 175 C




311


























312











of DHA













313

0

2

4

6

8

10

0

2

4

6

8

10

0

2

4

6

8

10

0

2

4

6

8

10

60 120 180 240 300

DH

A y

ield

[C

-mo

l]

Residence time [s]

(A) 125 C

60 120 180 240 300

Residence time [s]

(B) 150 C

DH

A y

ield

[C

-mo

l]

Residence time [s]

(C) 175 C

60 120 180 240 300

60 120 180 240 300



H-Beta-Al2O3 (MC)

Fo

rmic

aci

d y

ield

[C

-mo

l]

Residence time [s]

(D) 125 C

60 120 180 240 300

Residence time [s]

(E) 150 C

Fo

rmic

aci

d y

ield

[C

-mo

l]

Residence time [s]

(F) 175 C

60 120 180 240 300




314










0

4

8

12



H-Beta-Al2O3 (MC)

La

cti

c a

cid

yie

ld [

C-m

ol

]

Residence time [s]

at 175 C

60 120 180 240 300




315











such reaction



7331 Conclusion




316























317







318












319

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

32 36 400

1000

2000

3000

4000

6 8 10 20 22 240

2000

4000

6000

8000

10000

Inte

nsi

ty [

Co

un

ts]

2 [degree]

25 wt CuH-Beta-Al2O

3 MC

after 125 C

after 150 C

after 175 C

(A)

Red circle = -Al2O

3

(C)

Inte

nsi

ty [

Cou

nts

]

2 [degree]

CuO

(B)

Inte

nsi

ty [

Co

un

ts]








320

60 120 180 240 300

0

20

40

60

80

100

60 120 180 240 300

0

100

200

300

400

60 120 180 240 300

0

20

40

60

80

60 120 180 240 300

0

20

40

60

80

100

60 120 180 240 300

0

100

200

300

400

60 120 180 240 300

0

20

40

60

80

60 120 180 240 300

0

20

40

60

80

100

60 120 180 240 300

0

100

200

300

400

60 120 180 240 300

0

20

40

60

80

125 C

150 C

175 C


3 (MC)

Co

nce

ntr

ati

on

of

Al

[pp

m]

Residence Time [s]


3 (MC)

Co

nce

ntr

ati

on

of

Si

[pp

m]

Residence Time [s]


3 (MC)

Co

nce

ntr

ati

on

of

Cu

[p

pm

]

Residence Time [s]


3 (MC)

125 C

150 C

175 C

Co

nce

ntr

ati

on

of

Al

[pp

m]

Residence Time [s]


3 (MC)

Co

nce

ntr

ati

on

of

Si

[pp

m]

Residence Time [s]


3 (MC)

Co

nce

ntr

ati

on

of

Cu

[p

pm

]

Residence Time [s]

Co

nce

ntr

ati

on

of

Al

[pp

m]

Residence Time [s]

125 C

150 C

175 C

(A) Al_H-Beta-Al2O


2O

3 (MC)

Co

nce

ntr

ati

on

of

Si

[pp

m]

Residence Time [s]

(C) Cu_H-Beta-Al2O

3 (MC)

Co

nce

ntr

ati

on

of

Cu

[p

pm

]

Residence Time [s]




321









150 oC

















322




Si












323


81 Summary










doped zeolites










324























325



5 min







liquid products














326












(MC)








327














82 Future work







solution

328

















329

9 References


















Manchester












330







91-109





91-109



291-303









423










55(7-10) 474-479

331



9529-9541







Catalysis 159(1) 249-252










Journal 85(1) 53-59



Publishing











332


309-312



4(1-2) 27-42



2242























S1013610111




333



























9(9) 927-934







334




74-82





























335









Catalysis 257(1) 163-171






337(1ndash2) 106-112



1129



666 224-236














336








3430









11665-11676






182




Chemistry C 117(24) 12552-12559






ENERC2423-2012SI2673791



337






















403ndash404 41-46











338







193(1) 20-30






156(3ndash4) 93-99








Catalysis 31(6) 615-618








1417-1425





liquefaction oil

339


glycerol







3349-3358


















11739






133

340










2920








Chemistry 13(4) 854-862






293-299









341



1379-1391






58






713-714




877















342
































204

343



Research 45(12) 4169-4177


















156(3ndash4) 306-315











11576-11586

344



383-388



222














Catalysis 3(6) 1279-1291





2(5) 415-437







567-576



345













38(11) 2221-2295











4168



13(5) 1175-1181






346




141-148





























673-674

347


Thesis






Technology 4(11) 4065-4074










29(4) 269-292



Science 286(1) 268-273












348



SPEC ISS) 198-220































349










1161






566-579









1870




135-147






350













Publishing






114













351



214-220











Letters 83





Research 49(16) 7524-7529






109(10) 4485-4491





259-266




352



102(19) 9267-9271












Society 49(3) 271-278




















353












45(7) 2163-2173




3113-3119





















354






Letters 88(1-2) 1-8



191






86(1) 345-374





16(25) 7368-7371












A General 231(1) 117-123



355










45








2475

















356



1-56





41-52




319




388



















357



















4653-4655



19-28












358




























298(2) 535-542



Chemical 297(2) 101-109




359




51(1) 43-49


3298-3311





90-94





22(1) 46-60





1525








11810-11819



Technology 102(2) 1998-2003



360



42(5) 1724-1730



























(United States)


361

10 Appendix




used = 711

362


glycolic acid

y = 28146x + 1252

Rsup2 = 09849

y = 49077x - 16235

Rsup2 = 09979

y = 78768x - 12788

Rsup2 = 09838

y = 86171x - 05366

Rsup2 = 09996

y = 9912x + 13915

Rsup2 = 09953

0

100

200

300

400

500

600

700

800

900

1000

0 2 4 6 8 10 12 14

Are

a

Concentration [mM]





363



y = 16711x + 23975

Rsup2 = 09933

y = 19991x + 12406

Rsup2 = 0999

y = 56833x + 24233

Rsup2 = 099590

5000

10000

15000

20000

25000

30000

0 2 4 6 8 10 12 14

Are

a

Concentration [mM]


y = 28396x - 26609

Rsup2 = 09997

y = 64254x - 20459

Rsup2 = 09981

0

200

400

600

800

1000

1200

1400

1600

0 5 10 15 20 25

Are

a

Concentration [mM]



364


Temperature

[degC]

Residence time

[s]

Total flow rate

[mlmin]

Feed flow rate

[mlmin]

Water flow rate

[mlmin]

125 60 39286 1310 2619

120 19643 0655 1310

180 13095 0437 0873

240 09822 0327 0655

300 07857 0262 0524

150 60 38465 1282 2564

120 19232 0641 1282

180 12822 0427 0855

240 09616 0321 0641

300 07693 0256 0513

175 60 37662 1255 2511

120 18831 0628 1255

180 12554 0418 0837

240 09416 0314 0628

300 07532 0251 0502












365



















366

0 100 200 300 400 500 600

-20

-15

-10

-5

0

278

100 C

379

596 C

TGA

wei

gh

t lo

ss

NH4-Beta zeolite

943

186 C

-03

-02

-01

00

01

02

dTG

Der

iv w

eigh

t [

C

-1]

Temperature [C]

80

82

84

86

88

90

92

94

96

98

100

217 C

146 C

TGA

Wei

gh

t [

]

NH4-Beta zeolite

0 100 200 300 400 500 600

-20000

-15000

-10000

-5000

0

5000

DSC

Temperature [C]

Heat

Flo

w [

mWg

-1]


367

0 100 200 300 400 500 600

-15

-10

-5

0

502

161

116

30 C

436 C

327C

w

eigh

t lo

ss TGA

100C

207C

280

-010

-005

000

005

dTG

Der

iv w

eigh

t [

C

-1]

Temperature [C]

NH4-ZSM-5

0 100 200 300 400 500 600

-2500

-2000

-1500

-1000

-500

0

500

1000

1500

207 C

140 C

124 C

DSC

Temperature [C]

Hea

t F

low

[m

Wg

-1]

90

95

100

TGA

w

eig

ht

loss

NH4-ZSM-5


368

10 20 30 40 50 60 70

0

7000

0

7000

0

7000

0

7000

0

7000

2 [degree]

48 wt CeNH4-Beta

x CeO2

O ZnO SnO2+ NaCl

xx x

x

48 wt LaNH4-Beta

Inte

nsi

ty [

co

un

ts]

48 wt ZnNH4-Beta

O OO O

+

48 wt SnNH4-Beta

+

NH

4-Beta

+

+ +

+

+ +

+

+ + +

+

+

+ +

+

+





ο = SnO2 x = CeO2

369

10 20 30 40 50 60 70

0

7500

0

7500

0

7500

0

7500

0

7500

Inte

nsi

ty [

cou

nts

]

2 [degree]

48 wt CeNH4-ZSM5

+XX X

X

+ NaCl ZnO O SnO2

x CeO2

+

48 wt LaNH4-ZSM5

+

48 wt SnNH4-ZSM5

OO

OO

O

+

48 wt ZnNH4-ZSM5

+

NH

4-ZSM5+

+

+

+

+

+

+

++

+

++





370

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

8000

+

+

+ = NaCl

O

OO

O

H-Beta zeolite

deAl-BetaII4h


Inte

nsi

ty [

co

un

ts]

2 [degree]

O

= SnO

+

Inte

nsi

ty [

cou

nts

]

2 (degree)





371

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

8000

++

H-Beta zeolite

deAl-BetaII4h


Inte

nsi

ty [

cou

nts

]

2 [degree]

+ NaCl

+

ZnO

2 [degree]





372

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta




in TUD-1 (red)

373

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm

3g

-1]


adsorption_H-Beta

desorption_H-Beta








10 20 30 40 50 60 70

0

200

400

600

800

1000

1200

methyl cellulose

Inte

nsi

ty [

co

un

ts]

2 [degree]

10 20 30 40 50 60 70

0

200

400

600

800

1000

1200 bentonite clay

Inte

nsi

ty [

co

un

ts]

2 [degree]



as a binder

374

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta











375

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta


3 (MC)


3 (MC)



376

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta








377

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta








378

10 20 30 40 50 60 70

0

200

400

600

800

1000

1200

methyl cellulose

Inte

nsi

ty [

co

un

ts]

2 [degree]

10 20 30 40 50 60 70

0

200

400

600

800

1000

1200

Inte

nsi

ty [

co

un

ts]

2 [degree]

-Al2O3



379



Time

[min]

Conversion

[mol]

Yield [C-mol] Total



60 156 plusmn 01 01 01 02 13 00 00 17 04 36 03 08 10 82 00 00 105 23 231

120 331 plusmn 16 01 02 04 33 00 00 39 04 84 03 06 14 98 00 00 117 11 249

180 441 plusmn 41 02 03 20 54 00 00 32 04 115 05 07 48 125 00 00 74 09 267

240 433 plusmn 74 02 02 08 63 00 00 34 05 115 05 05 19 147 00 00 79 12 267

300 472 plusmn 33 04 04 09 74 00 00 26 04 120 07 08 19 154 00 00 56 08 252

60 431 plusmn 91 02 02 03 56 00 09 25 05 103 04 05 08 140 00 19 74 16 265

120 561plusmn00 04 04 06 102 00 03 15 04 138 07 07 10 181 00 06 27 07 246

180 655 plusmn 98 05 04 09 107 00 03 15 05 149 07 07 13 169 00 06 27 09 240

240 744 plusmn 62 06 05 06 139 00 06 15 04 180 08 07 08 188 00 08 22 05 247

300 760 plusmn 47 07 05 15 147 00 09 10 05 199 09 07 19 195 00 13 14 07 264

60 839 plusmn 24 12 05 04 207 00 10 37 07 282 14 06 04 246 00 12 44 09 335

120 859 plusmn 19 11 05 14 204 02 06 34 03 279 13 06 17 238 02 06 39 03 325

180 898 plusmn 14 16 12 05 238 02 09 19 03 303 17 13 05 266 02 10 21 03 337

240 954 plusmn 25 15 10 02 231 02 14 10 01 283 16 10 02 242 02 15 10 09 306

60 940 plusmn 20 24 11 00 243 00 07 13 02 301 26 12 00 259 00 07 14 02 319

120 975 plusmn 35 11 07 00 219 00 04 40 08 289 12 07 00 225 00 05 41 03 293

180 976 plusmn 07 23 11 00 237 00 09 08 00 288 24 11 00 243 00 09 09 00 295

240 998 plusmn 02 18 11 00 220 00 10 00 00 259 18 11 00 220 00 10 00 00 259


380



Time

[min]

Conversion

[mol]

Yield [C-mol] total



60 449 plusmn 33 01 04 09 30 00 00 26 10 80 03 09 19 67 00 00 59 22 179

120 572 plusmn 43 04 07 11 57 01 02 39 09 130 08 11 20 100 02 03 67 15 227

180 743 plusmn 43 04 09 13 71 03 04 30 06 139 05 11 17 96 04 05 41 08 187

240 773 plusmn 01 04 10 11 80 00 06 43 06 160 06 14 15 103 00 07 55 07 207

300 793 plusmn 01 04 10 14 84 00 05 29 06 151 05 13 18 106 00 06 36 07 191

60 827 plusmn 40 09 17 08 130 00 07 55 11 237 11 20 09 158 00 09 67 13 288

120 937 plusmn 29 07 20 05 133 00 09 15 06 195 08 22 05 142 00 09 16 07 208

180 930 plusmn 00 08 28 03 145 00 13 10 06 256 08 30 03 155 00 14 10 07 275

240 963 plusmn 12 09 30 00 137 00 13 10 05 204 10 31 00 142 00 13 10 05 212

300 990 plusmn 05 08 29 00 138 00 13 00 03 191 08 29 00 139 00 13 00 03 193

60 980 plusmn 17 09 29 00 189 00 14 15 06 262 10 30 00 192 00 14 15 06 268

120 990 plusmn 10 08 28 00 155 00 11 00 00 203 09 29 00 157 00 11 00 00 206

180 1000 plusmn 00 08 35 00 133 00 15 00 00 190 08 35 00 133 00 15 00 00 190

240 1000 plusmn 00 06 44 00 107 00 16 00 00 173 06 44 00 107 00 16 00 00 173

300 1000 plusmn 00 07 49 00 104 00 19 00 00 180 07 49 00 104 00 19 00 00 180


381



Time

[min]

Conversion

[mol]

Yield [C-mol] Total



60 01 16 02 51 00 27 06 102 48 06 151 00 82 18 305

120 01 05 02 87 00 36 06 136 14 05 236 00 99 16 370

180 01 10 02 125 04 27 03 172 23 05 289 09 63 07 397

240 01 15 02 145 00 27 03 193 35 05 331 00 62 07 439

300 01 12 04 141 00 27 03 188 23 08 268 00 52 06 356

60 204 01 00 35 00 30 07 73 05 00 173 146 32 356

120 280 04 02 70 00 20 03 100 16 08 252 00 71 12 358

180 454 06 02 86 00 30 03 127 12 05 189 00 65 07 278

240 390 09 02 106 00 20 03 140 23 06 271 00 51 08 358

300 335 09 04 161 00 40 03 217 26 13 479 00 118 10 647

60 166 05 04 51 00 09 03 72 30 24 305 00 55 18 433

120 639 17 02 158 00 27 00 205 27 03 247 00 43 00 320

180 597 21 04 172 00 36 03 237 36 07 289 00 61 05 397

240 720 31 06 193 14 27 03 275 44 08 267 20 38 04 381

300 676 31 08 180 14 18 03 255 46 12 267 21 27 04 378


382



weight ratio of 1

y = -3E-05x - 23164

Rsup2 = 09454-3

-28

-26

-24

-22

-2

0 5000 10000 15000 20000

ln[g

ly]

Time [s]


y = -8E-05x - 23627

Rsup2 = 09444-4

-38

-36

-34

-32

-3

-28

-26

-24

-22

-2

0 5000 10000 15000 20000

ln[g

ly]

Time [s]


y = -00002x - 27519

Rsup2 = 08891

-62

-57

-52

-47

-42

-37

-32

-27

-220 5000 10000 15000 20000

ln[g

ly]

Time [s]


383




Catalyst Temp

[degC] Time

[s]

[ Gly]

M

[AC]


No Catalyst 270 0 01024 00000 396E-07 753E-11 152E-06

3600 01024 00000

7200 01024 00000

10800 01024 00000

14400 00997 00007

18000 00969 00010

300degC 0 01143 00000 462E-05 273E-04 247E-05

3600 01087 00120

7200 00956 00158

10800 00886 00123

14400 00862 00165

18000 00773 00149

330degC 0 01020 00000 174E-05 488E-13 257E-05

3600 00882 00039

7200 00761 00088

10800 00669 00144

14400 00561 00190

18000 00415 00247


3600 00874 00020

7200 00752 00053

384

10800 00620 00088

14400 00602 00101

18000 00565 00116

300degC 0 01126 00000 278E-05 171E-06 780E-05

3600 00632 00094

7200 00494 00170

10800 00378 00180

14400 00282 00233

18000 00265 00248

330degC 0 01122 00000 141E-04 266E-12 297E-04

3600 00154 00281

7200 00149 00323

10800 00108 00378

14400 00050 00365

18000 00022 00365

360degC 0 01117 00000 319E-04 360E-06 574E-04

3600 00026 00364

7200 00070 00406

10800 00026 00397

14400 00003 00367

H-ZSM-5 270degC 0 01076 00000 174E-05 161E-06 101E-04

3600 00592 00049

7200 00461 00092

10800 00276 00115

14400 00244 00129

18000 00222 00135

300degC 0 00949 00000 108E-04 766E-06 362E-04

3600 00164 00185

7200 00060 00189

385

10800 00066 00206

14400 00035 00195

18000 00009 00196

330degC 0 01065 00000 309E-04 376E-05 807E-04

3600 00020 00278

7200 00011 00204

10800 00000 00212

14400 00000 00170

18000 00000 00166


3600 00736 00084

7200 00698 00144

10800 00627 00208

14400 00620 00241

18000 00523 00234

300degC 0 01015 00000 155E-05 287E-11 282E-05

3600 00808 00054

7200 00731 00107

10800 00554 00131

14400 00619 00161

18000 00675 00245

330degC 0 01102 00000 432E-05 300E-05 427E-05

3600 00919 00084

7200 00398 00261

10800 00444 00285

14400 00308 00318

18000 00357 00298


386



Zeolite Temp

[degC]

Time

[h] Al Si

ppm wt ppm wt


















H-Beta 330 008 420 183 60050 1692

017 271 118 58860 1658

025 374 163 60340 1700

05 356 155 60350 1700

075 298 130 61950 1745

1 232 101 62150 1751

387


H-ZSM-5 330 008 133 058 56978 1605

017 186 081 52511 1479

025 222 097 51823 1460

05 128 056 50890 1434

075 180 079 50150 1413

1 536 234 49880 1405

H-ZSM-5 360 008 163 071 50780 1430

017 106 046 49270 1388

025 095 041 48020 1353

05 077 034 50050 1410

075 142 062 50910 1434

1 262 114 50900 1434



388



389








Zeolite SiO2Al2O3

(manufacture)

Fe (ppm) Cu

[ppm]

Al

[ppm]

Na

[ppm]

ZSM-5 23 100-150 50-200

26000 500-600

Beta 25 150-200 25000 300-400

390




391




392








[mgL]

BP

[ordmC]

RT

[min] Area

1 Acetaldehyde 1000 202 20 1567

2 Acetol 3704 145 173 991

3 Glyceraldehyde 4504 140-150 67 124



6 Pyruvaldehyde 3603 72 24 55 62 71

7 Acrolein 2803 53 42 176 866 536

8 MeOH 3204

9 EtOH 7837


393




-100E-10

-800E-11

-600E-11

-400E-11

-200E-11

000E+00

200E-11

400E-11

600E-11

800E-11

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49

Ion

cu

rren

t

Mw

SN132-1

28 =N2

32 = O2

40 = Ar

44 = CO2

394



Temp

[degC]

Residence time

[s]

Conversion

[mol]



125 0 00 00 00 00 00 00 00 00 00 00

60 202 09 00 41 61 07 00 00 00 118

120 176 21 00 63 100 08 00 00 00 191

180 195 24 00 64 90 07 00 00 00 184

240 198 19 00 56 73 07 00 00 00 154

300 188 10 00 51 66 07 00 00 00 135

150 0 00 00 00 00 00 00 00 00 00 00

60 178 66 00 98 181 27 00 00 00 372

120 263 105 00 140 205 36 00 00 00 486

180 375 108 00 123 134 34 00 00 00 399

240 382 106 00 121 125 33 00 00 00 385

300 407 117 00 117 111 39 00 00 00 385

175 0 00 00 00 00 00 00 00 00 00 00

60 273 186 98 331 182 62 16 21 10 907

120 347 125 171 200 61 49 12 20 08 647

180 345 104 225 217 31 45 12 16 08 659

240 439 69 203 167 14 32 10 06 04 506

300 461 45 181 147 05 31 06 06 04 424


395

10 20 30 40 50 60 70

0

500

1000

1500In

ten

sity

[C

ou

nts

]

2 [degree]

H-Beta-Al2O

3 MC

after 125 C

after 150 C

Red circle = -Al2O

3




396



iii

Declaration






Suna Srisamai

London January 2016

iv






v

Abstract
























vi





vii

Acknowledgments






















viii

Nomenclature









Ɛ void fraction



FA formic acid








spectrometry




LA lactic acid


ix

MC methyl cellulose

MHz megahertz

mM millimolar

MPa megapascal


RT room temperature






TEA triethanolamine








Universiteit Delft







x

Table of Contents

Declaration iii

Abstract v

Acknowledgments vii

Nomenclature viii

Table of Contents x

1 Introduction 1











2211 Biomass 20

2212 Glycerol 23


2221 Biomass 25

2222 Glycerol 26




xi













3 Aim of study 89

31 Aim 89

32 Objectives 90













xii




























xiii


513 TPD-NH3 163




523 TPD-NH3 180






















xiv






643 Conclusion 280
















7331 Conclusion 315



81 Summary 323

82 Future work 327


xv


9 References 329

10 Appendix 361

1

1 Introduction








et al (2014))







2








00

05

10

15

20

25

30

35

Cru

de g

lycerol

[mil

lion

ton

ne]

Year

2004 2005 2006 2007 2008 2009 2010 2012 2014 2015 2023

0

100

200

300

400

500

Pric

e o

f cru

de g

lycerol (8

0

pu

re) [U

S $

ton

ne]






3





















2222



4











5




converting glycerol













6





glycerol 65-85 229-333 ~83


methanol 234-375 86-126 lt1

water 1-3 41-182 ~13

sodium 01-4 16-19 lt5

















7

























8








9

2 Literature review




















10








pressure water















11












12









13





Water

Subcritical

Water

Supercritical

Water

Acetone


Vapour pressure

[bar]

003 (24 degC) 1 (100 degC) to 221

(374 degC)

gt221 024

(20 degC)



bar) 692 (330 degC

300 bar)




7899 (20

degC 11

bar)


(25 degC)

L 277 G123

(101 degC) L504

G 307 (371 degC)

low 330

(25 degC)

Heat capacity Cp

[kJ kg-1K-1]

422 (25 degC) 486 13 (400 degC 250 bar) 218

(20 degC)

Dielectric

constant

785 (25 degC 1

bar)

271 (250 degC 50

bar) 182 (330 degC

300 bar)

59 (400 degC 250 bar)

105 (400 degC 500 bar)

206

(20 degC)


but still a liquid

(at 370 degC)

yes na

-logKw 14 na 21 na








14





(2012))

15











16






















17












information



Solvent MP

[ordmC]

BP

[ordmC]

Waste Environmental

impact

Health Flammability

amp Explosion

Reactivity

Stability

Life cycle

score

Legislation

Flag

EHS

Red Flag

Water 0 100 4 10 10 10 10 10

2-Propanol -88 82 3 9 8 6 8 4

1-Butanol -89 118 5 7 5 8 9 5

Ethanol -114 78 3 8 8 6 9 9

Methanol -98 65 4 9 5 5 10 9

Acetone -95 56 3 9 8 4 9 7

Acetic acid 17 118 4 8 6 8 7 8

Toluene -95 111 6 3 4 4 10 7

Heptane -91 98 6 3 8 3 10 7




18












solvents


treat


cool rapidly

Inexpensive

Non-flammable








19













20





2211 Biomass




21







grass



















22


























23



2212 Glycerol



















24


Equation 1



as














25



2221 Biomass






















26



















2222 Glycerol




27








119862119874 + 1198672119874 harr 1198621198742 + 1198672









28


























29















30










S (H2) = 85




promoters)



CO2 28 CH4






Wen et al (2008)


catalytic activity

Luo et al (2010)




King et al (2010)


phase


[1 wt amp 10wt]

NiCeO2

250 270 autogenous

(375 527)



Manfro et al (2011)

[5-85 wt]

PtAl2O3


at 5-45wt glycerol


31


























32
























33




biomass

















34






chemicals

35




Time


Ref








glucose 300-400 ˚C 250-400 bar

002-2 s




Fructose 300-400 ˚C 250-400 bar

002-2 s


Glucose 250-350 ˚C 276 bar 5

min



001-054 s


D-glucose other

mono-saccharides



124-benzenetriol

Srokol et al (2004)

sucrose hexoses

trioses


Co2+ Cu2+ Ni2+

Zn2+



75-180 s

HCl H2SO4

H3PO4 other

organic acids


(2006)

36

























37















38


39


























40






41




Time




300 s



anhydro-D-glucose


microcrystalline

cellulose

320-400 degC 250 bar 005

to 10 s




Y = 51

Sasaki et al (2000)


solid waste)


acid) = 26

Goto et al (2004)

cherry (hard wood)

cypress (soft wood)




cellulose starch

glucose

270-400 degC auto-

geneous 30-180 s



min

alkali alkaline

earth AlCl3 and

transition metal

chlorides


67

Peng et al (2010)


min

Ni Zn activated

C in NaOH



42


glycerol











43







44


of glycerol


process

Production

[tonnesyr]

Price

US $tonnes




pentaerythritol

crotonaldehyde


carbohydrates




DHA fermentation of

glycerol




(i) Acrolein











45


(2009))







glycerol





46



(ii) Acetaldehyde














47






(iii) Lactic acid


















48















2244 is desirable







studies

49













50





C2H4 C2H6

Antal et al (1985)

flow 349-475 degC 250 350 450 bar

32-165 s



H2



60 min



Watanabe et al

(2007)


acrolein

Qadariyah et al

(2011)


51















52







53



Catalyst Reactor

Type


Ref





H2SO4 flow 300-400 degC 250 300 345 bar

5-83 s



60 s




May et al (2010)


x103 kg-cat sm-3





(005- 8) x103 kg-cat sm-3


lactic acid



Beta Na-MFI


mlmiddoth-1



LHSV = 2 h-1



ZSM-23



54









at 400 degC 345 bar




such as

metal salts

metal oxides and

zeolites

Metal salts




55

Metal oxides











Zeolites











selectivity

56
















57




Time

Conversion

[]

Yield of

LA2 [] [LA]3 gL Ref


NaOH



KOH


25 M glycerol 275 M

NaOH


(2010)

011 M glycerol PtC


Semi-

batchwise



in 01 M H3BO3



045 M NaOH



in 054 M NaOH


033 M glycerol




58














59


























60


























61






Auneau et al (2012)












62













63



Pressure Time


Ref

045 M Crude

glycerol



or O2 or H2O2



was added


et al (2014)


O2 1 h 40 mM FeCl3

Ru(OH)4 on



1-90 wt

glycerol



(H3+nPVnMo12-nO40)



formaldehyde


(2015)


64











al 2014)














65


















66


Almutairi (2013)











and Davis 2013)



67

























68





69



Pressure Time

Note Ref


Mordenite (MOR)-20

Zeolite Y (FAU)-30





Kruger et al (2014)


ZSM-5 (MFI)-15 25 40

150 ˚C 200 ˚C

saturated vapour

pressure 1-6 h





saturated vapour

pressure 72 h


100





metakaolinite


ZSM-5 (MFI)-24 to 918





vapour pressure 72


= 50


decomposed

Lutz et al (2005)

H-Y (FAU)-25

H-USY (FAU)-19 9 3

35 ppm of HCl 190


750 rpm 50 bar H2

24 h




ZSM-5 (MFI)

mordenite (MOR)

Zeolite Beta (BEA)

Zeolite Y (FAU)

200 ˚C saturated


reaction time



Zhang et al (2015)

70


























71


















framework







72




al (2005)

73





















74




chemicals







75




Pressure Time


Ref

Cellulose (150 170 190 ˚C)

na (1 3 5 h)





min microwave-

assisted


Beta zeolite


acid lactic acid


Fructose (120 150 165 ˚C)

autogenous 05-2 h


an adsorbent




filtrated







Al-Beta Si-Beta




76




















77
























78





















pores is limited



79

























80























81


























82




(2010))












83











agglomerates













84





(plasticiser)





(SiAl = 125 or 25)

γ-Al2O3 HNO3

(peptiser)


at 205-230 degC pH2 = 50 bar 1198991198672119899ℎ119910119889119903119900119888119886119903119887119900119899 =


Bauer et al (2014)


(peptiser)



alcohol) 651




stream about 6 h



(plasticiser)



Melero et al (2008)

85











selectivity















86
























87





















88



Cracking of n-

hexane

538 ordmC Beta

zeoliteTUD-1

k = 025 while 011


Waller et al

(2004)

aldol condensation

of benzaldehyde

and n-amyl

alcohol


for our ZSM-5

Zhou et al

(2010)

cyclodehydration

of xylose

H2O-toluene

mixture 170

ordmC


yield = 74 while X

= 94 and furfural

yield = 58 for a

mixture of Beta and

TUD-1

Lima et al

(2010)

Friedel-Crafts

benzylation


pure H-Y zeolite

Hamdy and

Mul (2013)


conversion

89

3 Aim of study

31 Aim















233


addressed

90

32 Objectives





















91













zeolites prepared










92


doped zeolites




















93

















94




















95





1

[119881119886 (1198750

119875 minus 1 )]=

119862 minus 1

119881119898119862 times

119875

1198750+

1

119881119898119862

Where







surface ml




[119881119886(1198750119875

minus 1)] against

119875





1


96




119862 = [119878119897119900119901119890

119868119899119905119890119903119888119890119901119905] + 1


119881119898 = 1

119862 119868119899119905119890119903119888119890119901119905 119874119903

1

(119878119897119900119901119890 + 119868119899119905119890119903119888119890119901119905)


119878119861119864119879 = (119881119898 119873 119886)

119898 22400

Where




for N2)



97























98




materials










99

















Equation 9


119899120582 = 2119889 sin 120579

100













per step






015

101


119905 = 119870120582

119861 cos 120579
















specimens

102























103








and gold coated












104












105




















used

106


calorimetry (DSC)




















107






















spin

108

















multiplet)





109





time





(VWD) used and



solution)

110





111








acetaldehyde

hydrate









OHCH2CH(OH)CH2OH)



CH3CH(OH)COOH)




112


















113







CA

CB

= IA

IB

timesnB

nA






114









Istandard

times 2

3 timesCstandard





nB is 2

nA is 3






115











116











y = 1155x + 04549

Rsup2 = 09953

0

2

4

6

8

10

12

14

16

18

0 2 4 6 8 10 12 14 16

[lact

ate

] exp

erim

en

t (m

M)


117


















Retention time

(min)

Compounds

Retention time

(min)

Compounds







118












00302 mM 00284 mM


(ICP-OES)






119














120









System II)









1198791198944+ + 11986721198742 + 21198672119874 rarr 11986721198791198941198744 + 4119867+

121


TiOSO4






122



409 nm









y = 00005x - 00158

Rsup2 = 09995

0

02

04

06

08

1

12

0 500 1000 1500 2000 2500

Ab

sro

ba

nce

H2O2 (micromolL)

123









511986721198742 + 21198701198721198991198744 + 311986721198781198744 rarr 21198721198991198781198744 + 11987021198781198744 + 81198672119874 + 51198742





124




work




























125







methanol 99 VWR






Custom Multi

MBH



H2O2 (30 wv) VWR

H2SO4 95 VWR

HNO3 68 VWR












126









127






128




reactors

Zeolite


- Ce Ce La Sn Zn Cu

0 25 48 48 48 48 48

NH4-Beta

H-Beta

deAl-Beta





batch reactors

Zeolite


- Ce Ce La Sn Zn Cu

0 25 48 48 48 48 48

NH4-ZSM-5

H-ZSM-5

deAl-ZSM-5


129



Catalyst Catalyst

NH4-Beta NH4-ZSM-5












1 CedeAl-HBetaII4h

2 CedeAl-HBetaII4h

3 CedeAl-HBetaII4h

48 CedeAl-BetaII4h

48 CudeAl-BetaII4h

48 SndeAl-BetaII4h

48 ZndeAl-BetaII4h






the following means


130













(TUD-1)

Extrusion with clay








131

















132
























133







membranes








134



for 30 min











135






















136










TUD-1 matrix











137





















138















139







140









(Comark KM340)















141




pressure gague










142








carried out













143













461 Batch process









144
















145


146













147



















148























149





ie at 20 cm



150













151






















152



τ =VR 120576 ρR

V ρSTP







of glycerol









153


ε =119881119900119897119906119898119890 119900119891 119908119886119905119890119903 119894119899119904119894119889119890 119905ℎ119890 119903119890119886119888119905119900119903 minus 119898119894119888119903119900119901119900119903119890 119907119900119897119906119898119890 119900119891 119905ℎ119890 119888119886119905119886119897119910119904119905

119879119900119905119886119897 119907119900119897119906119898119890 119900119891 119905ℎ119890 119903119890119886119888119905119900119903

Therefore


74993 cm3= 0556




ρR =ρSTP


Where









154



56 in the Appendix

155











SEM-EDS and TPD-NH3











156










the present work













157

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

+ ++

+


++

+


+

++


++

+ NaCl

+ NaCl

2 [degree]

2 [degree]

+

+


Inte

nsi

ty [

co

un

ts]

Inte

nsi

ty [

co

un

ts]





= NaCl

158


550 ordmC for 5 h








159




[nm]

XRD relative

crystallinityb []























160

512 BET N2 analysis


















161

00 01 02 03 04 05 06 07 08 09 10

0

80

100

120

140

160

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]








162

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]















~31-39 nm is ~300-360 m2middotg-1

163



Sample BET N2

surface area

[msup2middotg-1]

Micropore

volume

[cmsup3middotg-1]

Micropore

area

[msup2middotg-1]

External

surface area

[msup2middotg-1]





513 TPD-NH3










gas flow rate used





164





in Table 29

100 200 300 400 500 600

0

100

200

300

0 1200 2400 3600 4800 6000

Co

ncen

tra

tio

n o

f N

H3 i

n g

as

flo

w [

pp

m]

Temperature [oC]


NH4-ZSM-5

Time [s]


H-ZSM-5

165

100 200 300 400 500 600

0

50

100

150

200

250

300

0 1200 2400 3600 4800 6000

Co

ncen

tra

tio

n o

f N

H3 i

n g

as

flo

w [

pp

m]

Temperature [oC]


(H-Beta zeolite)

NH4-Beta zeolite

Time [s]
























166

0 1000 2000 3000 4000 5000 6000

0

50

100

Experimental data


Co

nce

ntr

ati

on

of

NH

3 i

n g

as

flo

w [

pp

m]

Time [s]

(A) NH4-ZSM-5

0 1000 2000 3000 4000 5000 6000

0

50

100

150

200

250

300

Experimental data


Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Time [s]

(B) H-ZSM-5

0 1000 2000 3000 4000 5000 6000

0

50

100

150

200

250

300

Experimental data


Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Time [s]


0 1000 2000 3000 4000 5000 6000

0

50

100

150

200

250

Experimental data


Co

ncen

tra

tio

n o

f N

H3 i

n g

as

flo

w [

pp

m]

Time [s]

(D) H-Beta zeolite



167



Catalyst


desorbed

[micromolmiddotg-1]

Ref Tmax

[degC]

NH3

[micromolmiddotg-1]

Tmax

[degC]

NH3

[micromolmiddotg-1]

Tmax

[degC]

NH3

[micromolmiddotg-1]

NH4-ZSM-5 145 4 200 69 420 67 140 This work

H-ZSM-5 145 8 187 242 385 269a 520 This work

150 - 388 - - Long and Yang (2001)


- - - - 630 Alotaibi et al (2014)

H-Beta 124 2 176 105 300 236a 344 This work

277 - 377 - 750 Lenarda et al (2003)

197 653 363 209 862 Talebi et al (2008)


168

I ZSM-5





















169







170



















II Beta zeolite




171
























172























173























174















175

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

+x

x

+

+

xx

CeO2

48 wt CeH-Beta

+++

+

48 wt LaH-Beta

O

++

OOO

48 wt SnH-Beta

ZnO

O

++

+

+

x

SnO2

48 wt ZnH-Beta

+

+

+

Inte

nsi

ty [

co

un

ts]

2 [degree]

+ NaCl

H-Beta

+





x = CeO2

176

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

+X+

+

+

X

X

2 (degree)

48 wt CeH-ZSM5

X

+ ++

+

OOO

48 wt LaH-ZSM5

+

+

O

48 wt SnH-ZSM5

O

+++

+

48 wt ZnH-ZSM5

Inte

nsi

ty [

cou

nts

]

+ NaCl ZnO O SnO2

x CeO2

+ +

+

H-ZSM5

+





177





Sample Crystallite

sizea [nm]

XRD relative

crystallinityb

[]

Position of the

main peakc

(2θ) [degree]

Shift in 2θ of

the main peakc

[degree]

NH4-Beta 159 100 226 +009

H-Beta 151 105 225 000

48 CeNH4-Beta 145 55 225 +007

48 LaNH4-Beta 141 64 225 +003

48 SnNH4-Beta 144 47 225 +002

48 ZnNH4-Beta 121 76 225 -001

48 CeH-Beta 146 64 225 +007

48 LaH-Beta 137 68 226 +008

48 SnH-Beta 139 63 225 +004

48 ZnH-Beta 135 83 225 +006

NH4-ZSM-5 320 100 230 -005

H-ZSM-5 388 101 231 000

48 CeNH4-ZSM-5 331 60 230 -005

48 LaNH4-ZSM-5 372 71 231 -003

48 SnNH4-ZSM-5 381 65 231 000

48 ZnNH4-ZSM-5 369 98 231 000

48 CeH-ZSM-5 318 62 231 -003

48 LaH-ZSM-5 345 75 231 -003

48 SnH-ZSM-5 370 69 231 +003

48 ZnH-ZSM-5 351 84 231 -003





178

522 BET N2 analysis










00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

00 01 02 03 04 05 06 07 08 09 10

0

80

100

120

140

160

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]






(A) (B)

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]


adsorption_H-ZSM-5

desorption_H-ZSM-5







179








Sample

BET N2

surface area

[msup2g-1]

Micropore

volume

[cmsup3g-1]

Micropore

area

[msup2g-1]

External

surface area

[msup2g-1]

NH4-Beta 575 017 358 218

H-Beta 598 017 367 230

48 CeNH4-Beta 534 015 330 204

48 LaNH4-Beta 591 015 383 208

48 SnNH4-Beta 489 014 303 186

48 ZnNH4-Beta 526 015 326 200

48 CeH-Beta 539 015 333 206

48 LaH-Beta 567 015 371 196

48 SnH-Beta 514 014 301 213

48 ZnH-Beta 528 014 313 215

NH4-ZSM-5 299 013 257 42

H-ZSM-5 363 012 258 104

48 CeNH4-ZSM-5 294 010 213 81

48 LaNH4-ZSM-5 370 011 280 90

48 SnNH4-ZSM-5 323 011 228 95

48 ZnNH4-ZSM-5 336 012 250 86

48 CeH-ZSM-5 340 011 235 104

48 LaH-ZSM-5 359 011 284 76

48 SnH-ZSM-5 304 010 223 80

48 ZnH-ZSM-5 308 011 227 81

180

523 TPD-NH3



















about 5 degC




181



100 200 300 400 500 600

0

50

100

150

200

250

300

100 200 300 400 500 600

0

50

100

150

200

250

300

100 200 300 400 500 600

0

50

100

150

200

250

300

100 200 300 400 500 600

0

50

100

150

200

250

300




Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]

Temperature [oC]

(A)

NH4-Beta zeolite


(C)

Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]

Temperature [oC]

NH4-ZSM-5

48 SnNH4-ZSM-5

48 ZnNH4-ZSM-5

48 LaNH4-ZSM-5

48 CeNH4-ZSM-5

(B)

Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]

Temperature [oC]

H-Beta zeolite

48 SnH-Beta zeolite

48 ZnH-Beta zeolite

48 LaH-Beta zeolite

48 CeH-Beta zeolite

(D)

Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]Temperature [

oC]

48 CeH-ZSM-5

48 LaH-ZSM-5

48 ZnH-ZSM-5

H-ZSM-5

48 SnH-ZSM-5

182










Catalyst


Degree of ion

exchange b Tmax

[degC]

Tmax

[degC]

Tmax

[degC]

NH3

[micromolmiddotg-1]

NH4-Beta 127 165250 - - 0

H-Beta 124 176 300 236 a 0

48 CeNH4-Beta 134 177 306 94 36

48 LaNH4-Beta 138 178 317 107 43

48 SnNH4-Beta 136 171 304 147 22

48 ZnNH4-Beta 148 178 305 114 61

48 CeH-Beta 140 160 305 73 41

48 LaH-Beta 145 176 317 95 47

48 SnH-Beta 141 160 305 45 48

48 ZnH-Beta 149 180 305 103 67

NH4-ZSM-5 145 200 420 67 0

H-ZSM-5 145 187 385 270 a 0

48 CeNH4-ZSM-5 138 190 387 146 31

48 LaNH4-ZSM-5 146 191 400 113 52

48 SnNH4-ZSM-5 133 190 392 39 58

48 ZnNH4-ZSM-5 148 205 386 88 91

48 CeH-ZSM-5 - 187 380 73 49

48 LaH-ZSM-5 144 180 380 98 57

48 SnH-ZSM-5 144 172 391 35 59

48 ZnH-ZSM-5 145 187 380 57 106

183













to the H-ZSM-5








et al 2012)




184
















in Beta zeolite






Table 33

185




[g]

Treatment time

[h]



deAl-BetaI6h 1 6

deAl-BetaI20h 1 20

deAl-BetaII4h 2 4

deAl-BetaII6h 2 6

deAl-BetaII20h 2 20

deAl-BetaIII4h 3 4







preserved

186

0

300

600

900

10 20 30 40 50 60 70

0

300

600

900

H-ZSM-5In

ten

sity

[C

ou

nts

]


2 [degree]










187










188

0

4000

8000

0

4000

8000

0

4000

8000

10 20 30 40 50 60 70

0

4000

8000

+ +

+


+

+ ++

+

deAl-BetaII4h+ NaCl

Inte

nsi

ty [

Co

un

ts]

+ +

+


+ +

+

+


2 [degree]







189


zeolites

Catalyst BET-N2

surface area

[msup2middotg-1]

Crystallite

sizea

[nm]

Relative

crystallinityb

[]

2θ of d302

[degree]

shift of d302

[degree]

d302-spacing

[Aring]

SiAl

(XRF)

Al extractedc

[wt]

NH4-Beta zeolite 575 159 100 226 394 124 0

H-Beta zeolite 598 151 104 225 000 396 124 0

deAl-BetaI4hd 573 133 95 227 +017e 391 533 974

deAl-BetaI6h 572 137 94 227 +024 391 600 978

deAl-BetaI20h 554 141 89 226 +007 394 795 983

deAl-BetaII4h 580 129 100 227 +017 393 688 977

deAl-BetaII6h 551 130 94 227 +017 389 671 980

deAl-BetaII20h 542 154 89 226 +009 392 526 969

deAl-BetaIII4h 585 122 95 227 +017 392 556 974






190


























191







BET N2 analysis










192

6 8 10 20 22 24

0

2000

4000

6000

8000

H-Beta zeolite

deAl-BetaII4h

deAl-BetaII6h

deAl-BetaII20h

Inte

nsi

ty [

cou

nts

]

2 [degree]




193

0

25

50

75

100

Al

extr

act

ed [

wt

]

Treatment time [h]




0 4 6 20














194












195

100 200 300 400 500 600

0

50

100

150

200

250

300

deAl-BetaI20h

deAl-BetaII6h

deAl-BetaII4h

deAl-BetaII 15 min

deAl-BetaII 5min

H-Beta zeolite

Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Temperature [C]





measurement








196
























197





















198



deAl-BetaII4h


metalAlextracted

Weight ratio of

metalzeolite

XRD TPD-NH3 TEM-EDX

NH4-Beta - -

H-Beta - -

deAl-BetaII4h - -





















199









10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

8000

10000

X

XXX

H-Beta zeolite

deAl-BeatII4h

10 CedeAl-BetaII4h

6 CedeAl-BetaII4h

1 CedeAl-BetaII4h



Inte

nsi

ty [

cou

nts

]

2 [degree]

X

CeO2

Inte

nsi

ty [

cou

nts

]

2 (degree)







200














201










202

0

3000

6000

0

3000

6000

0

3000

6000

0

3000

6000

10 20 30 40 50 60 70

0

3000

6000

+ = NaCl

= ZnO

(D)

5 ZndeAl-BetaII4h

2 [degree]

+

+ = NaCl

O = SnO2

(C)

ooo+

88 SndeAl-BetaII4h

Inte

nsi

ty [

Co

un

ts]

+

+

+

o

+ = NaCl

(B)

++

+

10 LadeAl-BetaII4h

+ = NaCl

x = CeO2

xxx +

10 CedeAl-BetaII4h

+x

(A)

+ = NaCl

(E)

++

+

deAl-BetaII4h





ο = SnO2 x = CeO2

203




metalAlextracted

Phases identified

























204











205

0

3000

6000

9000

0

3000

6000

0

3000

6000

10 20 30 40 50 60 70

0

3000

6000



2 [degree]

+

(D)

(B)

(C)



ooo+

Inte

nsi

ty [

Cou

nts

]

+

+

+

o



+

x

x + x x

(A)

++

+

deAl-BetaII4h






= CeO2

206









salts under study

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

++

+ NaCl

H-Beta zeolite

deAl-BetaII4h


Inte

nsi

ty [

co

un

ts]

2 [degree]

+

Inte

nsi

ty [

cou

nts

]

2 [degree]





207




Sample Δd302

position

[degree]a

Crystallite

sizeb

[nm]

d302-

spacing

[Aring]

Δd302 [Aring]c

Relative

crystallinityd

NH4-Beta +009 159 394 100

H-Beta 000 151 396 000 105

deAl-BetaII4he +019 129 392 -004 100

045 CedeAl-BetaII4h +022 118 392 -004 82

07 CedeAl-BetaII4h +019 131 392 -004 79

1 CedeAl-BetaII4h +019 117 392 -004 78

6 CedeAl-BetaII4h +012 127 393 -002 64

10 CedeAl-BetaII4hf +038 110 389 -007 58

10 LadeAl-BetaII4h +016 110 393 -003 63

88 SndeAl-BetaII4h +012 135 393 -002 68

5 ZndeAl-BetaII4h +003 146 395 -001 92












208




(d302) and




















209

542 Surface acidity












210

100 200 300 400 500 600

0

50

100

150

200

250

300




deAl-BetaII4h

H-Beta zeolite

Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Temperature [C]




relative to zeolite


based catalysts





211






use See Chapter 551

















212





213

0

1000

2000

0

1000

2000

10 20 30 40 50 60 70

0

1000

2000

Inte

nsi

ty [

Co

un

ts]


2 [degree]

(A) H-Beta zeolite

2= 7776

2= 22630

2= 25456

2= 27158

2= 43971 2= 55980

2 = 7643

2= 22557

2 = 25356

2 = 26958

2 = 439670

(C) CHFM support






214












215



Temperature

[degC]

Residence time

[s]

Conversion

[mol]











216








matrix




217






















218

10 20 30 40 50 60 70

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

(D)

= CuO

Inte

nsi

ty [

Cou

nts

]

2 [degree]


48 wt CuH-Beta

(C)

xxx

x = CeO2


48 CeH-Beta

x

(B)

H-Beta in TUD-1

H-Beta

(A)

H-Beta






219













single measurement

Sample Micropore

volume

[cmsup3middotg-1]

Micropore

area

[msup2middotg-1]

External

surface area

[msup2middotg-1]

BET surface

area

[msup2middotg-1]



48 wt CuH-Beta 015 330 200 530

48 wt CuH-Beta in TUD-1 012 278 348 627



220







not performed





catalysts ie

H-Beta

25wt CuH-Beta and

48wt CuH-Beta






221










CuO

10 20 30 40 50 60 70

0

1000

2000

3000

4000

5000

6000

2 [degree]

= CuO

H-Beta

25 wt CuH-Beta

48 wt CuH-Beta

Inte

nsi

ty [

cou

nts

]



222










223

10 20 30 40 50 60 70

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

= CuO

Inte

nsi

ty [

Cou

nts

]

2 [degree]


(C) 48 wt CuH-Beta


(A) H-Beta




224
















measurement

Sample Micropore

volume

[cmsup3middotg-1]

Micropore

area

[msup2middotg-1]

External

surface area

[msup2middotg-1]

BET N2

surface area

[msup2middotg-1]



48 CuH-Beta 015 330 200 530




225













226











(MC)











not used



227




10 20 30 40 50 60 70

red circle-Al2O

3


3


3(MC)

(A) H-Beta

Inte

nsi

ty [

arb

un

its]

2 [degree]





228

10 20 30 40 50 60 70


3


3


3(MC)

Inte

nsi

ty [

arb

un

its]

2 [degree]

(A) 48 wt CuH-Beta






229

10 20 30 40 50 60 70


3


3 (MC)

Inte

nsi

ty [

arb

un

its]

2 [degree]

(B) 25 wt CuH-Beta







Catalysts


wt of zeolite

catalyst relative

to γ-Al2O3

H-Beta or






230





Catalyst BET N2

surface area

[m2middotg-1]

Micropore

Volume

[cmsup3middotg-1]

XRD relative

crystallinitya

[]

Post of d302

[degree 2θ]

TEM-EDS

SiO2Al2O3

mol ratio

NH4-Beta 575 017 100 226 25b

H-Beta 598 017 105 225 25 b


48 wt CuH-Beta 534 015 83 227


H-Betaγ-Al2O3 (MC)c 423 010 38 228 54

25 wt CuH-Betaγ-

Al2O3 (MC)c 419 009 nad 226 24

48 wt CuH-Betaγ-

Al2O3c

- - 56 227 44

48 wt CuH-Betaγ-

Al2O3 (MC)c 446 010 62 227 45











231
















232





















conversion rate

233

0 60 120 180 240 3000

20

40

60

80

100

0 60 120 180 240 3000

10

20

30

40

50

270 C

300 C

330 C

Gly

cero

l co

nv

ersi

on

[m

ol

]

Reaction time [min]

270 C

300 C

330 C

Sel

ecti

vit

y t

o a

ll l

iqu

id p

rod

uct

s [C

-mo

l]

Reaction time [min]



234






Temp

[degC]

Press

[bar]

Time

[min]

Conversion

[mol]a


[C-mol]b References


300 86 60 49 204 ˃100 39 70 Watanabe et al (2007)c

300 2955 60 100 005 0002 Qadariyah et al (2011)

270 55 240 26 plusmn 04 - - 137 183 - - - 08

300 53 plusmn 04 - - 96 127 - - - 11

300 86 60 49 plusmn 20 17 35 104 120 - - - 08

120 143 plusmn 15 25 07 11 158 - 32 - 36

180 206 plusmn 14 19 05 22 123 - 23 08 41

240 229 plusmn 23 18 04 33 165 - 20 07 62

300 306 plusmn 09 14 07 14 149 - 17 06 64

330 128 60 121 plusmn 19 29 08 46 215 - 53 21 45

120 241 plusmn 15 31 05 43 244 10 43 14 94

180 333 plusmn 56 45 08 38 287 11 40 07 145

240 441 plusmn 51 51 07 21 286 16 38 05 187

300 586 plusmn 65 50 06 18 281 22 36 00 241

235
















236











237


















Lopez et al 2010)

238










reaction times








gases




239












240

0 60 120 180 240 300

0

20

40

60

80

100

0 60 120 180 240 300

0

10

20

30

40

50

0 60 120 180 240 300

0

20

40

60

80

100

0 60 120 180 240 300

0

10

20

30

40

50

270 oC

300 oC

330 oC

(A) H-ZSM-5

270 oC

300 oC

330 oC

(B) H-ZSM-5

60 120 180 240 300

Temp [degC]





Reaction time [min]

Total yield [C-mol]

Gly

cerol

con

versi

on

[m

ol

]

270 oC

300 oC

330 oC

360 oC

Gly

cerol

con

versi

on

[m

ol

]

Reaction time [min]

(C) H-Beta

Sele

cti

vit

y t

o a

ll l

iqu

id p

rod

ucts

[C

-mol

]

270 oC

300 oC

330 oC

360 o

C

Sele

cti

vit

y t

o a

ll l

iqu

id p

rod

ucts

[C

-mol

]

Reaction time [min]

(D) H-Beta

60 120 180 240 300

Temp [degC]




Reaction time [min]

Total yield [C-mol]




241








are





solution











242

0

1

2

3

4

5

6

7

8

0

450

500

550

600

650

0

1

2

3

0

13

14

15

16

17

18

H-Beta

H-ZSM-5

Time [h]

Con

cen

trati

on

of

Al

[pp

m]

Time [h]

0 008 017 025 05 075 1

H-Beta

H-ZSM-5

Con

cen

trati

on

of

Si

[pp

m]

0 008 017 025 05 075 10 008 017 025 05 075 1

H-Beta

H-ZSM-5

Time [h]

Am

ou

nt

of

Al

[wt

]

Time [h]

0 008 017 025 05 075 1

H-Beta

H-ZSM-5

Am

ou

nt

of

Si

[wt

]




243

10 20 30 40 50 60 70

0

1000

2000

3000

Inte

nsi

ty [

Co

un

ts]

2 [degree]

H-Beta zeolite















244



products

245

0 60 120 180 240 300

0

20

40

60

80

100

0 60 120 180 240 300

0

20

40

60

80

100

Gly

cero

l con

ver

sion

[m

ol

]

270 oC

300 oC

330 oC

Reaction time [min]

Sel

ecti

vit

y t

o a

ll l

iqu

id p

rod

uct

s [C

-mol

]

270 oC

300 oC

330 oC

Reaction time [min]

60 120 180 240 300

Temp [degC]

270 7 10 13 14 22

300 10 14 17 19 19

330 7 20 24 28 26

Reaction time [min]

Total yield [C-mol]






experiment

246














glycerol

247

0

25

50

75

1000

25

50

75

100

gases amp char

acetol

acrolein

EtOH

acetaldehyde

lactic acid

acetic acid

MeOH

(A) H-Beta

Reaction Time [min]

(B) H-ZSM-5

0 5 10 15 30 45 60

Conversion

Co

nv

ersi

on

[m

ol

] o

r S

elec

tiv

ity

[C

-mo

l]







248















respectively

249










250



119892119897119910119888119890119903119900119897 1198961rarr 119886119888119890119905119886119897119889119890ℎ119910119889119890 Equation 23

119886119888119890119905119886119897119889119890ℎ119910119889119890 1198962rarr 119901119903119900119889119906119888119905119904 Equation 24

119892119897119910119888119890119903119900119897 1198963rarr 119901119903119900119889119906119888119905119904 Equation 25











kinetic analysis





as follows

251

119889[119892119897119910119888119890119903119900119897]

119889119905= minus(1198961 + 1198963)[119892119897119910119888119890119903119900119897] Equation 26

119889[119886119888119890119905119886119897119889119890ℎ119910119889119890]

119889119905= 1198961[119892119897119910119888119890119903119900119897] minus 1198962[119886119888119890119905119886119897119889119890ℎ119910119889119890] Equation 27






0 3600 7200 10800 14400 18000

000

002

004

006

008

010

012

Con

cen

trati

on

[M

]

Time [s]



curve fit_glycerol


k1 = 27787e

-5

k2 = 171056e

-6

k3 = 781408e

-5






252









300degC 462E-5 273E-4 247E-5

330degC 174E-5 488E-13 257E-5


300degC 278E-5 171E-6 780E-5

330degC 141E-4 266E-12 297E-4

360degC 319E-4 360E-6 574E-4

H-ZSM-5 270degC 174E-5 161E-6 101E-4

300degC 108E-4 766E-6 362E-4

330degC 309E-4 376E-5 807E-4


300degC 155E-5 287E-11 282E-5

330degC 432E-5 300E-5 427e-5






253



















119896 = 119860119890minus119864119886119877119879 Equation 28



temperature in K

254





Table 45

ln 119896 = ln 119860 minus119864119886

119877(

1

119879) Equation 29



analysed

y = -15767x + 18168

Rsup2 = 09847

y = -2393x - 6364

Rsup2 = 01825

y = -17817x + 20981

Rsup2 = 09314

y = -26229x + 33953

Rsup2 = 09138

-15

-14

-13

-12

-11

-10

-9

-8160E-03 165E-03 170E-03 175E-03 180E-03 185E-03 190E-03

ln k

1T [K-1]



255






H-ZSM-5 131 78E+07


















256

























257










258

No

cata

lyst

NH

4-Bet

a

H-B

eta

48

Ce

NH

4-Bet

a

48

La

NH

4-Bet

a

48

SnN

H4-

Bet

a

48

ZnN

H4-

Bet

a

48

Ce

H-B

eta

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

NH

4-ZSM

-5

H-Z

SM-5

48

Ce

NH

4-ZSM

-5

48

La

NH

4-ZSM

-5

48

SnN

H4-

ZSM

-5

48

ZnN

H4-

ZSM

-5

48

Ce

H-Z

SM-5

48

La

H-Z

SM-5

48

SnH

-ZSM

-5

48

ZnH

-ZSM

-5

0

25

50

75

100

[]

Conversion [mol]



0

50

100

150

200

250

300


]

Am

ou

nt

of

des

orb

ed N

H3 [

mo

lg

-1]





259



Catalyst Conversion

[mol]


[C-mol]

Total Yb


NH4-Beta 345 plusmn 28 24 07 39 346 07 33 11 468 161



48 LaNH4-Beta 560 plusmn 15 29 09 17 356 14 81 14 519 291

48 SnNH4-Beta 552 plusmn 06 21 05 38 290 09 82 07 451 249

48 ZnNH4-Beta 481 plusmn 02 22 05 59 244 08 83 12 433 208



48 SnH-Beta 737 plusmn 36 10 06 19 222 08 42 10 318 235

48 ZnH-Beta 556 plusmn 35 23 04 29 253 08 76 06 400 222

NH4-ZSM-5 583 plusmn 45 17 08 12 281 12 36 09 375 219

H-ZSM-5 980 plusmn 096 10 30 00 192 14 15 06 268 262

48 CeNH4-ZSM-5 938 plusmn 348 11 20 06 200 08 22 03 271 254

48 LaNH4-ZSM-5 836 plusmn 49 13 12 08 224 13 38 08 316 264

48 SnNH4-ZSM-5 832 plusmn 10 11 33 00 217 11 41 09 323 269

48 ZnNH4-ZSM-5 748 plusmn 47 20 07 13 302 10 76 10 439 328

48 CeH-ZSM-5 927 plusmn 42 12 23 11 206 11 23 05 289 268

48 LaH-ZSM-5 986 plusmn 081 12 29 11 229 09 34 04 328 324





260

NH

4-Bet

a

H-B

eta

48

Ce

NH

4-Bet

a

48

La

NH

4-Bet

a

48

SnN

H4-

Bet

a

48

ZnN

H4-

Bet

a

48

Ce

H-B

eta

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

0

25

50

75

100Y= 222 Y= 235 Y= 208

Co

nv

ersi

on

[m

ol

]Y= 223 Y= 207 Y= 291 Y= 286 Y= 282 Y= 161

Y= 249 Conversion

MeOH

acetic acid

lactic acid

acetaldehyde

EtOH

acrolein

0

10

20

30

40

Sel

ecti

vit

y [

C-m

ol

]




261

NH

4-ZSM

-5

H-Z

SM-5

48

Ce

NH

4-ZSM

-5

48

La

NH

4-ZSM

-5

48

SnN

H4-

ZSM

-5

48

ZnN

H4-

ZSM

-5

48

Ce

H-Z

SM-5

48

La

H-Z

SM-5

48

SnH

-ZSM

-5

48

ZnH

-ZSM

-5

0

25

50

75

100

Y = 296 Y = 278 Y = 324 Y = 268 Y = 328 Y = 269 Y = 264 Y = 254 Y = 262 C

on

ver

sio

n [

mo

l]

or

sele

ctiv

ity

[C

-mo


0

10

20

30

40

MeOH

acetic acid

lactic acid

acetaldehyde

EtOH

acrolein

Sel

ecti

vit

y [

C-m

ol

]




262

















263












264

10 20 30 40 50 60 70

0

1500

3000

5 6 7 8 9 16 18 20 22 240

1500

3000 H-Beta zeolite

150 C 1 h

150 C 20 h

Inte

nsi

ty [

cou

nts

]

2 [degree]



10 20 30 40 50 60 70

0

1500

3000

5 6 7 8 9 16 18 20 22 240

1500

3000

Inte

nsi

ty [

cou

nts

]

2 [degree]

H-Beta zeolite

200 C 1 h

200 C 3 h

200 C 5 h

200 C 20 h



265

10 20 30 40 50 60 70

0

1500

3000

5 6 7 8 9 16 18 20 22 240

1500

3000 H-Beta zeolite

250 C 1 h

250 C 20 h

Inte

nsi

ty [

co

un

ts]

2 [degree]







Temperature

[degC]

Time

[h]

XRD relative

crystallinity

20 0 100 plusmn 00

150 1 132 plusmn 38

20 105 plusmn 22

200 1 110 plusmn 39

3 108 plusmn 61

5 100 plusmn 53

20 76 plusmn 17

250 1 74 plusmn 45

20 40 plusmn 72

266


















times






267

















268

0

1

2

3

4

5

6

7

8

0

100

200

300

400

500

600

0

1

2

3

0

5

10

15

0 008 017 025 05 075 1 3 5 20 48

0 008 017 025 05 075 1 3 5 20 48

20 C

150 C

200 C

250 C

330 C

330 C_H-ZSM-5

Time [h]

Co

nce

ntr

ati

on

of

Al

[pp

m]

Time [h]

0 008 017 025 05 075 1 3 5 20 48

20 C

150 C

200 C

250 C

330 C

330 C_H-ZSM-5

Co

nce

ntr

ati

on

of

Si

[pp

m]

20 C

150 C

200 C

250 C

330 C

330 C_ H-ZSM-5

Time [h]

Am

ou

nt

of

Al

[wt

]

Time [h]

0 008 017 025 05 075 1 3 5 20 48

20 C

150 C

200 C

250 C

330 C

330 C_ H-ZSM-5

Am

ou

nt

of

Si

[wt

]





269


















90





270










[ppm]

Holding time [min]

5 10 15 30 45 60


Al 444 393 374 356 298 332

Si 6005 5886 6034 6195 620 6215


Al 266 191 236 229 228 163

Si 4581 4758 5108 4773 484 4789



271

0

25

50

75

100

Y= 498 mol

Y= 572 mol

Y= 423 mol

Y= 359 mol

Y= 141 mol

gases amp char

acetol

acrolein

acetaldehyde

acetic acid

MeOH

Y= 044 mol

Conversion

Co

nv

ersi

on

[m

ol

] o

r S

elec

tiv

ity

[C

-mo

l]

Reaction Time [min]

5 10 15 30 45 60




of mean (119878119864)











272



and pressures




273







was detected

274






[min]

Conversion

[mol]


products [C-mol]

Yield

[C-mol]

No 60 121 plusmn 19 372 45


10 610 plusmn 22 497 300

15 633 plusmn 46 512 315

30 732 plusmn 54 420 300

45 769 plusmn 21 408 311

60 839 plusmn 24 335 282


10 145 plusmn 09 100 14

15 163 plusmn 07 218 36

30 242 plusmn 26 177 42

45 264 plusmn 03 217 57

60 283 plusmn 12 174 50

deAl-BetaI20h


10 59 plusmn 00 125 07

15 111 plusmn 08 98 11

30 160 plusmn 17 130 21

45 1758 plusmn 25 123 21

60 174 plusmn 05 142 25

275

0 10 20 30 40 50 60

0

20

40

60

80

100

0 10 20 30 40 50 60

0

10

20

30

40

50

60



H-Beta zeolite

No catalyst



H-Beta zeolite

No catalyst

Gly

cero

l co

nver

sion

[m

ol

]


Sel

ecti

vit

y t

o a

ll l

iqu

id p

rod

uct

s [C

-mol

]




276


























277







[ppm]

Holding time [min]

5 10 15 30 45 60


Al 193 184 248 216 153 12

Si 2152 2253 2186 2167 2158 217


Al 04 036 029 024 034 024

Si 1838 18991 18861 19957 19424 19816



278

0

25

50

75

100

gases amp char

acetaldehyde

acetic acid

MeOH

Y= 248 mol

Y= 211 mol

Y= 205 mol

Y= 108 mol

Y= 074 mol

Y= 073 mol

Conversion

Con

ver

sion

[m

ol

] o

r S

elec

tiv

ity

[C

-mol

]

Reaction Time [min]

5 10 15 30 45 60














279














280

0

25

50

75

100

gases amp char

acetol

acrolein

EtOH

acetaldehyde

acetic acid

MeOH

Conversion

Co

nv

ersi

on

[m

ol

] o

r S

elec

tiv

ity

[C

-mo

l]

Reaction Time [min]

5 10 15 30 45 60




643 Conclusion







281










71 Batch process










282








283

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

Y = 164 06 Y = 178 03 Y = 211 00

Reaction time [min]

Y = 248 09

Con

ver

sion

[m

ol

] or

Sel

ecti

vit

y [

C-m

ol

]

125 C

30 60 120 180

150 C

Reaction time [min]

30 60 120 180

Y = 156 08 Y = 153 11 Y = 126 08

Con

ver

sion

[m

ol

] or

Sel

ecti

vit

y [

C-m

ol

]

Y = 148 05

Y = 131 19 Y = 1309 07 Y = 135 03

200 C175 C

Reaction time [min]

30 60 120

gases amp char

pyruvaldehyde

acetol

acrolein

glycolic acid

DHA

formic acid

acetaldehyde

acetic acid

Reaction time [min]

30 60 120 180

Y = 148 06

Conversion

Con

ver

sion

[m

ol

] o

r S

elec

tivit

y [

C-m

ol

]

Con

ver

sio

n [

mol

] or

Sel

ecti

vit

y [

C-m

ol

]

200 C

Y = 106 15 Y = 137 13 Y = 124 02



products [C-mol]

284




Temperature

[degC]

Reaction time

[min]

Conversion

[mol]


[C-mol]

Yield of liquids

[C-mol]

























285













286




et al 2011))




287






















288





than 30 min














289

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

gases amp char

lactic acid

pyruvaldehyde

acetol

glycolic acid


formic acid

acetaldehyde

acetic acid

(C) H-ZSM-5

Reaction time [min]

30 60 120 180

(A) No catalyst

Conversion

Con

versi

on

[m

ol

] or S

ele

cti

vit

y [

C-m

ol

]

(B) H-Beta

30 60 120 18030 60 120 180

Reaction time [min]

30 60 120 18030 60 120 180

Con

versi

on

[m

ol

] or S

ele

cti

vit

y [

C-m

ol


30 60 120 180

Con

versi

on

[m

ol

] or S

ele

cti

vit

y [

C-m

ol

]




290

















increase with time

291


Jin et al (2006))
















292

No

cata

lyst

48

Ce

H-B

eta

48

CuH

-Bet

a

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

0

20

40

60

80

100 conversion

acetic acid

lactic acid

formic acid


glycolic acid

acetol

pyruvaldehyde

acetaldehyde

Co

nv

ersi

on

[m

ol

]

0

5

10

15

20

25

Sel

ecti

vit

y [

C-m

ol

]




293

























294



295




Time

[min] Catalyst

Conversion

[mol]


[C-mol]

Total liquid yield



48 CeH-Beta 277 plusmn 08 24 00 198 149 59 15 00 00 445 123

48 CuH-Beta 418 plusmn 07 00 06 126 173 21 01 20 01 348 137

48 LaH-Beta 488 plusmn 04 10 00 103 48 27 20 01 03 213 104

48 SnH-Beta 415 plusmn 62 09 00 95 51 28 15 00 02 200 83

48 ZnH-Beta 507 plusmn 30 07 01 110 59 24 25 03 04 235 119


48 CeH-Beta 329 plusmn 16 30 148 141 00 24 04 02 04 353 116

48 CuH-Beta 430 plusmn 09 11 126 99 08 52 08 13 00 316 136

48 LaH-Beta 501 plusmn 00 24 68 199 00 56 36 00 08 382 191

48 SnH-Beta 396 plusmn 26 08 05 28 12 22 05 02 01 74 29

48 ZnH-Beta 467 plusmn 02 28 61 215 00 27 00 00 11 332 155



296

No

cata

lyst

48

Ce

H-B

eta

48

CuH

-Bet

a

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

0

20

40

60

80

100 conversion

acetic acid

lactic acid

formic acid


glycolic acid

acetol

pyruvaldehyde

acetaldehyde

Con

ver

sion

[m

ol

]

0

5

10

15

20

25

Sel

ecti

vit

y [

C-m

ol

]




297













from two issues









298













53











299













300

0

15

30

45

60

0

15

30

45

60

0

15

30

45

60

0

5

10

15

acetic acid

formic acid


glycolic acid


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Conversion

Con

ver

sion

[m

ol

]


0

5

10

15


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]


0

5

10

15


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]




301



Temp

[degC]

Residence Time

[s]

Conversion

[mol]


[C-mol]

Total yield

[C-mol]

H2O2 consumption


125 60 39 - 86 146 0 - 232 090 237

120 180 - 23 32 0 - 55 099 643

180 286 - 15 2 03 - 38 107 847

240 389 - 09 1 02 - 21 08 948

300 491 - 0 08 0 - 08 038 991

150 60 65 traces 10 108 22 - 231 149 737

120 213 traces 3 23 03 - 57 120 939

180 319 traces 16 12 02 traces 30 095 1000

240 399 traces 16 05 02 traces 23 093 999

300 480 traces 12 07 02 traces 20 097 1000

175 60 222 04 39 34 07 - 84 186 947

120 374 01 21 14 04 02 43 159 1000

180 458 01 2 08 05 03 38 172 1000

240 475 01 21 07 05 02 35 166 1000

300 550 0 17 - - traces 17 093 1000


302









and Figure 103














303




Temp

[degC]

Residence Time

[s]


Conversion

[mol]


[C-mol]

Yield to liquids

[C-mol]

Conversion

[mol]


[C-mol]

Yield to liquids

[C-mol]

125 60 39 232 09 202 118 24

120 180 55 10 176 191 34

180 286 38 11 195 184 36

240 389 21 08 198 154 31

300 491 08 04 188 135 25

150 60 65 231 15 178 372 66

120 213 57 12 263 486 128

180 319 30 10 375 399 149

240 399 23 09 382 385 147

300 480 20 10 407 385 157

175 60 222 84 19 273 907 239

120 374 43 16 347 647 214

180 458 38 17 345 659 219

240 475 35 17 439 506 217

300 550 170 09 461 424 191

304

0

15

30

45

0

15

30

45

0

15

30

45

0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mo

l]

60 120 180 240 300

Conversion

Co

nv

ersi

on

[m

ol

]


0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mo

l]

60 120 180 240 300

Co

nv

ersi

on

[m

ol

]


0

10

20

30

acetic acid

formic acid


glycolic acid

pyruvaldehyde

lactic acid

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mo

l]

60 120 180 240 300

Co

nv

ersi

on

[m

ol

]







305




include




andor HObull
















306


time











307















308




Temp

[degC]

Residence time

[s]


Conversion

[mol]

Selectivitya

[C-mol]

Yieldb

[C-mol]

Conversion

[mol]

Selectivitya

[C-mol]

Yieldb

[C-mol]

Conversion

[mol]

Selectivitya

[C-mol]

Yieldb

[C-mol]

125 60 202 118 24 130 51 07 na na na

120 176 191 34 125 85 11 76 593 45

180 195 184 36 153 167 26 118 620 73

240 198 154 31 164 212 35 166 396 65

300 188 135 25 159 233 37 259 231 60

150 60 178 372 66 155 224 35 251 403 95

120 263 486 128 266 306 82 278 630 165

180 375 399 150 374 209 78 334 601 190

240 382 385 147 384 231 89 397 480 183

300 407 385 157 408 205 82 432 464 192

175 60 273 907 239 364 420 143 450 170 70

120 347 647 214 377 552 197 434 294 119

180 345 659 219 401 554 212 371 493 175

240 439 506 217 393 604 233 463 456 206

300 461 424 191 382 567 212 473 361 168


a single experiment

309

0

15

30

45

0

15

30

45

0

15

30

45

0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Conversion

Con

ver

sion

[m

ol

]


0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]


0

10

20

30

acetic acid

formic acid


glycolic acid

pyruvaldehyde

lactic acid

Residence time [s]S

elec

tivit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]







310

0

15

30

45

0

15

30

45

0

15

30

45

0

10

20

30

40


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Conversion

Con

ver

sion

[m

ol

]


0

10

20

30

40


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]


0

10

20

30

40

acetic acid

formic acid


glycolic acid

pyruvaldehyde

lactic acid


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]60 120 180 240 300

Con

ver

sion

[m

ol

]



at 150 C and 175 C




311


























312











of DHA













313

0

2

4

6

8

10

0

2

4

6

8

10

0

2

4

6

8

10

0

2

4

6

8

10

60 120 180 240 300

DH

A y

ield

[C

-mo

l]

Residence time [s]

(A) 125 C

60 120 180 240 300

Residence time [s]

(B) 150 C

DH

A y

ield

[C

-mo

l]

Residence time [s]

(C) 175 C

60 120 180 240 300

60 120 180 240 300



H-Beta-Al2O3 (MC)

Fo

rmic

aci

d y

ield

[C

-mo

l]

Residence time [s]

(D) 125 C

60 120 180 240 300

Residence time [s]

(E) 150 C

Fo

rmic

aci

d y

ield

[C

-mo

l]

Residence time [s]

(F) 175 C

60 120 180 240 300




314










0

4

8

12



H-Beta-Al2O3 (MC)

La

cti

c a

cid

yie

ld [

C-m

ol

]

Residence time [s]

at 175 C

60 120 180 240 300




315











such reaction



7331 Conclusion




316























317







318












319

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

32 36 400

1000

2000

3000

4000

6 8 10 20 22 240

2000

4000

6000

8000

10000

Inte

nsi

ty [

Co

un

ts]

2 [degree]

25 wt CuH-Beta-Al2O

3 MC

after 125 C

after 150 C

after 175 C

(A)

Red circle = -Al2O

3

(C)

Inte

nsi

ty [

Cou

nts

]

2 [degree]

CuO

(B)

Inte

nsi

ty [

Co

un

ts]








320

60 120 180 240 300

0

20

40

60

80

100

60 120 180 240 300

0

100

200

300

400

60 120 180 240 300

0

20

40

60

80

60 120 180 240 300

0

20

40

60

80

100

60 120 180 240 300

0

100

200

300

400

60 120 180 240 300

0

20

40

60

80

60 120 180 240 300

0

20

40

60

80

100

60 120 180 240 300

0

100

200

300

400

60 120 180 240 300

0

20

40

60

80

125 C

150 C

175 C


3 (MC)

Co

nce

ntr

ati

on

of

Al

[pp

m]

Residence Time [s]


3 (MC)

Co

nce

ntr

ati

on

of

Si

[pp

m]

Residence Time [s]


3 (MC)

Co

nce

ntr

ati

on

of

Cu

[p

pm

]

Residence Time [s]


3 (MC)

125 C

150 C

175 C

Co

nce

ntr

ati

on

of

Al

[pp

m]

Residence Time [s]


3 (MC)

Co

nce

ntr

ati

on

of

Si

[pp

m]

Residence Time [s]


3 (MC)

Co

nce

ntr

ati

on

of

Cu

[p

pm

]

Residence Time [s]

Co

nce

ntr

ati

on

of

Al

[pp

m]

Residence Time [s]

125 C

150 C

175 C

(A) Al_H-Beta-Al2O


2O

3 (MC)

Co

nce

ntr

ati

on

of

Si

[pp

m]

Residence Time [s]

(C) Cu_H-Beta-Al2O

3 (MC)

Co

nce

ntr

ati

on

of

Cu

[p

pm

]

Residence Time [s]




321









150 oC

















322




Si












323


81 Summary










doped zeolites










324























325



5 min







liquid products














326












(MC)








327














82 Future work







solution

328

















329

9 References


















Manchester












330







91-109





91-109



291-303









423










55(7-10) 474-479

331



9529-9541







Catalysis 159(1) 249-252










Journal 85(1) 53-59



Publishing











332


309-312



4(1-2) 27-42



2242























S1013610111




333



























9(9) 927-934







334




74-82





























335









Catalysis 257(1) 163-171






337(1ndash2) 106-112



1129



666 224-236














336








3430









11665-11676






182




Chemistry C 117(24) 12552-12559






ENERC2423-2012SI2673791



337






















403ndash404 41-46











338







193(1) 20-30






156(3ndash4) 93-99








Catalysis 31(6) 615-618








1417-1425





liquefaction oil

339


glycerol







3349-3358


















11739






133

340










2920








Chemistry 13(4) 854-862






293-299









341



1379-1391






58






713-714




877















342
































204

343



Research 45(12) 4169-4177


















156(3ndash4) 306-315











11576-11586

344



383-388



222














Catalysis 3(6) 1279-1291





2(5) 415-437







567-576



345













38(11) 2221-2295











4168



13(5) 1175-1181






346




141-148





























673-674

347


Thesis






Technology 4(11) 4065-4074










29(4) 269-292



Science 286(1) 268-273












348



SPEC ISS) 198-220































349










1161






566-579









1870




135-147






350













Publishing






114













351



214-220











Letters 83





Research 49(16) 7524-7529






109(10) 4485-4491





259-266




352



102(19) 9267-9271












Society 49(3) 271-278




















353












45(7) 2163-2173




3113-3119





















354






Letters 88(1-2) 1-8



191






86(1) 345-374





16(25) 7368-7371












A General 231(1) 117-123



355










45








2475

















356



1-56





41-52




319




388



















357



















4653-4655



19-28












358




























298(2) 535-542



Chemical 297(2) 101-109




359




51(1) 43-49


3298-3311





90-94





22(1) 46-60





1525








11810-11819



Technology 102(2) 1998-2003



360



42(5) 1724-1730



























(United States)


361

10 Appendix




used = 711

362


glycolic acid

y = 28146x + 1252

Rsup2 = 09849

y = 49077x - 16235

Rsup2 = 09979

y = 78768x - 12788

Rsup2 = 09838

y = 86171x - 05366

Rsup2 = 09996

y = 9912x + 13915

Rsup2 = 09953

0

100

200

300

400

500

600

700

800

900

1000

0 2 4 6 8 10 12 14

Are

a

Concentration [mM]





363



y = 16711x + 23975

Rsup2 = 09933

y = 19991x + 12406

Rsup2 = 0999

y = 56833x + 24233

Rsup2 = 099590

5000

10000

15000

20000

25000

30000

0 2 4 6 8 10 12 14

Are

a

Concentration [mM]


y = 28396x - 26609

Rsup2 = 09997

y = 64254x - 20459

Rsup2 = 09981

0

200

400

600

800

1000

1200

1400

1600

0 5 10 15 20 25

Are

a

Concentration [mM]



364


Temperature

[degC]

Residence time

[s]

Total flow rate

[mlmin]

Feed flow rate

[mlmin]

Water flow rate

[mlmin]

125 60 39286 1310 2619

120 19643 0655 1310

180 13095 0437 0873

240 09822 0327 0655

300 07857 0262 0524

150 60 38465 1282 2564

120 19232 0641 1282

180 12822 0427 0855

240 09616 0321 0641

300 07693 0256 0513

175 60 37662 1255 2511

120 18831 0628 1255

180 12554 0418 0837

240 09416 0314 0628

300 07532 0251 0502












365



















366

0 100 200 300 400 500 600

-20

-15

-10

-5

0

278

100 C

379

596 C

TGA

wei

gh

t lo

ss

NH4-Beta zeolite

943

186 C

-03

-02

-01

00

01

02

dTG

Der

iv w

eigh

t [

C

-1]

Temperature [C]

80

82

84

86

88

90

92

94

96

98

100

217 C

146 C

TGA

Wei

gh

t [

]

NH4-Beta zeolite

0 100 200 300 400 500 600

-20000

-15000

-10000

-5000

0

5000

DSC

Temperature [C]

Heat

Flo

w [

mWg

-1]


367

0 100 200 300 400 500 600

-15

-10

-5

0

502

161

116

30 C

436 C

327C

w

eigh

t lo

ss TGA

100C

207C

280

-010

-005

000

005

dTG

Der

iv w

eigh

t [

C

-1]

Temperature [C]

NH4-ZSM-5

0 100 200 300 400 500 600

-2500

-2000

-1500

-1000

-500

0

500

1000

1500

207 C

140 C

124 C

DSC

Temperature [C]

Hea

t F

low

[m

Wg

-1]

90

95

100

TGA

w

eig

ht

loss

NH4-ZSM-5


368

10 20 30 40 50 60 70

0

7000

0

7000

0

7000

0

7000

0

7000

2 [degree]

48 wt CeNH4-Beta

x CeO2

O ZnO SnO2+ NaCl

xx x

x

48 wt LaNH4-Beta

Inte

nsi

ty [

co

un

ts]

48 wt ZnNH4-Beta

O OO O

+

48 wt SnNH4-Beta

+

NH

4-Beta

+

+ +

+

+ +

+

+ + +

+

+

+ +

+

+





ο = SnO2 x = CeO2

369

10 20 30 40 50 60 70

0

7500

0

7500

0

7500

0

7500

0

7500

Inte

nsi

ty [

cou

nts

]

2 [degree]

48 wt CeNH4-ZSM5

+XX X

X

+ NaCl ZnO O SnO2

x CeO2

+

48 wt LaNH4-ZSM5

+

48 wt SnNH4-ZSM5

OO

OO

O

+

48 wt ZnNH4-ZSM5

+

NH

4-ZSM5+

+

+

+

+

+

+

++

+

++





370

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

8000

+

+

+ = NaCl

O

OO

O

H-Beta zeolite

deAl-BetaII4h


Inte

nsi

ty [

co

un

ts]

2 [degree]

O

= SnO

+

Inte

nsi

ty [

cou

nts

]

2 (degree)





371

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

8000

++

H-Beta zeolite

deAl-BetaII4h


Inte

nsi

ty [

cou

nts

]

2 [degree]

+ NaCl

+

ZnO

2 [degree]





372

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta




in TUD-1 (red)

373

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm

3g

-1]


adsorption_H-Beta

desorption_H-Beta








10 20 30 40 50 60 70

0

200

400

600

800

1000

1200

methyl cellulose

Inte

nsi

ty [

co

un

ts]

2 [degree]

10 20 30 40 50 60 70

0

200

400

600

800

1000

1200 bentonite clay

Inte

nsi

ty [

co

un

ts]

2 [degree]



as a binder

374

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta











375

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta


3 (MC)


3 (MC)



376

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta








377

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta








378

10 20 30 40 50 60 70

0

200

400

600

800

1000

1200

methyl cellulose

Inte

nsi

ty [

co

un

ts]

2 [degree]

10 20 30 40 50 60 70

0

200

400

600

800

1000

1200

Inte

nsi

ty [

co

un

ts]

2 [degree]

-Al2O3



379



Time

[min]

Conversion

[mol]

Yield [C-mol] Total



60 156 plusmn 01 01 01 02 13 00 00 17 04 36 03 08 10 82 00 00 105 23 231

120 331 plusmn 16 01 02 04 33 00 00 39 04 84 03 06 14 98 00 00 117 11 249

180 441 plusmn 41 02 03 20 54 00 00 32 04 115 05 07 48 125 00 00 74 09 267

240 433 plusmn 74 02 02 08 63 00 00 34 05 115 05 05 19 147 00 00 79 12 267

300 472 plusmn 33 04 04 09 74 00 00 26 04 120 07 08 19 154 00 00 56 08 252

60 431 plusmn 91 02 02 03 56 00 09 25 05 103 04 05 08 140 00 19 74 16 265

120 561plusmn00 04 04 06 102 00 03 15 04 138 07 07 10 181 00 06 27 07 246

180 655 plusmn 98 05 04 09 107 00 03 15 05 149 07 07 13 169 00 06 27 09 240

240 744 plusmn 62 06 05 06 139 00 06 15 04 180 08 07 08 188 00 08 22 05 247

300 760 plusmn 47 07 05 15 147 00 09 10 05 199 09 07 19 195 00 13 14 07 264

60 839 plusmn 24 12 05 04 207 00 10 37 07 282 14 06 04 246 00 12 44 09 335

120 859 plusmn 19 11 05 14 204 02 06 34 03 279 13 06 17 238 02 06 39 03 325

180 898 plusmn 14 16 12 05 238 02 09 19 03 303 17 13 05 266 02 10 21 03 337

240 954 plusmn 25 15 10 02 231 02 14 10 01 283 16 10 02 242 02 15 10 09 306

60 940 plusmn 20 24 11 00 243 00 07 13 02 301 26 12 00 259 00 07 14 02 319

120 975 plusmn 35 11 07 00 219 00 04 40 08 289 12 07 00 225 00 05 41 03 293

180 976 plusmn 07 23 11 00 237 00 09 08 00 288 24 11 00 243 00 09 09 00 295

240 998 plusmn 02 18 11 00 220 00 10 00 00 259 18 11 00 220 00 10 00 00 259


380



Time

[min]

Conversion

[mol]

Yield [C-mol] total



60 449 plusmn 33 01 04 09 30 00 00 26 10 80 03 09 19 67 00 00 59 22 179

120 572 plusmn 43 04 07 11 57 01 02 39 09 130 08 11 20 100 02 03 67 15 227

180 743 plusmn 43 04 09 13 71 03 04 30 06 139 05 11 17 96 04 05 41 08 187

240 773 plusmn 01 04 10 11 80 00 06 43 06 160 06 14 15 103 00 07 55 07 207

300 793 plusmn 01 04 10 14 84 00 05 29 06 151 05 13 18 106 00 06 36 07 191

60 827 plusmn 40 09 17 08 130 00 07 55 11 237 11 20 09 158 00 09 67 13 288

120 937 plusmn 29 07 20 05 133 00 09 15 06 195 08 22 05 142 00 09 16 07 208

180 930 plusmn 00 08 28 03 145 00 13 10 06 256 08 30 03 155 00 14 10 07 275

240 963 plusmn 12 09 30 00 137 00 13 10 05 204 10 31 00 142 00 13 10 05 212

300 990 plusmn 05 08 29 00 138 00 13 00 03 191 08 29 00 139 00 13 00 03 193

60 980 plusmn 17 09 29 00 189 00 14 15 06 262 10 30 00 192 00 14 15 06 268

120 990 plusmn 10 08 28 00 155 00 11 00 00 203 09 29 00 157 00 11 00 00 206

180 1000 plusmn 00 08 35 00 133 00 15 00 00 190 08 35 00 133 00 15 00 00 190

240 1000 plusmn 00 06 44 00 107 00 16 00 00 173 06 44 00 107 00 16 00 00 173

300 1000 plusmn 00 07 49 00 104 00 19 00 00 180 07 49 00 104 00 19 00 00 180


381



Time

[min]

Conversion

[mol]

Yield [C-mol] Total



60 01 16 02 51 00 27 06 102 48 06 151 00 82 18 305

120 01 05 02 87 00 36 06 136 14 05 236 00 99 16 370

180 01 10 02 125 04 27 03 172 23 05 289 09 63 07 397

240 01 15 02 145 00 27 03 193 35 05 331 00 62 07 439

300 01 12 04 141 00 27 03 188 23 08 268 00 52 06 356

60 204 01 00 35 00 30 07 73 05 00 173 146 32 356

120 280 04 02 70 00 20 03 100 16 08 252 00 71 12 358

180 454 06 02 86 00 30 03 127 12 05 189 00 65 07 278

240 390 09 02 106 00 20 03 140 23 06 271 00 51 08 358

300 335 09 04 161 00 40 03 217 26 13 479 00 118 10 647

60 166 05 04 51 00 09 03 72 30 24 305 00 55 18 433

120 639 17 02 158 00 27 00 205 27 03 247 00 43 00 320

180 597 21 04 172 00 36 03 237 36 07 289 00 61 05 397

240 720 31 06 193 14 27 03 275 44 08 267 20 38 04 381

300 676 31 08 180 14 18 03 255 46 12 267 21 27 04 378


382



weight ratio of 1

y = -3E-05x - 23164

Rsup2 = 09454-3

-28

-26

-24

-22

-2

0 5000 10000 15000 20000

ln[g

ly]

Time [s]


y = -8E-05x - 23627

Rsup2 = 09444-4

-38

-36

-34

-32

-3

-28

-26

-24

-22

-2

0 5000 10000 15000 20000

ln[g

ly]

Time [s]


y = -00002x - 27519

Rsup2 = 08891

-62

-57

-52

-47

-42

-37

-32

-27

-220 5000 10000 15000 20000

ln[g

ly]

Time [s]


383




Catalyst Temp

[degC] Time

[s]

[ Gly]

M

[AC]


No Catalyst 270 0 01024 00000 396E-07 753E-11 152E-06

3600 01024 00000

7200 01024 00000

10800 01024 00000

14400 00997 00007

18000 00969 00010

300degC 0 01143 00000 462E-05 273E-04 247E-05

3600 01087 00120

7200 00956 00158

10800 00886 00123

14400 00862 00165

18000 00773 00149

330degC 0 01020 00000 174E-05 488E-13 257E-05

3600 00882 00039

7200 00761 00088

10800 00669 00144

14400 00561 00190

18000 00415 00247


3600 00874 00020

7200 00752 00053

384

10800 00620 00088

14400 00602 00101

18000 00565 00116

300degC 0 01126 00000 278E-05 171E-06 780E-05

3600 00632 00094

7200 00494 00170

10800 00378 00180

14400 00282 00233

18000 00265 00248

330degC 0 01122 00000 141E-04 266E-12 297E-04

3600 00154 00281

7200 00149 00323

10800 00108 00378

14400 00050 00365

18000 00022 00365

360degC 0 01117 00000 319E-04 360E-06 574E-04

3600 00026 00364

7200 00070 00406

10800 00026 00397

14400 00003 00367

H-ZSM-5 270degC 0 01076 00000 174E-05 161E-06 101E-04

3600 00592 00049

7200 00461 00092

10800 00276 00115

14400 00244 00129

18000 00222 00135

300degC 0 00949 00000 108E-04 766E-06 362E-04

3600 00164 00185

7200 00060 00189

385

10800 00066 00206

14400 00035 00195

18000 00009 00196

330degC 0 01065 00000 309E-04 376E-05 807E-04

3600 00020 00278

7200 00011 00204

10800 00000 00212

14400 00000 00170

18000 00000 00166


3600 00736 00084

7200 00698 00144

10800 00627 00208

14400 00620 00241

18000 00523 00234

300degC 0 01015 00000 155E-05 287E-11 282E-05

3600 00808 00054

7200 00731 00107

10800 00554 00131

14400 00619 00161

18000 00675 00245

330degC 0 01102 00000 432E-05 300E-05 427E-05

3600 00919 00084

7200 00398 00261

10800 00444 00285

14400 00308 00318

18000 00357 00298


386



Zeolite Temp

[degC]

Time

[h] Al Si

ppm wt ppm wt


















H-Beta 330 008 420 183 60050 1692

017 271 118 58860 1658

025 374 163 60340 1700

05 356 155 60350 1700

075 298 130 61950 1745

1 232 101 62150 1751

387


H-ZSM-5 330 008 133 058 56978 1605

017 186 081 52511 1479

025 222 097 51823 1460

05 128 056 50890 1434

075 180 079 50150 1413

1 536 234 49880 1405

H-ZSM-5 360 008 163 071 50780 1430

017 106 046 49270 1388

025 095 041 48020 1353

05 077 034 50050 1410

075 142 062 50910 1434

1 262 114 50900 1434



388



389








Zeolite SiO2Al2O3

(manufacture)

Fe (ppm) Cu

[ppm]

Al

[ppm]

Na

[ppm]

ZSM-5 23 100-150 50-200

26000 500-600

Beta 25 150-200 25000 300-400

390




391




392








[mgL]

BP

[ordmC]

RT

[min] Area

1 Acetaldehyde 1000 202 20 1567

2 Acetol 3704 145 173 991

3 Glyceraldehyde 4504 140-150 67 124



6 Pyruvaldehyde 3603 72 24 55 62 71

7 Acrolein 2803 53 42 176 866 536

8 MeOH 3204

9 EtOH 7837


393




-100E-10

-800E-11

-600E-11

-400E-11

-200E-11

000E+00

200E-11

400E-11

600E-11

800E-11

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49

Ion

cu

rren

t

Mw

SN132-1

28 =N2

32 = O2

40 = Ar

44 = CO2

394



Temp

[degC]

Residence time

[s]

Conversion

[mol]



125 0 00 00 00 00 00 00 00 00 00 00

60 202 09 00 41 61 07 00 00 00 118

120 176 21 00 63 100 08 00 00 00 191

180 195 24 00 64 90 07 00 00 00 184

240 198 19 00 56 73 07 00 00 00 154

300 188 10 00 51 66 07 00 00 00 135

150 0 00 00 00 00 00 00 00 00 00 00

60 178 66 00 98 181 27 00 00 00 372

120 263 105 00 140 205 36 00 00 00 486

180 375 108 00 123 134 34 00 00 00 399

240 382 106 00 121 125 33 00 00 00 385

300 407 117 00 117 111 39 00 00 00 385

175 0 00 00 00 00 00 00 00 00 00 00

60 273 186 98 331 182 62 16 21 10 907

120 347 125 171 200 61 49 12 20 08 647

180 345 104 225 217 31 45 12 16 08 659

240 439 69 203 167 14 32 10 06 04 506

300 461 45 181 147 05 31 06 06 04 424


395

10 20 30 40 50 60 70

0

500

1000

1500In

ten

sity

[C

ou

nts

]

2 [degree]

H-Beta-Al2O

3 MC

after 125 C

after 150 C

Red circle = -Al2O

3




396



iv






v

Abstract
























vi





vii

Acknowledgments






















viii

Nomenclature









Ɛ void fraction



FA formic acid








spectrometry




LA lactic acid


ix

MC methyl cellulose

MHz megahertz

mM millimolar

MPa megapascal


RT room temperature






TEA triethanolamine








Universiteit Delft







x

Table of Contents

Declaration iii

Abstract v

Acknowledgments vii

Nomenclature viii

Table of Contents x

1 Introduction 1











2211 Biomass 20

2212 Glycerol 23


2221 Biomass 25

2222 Glycerol 26




xi













3 Aim of study 89

31 Aim 89

32 Objectives 90













xii




























xiii


513 TPD-NH3 163




523 TPD-NH3 180






















xiv






643 Conclusion 280
















7331 Conclusion 315



81 Summary 323

82 Future work 327


xv


9 References 329

10 Appendix 361

1

1 Introduction








et al (2014))







2








00

05

10

15

20

25

30

35

Cru

de g

lycerol

[mil

lion

ton

ne]

Year

2004 2005 2006 2007 2008 2009 2010 2012 2014 2015 2023

0

100

200

300

400

500

Pric

e o

f cru

de g

lycerol (8

0

pu

re) [U

S $

ton

ne]






3





















2222



4











5




converting glycerol













6





glycerol 65-85 229-333 ~83


methanol 234-375 86-126 lt1

water 1-3 41-182 ~13

sodium 01-4 16-19 lt5

















7

























8








9

2 Literature review




















10








pressure water















11












12









13





Water

Subcritical

Water

Supercritical

Water

Acetone


Vapour pressure

[bar]

003 (24 degC) 1 (100 degC) to 221

(374 degC)

gt221 024

(20 degC)



bar) 692 (330 degC

300 bar)




7899 (20

degC 11

bar)


(25 degC)

L 277 G123

(101 degC) L504

G 307 (371 degC)

low 330

(25 degC)

Heat capacity Cp

[kJ kg-1K-1]

422 (25 degC) 486 13 (400 degC 250 bar) 218

(20 degC)

Dielectric

constant

785 (25 degC 1

bar)

271 (250 degC 50

bar) 182 (330 degC

300 bar)

59 (400 degC 250 bar)

105 (400 degC 500 bar)

206

(20 degC)


but still a liquid

(at 370 degC)

yes na

-logKw 14 na 21 na








14





(2012))

15











16






















17












information



Solvent MP

[ordmC]

BP

[ordmC]

Waste Environmental

impact

Health Flammability

amp Explosion

Reactivity

Stability

Life cycle

score

Legislation

Flag

EHS

Red Flag

Water 0 100 4 10 10 10 10 10

2-Propanol -88 82 3 9 8 6 8 4

1-Butanol -89 118 5 7 5 8 9 5

Ethanol -114 78 3 8 8 6 9 9

Methanol -98 65 4 9 5 5 10 9

Acetone -95 56 3 9 8 4 9 7

Acetic acid 17 118 4 8 6 8 7 8

Toluene -95 111 6 3 4 4 10 7

Heptane -91 98 6 3 8 3 10 7




18












solvents


treat


cool rapidly

Inexpensive

Non-flammable








19













20





2211 Biomass




21







grass



















22


























23



2212 Glycerol



















24


Equation 1



as














25



2221 Biomass






















26



















2222 Glycerol




27








119862119874 + 1198672119874 harr 1198621198742 + 1198672









28


























29















30










S (H2) = 85




promoters)



CO2 28 CH4






Wen et al (2008)


catalytic activity

Luo et al (2010)




King et al (2010)


phase


[1 wt amp 10wt]

NiCeO2

250 270 autogenous

(375 527)



Manfro et al (2011)

[5-85 wt]

PtAl2O3


at 5-45wt glycerol


31


























32
























33




biomass

















34






chemicals

35




Time


Ref








glucose 300-400 ˚C 250-400 bar

002-2 s




Fructose 300-400 ˚C 250-400 bar

002-2 s


Glucose 250-350 ˚C 276 bar 5

min



001-054 s


D-glucose other

mono-saccharides



124-benzenetriol

Srokol et al (2004)

sucrose hexoses

trioses


Co2+ Cu2+ Ni2+

Zn2+



75-180 s

HCl H2SO4

H3PO4 other

organic acids


(2006)

36

























37















38


39


























40






41




Time




300 s



anhydro-D-glucose


microcrystalline

cellulose

320-400 degC 250 bar 005

to 10 s




Y = 51

Sasaki et al (2000)


solid waste)


acid) = 26

Goto et al (2004)

cherry (hard wood)

cypress (soft wood)




cellulose starch

glucose

270-400 degC auto-

geneous 30-180 s



min

alkali alkaline

earth AlCl3 and

transition metal

chlorides


67

Peng et al (2010)


min

Ni Zn activated

C in NaOH



42


glycerol











43







44


of glycerol


process

Production

[tonnesyr]

Price

US $tonnes




pentaerythritol

crotonaldehyde


carbohydrates




DHA fermentation of

glycerol




(i) Acrolein











45


(2009))







glycerol





46



(ii) Acetaldehyde














47






(iii) Lactic acid


















48















2244 is desirable







studies

49













50





C2H4 C2H6

Antal et al (1985)

flow 349-475 degC 250 350 450 bar

32-165 s



H2



60 min



Watanabe et al

(2007)


acrolein

Qadariyah et al

(2011)


51















52







53



Catalyst Reactor

Type


Ref





H2SO4 flow 300-400 degC 250 300 345 bar

5-83 s



60 s




May et al (2010)


x103 kg-cat sm-3





(005- 8) x103 kg-cat sm-3


lactic acid



Beta Na-MFI


mlmiddoth-1



LHSV = 2 h-1



ZSM-23



54









at 400 degC 345 bar




such as

metal salts

metal oxides and

zeolites

Metal salts




55

Metal oxides











Zeolites











selectivity

56
















57




Time

Conversion

[]

Yield of

LA2 [] [LA]3 gL Ref


NaOH



KOH


25 M glycerol 275 M

NaOH


(2010)

011 M glycerol PtC


Semi-

batchwise



in 01 M H3BO3



045 M NaOH



in 054 M NaOH


033 M glycerol




58














59


























60


























61






Auneau et al (2012)












62













63



Pressure Time


Ref

045 M Crude

glycerol



or O2 or H2O2



was added


et al (2014)


O2 1 h 40 mM FeCl3

Ru(OH)4 on



1-90 wt

glycerol



(H3+nPVnMo12-nO40)



formaldehyde


(2015)


64











al 2014)














65


















66


Almutairi (2013)











and Davis 2013)



67

























68





69



Pressure Time

Note Ref


Mordenite (MOR)-20

Zeolite Y (FAU)-30





Kruger et al (2014)


ZSM-5 (MFI)-15 25 40

150 ˚C 200 ˚C

saturated vapour

pressure 1-6 h





saturated vapour

pressure 72 h


100





metakaolinite


ZSM-5 (MFI)-24 to 918





vapour pressure 72


= 50


decomposed

Lutz et al (2005)

H-Y (FAU)-25

H-USY (FAU)-19 9 3

35 ppm of HCl 190


750 rpm 50 bar H2

24 h




ZSM-5 (MFI)

mordenite (MOR)

Zeolite Beta (BEA)

Zeolite Y (FAU)

200 ˚C saturated


reaction time



Zhang et al (2015)

70


























71


















framework







72




al (2005)

73





















74




chemicals







75




Pressure Time


Ref

Cellulose (150 170 190 ˚C)

na (1 3 5 h)





min microwave-

assisted


Beta zeolite


acid lactic acid


Fructose (120 150 165 ˚C)

autogenous 05-2 h


an adsorbent




filtrated







Al-Beta Si-Beta




76




















77
























78





















pores is limited



79

























80























81


























82




(2010))












83











agglomerates













84





(plasticiser)





(SiAl = 125 or 25)

γ-Al2O3 HNO3

(peptiser)


at 205-230 degC pH2 = 50 bar 1198991198672119899ℎ119910119889119903119900119888119886119903119887119900119899 =


Bauer et al (2014)


(peptiser)



alcohol) 651




stream about 6 h



(plasticiser)



Melero et al (2008)

85











selectivity















86
























87





















88



Cracking of n-

hexane

538 ordmC Beta

zeoliteTUD-1

k = 025 while 011


Waller et al

(2004)

aldol condensation

of benzaldehyde

and n-amyl

alcohol


for our ZSM-5

Zhou et al

(2010)

cyclodehydration

of xylose

H2O-toluene

mixture 170

ordmC


yield = 74 while X

= 94 and furfural

yield = 58 for a

mixture of Beta and

TUD-1

Lima et al

(2010)

Friedel-Crafts

benzylation


pure H-Y zeolite

Hamdy and

Mul (2013)


conversion

89

3 Aim of study

31 Aim















233


addressed

90

32 Objectives





















91













zeolites prepared










92


doped zeolites




















93

















94




















95





1

[119881119886 (1198750

119875 minus 1 )]=

119862 minus 1

119881119898119862 times

119875

1198750+

1

119881119898119862

Where







surface ml




[119881119886(1198750119875

minus 1)] against

119875





1


96




119862 = [119878119897119900119901119890

119868119899119905119890119903119888119890119901119905] + 1


119881119898 = 1

119862 119868119899119905119890119903119888119890119901119905 119874119903

1

(119878119897119900119901119890 + 119868119899119905119890119903119888119890119901119905)


119878119861119864119879 = (119881119898 119873 119886)

119898 22400

Where




for N2)



97























98




materials










99

















Equation 9


119899120582 = 2119889 sin 120579

100













per step






015

101


119905 = 119870120582

119861 cos 120579
















specimens

102























103








and gold coated












104












105




















used

106


calorimetry (DSC)




















107






















spin

108

















multiplet)





109





time





(VWD) used and



solution)

110





111








acetaldehyde

hydrate









OHCH2CH(OH)CH2OH)



CH3CH(OH)COOH)




112


















113







CA

CB

= IA

IB

timesnB

nA






114









Istandard

times 2

3 timesCstandard





nB is 2

nA is 3






115











116











y = 1155x + 04549

Rsup2 = 09953

0

2

4

6

8

10

12

14

16

18

0 2 4 6 8 10 12 14 16

[lact

ate

] exp

erim

en

t (m

M)


117


















Retention time

(min)

Compounds

Retention time

(min)

Compounds







118












00302 mM 00284 mM


(ICP-OES)






119














120









System II)









1198791198944+ + 11986721198742 + 21198672119874 rarr 11986721198791198941198744 + 4119867+

121


TiOSO4






122



409 nm









y = 00005x - 00158

Rsup2 = 09995

0

02

04

06

08

1

12

0 500 1000 1500 2000 2500

Ab

sro

ba

nce

H2O2 (micromolL)

123









511986721198742 + 21198701198721198991198744 + 311986721198781198744 rarr 21198721198991198781198744 + 11987021198781198744 + 81198672119874 + 51198742





124




work




























125







methanol 99 VWR






Custom Multi

MBH



H2O2 (30 wv) VWR

H2SO4 95 VWR

HNO3 68 VWR












126









127






128




reactors

Zeolite


- Ce Ce La Sn Zn Cu

0 25 48 48 48 48 48

NH4-Beta

H-Beta

deAl-Beta





batch reactors

Zeolite


- Ce Ce La Sn Zn Cu

0 25 48 48 48 48 48

NH4-ZSM-5

H-ZSM-5

deAl-ZSM-5


129



Catalyst Catalyst

NH4-Beta NH4-ZSM-5












1 CedeAl-HBetaII4h

2 CedeAl-HBetaII4h

3 CedeAl-HBetaII4h

48 CedeAl-BetaII4h

48 CudeAl-BetaII4h

48 SndeAl-BetaII4h

48 ZndeAl-BetaII4h






the following means


130













(TUD-1)

Extrusion with clay








131

















132
























133







membranes








134



for 30 min











135






















136










TUD-1 matrix











137





















138















139







140









(Comark KM340)















141




pressure gague










142








carried out













143













461 Batch process









144
















145


146













147



















148























149





ie at 20 cm



150













151






















152



τ =VR 120576 ρR

V ρSTP







of glycerol









153


ε =119881119900119897119906119898119890 119900119891 119908119886119905119890119903 119894119899119904119894119889119890 119905ℎ119890 119903119890119886119888119905119900119903 minus 119898119894119888119903119900119901119900119903119890 119907119900119897119906119898119890 119900119891 119905ℎ119890 119888119886119905119886119897119910119904119905

119879119900119905119886119897 119907119900119897119906119898119890 119900119891 119905ℎ119890 119903119890119886119888119905119900119903

Therefore


74993 cm3= 0556




ρR =ρSTP


Where









154



56 in the Appendix

155











SEM-EDS and TPD-NH3











156










the present work













157

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

+ ++

+


++

+


+

++


++

+ NaCl

+ NaCl

2 [degree]

2 [degree]

+

+


Inte

nsi

ty [

co

un

ts]

Inte

nsi

ty [

co

un

ts]





= NaCl

158


550 ordmC for 5 h








159




[nm]

XRD relative

crystallinityb []























160

512 BET N2 analysis


















161

00 01 02 03 04 05 06 07 08 09 10

0

80

100

120

140

160

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]








162

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]















~31-39 nm is ~300-360 m2middotg-1

163



Sample BET N2

surface area

[msup2middotg-1]

Micropore

volume

[cmsup3middotg-1]

Micropore

area

[msup2middotg-1]

External

surface area

[msup2middotg-1]





513 TPD-NH3










gas flow rate used





164





in Table 29

100 200 300 400 500 600

0

100

200

300

0 1200 2400 3600 4800 6000

Co

ncen

tra

tio

n o

f N

H3 i

n g

as

flo

w [

pp

m]

Temperature [oC]


NH4-ZSM-5

Time [s]


H-ZSM-5

165

100 200 300 400 500 600

0

50

100

150

200

250

300

0 1200 2400 3600 4800 6000

Co

ncen

tra

tio

n o

f N

H3 i

n g

as

flo

w [

pp

m]

Temperature [oC]


(H-Beta zeolite)

NH4-Beta zeolite

Time [s]
























166

0 1000 2000 3000 4000 5000 6000

0

50

100

Experimental data


Co

nce

ntr

ati

on

of

NH

3 i

n g

as

flo

w [

pp

m]

Time [s]

(A) NH4-ZSM-5

0 1000 2000 3000 4000 5000 6000

0

50

100

150

200

250

300

Experimental data


Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Time [s]

(B) H-ZSM-5

0 1000 2000 3000 4000 5000 6000

0

50

100

150

200

250

300

Experimental data


Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Time [s]


0 1000 2000 3000 4000 5000 6000

0

50

100

150

200

250

Experimental data


Co

ncen

tra

tio

n o

f N

H3 i

n g

as

flo

w [

pp

m]

Time [s]

(D) H-Beta zeolite



167



Catalyst


desorbed

[micromolmiddotg-1]

Ref Tmax

[degC]

NH3

[micromolmiddotg-1]

Tmax

[degC]

NH3

[micromolmiddotg-1]

Tmax

[degC]

NH3

[micromolmiddotg-1]

NH4-ZSM-5 145 4 200 69 420 67 140 This work

H-ZSM-5 145 8 187 242 385 269a 520 This work

150 - 388 - - Long and Yang (2001)


- - - - 630 Alotaibi et al (2014)

H-Beta 124 2 176 105 300 236a 344 This work

277 - 377 - 750 Lenarda et al (2003)

197 653 363 209 862 Talebi et al (2008)


168

I ZSM-5





















169







170



















II Beta zeolite




171
























172























173























174















175

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

+x

x

+

+

xx

CeO2

48 wt CeH-Beta

+++

+

48 wt LaH-Beta

O

++

OOO

48 wt SnH-Beta

ZnO

O

++

+

+

x

SnO2

48 wt ZnH-Beta

+

+

+

Inte

nsi

ty [

co

un

ts]

2 [degree]

+ NaCl

H-Beta

+





x = CeO2

176

10 20 30 40 50 60 70

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

0

5000

10000

+X+

+

+

X

X

2 (degree)

48 wt CeH-ZSM5

X

+ ++

+

OOO

48 wt LaH-ZSM5

+

+

O

48 wt SnH-ZSM5

O

+++

+

48 wt ZnH-ZSM5

Inte

nsi

ty [

cou

nts

]

+ NaCl ZnO O SnO2

x CeO2

+ +

+

H-ZSM5

+





177





Sample Crystallite

sizea [nm]

XRD relative

crystallinityb

[]

Position of the

main peakc

(2θ) [degree]

Shift in 2θ of

the main peakc

[degree]

NH4-Beta 159 100 226 +009

H-Beta 151 105 225 000

48 CeNH4-Beta 145 55 225 +007

48 LaNH4-Beta 141 64 225 +003

48 SnNH4-Beta 144 47 225 +002

48 ZnNH4-Beta 121 76 225 -001

48 CeH-Beta 146 64 225 +007

48 LaH-Beta 137 68 226 +008

48 SnH-Beta 139 63 225 +004

48 ZnH-Beta 135 83 225 +006

NH4-ZSM-5 320 100 230 -005

H-ZSM-5 388 101 231 000

48 CeNH4-ZSM-5 331 60 230 -005

48 LaNH4-ZSM-5 372 71 231 -003

48 SnNH4-ZSM-5 381 65 231 000

48 ZnNH4-ZSM-5 369 98 231 000

48 CeH-ZSM-5 318 62 231 -003

48 LaH-ZSM-5 345 75 231 -003

48 SnH-ZSM-5 370 69 231 +003

48 ZnH-ZSM-5 351 84 231 -003





178

522 BET N2 analysis










00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

00 01 02 03 04 05 06 07 08 09 10

0

80

100

120

140

160

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]






(A) (B)

Qu

an

tity

N2 a

dso

rb

ed

deso

rb

ed

[cm

3g

-1]


adsorption_H-ZSM-5

desorption_H-ZSM-5







179








Sample

BET N2

surface area

[msup2g-1]

Micropore

volume

[cmsup3g-1]

Micropore

area

[msup2g-1]

External

surface area

[msup2g-1]

NH4-Beta 575 017 358 218

H-Beta 598 017 367 230

48 CeNH4-Beta 534 015 330 204

48 LaNH4-Beta 591 015 383 208

48 SnNH4-Beta 489 014 303 186

48 ZnNH4-Beta 526 015 326 200

48 CeH-Beta 539 015 333 206

48 LaH-Beta 567 015 371 196

48 SnH-Beta 514 014 301 213

48 ZnH-Beta 528 014 313 215

NH4-ZSM-5 299 013 257 42

H-ZSM-5 363 012 258 104

48 CeNH4-ZSM-5 294 010 213 81

48 LaNH4-ZSM-5 370 011 280 90

48 SnNH4-ZSM-5 323 011 228 95

48 ZnNH4-ZSM-5 336 012 250 86

48 CeH-ZSM-5 340 011 235 104

48 LaH-ZSM-5 359 011 284 76

48 SnH-ZSM-5 304 010 223 80

48 ZnH-ZSM-5 308 011 227 81

180

523 TPD-NH3



















about 5 degC




181



100 200 300 400 500 600

0

50

100

150

200

250

300

100 200 300 400 500 600

0

50

100

150

200

250

300

100 200 300 400 500 600

0

50

100

150

200

250

300

100 200 300 400 500 600

0

50

100

150

200

250

300




Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]

Temperature [oC]

(A)

NH4-Beta zeolite


(C)

Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]

Temperature [oC]

NH4-ZSM-5

48 SnNH4-ZSM-5

48 ZnNH4-ZSM-5

48 LaNH4-ZSM-5

48 CeNH4-ZSM-5

(B)

Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]

Temperature [oC]

H-Beta zeolite

48 SnH-Beta zeolite

48 ZnH-Beta zeolite

48 LaH-Beta zeolite

48 CeH-Beta zeolite

(D)

Co

ncen

tra

tio

n o

f N

H3

in

ga

s fl

ow

[p

pm

]Temperature [

oC]

48 CeH-ZSM-5

48 LaH-ZSM-5

48 ZnH-ZSM-5

H-ZSM-5

48 SnH-ZSM-5

182










Catalyst


Degree of ion

exchange b Tmax

[degC]

Tmax

[degC]

Tmax

[degC]

NH3

[micromolmiddotg-1]

NH4-Beta 127 165250 - - 0

H-Beta 124 176 300 236 a 0

48 CeNH4-Beta 134 177 306 94 36

48 LaNH4-Beta 138 178 317 107 43

48 SnNH4-Beta 136 171 304 147 22

48 ZnNH4-Beta 148 178 305 114 61

48 CeH-Beta 140 160 305 73 41

48 LaH-Beta 145 176 317 95 47

48 SnH-Beta 141 160 305 45 48

48 ZnH-Beta 149 180 305 103 67

NH4-ZSM-5 145 200 420 67 0

H-ZSM-5 145 187 385 270 a 0

48 CeNH4-ZSM-5 138 190 387 146 31

48 LaNH4-ZSM-5 146 191 400 113 52

48 SnNH4-ZSM-5 133 190 392 39 58

48 ZnNH4-ZSM-5 148 205 386 88 91

48 CeH-ZSM-5 - 187 380 73 49

48 LaH-ZSM-5 144 180 380 98 57

48 SnH-ZSM-5 144 172 391 35 59

48 ZnH-ZSM-5 145 187 380 57 106

183













to the H-ZSM-5








et al 2012)




184
















in Beta zeolite






Table 33

185




[g]

Treatment time

[h]



deAl-BetaI6h 1 6

deAl-BetaI20h 1 20

deAl-BetaII4h 2 4

deAl-BetaII6h 2 6

deAl-BetaII20h 2 20

deAl-BetaIII4h 3 4







preserved

186

0

300

600

900

10 20 30 40 50 60 70

0

300

600

900

H-ZSM-5In

ten

sity

[C

ou

nts

]


2 [degree]










187










188

0

4000

8000

0

4000

8000

0

4000

8000

10 20 30 40 50 60 70

0

4000

8000

+ +

+


+

+ ++

+

deAl-BetaII4h+ NaCl

Inte

nsi

ty [

Co

un

ts]

+ +

+


+ +

+

+


2 [degree]







189


zeolites

Catalyst BET-N2

surface area

[msup2middotg-1]

Crystallite

sizea

[nm]

Relative

crystallinityb

[]

2θ of d302

[degree]

shift of d302

[degree]

d302-spacing

[Aring]

SiAl

(XRF)

Al extractedc

[wt]

NH4-Beta zeolite 575 159 100 226 394 124 0

H-Beta zeolite 598 151 104 225 000 396 124 0

deAl-BetaI4hd 573 133 95 227 +017e 391 533 974

deAl-BetaI6h 572 137 94 227 +024 391 600 978

deAl-BetaI20h 554 141 89 226 +007 394 795 983

deAl-BetaII4h 580 129 100 227 +017 393 688 977

deAl-BetaII6h 551 130 94 227 +017 389 671 980

deAl-BetaII20h 542 154 89 226 +009 392 526 969

deAl-BetaIII4h 585 122 95 227 +017 392 556 974






190


























191







BET N2 analysis










192

6 8 10 20 22 24

0

2000

4000

6000

8000

H-Beta zeolite

deAl-BetaII4h

deAl-BetaII6h

deAl-BetaII20h

Inte

nsi

ty [

cou

nts

]

2 [degree]




193

0

25

50

75

100

Al

extr

act

ed [

wt

]

Treatment time [h]




0 4 6 20














194












195

100 200 300 400 500 600

0

50

100

150

200

250

300

deAl-BetaI20h

deAl-BetaII6h

deAl-BetaII4h

deAl-BetaII 15 min

deAl-BetaII 5min

H-Beta zeolite

Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Temperature [C]





measurement








196
























197





















198



deAl-BetaII4h


metalAlextracted

Weight ratio of

metalzeolite

XRD TPD-NH3 TEM-EDX

NH4-Beta - -

H-Beta - -

deAl-BetaII4h - -





















199









10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

8000

10000

X

XXX

H-Beta zeolite

deAl-BeatII4h

10 CedeAl-BetaII4h

6 CedeAl-BetaII4h

1 CedeAl-BetaII4h



Inte

nsi

ty [

cou

nts

]

2 [degree]

X

CeO2

Inte

nsi

ty [

cou

nts

]

2 (degree)







200














201










202

0

3000

6000

0

3000

6000

0

3000

6000

0

3000

6000

10 20 30 40 50 60 70

0

3000

6000

+ = NaCl

= ZnO

(D)

5 ZndeAl-BetaII4h

2 [degree]

+

+ = NaCl

O = SnO2

(C)

ooo+

88 SndeAl-BetaII4h

Inte

nsi

ty [

Co

un

ts]

+

+

+

o

+ = NaCl

(B)

++

+

10 LadeAl-BetaII4h

+ = NaCl

x = CeO2

xxx +

10 CedeAl-BetaII4h

+x

(A)

+ = NaCl

(E)

++

+

deAl-BetaII4h





ο = SnO2 x = CeO2

203




metalAlextracted

Phases identified

























204











205

0

3000

6000

9000

0

3000

6000

0

3000

6000

10 20 30 40 50 60 70

0

3000

6000



2 [degree]

+

(D)

(B)

(C)



ooo+

Inte

nsi

ty [

Cou

nts

]

+

+

+

o



+

x

x + x x

(A)

++

+

deAl-BetaII4h






= CeO2

206









salts under study

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

++

+ NaCl

H-Beta zeolite

deAl-BetaII4h


Inte

nsi

ty [

co

un

ts]

2 [degree]

+

Inte

nsi

ty [

cou

nts

]

2 [degree]





207




Sample Δd302

position

[degree]a

Crystallite

sizeb

[nm]

d302-

spacing

[Aring]

Δd302 [Aring]c

Relative

crystallinityd

NH4-Beta +009 159 394 100

H-Beta 000 151 396 000 105

deAl-BetaII4he +019 129 392 -004 100

045 CedeAl-BetaII4h +022 118 392 -004 82

07 CedeAl-BetaII4h +019 131 392 -004 79

1 CedeAl-BetaII4h +019 117 392 -004 78

6 CedeAl-BetaII4h +012 127 393 -002 64

10 CedeAl-BetaII4hf +038 110 389 -007 58

10 LadeAl-BetaII4h +016 110 393 -003 63

88 SndeAl-BetaII4h +012 135 393 -002 68

5 ZndeAl-BetaII4h +003 146 395 -001 92












208




(d302) and




















209

542 Surface acidity












210

100 200 300 400 500 600

0

50

100

150

200

250

300




deAl-BetaII4h

H-Beta zeolite

Con

cen

trati

on

of

NH

3 i

n g

as

flow

[p

pm

]

Temperature [C]




relative to zeolite


based catalysts





211






use See Chapter 551

















212





213

0

1000

2000

0

1000

2000

10 20 30 40 50 60 70

0

1000

2000

Inte

nsi

ty [

Co

un

ts]


2 [degree]

(A) H-Beta zeolite

2= 7776

2= 22630

2= 25456

2= 27158

2= 43971 2= 55980

2 = 7643

2= 22557

2 = 25356

2 = 26958

2 = 439670

(C) CHFM support






214












215



Temperature

[degC]

Residence time

[s]

Conversion

[mol]











216








matrix




217






















218

10 20 30 40 50 60 70

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

(D)

= CuO

Inte

nsi

ty [

Cou

nts

]

2 [degree]


48 wt CuH-Beta

(C)

xxx

x = CeO2


48 CeH-Beta

x

(B)

H-Beta in TUD-1

H-Beta

(A)

H-Beta






219













single measurement

Sample Micropore

volume

[cmsup3middotg-1]

Micropore

area

[msup2middotg-1]

External

surface area

[msup2middotg-1]

BET surface

area

[msup2middotg-1]



48 wt CuH-Beta 015 330 200 530

48 wt CuH-Beta in TUD-1 012 278 348 627



220







not performed





catalysts ie

H-Beta

25wt CuH-Beta and

48wt CuH-Beta






221










CuO

10 20 30 40 50 60 70

0

1000

2000

3000

4000

5000

6000

2 [degree]

= CuO

H-Beta

25 wt CuH-Beta

48 wt CuH-Beta

Inte

nsi

ty [

cou

nts

]



222










223

10 20 30 40 50 60 70

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

0

750

1500

2250

= CuO

Inte

nsi

ty [

Cou

nts

]

2 [degree]


(C) 48 wt CuH-Beta


(A) H-Beta




224
















measurement

Sample Micropore

volume

[cmsup3middotg-1]

Micropore

area

[msup2middotg-1]

External

surface area

[msup2middotg-1]

BET N2

surface area

[msup2middotg-1]



48 CuH-Beta 015 330 200 530




225













226











(MC)











not used



227




10 20 30 40 50 60 70

red circle-Al2O

3


3


3(MC)

(A) H-Beta

Inte

nsi

ty [

arb

un

its]

2 [degree]





228

10 20 30 40 50 60 70


3


3


3(MC)

Inte

nsi

ty [

arb

un

its]

2 [degree]

(A) 48 wt CuH-Beta






229

10 20 30 40 50 60 70


3


3 (MC)

Inte

nsi

ty [

arb

un

its]

2 [degree]

(B) 25 wt CuH-Beta







Catalysts


wt of zeolite

catalyst relative

to γ-Al2O3

H-Beta or






230





Catalyst BET N2

surface area

[m2middotg-1]

Micropore

Volume

[cmsup3middotg-1]

XRD relative

crystallinitya

[]

Post of d302

[degree 2θ]

TEM-EDS

SiO2Al2O3

mol ratio

NH4-Beta 575 017 100 226 25b

H-Beta 598 017 105 225 25 b


48 wt CuH-Beta 534 015 83 227


H-Betaγ-Al2O3 (MC)c 423 010 38 228 54

25 wt CuH-Betaγ-

Al2O3 (MC)c 419 009 nad 226 24

48 wt CuH-Betaγ-

Al2O3c

- - 56 227 44

48 wt CuH-Betaγ-

Al2O3 (MC)c 446 010 62 227 45











231
















232





















conversion rate

233

0 60 120 180 240 3000

20

40

60

80

100

0 60 120 180 240 3000

10

20

30

40

50

270 C

300 C

330 C

Gly

cero

l co

nv

ersi

on

[m

ol

]

Reaction time [min]

270 C

300 C

330 C

Sel

ecti

vit

y t

o a

ll l

iqu

id p

rod

uct

s [C

-mo

l]

Reaction time [min]



234






Temp

[degC]

Press

[bar]

Time

[min]

Conversion

[mol]a


[C-mol]b References


300 86 60 49 204 ˃100 39 70 Watanabe et al (2007)c

300 2955 60 100 005 0002 Qadariyah et al (2011)

270 55 240 26 plusmn 04 - - 137 183 - - - 08

300 53 plusmn 04 - - 96 127 - - - 11

300 86 60 49 plusmn 20 17 35 104 120 - - - 08

120 143 plusmn 15 25 07 11 158 - 32 - 36

180 206 plusmn 14 19 05 22 123 - 23 08 41

240 229 plusmn 23 18 04 33 165 - 20 07 62

300 306 plusmn 09 14 07 14 149 - 17 06 64

330 128 60 121 plusmn 19 29 08 46 215 - 53 21 45

120 241 plusmn 15 31 05 43 244 10 43 14 94

180 333 plusmn 56 45 08 38 287 11 40 07 145

240 441 plusmn 51 51 07 21 286 16 38 05 187

300 586 plusmn 65 50 06 18 281 22 36 00 241

235
















236











237


















Lopez et al 2010)

238










reaction times








gases




239












240

0 60 120 180 240 300

0

20

40

60

80

100

0 60 120 180 240 300

0

10

20

30

40

50

0 60 120 180 240 300

0

20

40

60

80

100

0 60 120 180 240 300

0

10

20

30

40

50

270 oC

300 oC

330 oC

(A) H-ZSM-5

270 oC

300 oC

330 oC

(B) H-ZSM-5

60 120 180 240 300

Temp [degC]





Reaction time [min]

Total yield [C-mol]

Gly

cerol

con

versi

on

[m

ol

]

270 oC

300 oC

330 oC

360 oC

Gly

cerol

con

versi

on

[m

ol

]

Reaction time [min]

(C) H-Beta

Sele

cti

vit

y t

o a

ll l

iqu

id p

rod

ucts

[C

-mol

]

270 oC

300 oC

330 oC

360 o

C

Sele

cti

vit

y t

o a

ll l

iqu

id p

rod

ucts

[C

-mol

]

Reaction time [min]

(D) H-Beta

60 120 180 240 300

Temp [degC]




Reaction time [min]

Total yield [C-mol]




241








are





solution











242

0

1

2

3

4

5

6

7

8

0

450

500

550

600

650

0

1

2

3

0

13

14

15

16

17

18

H-Beta

H-ZSM-5

Time [h]

Con

cen

trati

on

of

Al

[pp

m]

Time [h]

0 008 017 025 05 075 1

H-Beta

H-ZSM-5

Con

cen

trati

on

of

Si

[pp

m]

0 008 017 025 05 075 10 008 017 025 05 075 1

H-Beta

H-ZSM-5

Time [h]

Am

ou

nt

of

Al

[wt

]

Time [h]

0 008 017 025 05 075 1

H-Beta

H-ZSM-5

Am

ou

nt

of

Si

[wt

]




243

10 20 30 40 50 60 70

0

1000

2000

3000

Inte

nsi

ty [

Co

un

ts]

2 [degree]

H-Beta zeolite















244



products

245

0 60 120 180 240 300

0

20

40

60

80

100

0 60 120 180 240 300

0

20

40

60

80

100

Gly

cero

l con

ver

sion

[m

ol

]

270 oC

300 oC

330 oC

Reaction time [min]

Sel

ecti

vit

y t

o a

ll l

iqu

id p

rod

uct

s [C

-mol

]

270 oC

300 oC

330 oC

Reaction time [min]

60 120 180 240 300

Temp [degC]

270 7 10 13 14 22

300 10 14 17 19 19

330 7 20 24 28 26

Reaction time [min]

Total yield [C-mol]






experiment

246














glycerol

247

0

25

50

75

1000

25

50

75

100

gases amp char

acetol

acrolein

EtOH

acetaldehyde

lactic acid

acetic acid

MeOH

(A) H-Beta

Reaction Time [min]

(B) H-ZSM-5

0 5 10 15 30 45 60

Conversion

Co

nv

ersi

on

[m

ol

] o

r S

elec

tiv

ity

[C

-mo

l]







248















respectively

249










250



119892119897119910119888119890119903119900119897 1198961rarr 119886119888119890119905119886119897119889119890ℎ119910119889119890 Equation 23

119886119888119890119905119886119897119889119890ℎ119910119889119890 1198962rarr 119901119903119900119889119906119888119905119904 Equation 24

119892119897119910119888119890119903119900119897 1198963rarr 119901119903119900119889119906119888119905119904 Equation 25











kinetic analysis





as follows

251

119889[119892119897119910119888119890119903119900119897]

119889119905= minus(1198961 + 1198963)[119892119897119910119888119890119903119900119897] Equation 26

119889[119886119888119890119905119886119897119889119890ℎ119910119889119890]

119889119905= 1198961[119892119897119910119888119890119903119900119897] minus 1198962[119886119888119890119905119886119897119889119890ℎ119910119889119890] Equation 27






0 3600 7200 10800 14400 18000

000

002

004

006

008

010

012

Con

cen

trati

on

[M

]

Time [s]



curve fit_glycerol


k1 = 27787e

-5

k2 = 171056e

-6

k3 = 781408e

-5






252









300degC 462E-5 273E-4 247E-5

330degC 174E-5 488E-13 257E-5


300degC 278E-5 171E-6 780E-5

330degC 141E-4 266E-12 297E-4

360degC 319E-4 360E-6 574E-4

H-ZSM-5 270degC 174E-5 161E-6 101E-4

300degC 108E-4 766E-6 362E-4

330degC 309E-4 376E-5 807E-4


300degC 155E-5 287E-11 282E-5

330degC 432E-5 300E-5 427e-5






253



















119896 = 119860119890minus119864119886119877119879 Equation 28



temperature in K

254





Table 45

ln 119896 = ln 119860 minus119864119886

119877(

1

119879) Equation 29



analysed

y = -15767x + 18168

Rsup2 = 09847

y = -2393x - 6364

Rsup2 = 01825

y = -17817x + 20981

Rsup2 = 09314

y = -26229x + 33953

Rsup2 = 09138

-15

-14

-13

-12

-11

-10

-9

-8160E-03 165E-03 170E-03 175E-03 180E-03 185E-03 190E-03

ln k

1T [K-1]



255






H-ZSM-5 131 78E+07


















256

























257










258

No

cata

lyst

NH

4-Bet

a

H-B

eta

48

Ce

NH

4-Bet

a

48

La

NH

4-Bet

a

48

SnN

H4-

Bet

a

48

ZnN

H4-

Bet

a

48

Ce

H-B

eta

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

NH

4-ZSM

-5

H-Z

SM-5

48

Ce

NH

4-ZSM

-5

48

La

NH

4-ZSM

-5

48

SnN

H4-

ZSM

-5

48

ZnN

H4-

ZSM

-5

48

Ce

H-Z

SM-5

48

La

H-Z

SM-5

48

SnH

-ZSM

-5

48

ZnH

-ZSM

-5

0

25

50

75

100

[]

Conversion [mol]



0

50

100

150

200

250

300


]

Am

ou

nt

of

des

orb

ed N

H3 [

mo

lg

-1]





259



Catalyst Conversion

[mol]


[C-mol]

Total Yb


NH4-Beta 345 plusmn 28 24 07 39 346 07 33 11 468 161



48 LaNH4-Beta 560 plusmn 15 29 09 17 356 14 81 14 519 291

48 SnNH4-Beta 552 plusmn 06 21 05 38 290 09 82 07 451 249

48 ZnNH4-Beta 481 plusmn 02 22 05 59 244 08 83 12 433 208



48 SnH-Beta 737 plusmn 36 10 06 19 222 08 42 10 318 235

48 ZnH-Beta 556 plusmn 35 23 04 29 253 08 76 06 400 222

NH4-ZSM-5 583 plusmn 45 17 08 12 281 12 36 09 375 219

H-ZSM-5 980 plusmn 096 10 30 00 192 14 15 06 268 262

48 CeNH4-ZSM-5 938 plusmn 348 11 20 06 200 08 22 03 271 254

48 LaNH4-ZSM-5 836 plusmn 49 13 12 08 224 13 38 08 316 264

48 SnNH4-ZSM-5 832 plusmn 10 11 33 00 217 11 41 09 323 269

48 ZnNH4-ZSM-5 748 plusmn 47 20 07 13 302 10 76 10 439 328

48 CeH-ZSM-5 927 plusmn 42 12 23 11 206 11 23 05 289 268

48 LaH-ZSM-5 986 plusmn 081 12 29 11 229 09 34 04 328 324





260

NH

4-Bet

a

H-B

eta

48

Ce

NH

4-Bet

a

48

La

NH

4-Bet

a

48

SnN

H4-

Bet

a

48

ZnN

H4-

Bet

a

48

Ce

H-B

eta

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

0

25

50

75

100Y= 222 Y= 235 Y= 208

Co

nv

ersi

on

[m

ol

]Y= 223 Y= 207 Y= 291 Y= 286 Y= 282 Y= 161

Y= 249 Conversion

MeOH

acetic acid

lactic acid

acetaldehyde

EtOH

acrolein

0

10

20

30

40

Sel

ecti

vit

y [

C-m

ol

]




261

NH

4-ZSM

-5

H-Z

SM-5

48

Ce

NH

4-ZSM

-5

48

La

NH

4-ZSM

-5

48

SnN

H4-

ZSM

-5

48

ZnN

H4-

ZSM

-5

48

Ce

H-Z

SM-5

48

La

H-Z

SM-5

48

SnH

-ZSM

-5

48

ZnH

-ZSM

-5

0

25

50

75

100

Y = 296 Y = 278 Y = 324 Y = 268 Y = 328 Y = 269 Y = 264 Y = 254 Y = 262 C

on

ver

sio

n [

mo

l]

or

sele

ctiv

ity

[C

-mo


0

10

20

30

40

MeOH

acetic acid

lactic acid

acetaldehyde

EtOH

acrolein

Sel

ecti

vit

y [

C-m

ol

]




262

















263












264

10 20 30 40 50 60 70

0

1500

3000

5 6 7 8 9 16 18 20 22 240

1500

3000 H-Beta zeolite

150 C 1 h

150 C 20 h

Inte

nsi

ty [

cou

nts

]

2 [degree]



10 20 30 40 50 60 70

0

1500

3000

5 6 7 8 9 16 18 20 22 240

1500

3000

Inte

nsi

ty [

cou

nts

]

2 [degree]

H-Beta zeolite

200 C 1 h

200 C 3 h

200 C 5 h

200 C 20 h



265

10 20 30 40 50 60 70

0

1500

3000

5 6 7 8 9 16 18 20 22 240

1500

3000 H-Beta zeolite

250 C 1 h

250 C 20 h

Inte

nsi

ty [

co

un

ts]

2 [degree]







Temperature

[degC]

Time

[h]

XRD relative

crystallinity

20 0 100 plusmn 00

150 1 132 plusmn 38

20 105 plusmn 22

200 1 110 plusmn 39

3 108 plusmn 61

5 100 plusmn 53

20 76 plusmn 17

250 1 74 plusmn 45

20 40 plusmn 72

266


















times






267

















268

0

1

2

3

4

5

6

7

8

0

100

200

300

400

500

600

0

1

2

3

0

5

10

15

0 008 017 025 05 075 1 3 5 20 48

0 008 017 025 05 075 1 3 5 20 48

20 C

150 C

200 C

250 C

330 C

330 C_H-ZSM-5

Time [h]

Co

nce

ntr

ati

on

of

Al

[pp

m]

Time [h]

0 008 017 025 05 075 1 3 5 20 48

20 C

150 C

200 C

250 C

330 C

330 C_H-ZSM-5

Co

nce

ntr

ati

on

of

Si

[pp

m]

20 C

150 C

200 C

250 C

330 C

330 C_ H-ZSM-5

Time [h]

Am

ou

nt

of

Al

[wt

]

Time [h]

0 008 017 025 05 075 1 3 5 20 48

20 C

150 C

200 C

250 C

330 C

330 C_ H-ZSM-5

Am

ou

nt

of

Si

[wt

]





269


















90





270










[ppm]

Holding time [min]

5 10 15 30 45 60


Al 444 393 374 356 298 332

Si 6005 5886 6034 6195 620 6215


Al 266 191 236 229 228 163

Si 4581 4758 5108 4773 484 4789



271

0

25

50

75

100

Y= 498 mol

Y= 572 mol

Y= 423 mol

Y= 359 mol

Y= 141 mol

gases amp char

acetol

acrolein

acetaldehyde

acetic acid

MeOH

Y= 044 mol

Conversion

Co

nv

ersi

on

[m

ol

] o

r S

elec

tiv

ity

[C

-mo

l]

Reaction Time [min]

5 10 15 30 45 60




of mean (119878119864)











272



and pressures




273







was detected

274






[min]

Conversion

[mol]


products [C-mol]

Yield

[C-mol]

No 60 121 plusmn 19 372 45


10 610 plusmn 22 497 300

15 633 plusmn 46 512 315

30 732 plusmn 54 420 300

45 769 plusmn 21 408 311

60 839 plusmn 24 335 282


10 145 plusmn 09 100 14

15 163 plusmn 07 218 36

30 242 plusmn 26 177 42

45 264 plusmn 03 217 57

60 283 plusmn 12 174 50

deAl-BetaI20h


10 59 plusmn 00 125 07

15 111 plusmn 08 98 11

30 160 plusmn 17 130 21

45 1758 plusmn 25 123 21

60 174 plusmn 05 142 25

275

0 10 20 30 40 50 60

0

20

40

60

80

100

0 10 20 30 40 50 60

0

10

20

30

40

50

60



H-Beta zeolite

No catalyst



H-Beta zeolite

No catalyst

Gly

cero

l co

nver

sion

[m

ol

]


Sel

ecti

vit

y t

o a

ll l

iqu

id p

rod

uct

s [C

-mol

]




276


























277







[ppm]

Holding time [min]

5 10 15 30 45 60


Al 193 184 248 216 153 12

Si 2152 2253 2186 2167 2158 217


Al 04 036 029 024 034 024

Si 1838 18991 18861 19957 19424 19816



278

0

25

50

75

100

gases amp char

acetaldehyde

acetic acid

MeOH

Y= 248 mol

Y= 211 mol

Y= 205 mol

Y= 108 mol

Y= 074 mol

Y= 073 mol

Conversion

Con

ver

sion

[m

ol

] o

r S

elec

tiv

ity

[C

-mol

]

Reaction Time [min]

5 10 15 30 45 60














279














280

0

25

50

75

100

gases amp char

acetol

acrolein

EtOH

acetaldehyde

acetic acid

MeOH

Conversion

Co

nv

ersi

on

[m

ol

] o

r S

elec

tiv

ity

[C

-mo

l]

Reaction Time [min]

5 10 15 30 45 60




643 Conclusion







281










71 Batch process










282








283

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

Y = 164 06 Y = 178 03 Y = 211 00

Reaction time [min]

Y = 248 09

Con

ver

sion

[m

ol

] or

Sel

ecti

vit

y [

C-m

ol

]

125 C

30 60 120 180

150 C

Reaction time [min]

30 60 120 180

Y = 156 08 Y = 153 11 Y = 126 08

Con

ver

sion

[m

ol

] or

Sel

ecti

vit

y [

C-m

ol

]

Y = 148 05

Y = 131 19 Y = 1309 07 Y = 135 03

200 C175 C

Reaction time [min]

30 60 120

gases amp char

pyruvaldehyde

acetol

acrolein

glycolic acid

DHA

formic acid

acetaldehyde

acetic acid

Reaction time [min]

30 60 120 180

Y = 148 06

Conversion

Con

ver

sion

[m

ol

] o

r S

elec

tivit

y [

C-m

ol

]

Con

ver

sio

n [

mol

] or

Sel

ecti

vit

y [

C-m

ol

]

200 C

Y = 106 15 Y = 137 13 Y = 124 02



products [C-mol]

284




Temperature

[degC]

Reaction time

[min]

Conversion

[mol]


[C-mol]

Yield of liquids

[C-mol]

























285













286




et al 2011))




287






















288





than 30 min














289

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

gases amp char

lactic acid

pyruvaldehyde

acetol

glycolic acid


formic acid

acetaldehyde

acetic acid

(C) H-ZSM-5

Reaction time [min]

30 60 120 180

(A) No catalyst

Conversion

Con

versi

on

[m

ol

] or S

ele

cti

vit

y [

C-m

ol

]

(B) H-Beta

30 60 120 18030 60 120 180

Reaction time [min]

30 60 120 18030 60 120 180

Con

versi

on

[m

ol

] or S

ele

cti

vit

y [

C-m

ol


30 60 120 180

Con

versi

on

[m

ol

] or S

ele

cti

vit

y [

C-m

ol

]




290

















increase with time

291


Jin et al (2006))
















292

No

cata

lyst

48

Ce

H-B

eta

48

CuH

-Bet

a

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

0

20

40

60

80

100 conversion

acetic acid

lactic acid

formic acid


glycolic acid

acetol

pyruvaldehyde

acetaldehyde

Co

nv

ersi

on

[m

ol

]

0

5

10

15

20

25

Sel

ecti

vit

y [

C-m

ol

]




293

























294



295




Time

[min] Catalyst

Conversion

[mol]


[C-mol]

Total liquid yield



48 CeH-Beta 277 plusmn 08 24 00 198 149 59 15 00 00 445 123

48 CuH-Beta 418 plusmn 07 00 06 126 173 21 01 20 01 348 137

48 LaH-Beta 488 plusmn 04 10 00 103 48 27 20 01 03 213 104

48 SnH-Beta 415 plusmn 62 09 00 95 51 28 15 00 02 200 83

48 ZnH-Beta 507 plusmn 30 07 01 110 59 24 25 03 04 235 119


48 CeH-Beta 329 plusmn 16 30 148 141 00 24 04 02 04 353 116

48 CuH-Beta 430 plusmn 09 11 126 99 08 52 08 13 00 316 136

48 LaH-Beta 501 plusmn 00 24 68 199 00 56 36 00 08 382 191

48 SnH-Beta 396 plusmn 26 08 05 28 12 22 05 02 01 74 29

48 ZnH-Beta 467 plusmn 02 28 61 215 00 27 00 00 11 332 155



296

No

cata

lyst

48

Ce

H-B

eta

48

CuH

-Bet

a

48

La

H-B

eta

48

SnH

-Bet

a

48

ZnH

-Bet

a

0

20

40

60

80

100 conversion

acetic acid

lactic acid

formic acid


glycolic acid

acetol

pyruvaldehyde

acetaldehyde

Con

ver

sion

[m

ol

]

0

5

10

15

20

25

Sel

ecti

vit

y [

C-m

ol

]




297













from two issues









298













53











299













300

0

15

30

45

60

0

15

30

45

60

0

15

30

45

60

0

5

10

15

acetic acid

formic acid


glycolic acid


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Conversion

Con

ver

sion

[m

ol

]


0

5

10

15


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]


0

5

10

15


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]




301



Temp

[degC]

Residence Time

[s]

Conversion

[mol]


[C-mol]

Total yield

[C-mol]

H2O2 consumption


125 60 39 - 86 146 0 - 232 090 237

120 180 - 23 32 0 - 55 099 643

180 286 - 15 2 03 - 38 107 847

240 389 - 09 1 02 - 21 08 948

300 491 - 0 08 0 - 08 038 991

150 60 65 traces 10 108 22 - 231 149 737

120 213 traces 3 23 03 - 57 120 939

180 319 traces 16 12 02 traces 30 095 1000

240 399 traces 16 05 02 traces 23 093 999

300 480 traces 12 07 02 traces 20 097 1000

175 60 222 04 39 34 07 - 84 186 947

120 374 01 21 14 04 02 43 159 1000

180 458 01 2 08 05 03 38 172 1000

240 475 01 21 07 05 02 35 166 1000

300 550 0 17 - - traces 17 093 1000


302









and Figure 103














303




Temp

[degC]

Residence Time

[s]


Conversion

[mol]


[C-mol]

Yield to liquids

[C-mol]

Conversion

[mol]


[C-mol]

Yield to liquids

[C-mol]

125 60 39 232 09 202 118 24

120 180 55 10 176 191 34

180 286 38 11 195 184 36

240 389 21 08 198 154 31

300 491 08 04 188 135 25

150 60 65 231 15 178 372 66

120 213 57 12 263 486 128

180 319 30 10 375 399 149

240 399 23 09 382 385 147

300 480 20 10 407 385 157

175 60 222 84 19 273 907 239

120 374 43 16 347 647 214

180 458 38 17 345 659 219

240 475 35 17 439 506 217

300 550 170 09 461 424 191

304

0

15

30

45

0

15

30

45

0

15

30

45

0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mo

l]

60 120 180 240 300

Conversion

Co

nv

ersi

on

[m

ol

]


0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mo

l]

60 120 180 240 300

Co

nv

ersi

on

[m

ol

]


0

10

20

30

acetic acid

formic acid


glycolic acid

pyruvaldehyde

lactic acid

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mo

l]

60 120 180 240 300

Co

nv

ersi

on

[m

ol

]







305




include




andor HObull
















306


time











307















308




Temp

[degC]

Residence time

[s]


Conversion

[mol]

Selectivitya

[C-mol]

Yieldb

[C-mol]

Conversion

[mol]

Selectivitya

[C-mol]

Yieldb

[C-mol]

Conversion

[mol]

Selectivitya

[C-mol]

Yieldb

[C-mol]

125 60 202 118 24 130 51 07 na na na

120 176 191 34 125 85 11 76 593 45

180 195 184 36 153 167 26 118 620 73

240 198 154 31 164 212 35 166 396 65

300 188 135 25 159 233 37 259 231 60

150 60 178 372 66 155 224 35 251 403 95

120 263 486 128 266 306 82 278 630 165

180 375 399 150 374 209 78 334 601 190

240 382 385 147 384 231 89 397 480 183

300 407 385 157 408 205 82 432 464 192

175 60 273 907 239 364 420 143 450 170 70

120 347 647 214 377 552 197 434 294 119

180 345 659 219 401 554 212 371 493 175

240 439 506 217 393 604 233 463 456 206

300 461 424 191 382 567 212 473 361 168


a single experiment

309

0

15

30

45

0

15

30

45

0

15

30

45

0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Conversion

Con

ver

sion

[m

ol

]


0

10

20

30

Residence time [s]

Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]


0

10

20

30

acetic acid

formic acid


glycolic acid

pyruvaldehyde

lactic acid

Residence time [s]S

elec

tivit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]







310

0

15

30

45

0

15

30

45

0

15

30

45

0

10

20

30

40


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Conversion

Con

ver

sion

[m

ol

]


0

10

20

30

40


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]

60 120 180 240 300

Con

ver

sion

[m

ol

]


0

10

20

30

40

acetic acid

formic acid


glycolic acid

pyruvaldehyde

lactic acid


Sel

ecti

vit

y t

o l

iqu

id p

rod

uct

s [C

-mol

]60 120 180 240 300

Con

ver

sion

[m

ol

]



at 150 C and 175 C




311


























312











of DHA













313

0

2

4

6

8

10

0

2

4

6

8

10

0

2

4

6

8

10

0

2

4

6

8

10

60 120 180 240 300

DH

A y

ield

[C

-mo

l]

Residence time [s]

(A) 125 C

60 120 180 240 300

Residence time [s]

(B) 150 C

DH

A y

ield

[C

-mo

l]

Residence time [s]

(C) 175 C

60 120 180 240 300

60 120 180 240 300



H-Beta-Al2O3 (MC)

Fo

rmic

aci

d y

ield

[C

-mo

l]

Residence time [s]

(D) 125 C

60 120 180 240 300

Residence time [s]

(E) 150 C

Fo

rmic

aci

d y

ield

[C

-mo

l]

Residence time [s]

(F) 175 C

60 120 180 240 300




314










0

4

8

12



H-Beta-Al2O3 (MC)

La

cti

c a

cid

yie

ld [

C-m

ol

]

Residence time [s]

at 175 C

60 120 180 240 300




315











such reaction



7331 Conclusion




316























317







318












319

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

32 36 400

1000

2000

3000

4000

6 8 10 20 22 240

2000

4000

6000

8000

10000

Inte

nsi

ty [

Co

un

ts]

2 [degree]

25 wt CuH-Beta-Al2O

3 MC

after 125 C

after 150 C

after 175 C

(A)

Red circle = -Al2O

3

(C)

Inte

nsi

ty [

Cou

nts

]

2 [degree]

CuO

(B)

Inte

nsi

ty [

Co

un

ts]








320

60 120 180 240 300

0

20

40

60

80

100

60 120 180 240 300

0

100

200

300

400

60 120 180 240 300

0

20

40

60

80

60 120 180 240 300

0

20

40

60

80

100

60 120 180 240 300

0

100

200

300

400

60 120 180 240 300

0

20

40

60

80

60 120 180 240 300

0

20

40

60

80

100

60 120 180 240 300

0

100

200

300

400

60 120 180 240 300

0

20

40

60

80

125 C

150 C

175 C


3 (MC)

Co

nce

ntr

ati

on

of

Al

[pp

m]

Residence Time [s]


3 (MC)

Co

nce

ntr

ati

on

of

Si

[pp

m]

Residence Time [s]


3 (MC)

Co

nce

ntr

ati

on

of

Cu

[p

pm

]

Residence Time [s]


3 (MC)

125 C

150 C

175 C

Co

nce

ntr

ati

on

of

Al

[pp

m]

Residence Time [s]


3 (MC)

Co

nce

ntr

ati

on

of

Si

[pp

m]

Residence Time [s]


3 (MC)

Co

nce

ntr

ati

on

of

Cu

[p

pm

]

Residence Time [s]

Co

nce

ntr

ati

on

of

Al

[pp

m]

Residence Time [s]

125 C

150 C

175 C

(A) Al_H-Beta-Al2O


2O

3 (MC)

Co

nce

ntr

ati

on

of

Si

[pp

m]

Residence Time [s]

(C) Cu_H-Beta-Al2O

3 (MC)

Co

nce

ntr

ati

on

of

Cu

[p

pm

]

Residence Time [s]




321









150 oC

















322




Si












323


81 Summary










doped zeolites










324























325



5 min







liquid products














326












(MC)








327














82 Future work







solution

328

















329

9 References


















Manchester












330







91-109





91-109



291-303









423










55(7-10) 474-479

331



9529-9541







Catalysis 159(1) 249-252










Journal 85(1) 53-59



Publishing











332


309-312



4(1-2) 27-42



2242























S1013610111




333



























9(9) 927-934







334




74-82





























335









Catalysis 257(1) 163-171






337(1ndash2) 106-112



1129



666 224-236














336








3430









11665-11676






182




Chemistry C 117(24) 12552-12559






ENERC2423-2012SI2673791



337






















403ndash404 41-46











338







193(1) 20-30






156(3ndash4) 93-99








Catalysis 31(6) 615-618








1417-1425





liquefaction oil

339


glycerol







3349-3358


















11739






133

340










2920








Chemistry 13(4) 854-862






293-299









341



1379-1391






58






713-714




877















342
































204

343



Research 45(12) 4169-4177


















156(3ndash4) 306-315











11576-11586

344



383-388



222














Catalysis 3(6) 1279-1291





2(5) 415-437







567-576



345













38(11) 2221-2295











4168



13(5) 1175-1181






346




141-148





























673-674

347


Thesis






Technology 4(11) 4065-4074










29(4) 269-292



Science 286(1) 268-273












348



SPEC ISS) 198-220































349










1161






566-579









1870




135-147






350













Publishing






114













351



214-220











Letters 83





Research 49(16) 7524-7529






109(10) 4485-4491





259-266




352



102(19) 9267-9271












Society 49(3) 271-278




















353












45(7) 2163-2173




3113-3119





















354






Letters 88(1-2) 1-8



191






86(1) 345-374





16(25) 7368-7371












A General 231(1) 117-123



355










45








2475

















356



1-56





41-52




319




388



















357



















4653-4655



19-28












358




























298(2) 535-542



Chemical 297(2) 101-109




359




51(1) 43-49


3298-3311





90-94





22(1) 46-60





1525








11810-11819



Technology 102(2) 1998-2003



360



42(5) 1724-1730



























(United States)


361

10 Appendix




used = 711

362


glycolic acid

y = 28146x + 1252

Rsup2 = 09849

y = 49077x - 16235

Rsup2 = 09979

y = 78768x - 12788

Rsup2 = 09838

y = 86171x - 05366

Rsup2 = 09996

y = 9912x + 13915

Rsup2 = 09953

0

100

200

300

400

500

600

700

800

900

1000

0 2 4 6 8 10 12 14

Are

a

Concentration [mM]





363



y = 16711x + 23975

Rsup2 = 09933

y = 19991x + 12406

Rsup2 = 0999

y = 56833x + 24233

Rsup2 = 099590

5000

10000

15000

20000

25000

30000

0 2 4 6 8 10 12 14

Are

a

Concentration [mM]


y = 28396x - 26609

Rsup2 = 09997

y = 64254x - 20459

Rsup2 = 09981

0

200

400

600

800

1000

1200

1400

1600

0 5 10 15 20 25

Are

a

Concentration [mM]



364


Temperature

[degC]

Residence time

[s]

Total flow rate

[mlmin]

Feed flow rate

[mlmin]

Water flow rate

[mlmin]

125 60 39286 1310 2619

120 19643 0655 1310

180 13095 0437 0873

240 09822 0327 0655

300 07857 0262 0524

150 60 38465 1282 2564

120 19232 0641 1282

180 12822 0427 0855

240 09616 0321 0641

300 07693 0256 0513

175 60 37662 1255 2511

120 18831 0628 1255

180 12554 0418 0837

240 09416 0314 0628

300 07532 0251 0502












365



















366

0 100 200 300 400 500 600

-20

-15

-10

-5

0

278

100 C

379

596 C

TGA

wei

gh

t lo

ss

NH4-Beta zeolite

943

186 C

-03

-02

-01

00

01

02

dTG

Der

iv w

eigh

t [

C

-1]

Temperature [C]

80

82

84

86

88

90

92

94

96

98

100

217 C

146 C

TGA

Wei

gh

t [

]

NH4-Beta zeolite

0 100 200 300 400 500 600

-20000

-15000

-10000

-5000

0

5000

DSC

Temperature [C]

Heat

Flo

w [

mWg

-1]


367

0 100 200 300 400 500 600

-15

-10

-5

0

502

161

116

30 C

436 C

327C

w

eigh

t lo

ss TGA

100C

207C

280

-010

-005

000

005

dTG

Der

iv w

eigh

t [

C

-1]

Temperature [C]

NH4-ZSM-5

0 100 200 300 400 500 600

-2500

-2000

-1500

-1000

-500

0

500

1000

1500

207 C

140 C

124 C

DSC

Temperature [C]

Hea

t F

low

[m

Wg

-1]

90

95

100

TGA

w

eig

ht

loss

NH4-ZSM-5


368

10 20 30 40 50 60 70

0

7000

0

7000

0

7000

0

7000

0

7000

2 [degree]

48 wt CeNH4-Beta

x CeO2

O ZnO SnO2+ NaCl

xx x

x

48 wt LaNH4-Beta

Inte

nsi

ty [

co

un

ts]

48 wt ZnNH4-Beta

O OO O

+

48 wt SnNH4-Beta

+

NH

4-Beta

+

+ +

+

+ +

+

+ + +

+

+

+ +

+

+





ο = SnO2 x = CeO2

369

10 20 30 40 50 60 70

0

7500

0

7500

0

7500

0

7500

0

7500

Inte

nsi

ty [

cou

nts

]

2 [degree]

48 wt CeNH4-ZSM5

+XX X

X

+ NaCl ZnO O SnO2

x CeO2

+

48 wt LaNH4-ZSM5

+

48 wt SnNH4-ZSM5

OO

OO

O

+

48 wt ZnNH4-ZSM5

+

NH

4-ZSM5+

+

+

+

+

+

+

++

+

++





370

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

8000

+

+

+ = NaCl

O

OO

O

H-Beta zeolite

deAl-BetaII4h


Inte

nsi

ty [

co

un

ts]

2 [degree]

O

= SnO

+

Inte

nsi

ty [

cou

nts

]

2 (degree)





371

10 20 30 40 50 60 70

0

2000

4000

6000

8000

10000

12000

6 8 10 20 22 24

0

2000

4000

6000

8000

++

H-Beta zeolite

deAl-BetaII4h


Inte

nsi

ty [

cou

nts

]

2 [degree]

+ NaCl

+

ZnO

2 [degree]





372

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta




in TUD-1 (red)

373

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm

3g

-1]


adsorption_H-Beta

desorption_H-Beta








10 20 30 40 50 60 70

0

200

400

600

800

1000

1200

methyl cellulose

Inte

nsi

ty [

co

un

ts]

2 [degree]

10 20 30 40 50 60 70

0

200

400

600

800

1000

1200 bentonite clay

Inte

nsi

ty [

co

un

ts]

2 [degree]



as a binder

374

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta











375

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta


3 (MC)


3 (MC)



376

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta








377

00 01 02 03 04 05 06 07 08 09 10

0

100

200

300

400

500

600

Qu

an

tity

N2 a

dso

rbed

des

orb

ed [

cm3g

-1]


adsorption_H-Beta

desorption_H-Beta








378

10 20 30 40 50 60 70

0

200

400

600

800

1000

1200

methyl cellulose

Inte

nsi

ty [

co

un

ts]

2 [degree]

10 20 30 40 50 60 70

0

200

400

600

800

1000

1200

Inte

nsi

ty [

co

un

ts]

2 [degree]

-Al2O3



379



Time

[min]

Conversion

[mol]

Yield [C-mol] Total



60 156 plusmn 01 01 01 02 13 00 00 17 04 36 03 08 10 82 00 00 105 23 231

120 331 plusmn 16 01 02 04 33 00 00 39 04 84 03 06 14 98 00 00 117 11 249

180 441 plusmn 41 02 03 20 54 00 00 32 04 115 05 07 48 125 00 00 74 09 267

240 433 plusmn 74 02 02 08 63 00 00 34 05 115 05 05 19 147 00 00 79 12 267

300 472 plusmn 33 04 04 09 74 00 00 26 04 120 07 08 19 154 00 00 56 08 252

60 431 plusmn 91 02 02 03 56 00 09 25 05 103 04 05 08 140 00 19 74 16 265

120 561plusmn00 04 04 06 102 00 03 15 04 138 07 07 10 181 00 06 27 07 246

180 655 plusmn 98 05 04 09 107 00 03 15 05 149 07 07 13 169 00 06 27 09 240

240 744 plusmn 62 06 05 06 139 00 06 15 04 180 08 07 08 188 00 08 22 05 247

300 760 plusmn 47 07 05 15 147 00 09 10 05 199 09 07 19 195 00 13 14 07 264

60 839 plusmn 24 12 05 04 207 00 10 37 07 282 14 06 04 246 00 12 44 09 335

120 859 plusmn 19 11 05 14 204 02 06 34 03 279 13 06 17 238 02 06 39 03 325

180 898 plusmn 14 16 12 05 238 02 09 19 03 303 17 13 05 266 02 10 21 03 337

240 954 plusmn 25 15 10 02 231 02 14 10 01 283 16 10 02 242 02 15 10 09 306

60 940 plusmn 20 24 11 00 243 00 07 13 02 301 26 12 00 259 00 07 14 02 319

120 975 plusmn 35 11 07 00 219 00 04 40 08 289 12 07 00 225 00 05 41 03 293

180 976 plusmn 07 23 11 00 237 00 09 08 00 288 24 11 00 243 00 09 09 00 295

240 998 plusmn 02 18 11 00 220 00 10 00 00 259 18 11 00 220 00 10 00 00 259


380



Time

[min]

Conversion

[mol]

Yield [C-mol] total



60 449 plusmn 33 01 04 09 30 00 00 26 10 80 03 09 19 67 00 00 59 22 179

120 572 plusmn 43 04 07 11 57 01 02 39 09 130 08 11 20 100 02 03 67 15 227

180 743 plusmn 43 04 09 13 71 03 04 30 06 139 05 11 17 96 04 05 41 08 187

240 773 plusmn 01 04 10 11 80 00 06 43 06 160 06 14 15 103 00 07 55 07 207

300 793 plusmn 01 04 10 14 84 00 05 29 06 151 05 13 18 106 00 06 36 07 191

60 827 plusmn 40 09 17 08 130 00 07 55 11 237 11 20 09 158 00 09 67 13 288

120 937 plusmn 29 07 20 05 133 00 09 15 06 195 08 22 05 142 00 09 16 07 208

180 930 plusmn 00 08 28 03 145 00 13 10 06 256 08 30 03 155 00 14 10 07 275

240 963 plusmn 12 09 30 00 137 00 13 10 05 204 10 31 00 142 00 13 10 05 212

300 990 plusmn 05 08 29 00 138 00 13 00 03 191 08 29 00 139 00 13 00 03 193

60 980 plusmn 17 09 29 00 189 00 14 15 06 262 10 30 00 192 00 14 15 06 268

120 990 plusmn 10 08 28 00 155 00 11 00 00 203 09 29 00 157 00 11 00 00 206

180 1000 plusmn 00 08 35 00 133 00 15 00 00 190 08 35 00 133 00 15 00 00 190

240 1000 plusmn 00 06 44 00 107 00 16 00 00 173 06 44 00 107 00 16 00 00 173

300 1000 plusmn 00 07 49 00 104 00 19 00 00 180 07 49 00 104 00 19 00 00 180


381



Time

[min]

Conversion

[mol]

Yield [C-mol] Total



60 01 16 02 51 00 27 06 102 48 06 151 00 82 18 305

120 01 05 02 87 00 36 06 136 14 05 236 00 99 16 370

180 01 10 02 125 04 27 03 172 23 05 289 09 63 07 397

240 01 15 02 145 00 27 03 193 35 05 331 00 62 07 439

300 01 12 04 141 00 27 03 188 23 08 268 00 52 06 356

60 204 01 00 35 00 30 07 73 05 00 173 146 32 356

120 280 04 02 70 00 20 03 100 16 08 252 00 71 12 358

180 454 06 02 86 00 30 03 127 12 05 189 00 65 07 278

240 390 09 02 106 00 20 03 140 23 06 271 00 51 08 358

300 335 09 04 161 00 40 03 217 26 13 479 00 118 10 647

60 166 05 04 51 00 09 03 72 30 24 305 00 55 18 433

120 639 17 02 158 00 27 00 205 27 03 247 00 43 00 320

180 597 21 04 172 00 36 03 237 36 07 289 00 61 05 397

240 720 31 06 193 14 27 03 275 44 08 267 20 38 04 381

300 676 31 08 180 14 18 03 255 46 12 267 21 27 04 378


382



weight ratio of 1

y = -3E-05x - 23164

Rsup2 = 09454-3

-28

-26

-24

-22

-2

0 5000 10000 15000 20000

ln[g

ly]

Time [s]


y = -8E-05x - 23627

Rsup2 = 09444-4

-38

-36

-34

-32

-3

-28

-26

-24

-22

-2

0 5000 10000 15000 20000

ln[g

ly]

Time [s]


y = -00002x - 27519

Rsup2 = 08891

-62

-57

-52

-47

-42

-37

-32

-27

-220 5000 10000 15000 20000

ln[g

ly]

Time [s]


383




Catalyst Temp

[degC] Time

[s]

[ Gly]

M

[AC]


No Catalyst 270 0 01024 00000 396E-07 753E-11 152E-06

3600 01024 00000

7200 01024 00000

10800 01024 00000

14400 00997 00007

18000 00969 00010

300degC 0 01143 00000 462E-05 273E-04 247E-05

3600 01087 00120

7200 00956 00158

10800 00886 00123

14400 00862 00165

18000 00773 00149

330degC 0 01020 00000 174E-05 488E-13 257E-05

3600 00882 00039

7200 00761 00088

10800 00669 00144

14400 00561 00190

18000 00415 00247


3600 00874 00020

7200 00752 00053

384

10800 00620 00088

14400 00602 00101

18000 00565 00116

300degC 0 01126 00000 278E-05 171E-06 780E-05

3600 00632 00094

7200 00494 00170

10800 00378 00180

14400 00282 00233

18000 00265 00248

330degC 0 01122 00000 141E-04 266E-12 297E-04

3600 00154 00281

7200 00149 00323

10800 00108 00378

14400 00050 00365

18000 00022 00365

360degC 0 01117 00000 319E-04 360E-06 574E-04

3600 00026 00364

7200 00070 00406

10800 00026 00397

14400 00003 00367

H-ZSM-5 270degC 0 01076 00000 174E-05 161E-06 101E-04

3600 00592 00049

7200 00461 00092

10800 00276 00115

14400 00244 00129

18000 00222 00135

300degC 0 00949 00000 108E-04 766E-06 362E-04

3600 00164 00185

7200 00060 00189

385

10800 00066 00206

14400 00035 00195

18000 00009 00196

330degC 0 01065 00000 309E-04 376E-05 807E-04

3600 00020 00278

7200 00011 00204

10800 00000 00212

14400 00000 00170

18000 00000 00166


3600 00736 00084

7200 00698 00144

10800 00627 00208

14400 00620 00241

18000 00523 00234

300degC 0 01015 00000 155E-05 287E-11 282E-05

3600 00808 00054

7200 00731 00107

10800 00554 00131

14400 00619 00161

18000 00675 00245

330degC 0 01102 00000 432E-05 300E-05 427E-05

3600 00919 00084

7200 00398 00261

10800 00444 00285

14400 00308 00318

18000 00357 00298


386



Zeolite Temp

[degC]

Time

[h] Al Si

ppm wt ppm wt


















H-Beta 330 008 420 183 60050 1692

017 271 118 58860 1658

025 374 163 60340 1700

05 356 155 60350 1700

075 298 130 61950 1745

1 232 101 62150 1751

387


H-ZSM-5 330 008 133 058 56978 1605

017 186 081 52511 1479

025 222 097 51823 1460

05 128 056 50890 1434

075 180 079 50150 1413

1 536 234 49880 1405

H-ZSM-5 360 008 163 071 50780 1430

017 106 046 49270 1388

025 095 041 48020 1353

05 077 034 50050 1410

075 142 062 50910 1434

1 262 114 50900 1434



388



389








Zeolite SiO2Al2O3

(manufacture)

Fe (ppm) Cu

[ppm]

Al

[ppm]

Na

[ppm]

ZSM-5 23 100-150 50-200

26000 500-600

Beta 25 150-200 25000 300-400

390




391




392








[mgL]

BP

[ordmC]

RT

[min] Area

1 Acetaldehyde 1000 202 20 1567

2 Acetol 3704 145 173 991

3 Glyceraldehyde 4504 140-150 67 124



6 Pyruvaldehyde 3603 72 24 55 62 71

7 Acrolein 2803 53 42 176 866 536

8 MeOH 3204

9 EtOH 7837


393




-100E-10

-800E-11

-600E-11

-400E-11

-200E-11

000E+00

200E-11

400E-11

600E-11

800E-11

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49

Ion

cu

rren

t

Mw

SN132-1

28 =N2

32 = O2

40 = Ar

44 = CO2

394



Temp

[degC]

Residence time

[s]

Conversion

[mol]



125 0 00 00 00 00 00 00 00 00 00 00

60 202 09 00 41 61 07 00 00 00 118

120 176 21 00 63 100 08 00 00 00 191

180 195 24 00 64 90 07 00 00 00 184

240 198 19 00 56 73 07 00 00 00 154

300 188 10 00 51 66 07 00 00 00 135

150 0 00 00 00 00 00 00 00 00 00 00

60 178 66 00 98 181 27 00 00 00 372

120 263 105 00 140 205 36 00 00 00 486

180 375 108 00 123 134 34 00 00 00 399

240 382 106 00 121 125 33 00 00 00 385

300 407 117 00 117 111 39 00 00 00 385

175 0 00 00 00 00 00 00 00 00 00 00

60 273 186 98 331 182 62 16 21 10 907

120 347 125 171 200 61 49 12 20 08 647

180 345 104 225 217 31 45 12 16 08 659

240 439 69 203 167 14 32 10 06 04 506

300 461 45 181 147 05 31 06 06 04 424


395

10 20 30 40 50 60 70

0

500

1000

1500In

ten

sity

[C

ou

nts

]

2 [degree]

H-Beta-Al2O

3 MC

after 125 C

after 150 C

Red circle = -Al2O

3




396



hydrothermal transformations of glycerol into value-added chemicals using zeolite-based catalysts

Documents