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JOHNSON MATTHEY TECHNOLOGY REVIEW

Johnson Matthey’s international journal of research exploring science and technology in industrial applications

www.technology.matthey.com

Volume 61, Issue 3, July 2017Published by Johnson Matthey

ISSN 2056-5135

© Copyright 2017 Johnson Matthey

Johnson Matthey Technology Review is published by Johnson Matthey Plc.

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Contents Volume 61, Issue 3, July 2017

JOHNSON MATTHEY TECHNOLOGY REVIEW

Johnson Matthey’s international journal of research exploring science and technology in industrial applications


170 Guest Editorial: Industry and Sustainability By Deirdre Black

172 Methanol Production – A Technical History By Daniel Sheldon

183 One Hundred Years of Gauze Innovation By Hannah Frankland, Chris Brown, Helen Goddin, Oliver Kay and Torsten Bünnagel

190 Osmium vs. ‘Ptène’: The Naming of the Densest Metal By Rolf Haubrichs and Pierre-Léonard Zaffalon

196 The ‘Nano-to-Nano’ Effect Applied to Organic Synthesis in Water By Bruce H. Lipshutz

203 “Sustainability Calling: Underpinning Technologies” A book review by Niyati Shukla and Massimo Peruffo

207 Highlights of the Impacts of Green and Sustainable Chemistry on Industry, Academia and Society in the USA

By Anne Marteel-Parrish and Karli M. Newcity

222 UK Energy Storage Conference A conference review by Jacqueline Edge

227 “Particle Technology and Engineering: An Engineer’s Guide to Particles and Powders: Fundamentals and Computational Approaches”

A book review by Domenico Daraio, Giuseppe Raso and Michele Marigo

231 Organometallic Catalysis and Sustainability: From Origin to Date By Justin D. Smith, Fabrice Gallou and Sachin Handa

246 Industrial Low Pressure Hydroformylation: Forty-Five Years of Progress for the LP OxoSM Process

By Richard Tudor and Atul Shah

257 Two Hundred Proud Years – the Bicentenary of Johnson Matthey By W. P. Griffith

262 Johnson Matthey Highlights

www.technology.matthey.comJOHNSON MATTHEY TECHNOLOGY REVIEW

http://dx.doi.org/10.1595/205651317X695857 Johnson Matthey Technol. Rev., 2017, 61, (3), 170–171

170 © 2017 Johnson Matthey

Guest Editorial

Industry and Sustainability

This themed issue focuses on ‘Sustainable Industry’ from the perspective of research advances and technological solutions. Starting with a high level policy context, it is clear that the roles and responsibilities of industry are broader than technology and go way beyond what happens within industry.

People have been thinking about the issues and options encompassed in the word ‘sustainability’ for decades. An important example is the “Limits to Growth” report from the Club of Rome (1). This organisation started as an informal group of “scientists, educators, economists, humanists, industrialists, and national and international civil servants” and the 1972 report was for its ‘Project on the Predicament of Mankind’.

Today, the language and approach to sustainability focuses on solutions and opportunities as well as understanding “predicaments” and “problems”. In 2015 world leaders adopted the Sustainable Development Goals which are at the core of the United Nations (UN) 2030 agenda for sustainable development (2); that is “development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (3).

Sustainability has many facets, each with layers, interactions and tensions. One dimension is trade-offs in terms of what is sustainable from environmental, public health, economic and societal perspectives. Another is balance between short-term options and long-term consequences. A third dimension is impacts and solutions on local, national and global scales. A fourth element is people, behaviour and accountability across individual citizens, organisations, companies and policymakers.

Sustainable Industry

One lens for seeing the key role of industry in sustainability looks within companies. There are

opportunities to pursue sustainable options – and challenges in pursing them – all along a value chain. The specifics depend on company size and business area, but many companies are including an explicit narrative about sustainability in their strategy and identity.

Companies are building thinking about sustainability into their business models and operations. Products and components can be designed for reuse or recycling, to last longer or to be lighter. Companies are committing to using energy from renewable sources, to reducing the use of water in manufacturing, to working together through industrial symbiosis and colocation of raw material sourcing, component production, manufacturing and waste management.

In terms of the science and technology innovation focus of this journal there are many promising research advances: catalysis to increase energy efficiency, reduce dependence on platinum group metals, recycle carbon dioxide or enable nitrogen fixation; green chemistry; reducing the use of solvents or improving their recycling or disposal; and bio-based feedstocks enabling reduction in energy use and environmental impacts associated with raw material extraction or production.

The Voice of Industry

The importance of industry in the sustainability agenda lies also in informing, influencing and implementing policy. Many issues fit under the ‘sustainability-related policy’ umbrella – from broad areas like energy, climate, air, food and water to specific topics like chemicals regulation and waste management. Industry can also influence research and innovation policy as an advocate for funding for research and development on sustainable technologies.


http://dx.doi.org/10.1595/205651317X695857 Johnson Matthey Technol. Rev., 2017, 61, (3)

Leaders in industry are being proactive in making the business as well as the environmental case for sustainability and at the same time policymakers increasingly recognise the need to include a business perspective and its value in identifying realistic options.

This is visible for climate change where Christiana Figueres, the UN diplomat at the heart of the 2015 21st Conference of the Parties (COP-21) process and the Paris Agreement, has been unequivocal about the importance of having industry at the table: “We’re delighted that at every COP, we are able to open that door more and more to the recognition of business” (4).

On the industry side there are perspectives from groups like the World Business Council for Sustainable Development chaired by Paul Polman, Unilever CEO: “The reality is, if we don’t tackle climate change we won’t achieve economic growth” (5). Or the Risky Business project quantifying the economic risks of climate change, such as a likely US$35 billion increase in the annual average price tag associated with hurricanes and other coastal storms in the USA (6).

Another example of the industry-policy-sustainability interplay is the May 2016 United Nations Environmental Programme resolution on Sound Management of Chemicals and Waste (7), calling on the private sector to play a significant role in financing and capacity building and inviting industry to join other stakeholders in supporting the Global Partnership on Waste Management.

This is paralleled by the Responsible Care® initiative from the International Council of Chemical Associations and by participation of industry in the development of regulation like the European Regulation on Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) or the US Toxic Substances Control Act (TSCA) and in new areas like microplastics and persistent pharmaceutical pollutants.

Industry is critical in collecting and reporting data to enable development and implementation of environmental regulation. This is costly so there may need to be incentives or imperatives for companies to invest in monitoring and reporting systems and to make information available to policymakers and agencies.

Sustainable Solutions

Sustainability challenges like climate, water, energy and air are related in what is often called a nexus. This gives cause for optimism in that solutions in one

area can often have a positive impact on another. An example is transport where reducing the number of journeys, increasing engine efficiency, switching to non-fossil fuels or using electric vehicles usually reduces both carbon dioxide emission and air pollution.

To be truly sustainable, opportunities to develop and deploy environmentally sustainable solutions must also be societally and economically sustainable. The division of risk, responsibility and reward between the public and private sectors will vary by issue, place and time. What is clear is that industry is pivotal in achieving sustainable development, because of what companies do and because of what leaders in industry say.

DEIRDRE BLACKScience Manager

Royal Society of Chemistry, Thomas Graham House,Science Park, Milton Road, Cambridge, CB4 0WF, UK

Email: [email protected]

References1. D. H. Meadows, D. L. Meadows, J. Randers and W. W.

Behrens III, “The Limits to Growth”, Universe Books, New York, USA, 1972

2. Resolution Adopted by the General Assembly on 25 September 2015, ‘Transforming our World: The 2030 Agenda for Sustainable Development’, A/RES/70/1, United Nations, General Assembly, New York, USA, 21st October, 2015

3. ‘Our Common Future, Chapter 2: Towards Sustainable Development’, from “Our Common Future: Report of the World Commission on Environment and Development”, A/42/427, UN Documents, United Nations, Secretary General, New York, USA, 4th August, 1987

4. J. Makower, ‘Christiana Figueres: Why business matters at COP’, GreenBiz Group Inc, Oakland, CA, USA, 18th June, 2015

5. R. Harrabin, ‘Unilever Boss Urges World Leaders to Reduce Carbon Output’, BBC News, London, UK, 18th May, 2015

6. “Risky Business, The Economic Risks of Climate Change in the United States”, A Climate Risk Assessment for the United States, Risky Business, New York, USA, June, 2014

7. ‘Sound Management of Chemicals and Waste’, UNEP/EA.2/Res.7, United Nations Environment Assembly of the United Nations Environment Programme, Nairobi, Kenya, 3rd August, 2016




Methanol Production – A Technical HistoryA review of the last 100 years of the industrial history of methanol production and a look into the future of the industry

By Daniel SheldonJohnson Matthey, PO Box 1, Belasis Avenue, Billingham, Cleveland TS23 1LB, UK


Global methanol production in 2016 was around 85 million metric tonnes (1), enough to fill an Olympic-sized swimming pool every twelve minutes. And if all the global production capacity were in full use, it would only take eight minutes. The vast majority of the produced methanol undergoes at least one further chemical transformation, more likely two or three before being turned into a final product. Methanol is one of the first building blocks in a wide variety of synthetic materials that make up many modern products and is also used as a fuel and a fuel additive. This paper looks at the last 100 years or so of the industrial history of methanol production.

Introduction

Methanol has been produced and used for millennia, with the ancient Egyptians using it in the embalming process – it was part of the mixture of substances produced in the destructive distillation (pyrolysis) of wood. However, it was not until 1661 that Robert Boyle produced pure methanol through further distillation, and only in 1834 was the elemental composition determined by Jean-Baptiste Dumas and Eugene

Peligot. At a similar time, commercial operations using destructive distillation were beginning to operate (2).

There are many parallels between the industrial production of methanol and ammonia and it was the early development of the high pressure catalytic process for the production of ammonia that triggered investigations into organic compounds: hydrocarbons, alcohols and so on. At high pressure and temperature, hydrogen and nitrogen will only form ammonia, however the story is very different when combining hydrogen and carbon oxides at high pressure and temperature, where the list of potential products is lengthy and almost all processes result in a mixture of products. Through variations in the process, the catalyst, the conditions, the equipment or the feedstock, a massive slate of industrial ingredients suddenly became available and a race to develop commercial processes ensued.

The First Drops

Early research into methanol production quickly focused on copper as a prime contender for the basis of a catalytic process to methanol, with Paul Sabatier and Jean-Baptiste Senderens (3) discovering in 1905 that copper effectively catalysed the decomposition of methanol and to a lesser extent its formation. A lot of the early testing looked at what catalysts could effectively destroy methanol, assuming they would be equally as effective under alternative conditions at forming methanol. Following the start of large scale ammonia production in Germany during 1913, the



pace of research picked up and in 1921 Georges Patart patented the basis of a high pressure catalytic process that used a variety of materials including copper (along with nickel, silver or iron) for methanol synthesis (4). A small experimental plant was later built using this process in Patart’s native France, near Asnières (5).

The German Effort

The wood-based processes were always very limited in scale and it was 1923 before production could be considered ‘industrial’ with a catalytic process developed by Mathias Pier at Badische Anilin- & Sodafabrik (BASF), Germany (Figure 1).

The BASF process produced methanol from synthesis gas (syngas), which at the time was a mixture of hydrogen and carbon monoxide. The process works by the following reactions:

CO + 2H2 D CH3OH ΔH = –90.6 kJ (i)

CO2 + 3H2 D CH3OH + H2O ΔH = –49.5 kJ (ii)

CO + H2O D CO2 + H2 ΔH = –41.2 kJ (iii)

Methanol formation (Equations (i) and (ii)) is favoured by low temperatures and high pressures. All three equilibrium reactions occur simultaneously, although it is common to only consider two of the three to simplify any analysis, as it can be seen that Equations (ii) and (iii) combined are the same as Equation (i).

The BASF process operated at above 300 atm and 300–400°C, using a zinc chromite (Cr2O3-ZnO) catalyst developed by Alwin Mittasch (6), about a decade after

his work on the first industrial ammonia synthesis catalyst. The high pressures benefitted conversion to methanol and to achieve sufficiently quick reaction rates, high temperatures also had to be used. Further increases in temperature would have drastic effects on the selectivity and equilibrium, so conditions were selected to be a compromise. Methanol production began on 26th September 1923 at the Leuna site (7).

Early Catalysts

The subsequent research into the catalyst was extensive, with the list of possible candidates covering large swathes of the periodic table, from antimony to zirconium, bismuth to uranium (itself a popular catalyst of the time) (5, 8). Given the extensive testing, it is perhaps unsurprising that in the list can be found many of the components that make up the modern catalysts used in methanol plants in the 21st century.

Initially, iron was to be used for methanol production (as with ammonia production), but this along with nickel was phased out in successive patent applications until the requirement for the process to be ‘completely excluding iron from the reaction’ was included in the mid 1920s (9). During the early years there was a lot of effort looking at other combinations of carbon, hydrogen and oxygen. One major application was Fischer-Tropsch reactions: the creation of straight chain saturated hydrocarbons, for example for fuels. This is readily catalysed by iron at similar conditions to methanol synthesis. With early iron-containing methanol synthesis catalysts, it was found that the iron would react with the carbon monoxide to form iron carbonyl, which decomposes at high temperatures to iron metal. It was therefore easy to transform the catalyst into one much more efficient at making hydrocarbons than methanol; reactions that are even more exothermic and not equilibrium limited, hence at risk of thermal runaway. The catalyst is not the only source of iron in such processes, with the obvious choice for construction of the early reactor vessels being steel, which itself contains iron. Many of the early plants were therefore either lined or made of non-ferrous metals, such as copper, silver or aluminium (10).

Early Processes

The equilibrium limitations of the methanol formation reactions (Equations (i)–(iii)), especially under the early operating conditions, were such that conversion to methanol in a single pass through a reactor was

Fig. 1. First shipment of synthetic methanol from BASF Leuna, 1923 (Courtesy of BASF Corporate Archives, Ludwigshafen/Rhine, Germany)



very low. To overcome this, the gas had to be recycled over the catalyst a number of times. Each time, the gas is cooled to condense any product methanol and the consumed reactants are replaced with fresh synthesis gas. The gas is rarely pure hydrogen and carbon monoxide, and any non-reacting species, such as methane or nitrogen, introduced through the fresh gas supply accumulate in such a loop, so a small fraction of the gas must be purged, also losing some reactants. Figure 2 shows the basic components of a methanol synthesis loop, which are still used today.

The interchanger is a more modern concept, reducing energy consumption by using the hot gas exiting the converter to heat the inlet gas. Early patents (11) show a lot of the aspects of modern methanol production, including the recycle loop and the use of a guard bed of additional catalyst or absorbent to remove “traces of substances deleterious to the reaction”, early versions tending to be copper based. The loss of reactants through the purge was also considered in early processes, with Forrest Reed filing a patent in 1932 (12) for recycling the purged gas through an additional reactor in a loop with high concentrations of non-reacting components, complete with condensation and separation. This approach is now used to revamp and add capacity to modern methanol plants.

The general concept spread rapidly and plants could be found around the world by the end of the 1920s producing a total of around 42,000 metric tonnes per

year of methanol in new, catalysed, high-pressure processes (13).

Catalyst Developments

Early on it was recognised that the most effective catalysts used a combination of copper and another metal oxide, but the synthesis section and catalyst remained very similar for about 25 years. Eugeniusz Błasiak filed a patent in 1947 for a new catalyst containing copper, zinc and aluminium, manufactured by co-precipitation (14). The patent claimed a method for producing a “highly active catalyst for methanol synthesis” and further laboratory testing over the following decades proved this.

The biggest impediment to the use of copper catalyst was the rate of poisoning by sulfur compared to the zinc chromite catalysts typically used in those plants. The syngas generation process had moved on from coal and coke feeds to natural gas reforming, and it was accepted that sulfur in the feed would poison the reforming catalyst and reduce the activity. The reformers were therefore run at close to atmospheric pressure to prevent hydrocarbon cracking over the poisoned catalyst, which would cover the surface in a layer of carbon and remove all residual activity. Around this time, work was underway to create an alkalised reforming catalyst which was protected against carbon deposition and could therefore run at elevated pressure (initially 14 atm, but soon after up to 35 atm) (15). A second development at a similar time gave hydro-desulfurisation catalysts, which remove sulfur from the naphtha or natural gas feedstock and preserve the activity of the reforming catalyst. This gave a process for supplying high purity syngas at increased pressure. The cost of compressing syngas is much greater than the cost of compressing natural gas, so the opportunity to move compression duty upstream also provided an energy efficiency benefit to plant designs.

By the 1960s, methanol was being made almost solely from natural gas and naphtha using low pressure reforming and high pressure synthesis, with a broad range of process licensors all offering a very similar configuration. Substantial gains in process efficiency had been made since the very early plants, partly due to the larger scale of the later plants. One technology that the largest plants of the time could take advantage of was centrifugal compressors, offering much lower costs at high gas flow rates compared to the previous reciprocating machines (16). With these gains

Converter

Synthesis gas

Circulator

Purge gas

Catchpot

Methanol Crude cooler

Interchanger

Fig. 2. Basic components of a pressurised methanol synthesis loop



increasing with equipment size, the drive for bigger and bigger plants continued.

The British Intervention

In the 1960s, arguably the biggest change to the industry was introduced by Imperial Chemical Industries (ICI), UK. This began in 1963 when Phineas Davies and Frederick Snowdon filed a patent for a methanol production process operating at 30–120 atm (17). Using a copper, zinc and chromium catalyst, they had created a process capable of producing high quantities of methanol without the need for very high pressures. The lower pressures meant that fast reaction rates could be achieved at lower temperatures of 200–300°C, which reduced the formation of byproducts. This meant the catalyst was able to achieve a selectivity of greater than 99.5%, based on organic impurities in the liquid methanol.

At a similar time, ICI had developed its ‘high pressure’ steam reformer, capable of transforming naphtha or later, natural gas into syngas. The process was therefore not just a method of synthesising methanol, but a complete process from natural gas to methanol: the Low Pressure Methanol (LPM) process, which remains the leading route to methanol to this day.

The catalyst was soon revised with a patent application by John Thomas Gallagher and John Mitchell Kidd

of ICI in August 1965 (18) to a catalyst containing the oxides of copper, zinc and another element from Groups II to IV of the periodic table, with aluminium being the preferred candidate. This was the catalyst that ICI installed in its own methanol plant constructed at the time and forms the basis of the KATALCOJM

TM 51-series of catalysts sold around the world by Johnson Matthey today.ICI constructed and commissioned the first LPM plant

at its site in Billingham, UK, in 1966 (Figure 3) with a design capacity of 300 metric tonnes per day (MTPD) and an expected catalyst lifetime of six months. The synthesis section operated at only 50 atm (19). Two years later the catalyst was still operating and the plant could consistently produce 400 MTPD. This increased to 550 MTPD with the second catalyst charge and some further plant upgrades. The converter had 71 m3 of catalyst, with three cold shots of gas injected partway down the bed to cool the reacting gas. The plant operated until 1985.

At the lower pressure of the new process, the circulating gas volumes were greater and therefore centrifugal compressors were advantageous at lower plant capacities (16). Much more efficient plants were then available without needing to construct a large-scale facility.

ICI by this time had a long history of methanol production, stretching back to 1929 with its first high

Fig. 3. ICI (low pressure) methanol 1 plant at Billingham



pressure plant operated under licence from IG Farben (then owners of BASF). Following a few years of successful operation of the Billingham plant, ICI licensed the technology and in 1970 a 130 MTPD plant was commissioned for Chang Chun Petrochemical Co Ltd in Taiwan (20). In spite of a challenging two weeks of commissioning, with “torrential rain, a typhoon and an earthquake”, this plant was to be the first of many and later that year a 1000 MTPD plant was commissioned for Monsanto at Texas City, Texas, USA. Only a single high pressure synthesis plant was built after 1966 (21).

Methanol Converters

The most distinguishing feature of most methanol plants (or licensors) is the type of converter used for methanol synthesis. Broadly the converters can be divided into two categories based on how they remove the heat of reaction to maximise conversion: i. multiple adiabatic catalyst beds with external

cooling of the gasii. internal cooling within one or more catalyst beds.

Externally cooled converters come in a variety of configurations: quench converters inject cold, unreacted gas after each adiabatic bed to reduce the temperature, whereas series adiabatic converters use heat exchangers between the catalyst beds. Both externally and internally cooled types were used in the early low pressure plants, with the quench converters offered by ICI benefitting from the simple vessel design minimising cost. The early versions employed a single catalyst bed with gas injection points at multiple locations down the vessel. These designs were susceptible to large temperature distributions developing and propagating down the vessel. A subsequent improvement on the design therefore collected the gas, mixed it with the incoming quench gas and distributed it across the next bed. This prevented temperature variations propagating from bed to bed. Many reactors of this design operate around the world today as ARC reactors, a joint ICI and Casale SA, Switzerland, design from the early 1990s. Figure 4 shows the reaction pathway of a quench converter, with successive additions of cold gas taking it back away from the equilibrium line to maximise conversion.Series adiabatic converters are more efficient users

of catalyst as, without the need for quench gas that bypasses the early beds, all the gas passes over all the catalyst and the temperature control for each bed is truly independent. Additional heat exchangers in

the loop contribute to higher capital costs and series adiabatic beds never really found favour in the industry.

Internally cooled reactors began with Lurgi GmbH, Germany, shortly after the first LPM plant from ICI. The Lurgi reactor was one that had already been used for many years in Fischer-Tropsch synthesis and consisted of catalyst-filled vertical tubes surrounded by a shell of boiling water, with the reaction heat transferred into the shell to generate steam to be used elsewhere in the process. A steam drum local to the converter provides a constant supply of water at boiling temperature through natural circulation. This design achieved a more even temperature distribution and lower peak temperature. Whilst the converter was more complicated than the ICI design, and therefore more expensive, the steam it generated at about 250ºC could be used elsewhere for an efficiency benefit or even exported. The design also required a lower catalyst volume. Figure 5 shows the reaction pathway in such a converter, following more closely the temperature for maximum reaction rate compared to quench converters. Many variations exist on this theme today, some with the catalyst and boiling water reversed, such as in the Variobar of Linde AG, Germany, which uses helical tubes in an axial catalyst bed to achieve pseudo-cross flow.

Other internally cooled converters use process gas on the cooling side, including ICI’s subsequent tube cooled converter, in which cold gas rises inside empty vertical tubes, absorbing heat from the surrounding catalyst bed before turning over at the top of the converter and

Met

hano

l, %

Low High

Temperature

Equilibrium line

Reaction path

Fig. 4. Reaction path in a quench converter



flowing back down through the catalyst bed. The large amount of heat generated by the synthesis reactions requires a high flow rate on the cooling side, which for gas-based cooling is typically only available within the synthesis loop, with different designs utilising gas from different parts of the loop.

Most modern converters use internal cooling, either with circulating gas or by raising steam, which broadly allows the temperature in the catalyst bed to track the

point of maximum reaction rate, a balance of the kinetic limitations of low temperature and the thermodynamic (equilibrium) limitations of high temperature.

Capacity Expansion

The basic formula was now set and so the plants could grow in size and scale. By the early 1970s the plants had gone from the 150 MTPD of the early low pressure plants to 1500 MTPD. The second plant ICI built at Billingham in 1972 had a design capacity of 1100 MTPD and used 110 m3 of catalyst (22) operating at 100 atm. This second plant operated through to 2001 and struck a better balance of operating pressure and equilibrium, with the vast majority of plants since having been designed for 80–100 atm. This heralded the start of the first golden age of methanol expansion in the early part of the 1970s as people recognised the benefits of the new LPM process. Figure 6 shows the approximate capacity added each year using LPM technology, with a notable peak in the 1970s and further peaks in the 1980s and around 2010 that will be explored in the second half of this history.

By the early 1980s all new plants were being constructed using low-pressure technology and almost all of the high-pressure plants had been converted to low pressure (23). Interestingly the pyrolysis of wood had not completely ceased as the use of ‘synthetic’ methanol had not yet been accepted as an alcohol denaturant in some countries. British Law to this day

Add

ed c

apac

ity, t

onne

s pe

r day

× 1

03

1960 1970 1980 1990 2000 2010 2020

Year

50

40

30

20

10

0

Fig. 6. Added global methanol capacity by year

Met

hano

l, %

Low High

Temperature

Reaction path

Equilibrium line

Fig. 5. Reaction path in a water cooled converter



(24) is based on the use of ‘wood naphtha’ to denature pure ethanol, a process whereby it is made unsuitable for human consumption and therefore exempt from beverage sales taxes. Wood naphtha is the mixture of substances derived from pyrolysis, primarily methyl alcohol (methanol).

The 1980s saw the impact of the second oil crisis that followed the Iranian Revolution in 1979 and the Iran-Iraq war that started soon after. The increased oil price meant that oil producing nations had significantly increased revenues and this allowed them to increase petrochemical production, including methanol. Thus began the second golden age of methanol expansion. But the oil crisis also prompted countries to start looking at how they could become less reliant on imported oil and to start looking at production of synthetic fuels.

Synthetic Fuels

The expansion of methanol is driven by demand for derivatives and a recurring theme throughout the history is its potential use as an intermediate in the production of synthetic automobile fuel. Whilst interest has peaked on a number of occasions, typically when a nation struggles with domestic supply, there have been few plants actually constructed. One example is the two methanol plants in Motunui, New Zealand, which were constructed for synthetic fuel production in 1985, using the Mobil licensed methanol to gasoline (MTG) process (25). Both plants now solely produce methanol and the MTG equipment has been removed. Whilst the production of a direct petrol replacement has never found lasting favour, many plants today are being constructed to feed methanol to olefins (MTO) processes to produce olefins from coal instead of from naphtha or ethane, and an increasing amount of methanol is blended into gasoline supplies around the world to meet legislative requirements.

Autothermal Reforming and Alternative Reforming

For a typical natural gas to methanol plant using steam reforming technology, roughly a half of the capital cost is in the steam reformer and it also accounts for a large part of the footprint. Available technology limited the maximum economic size of a single reformer and a new technology was therefore required to allow plant capacities to expand beyond about 2500 MTPD (26). This limit was first identified in the early 1970s when

methanol was being considered as a way to move energy around in the face of global imbalance. To produce sufficient quantities of methanol to achieve this, production capacity would need to increase rapidly with plants of up to 5000 MTPD, which would have required 2000 tube steam reformers. The largest constructed at that time had only 600 (27). The gap was ultimately filled with autothermal

reforming; the controlled introduction of oxygen into (partially) reformed gas to combust some of the hydrogen, providing the heat for further reforming reactions across another bed of catalyst. As the heat is produced and retained within the process, a lot of the equipment associated with reformers is not needed, although a supply of oxygen is required, typically from an air separation unit. The technology is deployed in various configurations:• parallel reforming – a steam reformer and

autothermal reformer (ATR) are used in parallel• combined reforming – the steam reformer is

partially bypassed and the bypass and reformed gas are combined and fed to the ATR to complete the reforming process.

A further development by ICI in the 1980s was to completely remove the traditional steam reformer in the Leading Concept Methanol (LCM) process. Rather than burning fuel gas to provide the heat for the reforming reactions, the hot, autothermally reformed gas was used to heat the catalyst tubes in a gas heated reformer (GHR). The feed gas first passes through the catalyst in the GHR, then the ATR and finally the heating side of the GHR to provide the heat for the initial reaction.

It is possible to take these concepts even further and some plants have only an ATR. Autothermal Reforming is susceptible to soot formation if significant quantities of higher hydrocarbons are present and so a simple adiabatic pre-reformer is required to de-rich the natural gas. This arrangement produces a gas very rich in carbon oxides and is therefore most effective where a source of additional hydrogen is present to balance the stoichiometry of the gas.

Typically, combined reforming gives a plant with a reasonably sized steam reformer, a low level of methane in the syngas and a stoichiometrically balanced syngas for methanol formation.

Modern Catalysts

The speed of catalyst development had greatly increased since the mid 1970s when testing equipment



began to be automated, greatly increasing the amount of test work that could be conducted. This led to a number of step changes in the performance of methanol synthesis catalysts, although the base recipe of copper with a combination of zinc and aluminium or chromium oxides remained very similar. One such step change was in the early 1990s, with a new generation of catalysts being introduced, just as capacities were ramping up and plant operators were looking to uprate their original low pressure plants (28). ICI introduced a new, more active catalyst using a four-component system, adding magnesium to the existing copper, zinc and aluminium (Figure 7).

Modern catalysts are expected to last at least three years and typically between four and six years is achieved, although six to eight years is not uncommon. The catalysts are highly selective towards methanol synthesis and the effects of some of the early catalyst candidates (iron and nickel) are better appreciated, especially their role in the formation of paraffinic hydrocarbons, and these are now seen as catalyst poisons. Despite the selectivity of modern catalysts being in excess of 99.5%, there is still a need to remove various impurities from the condensed product methanol to achieve either chemical or fuel sales grades. Generally, this is achieved at low pressure with one, two or three distillation columns in series. Dissolved gases are removed first, along with low boiling point byproducts and then the difficult methanol-ethanol separation must be conducted, along with water removal. The water can be reused in the steam system, the light ends as fuel and the ethanol (actually a mixture of many heavier organic compounds) can be

added back into the process before the reformer, to be reformed and reused.In 2004, the long destined capacity of 5000 MTPD

was achieved when the Atlas plant was commissioned in Trinidad, only for it to be overtaken the following year by M5000, also in Trinidad, producing up to 5400 MTPD. This latter plant achieved its capacity with only a steam reformer containing less than 1000 tubes, showing the simultaneous improvements in reforming catalyst and technology. Figure 8 shows the twin synthesis converters on M5000.

China – The Coal Story

A lot of the growth in the methanol industry through the early 21st century (the third golden age of methanol expansion) came from China and its booming economy. China’s petrochemical industry had been heavily dependent on imported crude oil, although China had plentiful supplies of cheap coal. China began to embrace new technologies for converting their coal into other chemicals and one key building block in that process was methanol. Rapidly increasing demand for a wide range of methanol derivatives, particularly olefins via the MTO process, has required a continuous supply of new methanol plants using coal gasification to provide the syngas for methanol synthesis.

To take advantage of the economies of scale, and in some cases to fit in with the economic size of a downstream MTO plant, the demand for higher and higher capacity synthesis loops has grown. With the methanol plants typically near to the coal in remote locations, the main process equipment must be

Fig. 8. 5000 MTPD of methanol synthesis capacity at M5000, Trinidad

Fig. 7. An example of the latest generation of methanol synthesis catalysts; Johnson Matthey KATALCOJM

TM 51-9S



transported to the sites by rail, where bridges in particular limit the maximum diameter and the infrastructure can limit the maximum weight. Whilst vessels can be made taller and taller, for catalyst beds this will soon result in very high pressure drops. For synthesis loops above about 3000 MTPD the catalyst requirement is too great to use a single vessel and multiple converters in a single loop are required. Initially and at modest capacities, two identical parallel converters were sufficient. As capacities continued to increase, so did the complexity, with multiple converters of different types used within single loops to reduce the capital cost of the loop equipment, as shown in Figure 9 with the Johnson Matthey Combi Loop. Other loops were designed using the Johnson Matthey Series Loop where product is recovered between converters to reset the equilibrium and increase production. The largest plants in operation by 2010 would typically have two or more converters to make up to 5500 MTPD of methanol. To minimise pressure drop and therefore compression duty in large synthesis loops, larger water cooled reactors are now available in radial flow configurations.

The second aspect of the growth in China is the coal to methanol story, which uses gasification technologies to convert coal and steam at very high temperature to

syngas. Modern purification systems now allow the syngas to be substantially cleaned of sulfur and other impurities and a very pure gas is fed to the synthesis loop, unlike the systems from the 1920s and 1930s. Typically, coal-fed plants give a much more carbon monoxide-rich syngas compared to steam reforming of natural gas, the more exothermic route to methanol and so the ability to remove heat is even more important.

Energy and Environmental Efficiency

Since the introduction of the low pressure process, the focus turned to energy efficiency, especially during increasing energy prices in the 1970s and 1980s. Table I shows the progression of efficiency over these years by ICI through successive improvements to the integration of the whole plant.

With the ever increasing focus on environmental performance, there are a number of designs and new plants in recent years which aim to set new standards for efficiency or emissions. One particular plant is Carbon Recycling International’s (CRI) George Olah Plant in Iceland, fully commissioned in 2012. Using electricity from the fully renewable Icelandic grid, it electrolyses water to provide hydrogen, which is

Axial steam-raising converter

Steam

Boiler feed water

Steam drum

Circulator

Purge

Separator

Crude methanol

Condenser

Interchanger

Feed

Tube cooled converter

Fig. 9. Modern synthesis loop – Johnson Matthey Combi Loop



combined with carbon dioxide recovered from a local geothermal power station (30).

Other new plants are considering the emissions benefits of avoiding a steam reformer and using the GHR technology to set new standards for low emission natural gas-based plants. The plans for Northwest Innovation Works (NWIW), USA, use the technology and will be among the largest plants in the world (31).

The Future

With the imminent start-up of the 7000 MTPD plant of Kaveh in Iran (32), the scale of plants continues to grow.

Methanol demand has grown steadily for many years fuelled by economic growth in major countries around the world, a trend which is likely to continue. Many of the current plant licensors and designers have flow sheets capable of scaling up to 10,000 MTPD, but after a number of purported projects, it remains to be seen if the economy of scale is ready to be stretched that far or if the security of multiple trains once again wins out.

At least for now, the production of methanol via the LPM process remains dominant, despite research interest into other themodynamically attractive routes. Recent examples based on the partial oxidation of methane to methanol include the work of Zhijun Zuo et al. (33) and Patrick Tomkins et al. (34). Whilst work such as this could open up a new, low temperature route to methanol, no such new routes have so far left the laboratory.

KATALCOTM is a trademark of the Johnson Matthey group of companies.

References 1. M. Berggren, ‘Global Methanol: Demand Grows

as Margins Atrophy’, 19th IMPCA Asian Methanol Conference, Singapore, 1st–3rd November, 2016

2. “Methanol Production and Use”, eds. W.-H. Cheng and H. H. Kung, Marcel Dekker, Inc, New York, USA, 1994, p. 2

3. P. Sabatier and J.-B. Senderens, Ann. Chim. Phys., 1905, 4, (8), 319

4. G. Patart, ‘Procédé de Production d’Alcools, d’Aldéhydes et d’Acides à Partir de Mélanges Gazeux Maintenus sous Pression et Soumis à l’Action d’Agents Catalytiques ou de l’Électricité’, French Patent Appl. 1922/540,543

5. J. B. C. Kershaw, ‘The World’s Future Supplies of Liquid Fuels’, The Engineer, 25th March, 1927, 316

6. A. Mittasch, M. Pier and K. Winkler, BASF AG, ‘Ausführung Organischer Katalysen’, German Patent 415,686; 1925

7. ‘1902–1924: The Haber-Bosch Process and the Era of Fertilizers’, BASF, Ludwigshafen, Germany: https:/ /www.basf.com/en/company/about-us/history/1902-1924.html (Accessed on 16th May 2017)

8. A. Mittasch, M. Pier and C. Müller, IG Farbenindustrie AG, ‘Manufacture of Oxygenated Organic Compounds’, US Patent Appl. 1931/1,791,568

9. A. Mittasch and M. Pier, BASF AG, ‘Synthetic Manufacture of Methanol’, US Patent Appl. 1926/1,569,775

10. BASF AG, ‘Improvements in the Manufacture of Methyl Alcohol and Other Oxygenated Organic Compounds’, British Patent Appl. 1925/231,285

11. A. Mittasch and C. Schneider, BASF AG, ‘Producing

Table I Improvements in Feed and Fuel Consumption (29)

Flow sheet Year Consumption,GJ MT–1

HP Pre-1966 42

LP – 50 atm 1966 36

LP – 100 atm 1972 36

BFW heating 1973 32.6

Optimisation 1975 32.2

Quench pre-heating 1977 31.4

Saturator 1978 30.1

Tube cooled converter 1983 29.3

LCM 1989 28.6



Compounds Containing Carbon and Hydrogen’, US Patent Appl. 1916/1,201,850

12. F. C. Reed, ‘Process of Producing Compounds Containing Carbon, Hydrogen, and Oxygen’, US Patent Appl. 1934/1,959,219

13. “The Methanol Industry Past, Present and Working Towards a Sustainable Future”, Johnson Matthey Process Technologies, online video clip, YouTubeGB, 29th November, 2016

14. E. Błasiak, ‘Sposób Wytwarzania Wysokoaktywnego Katalizatora do Syntezy Metanolu’, Polish Patent 34,000; 1947

15. C. Murkin and J. Brightling, Johnson Matthey Technol. Rev., 2016, 60, (4), 263

16. G. E. Haddeland, “Synthetic Methanol”, Report No. 43, Process Economics Program, Stanford Research Institute, California, USA, 1968, p. 4

17. P. Davies, F. F. Snowdon, G. W. Bridger, D. O. Hughes and P. W. Young, ICI Ltd, ‘Water-Gas Conversion and Catalysts Therefor’, British Patent Appl. 1965/1,010,871

18. J. T. Gallagher and J. M. Kidd, ICI Ltd, ‘Methanol Synthesis’, British Patent Appl. 1969/1,159,035

19. M. Appl, ‘Methanol-Born in 1923 and Still Going Strong’, World Methanol Conference, Frankfurt, Germany, 15th December, 1998

20. ‘Stormy Start Up’, Process & Catalyst News, Number 1, ICI, Agricultural Division, 1st January, 1971

21. K. Mansfield, Nitrogen, 1996, 221, 27

22. J. Brownless and E. Scott, ‘Experience of the No. 2 Methanol Plant Synthesis Converter at Billingham’, International Methanol Technology Operators Forum (IMTOF), London, UK, September, 1991

23. G. E. Haddeland, “Synthetic Methanol”, Report No. 43B, Process Economics Program, Stanford Research

Institute, California, USA, 1968, 146 pp

24. ‘The Denatured Alcohol Regulations 2005’, 2005 No. 1524, The Stationery Office Limited, London, UK, 8th June, 2005

25. J. Ross, “Heterogeneous Catalysis: Fundamentals and Applications”, 1st Edn., Elsevier BV, Amsterdam, The Netherlands, 2012, p. 188

26. K. Aasberg-Petersen, C. S. Nielsen, I. Dybkjær and J. Perregaard, “Large Scale Methanol Production from Natural Gas”, Haldor Topsøe, Lyngby, Denmark, 2008

27. B. M. Blythe and R. W. Sampson, Am. Chem. Soc., Div. Fuel Chem., Prepr., 1973, 18, (3), 84

28. T. J. Fitzpatrick, ‘New Developments in Methanol Synthesis Catalysts and Technology’, International Methanol Technology Operators Forum (IMTOF), London, UK, 15th–16th June, 1993

29. K. Mansfield, ‘ICI Katalco and Methanol, Past, Present and Future’, International Methanol Technology Operators Forum (IMTOF), San Francisco, USA, 19th–22nd June, 1995

30. ‘World’s Largest CO2 Methanol Plant’, Carbon Recycling International, Kopavogur, Iceland, 14th February, 2016

31. ‘NWIW Adopts Pioneering Technology to Substantially Reduce Facility Emissions’, Johnson Matthey Process Technologies, Royston, UK, 6th August, 2015

32. ‘World’s Largest Methanol Plant to be Commissioned in Iran’, Chemicals Technology, News, London, UK, 27th February, 2015

33. Z. Zuo, P. J. Ramírez, S. D. Senanayake, P. Liu and J. A. Rodriguez, J. Am. Chem. Soc., 2016, 138, (42), 13810

34. P. Tomkins, A. Mansouri, S. E. Bozbag, F. Krumeich, M. B. Park, E. M. C. Alayon, M. Ranocchiari and J. A. van Bokhoven, Angew. Chem. Int. Ed., 2016, 55, (18), 5467

The Author

Daniel Sheldon is a Senior Process Engineer at Johnson Matthey, Chilton, UK. He obtained his MEng (Hons) in chemical engineering from the University of Manchester, UK. He joined Johnson Matthey on the graduate training scheme in 2011 and has spent time in catalyst manufacturing and technology development for the ammonia and methanol industries. Currently he provides technical support to Key Methanol Customers. He is a Chartered Member of the Institute of Chemical Engineers (IChemE).




One Hundred Years of Gauze InnovationPlatinum gauzes for nitric acid manufacture celebrate a centenary

By Hannah Frankland*, Chris Brown, Helen Goddin, Oliver Kay and Torsten BünnagelJohnson Matthey Plc, Orchard Road, Royston, Hertfordshire, SG8 5HE, UK

*Email: [email protected]

In the century since the first platinum gauze for nitric acid production was made by Johnson Matthey, the demand for nitric acid has increased considerably with its vast number of applications: from fertiliser production to mining explosives and gold extraction. Throughout the significant changes in the industry over the past 100 years, there has been continual development in Johnson Matthey’s gauze technology to meet the changing needs of customers: improving efficiency, increasing campaign length, reducing metal losses and reducing harmful nitrous oxide emissions. This article reviews the progress in gauze development over the past century and looks at recent developments.

Introduction

Johnson Matthey Plc recently celebrated a centenary since making its first platinum gauze pack (Figure 1), sold to the UK Munitions Invention Department in October 1916 for £25 to make nitric acid for explosives during the First World War. The two 4″ × 6″ (approximately 101 × 152 mm) woven gauzes were made with 0.065 mm diameter wire, woven in a square mesh with 80 meshes per linear inch.

In the 1930s small amounts of rhodium began to be included in the gauzes to prevent losses of platinum while increasing the strength and conversion efficiency.

Palladium catchment gauzes were introduced in the 1960s for platinum recovery, offering economic benefits. These were initially palladium-gold, but as the price of gold increased it was replaced by nickel.

1996 saw the invention of knitted gauzes (Figures 2 to 4), which allowed a diverse range of structures and alloys to be used in the gauze packs, giving a better metal distribution and contact area. This considerably improved conversion efficiency and overall plant performance while also reducing manufacturing time compared to woven gauzes. This technology, pioneered by Johnson Matthey, became the industry standard.

A few years later gauze packs were developed with Johnson Matthey’s proprietary Advanced Coating

Fig. 1. Johnson Matthey’s first woven gauze



Technology (ACTTM), reducing the time required to reach maximum production. Later in 2006 the company partnered with Yara International ASA, Norway, to supply its abatement catalyst to minimise harmful nitrous oxide emissions released during nitric acid production.

Gauze Development

In the same year, the catalyst and catchment were combined for the first time through Eco-CatTM systems. This combines platinum group metal (pgm) with complex ternary alloys and knit structures. Compared to conventional gauze alloys, it uses palladium in a controlled manner to replace some of the platinum, exploiting its metal recovery properties to catch platinum that is lost from the gauze during ammonia oxidation. This system has shown an increased

Fig. 2. (a) The structure of a knitted gauze; (b) a gauze knitting machine

(a) (b)

Fig. 3. HICON corrugated gauze

Fig. 4. Installation of a gauze pack at a customer plant supplied by Paite, Johnson Matthey’s Chinese licensee



performance compared to standard catalyst packs, and (subject to plant operating parameters) offers nitric acid manufacturers benefits including: extended campaign lengths by 50–100%; maintained or improved average conversion efficiency; a reduction in installed pgm weight by 40–50%; a reduction in installed platinum weight by 30–40%; reduced metal losses by approximately 30–50%; and reduced nitrous oxide emissions.

The improved performance of Eco-CatTM technology compared to standard gauze packs is demonstrated in Table I, showing the increase in campaign length and nitric acid production when using an Eco-CatTM system in a medium pressure plant.

Case Study: Reducing the Cost of Nitric Acid Production

Recently, Johnson Matthey worked with one customer to create a tailored Eco-CatTM system to solve its three main requirements: increasing average conversion efficiency, reducing the installed pgm content of the gauze packs and reducing metal losses. A progressive approach was taken to customising the gauze pack for the customer’s specific plant conditions using in-depth analytical data.

Detailed examination of gauze samples from the first installed Eco-CatTM system uncovered an operational issue related to the plant design that was impacting the gas flow over the catalyst. Upon measuring

the relative gas flow variations in the burner, it was found to be higher in certain areas. This was causing faster depletion of the gauze in these regions and therefore resulting in more platinum movement, while also adversely affecting the ammonia conversion efficiency.

The solution drew upon a vast range of gauze structures and their mechanical properties, addressing the regional flow issues in the burner while also considering one of the customer’s key requirements of reducing the installed pgm content. As a result, the customer noticed an improvement in the conversion efficiency.

Analysis from previous campaigns along with the producer’s data allowed the design of the catalyst to be improved through tailored wire diameters and knit structures. This optimised the reaction zone while also further reducing the installed pgm content.

As shown in Figures 5–7, the customised Eco-CatTM system contributed to a substantial reduction in the producer’s costs per tonne of nitric acid.

Faster Light Off

A key goal for most nitric acid producers is to reduce the time required to reach peak conversion efficiency. In-house laboratory research into how peak efficiency is reached has found that platinum is volatilised during normal operation and forms cauliflower-like structures on the wire, which increases catalytic surface area. ACTTM allows a thin layer of platinum to be sprayed

Table I Nitric Acid Campaign Results using a Standard Johnson Matthey Gauze Pack and Two Developments of Eco-CatTM Technology

Standard gauze Eco-CatTM system (Campaign 1)

Eco-CatTM system (Campaign 2)

Campaign length, days ~100 ~175 ~210

100% HNO3 produced, kilotonnes equivalent ~85 ~135 ~160

Total mass of installed platinum, kg ~50 ~40 ~40

Total mass of installed rhodium, kg ~3 ~2 ~2

Total mass of installed palladium, kg 0 ~10 ~15



Eco-cat version 1 Eco-cat version 2 Eco-cat version 3Eco-cat version 4 Eco-cat version 5

Total pgm per annum, kg Installed metal value per annum, €100,000

250

200

150

100

50

0

216 198

205

182

174

67.8 59.2 61.2 54.4

48.8

Fig. 5. The pgm content and value in developments of Eco-CatTM packs

Fig. 6. The pgm losses in developments of Eco-CatTM packs


80

70

60

50

40

30

20

10

0 Net loss Pt, mg tonne–1 Net loss Rh, mg tonne–1 Net loss Pd, mg tonne–1

60 61 52

45

33

6 5 6 5 4

70 65

70 72 75

Fig. 7. Overall costs and cost per tonne of acid in various developments of Eco-CatTM packs. (Overall cost = manufacturing cost + metal handling charge + refining assay + net metal loss)


Overall cost per annum, Cost per tonne acid, € €millions

6

5

4

3

2

1

0

1.4 1.35 1.3 1.19 1.11

4.92 4.53

4.38

4.02

3.72

onto the surface of selected gauze layers to improve the gauze pack’s activation, resulting in faster light-off (Figure 8).

This technology has been shown to improve the early performance of the gauze packs in several plants when used in the top layers, but Johnson Matthey has recently been investigating how ACTTM coatings can further improve light-off and conversion efficiency.

Using the company’s in-house ammonia oxidation facilities, data on light-off, selectivity and long-term performance have been analysed to improve the design of the gauze pack. Initial trials of ACTTM coated gauzes in two different knit structures (Nitro-LokTM gauze and Hi-LokTM gauze) both showed a 45% reduction in light-off temperature compared to the uncoated gauze (Figure 9).



Fundamental to the design improvement is understanding how the gauze changes with time. Scanning electron microscopy (SEM) has shown the ACTTM coating forming a series of discrete islands on the gauze, each of which locally increases the surface area and becomes a focus point for light-off (Figure 10). Inspection of the samples from the trials has also shown the ACTTM coating restructuring (Figure 11) much earlier than expected; a change to the ACTTM

coating placement or weight has the potential to make a significant improvement on the time taken to reach peak conversion efficiency.

This increased understanding of the mechanisms behind the coating and how this reduces the time to reach peak conversion efficiency has exciting implications for nitric acid plants, allowing the position and weight of the ACTTM coating to be tailored to minimise costs for producers.

Process Modelling

Along with catalyst, catchment and abatement solutions that Johnson Matthey supplies to the nitric acid industry, complex models of the reaction system can be provided using its fundamental chemical and physical properties alongside proprietary data. Through this knowledge and modelling of the burner, more information can be found on the selectivity of ammonia conversion, in particular the extent and type of reaction.

The complex model of the burner has been built from extensive experience of gauze design along with known process conditions using spent gauze analysis,

Fig. 8. ACTTM machine

Ligh

t-off

tem

pera

ture

, ºC

Nitro-LokTM gauze ACTTM coated Hi-LokTM gauze ACTTM coated Nitro-LokTM gauze Hi-LokTM gauze

Fig. 9. Graph demonstrating a reduction in light-off temperature with ACTTM coatings

Fig. 10. Scanning electron microscopy (SEM) images of the ACTTM coated gauze

(a) (b)

57.5 mm76 mm



test rig data and historical plant data. This provides an in-depth understanding of how gauzes change over time and how this impacts the overall conversion efficiency. It can also help to identify where efficiency losses may be occurring; once this is found different sensitivities can be investigated to optimise the process, resulting in maximum plant conversion efficiency. Compared to a process model that is theoretically derived, this model provides more accurate and valid data through the dynamic kinetic model of the burner.

The detailed kinetic model allows predictions to be made for the optimal knit structures and alloy compositions for a campaign, for example looking at the gauze restructuring which is closely linked to the catalyst performance, where an increase in active surface area can improve the conversion efficiency. The model can also relate specific plant conditions to metal losses, which can reduce costs for the producer and again improve conversion efficiency of the burner. Any findings from the model can then be compared to experimental observations from gauze analysis.

This robust gauze model overcomes difficulties producers have historically faced in directly measuring

conversion efficiency and selectivity, where high gas temperatures and testing conditions of the sampling point make it challenging to obtain a representative gas sample over the gauzes. This makes it an extremely useful tool in optimising the overall plant operation.

Present Day

100 years after making the first gauze catalyst, Johnson Matthey now offers a full service package for nitric acid manufacturers: catalyst, catchment, N2O abatement and containment engineering, technical analysis, plant cleaning to recover metal through a partnership with R S Bruce Metals and Machinery Ltd, UK, and process simulation through a partnership with ProSim SA, France. The latest additions to these services are absorption tower scanning through Tracerco and water treatment for cooling and process water through MIOX®, both part of the Johnson Matthey group.

ACTTM, Eco-CatTM, Nitro-LokTM, Hi-LokTM and MIOX® are trademarks of Johnson Matthey Plc, UK.

Fig. 11. SEM images of the ACTTM coating: (a) before and (b) after restructuring

2 mm 2 mm

(a) (b)

The Authors

Hannah Frankland joined Johnson Matthey as Marketing Specialist for the Noble Metals business unit in 2015 after previously working for the Royal Society of Chemistry, Cambridge, UK, where she was primarily involved in membership communications. With a Chemistry degree from the University of Bath, UK, she enjoys combining her technical knowledge with her passion for marketing.



Christopher Brown originally joined Johnson Matthey in 2001 as a Materials Scientist in the Noble Metals technology group after graduating from the University of Nottingham, UK. After moving into sales and marketing in 2004, Chris has worked in technical sales roles, primarily in the Nitro Technologies sector which has combined his passion for business, people and travel.

Helen Goddin is the Research Group Leader for Nitro Technologies, leading developments in ammonia oxidation products. Prior to joining Johnson Matthey two years ago, she worked at TWI, leading research projects on materials development and joining processes. She has a PhD in High Temperature Electronic Materials, from the University of Cambridge, UK.

Oliver Kay joined Johnson Matthey in 2015, from the University of Leeds, UK, where he read Chemical Engineering. Oliver is part of the Graduate Programme, originally based in Noble Metals, where he was involved in developing a service offering for the nitric acid business. Now Oliver is based in Maastricht, The Netherlands, working for Advanced Glass Technologies, where he has a varied role, ranging from New Business Development to Operational Excellence projects.

Dr Torsten W. Bünnagel began his career with Johnson Matthey in 2011 in the Technical Sales Team of Noble Metals, Royston, UK, advising nitric acid, caprolactam and hydrogen cyanide businesses around the globe on new developments in the areas of catalytic ammonia oxidation and N2O abatement systems. In his current role as Sales Manager – Organometallics, Dr Bünnagel is commercialising novel materials utilised in various advanced chemical processes and technical applications. Prior to Johnson Matthey, he developed OLEDs for lighting applications and consumer electronics for Sumitomo Chemicals Company, Japan. He earned a Diploma Degree in Chemistry at the University of Wuppertal, Germany, and completed a PhD in Macromolecular Chemistry in the area of Organic Electronics in 2008.




Osmium vs. ‘Ptène’: The Naming of the Densest MetalThe early name ‘ptène’ is attributed to French chemists Fourcroy and Vauquelin

By Rolf Haubrichs and Pierre-Léonard Zaffalon*CristalTech Sàrl, Rue du Pré-Bouvier 7, 1217 Meyrin, Switzerland


This paper reviews the use and relation of the word ‘ptène’ to osmium. While Smithson Tennant discovered osmium in platinum ore in 1804, the French chemists Antoine-François Fourcroy and Nicolas-Louis Vauquelin simultaneously identified in a platinum residue a metal they called ‘ptène’. This name was most probably attributed to a mixture of platinoids (excluding platinum), mainly osmium and iridium. Nevertheless, Fourcroy later considered that ‘ptène’ was the name they attributed to osmium.

Introduction

In a paper celebrating the bicentenary of the discovery of osmium and iridium, the name ‘ptene’ or ‘ptène’ was reported as an early synonym for osmium. No origin for this name could be found except the references cited by the historians of science James Riddick Partington (1886–1965) and John Albert Newton-Friend (1881–1966) (1–3). Both authors were contradictory on the origin of the word ‘ptène’ and it could not be determined whether the author was Smithson Tennant (1761–1815), the British discoverer of osmium, or one of the French chemists Antoine-François Fourcroy

(1755–1809), Nicolas-Louis Vauquelin (1763–1829) and Hippolyte-Victor Collet-Descotils (1773–1815), as they were all involved in the study of platinum ore in the 1800s. In an earlier paper, the same author had concluded that Tennant was first inclined to call the new element ‘ptène’ instead of osmium (4).

In fact, we can confirm the later statement of Jaime Wisniak that the origin of ‘ptène’ was French (5).

A New Metal in Platinum Ore: ‘Ptène’

The origin of the early research on platinoids was the partnership between Smithson Tennant (1761–1815) and William Hyde Wollaston (1766–1828), two alumni of Cambridge University, UK, to isolate any valuable substance from platinum ore. Wollaston was in charge of the soluble part in aqua regia while Tennant took care of the black residue. Wealthier than his friend, Tennant probably provided the money for the first purchase of nearly 6000 ounces of platinum ore and from 1800 they started their research separately (at Tennant’s death in 1815, the amount of platinum they had purchased totaled 47,000 ounces. A major supplier of Wollaston was John Johnson, a commercial assayer in London and the father of Percival Johnson, co-founder of Johnson Matthey Plc) (6–8).

On 21st June, 1804, Tennant read a paper to the Royal Society on the experiments he performed during the summer of 1803 on a platinum ore from New Granada (now known as Colombia) (7). In his paper, he announced the discovery, isolation and naming of two new chemical elements: iridium and osmium, the latter



because of the “pungent and peculiar smell […] [of its] very volatile metallic oxide” (osmium tetroxide (OsO4)) (9). Across the Channel, an extract of Tennant’s paper was translated in the Bibliothèque Britannique published in Geneva, Switzerland, and partially reprinted in the Annales de Chimie on 22nd October, 1804 (10).

Meanwhile, Fourcroy and Vauquelin were repeating experiments by the young Collet-Descotils who claimed to have isolated a new element from the black residue of platinum after its treatment with aqua regia (11–14). Tennant himself was aware of these experiments and cited them in his 1804 paper (9).

The main interest of the French chemists was to isolate palladium. In April 1803 a strange notice circulated in the English gazettes that a new metal isolated from platinum ore was sold under the name of palladium by a merchant named Mr Foster in London. Wollaston resorted to this kind of subterfuge to establish his priority on the first isolation of palladium while keeping his process secret until he had completed his research on platinum melting (Wollaston was later involved in the preparation and sale of platinum hardware). Unfortunately the new metal was not recognised because a well-known analytical chemist, Richard Chenevix (1774–1830), considered it as a mixture of mercury and platinum (15, 16). This conclusion intrigued the scientific community and several famous chemists, including Vauquelin and Fourcroy, started analysing platinum (11–14).

The first results of the three French chemists were read at the Institut National (Class of sciences, mathematics and physics) on 26th September and 10th October, 1803 (11–14). Collet-Descotils, a student of Fourcroy and Vauquelin, described a product with iridium-related properties (11).

On 13th February, 1804, Fourcroy and Vauquelin presented their whole research in a second dissertation where they concluded on this newly discovered element:

“we will not decide yet ... on the naming of this metallic body so different from those of the same type” (“nous ne nous prononcerons encore … sur le nom qu’il faudra imposer à ce corps métallique si différent de tous ceux du même genre”) (17).

In a second set of publications on the same subject, Fourcroy mentioned:

“the platinum ore imported from Peru contains at least nine different substances; namely quartz and iron-bearing sand, iron, sulfur likely

combined in metallic sulfides, copper, titanium, chromium, gold, platinum and a new metal” (“le platine brut apporté en grains du Pérou, contient au moins neuf substances différentes; savoir, du sable quartzeux et ferrugineux, du fer, du soufre vraisemblablement combiné en sulfures métalliques, du cuivre, du titane, du chrôme, de l’or, du platine et un métal nouveau”) (18).

A second note was added in the next volume where different reactions on this new metal were reported without naming it and the presence of osmium in the insoluble residue was noted by Fourcroy who reported a “pungent, spicy astringent” smell (“âcre, piquante comme styptique”) (an indication of OsO4) (19).

Although Collet-Descotils repeated Wollaston’s experiments, no further paper was published by the French chemists in 1805 (20, 21). However, in the fourth volume of the Encyclopédie Méthodique, Fourcroy compiled and defined chemical terms and under the item ‘Docimasie’, we can read:

“We did not speak about either the colombium discovered by Mr Hatchette nor tantalum found recently by Mr Ekheberg nor ptene nor cerium newly announced by Messrs Hisenger & Berzelius because their ores are still too uncommon”(“On n’a point parlé ici du colombium découvert par M. Hatchette, ni du tantale trouvé dernièrement par M. Ekheberg, ni enfin du ptène, ni du cérium annoncé tout récemment par MM. Hisenger & Berzelius, parce que leurs mines sont encore trop rares”) (22).

In the same volume, three ‘ptène’ derivatives were presented as possible compounds: the “ptene malate” (“malate de ptène”), “ptene gallate” (“gallate de ptène”) and “ptene fluoride” (“fluate de ptène”) (22). However, they were still unknown because nobody had isolated ‘ptène’ “in a state of purity and very abundantly” (“à l’état de pureté & assez abondamment”) (22). The only definition available in 1805 for ‘ptène’ was settled as “metal combined with platinum” (“métal qui accompagne le platine”) (22). A more elaborated definition was expected in the next volume but it never appeared (23).

On 17th March, 1806, Fourcroy finally recognised the presence of four new elements in platinum (in addition to osmium and iridium, there were also palladium and rhodium). He admitted that the metal they named ‘ptène’ was constituted of two distinct elements (although he also considered that the name ‘ptène’ was attributed



to osmium) (24). A note was added to remember the contribution of Collet-Descotils (25). (This note contains a mistake: the paper of Collet-Descotils it refers to was printed in the 7th issue. The 5th and the 6th issues were wrongly written in the title and the content of the note.)

“In a first report of my work on platinum [...] we announced [...] the existence of a new metal firstly named ptene and later osmium and iridium in the black powder that resists the action of nitro-muriatic acid [aqua regia] […] osmium is very volatile, very easily oxidised. We were the first to discover this singular and very different metal in summer 1803 [...] Mr Tennant found and distinguished it only a few months after us because he mentioned in his dissertation the first Mémoire we had published in the Annales de Chimie. We had proposed ptene as a name for this metal but we willingly accept the denomination of osmium which seems preferable to us”(“Dans un premier extrait de mon travail sur le platine […] nous avons annoncé […] l’existence d’un métal nouveau nommé d’abord ptène et depuis osmium et iridium dans la poudre noire qui résiste à l’action de l’acide nitro-muriatique [aqua regia] […] L’osmium […] est très volatil, très oxydable. Nous avons découvert, les premiers, dans l’été 1803, ce métal singulier et très-différent […] M. Tennant ne l’a trouvé et distingué que quelques mois après nous, parce qu’il cite dans sa dissertation le premier Mémoire que nous avions publié dans les Annales de Chimie. Nous avions proposé d’appeler ce métal ptène; mais nous adoptons volontiers la dénomination d’osmium qui nous paraît préférable”) (24).

This naming history was summarised two years later in the Encyclopédie Méthodique where Fourcroy wrote an article on osmium:

“From its last characteristic [the pungent smell of OsO4] Mr Tennant proposed the name of osmium from the Greek osmè, smell. We had already discovered these features and we had proposed the name of ptene for which the name osmium, which we prefer, was substituted”(“c’est de cette dernière propriété que M. Tennant a tiré le nom d’osmium, du mot grec osmè, odeur. Nous avions déjà découvert ces caractères, & nous en avions tiré le nom de ptène, auquel celui d’osmium, que nous préférons, a été substitué”) (23).

None of the references from the Encyclopédie Méthodique (in 1805 and 1808) refer to a possible paper on the naming of ‘ptène’ (22, 23). What should we understand? We believe that between 21st June, 1804, and 17th March, 1806, the French chemists were uncertain of the platinum chemistry and they did not want to publish anything until their results were definitive. A possible source of delay to confirm Tennant’s results was the difficulty in obtaining platinum for their experiments (7).

A first account of splitting ‘ptène’ into two distinct elements (osmium and iridium) had been suggested by Jean-André-Henri Lucas (1780–1825) in his book “Tableau méthodique des espèces minérales” (1806) whose acceptance for publication dated back to 13th November, 1805 (26). A similar observation was done in Joseph Capuron’s work (27). The distinction between the platinoids was not clear to everyone: a publication in the Journal de Physique (January 1806) presented rhodium and iridium as ‘ptène’ (28). A possible explanation for this mistake may be due to a correction in the third edition of the Philosophie Chimique (1806) of Fourcroy where ‘ptène’ was mentioned with platinum (29).

The story of ‘ptène’ was later revived by Jöns Jacob Berzelius (1779–1848) during his research on osmium in 1828. The history of the discovery of platinoids was summarised as follows:

“The ancient chemists associated every metal contained in platiniferous sand, except gold, with platinum until Collet-Descotils discovered two new substances; a blue sublimate … and a red substance colouring the ammoniac muriate of platinum which he attributed to an unknown metal. While Collet-Descotils was still involved in his research, Fourcroy and Vauquelin, aware of it, started their own experiments and discovered several properties of this new metal they named ptene. Like Collet-Descotils they confounded under this name every metal associated with platinum. Soon afterwards Wollaston discovered palladium and then rhodium … Tennant taking care of the fraction of platinum insoluble in aqua regia found iridium and osmium at about the same period”(“Les anciens chimistes prenaient tous les métaux contenus dans le sable platinifère, excepté l’or, pour du platine, jusqu’au moment où Collet-Descotils fit connaître deux substances nouvelles; un sublimé bleu … et la matière



colorant en rouge le muriate ammoniacal de platine, qu’il attribua à la présence d’un métal nouveau auquel il ne donna aucun nom particulier. Pendant que Collet-Descotils était encore occupé à ses expériences, Fourcroy et Vauquelin, instruits de ses expériences, commencèrent des recherches semblables, et découvrirent plusieurs propriétés de ce nouveau métal, qu’ils nommèrent ptène; mais ils confondirent, comme Collet-Descotils, sous ce nom tous les métaux inconnus qui accompagnent le platine. Wollaston découvrit peu de temps après le palladium, et plus tard le rhodium … Tennant, en s’occupant de la partie de platine insoluble dans l’eau régale, trouva presqu’en même temps l’iridium et l’osmium”) (30).

W. A. Smeaton adopted the same conclusions as Berzelius: in their 1803 and 1804 memoirs, the French chemists reported the characteristics of iridium ammonium salts and OsO4 (maybe rhodium derivatives too) but failed to isolate a metal from the residue of platinum ore (31). The precise description of the pungent smell of OsO4 by Fourcroy and Vauquelin led them to consider that the name ‘ptène’ was mainly attributed to osmium (23–25).

On the etymology of osmium or ‘ptène’, neither Tennant nor Fourcroy and Vauquelin were clear on a Greek origin in their first publications (9, 24). Tennant only mentioned a connection with smell:

“… as this smell is one of the most distinguishing character, I should on that account incline to call the metal osmium.” (9)

In 1808, Fourcroy and Klaproth separately mentioned the Greek origin of osmium (osmè: smell) and of ‘ptène’ (ptènos: winged) (23, 32).

History of the Element Symbols

The story was not finished. None of the English, French or Swedish scientists discovered the last element of the platinum group, ruthenium (Ru). It was only in 1844 that Carl Claus (1796–1864) isolated this metal and the aging but world-respected Berzelius validated his discovery (33, 34). This discovery had an impact on rhodium: it changed its chemical symbol from R to Rh.

In 1813, Berzelius, inspired by the “System of Chemistry” of Thomas Thomson (1773–1852), had decided to give a chemical sign to each atom:

“I shall take, therefore, for the chemical sign, the initial letter of the Latin name of each elementary substance: but as several have the same initial letter, I shall distinguish them in the following manner: 1. In the class which I call metalloids, I shall employ the initial letter only, even when this letter is common to the metalloid and to some metal. 2. In the class of metals, I shall distinguish those that have the same initials with another metal, or a metalloid, by writing the first two letters of the word. 3. If the first two letters be common to the two metals, I shall, in that case, add to the initial letter the first consonant which they have not in common: for example, S = sulfur, Si = silicium, St = stibium (antimony), Sn = stannum (tin), C = carbonicum, Co = Cobaltum (cobalt), Cu = cuprum (copper), O = oxygen, Os = osmium, &” (35).

A general survey of the Berzelian symbolism can be found in the literature (36) and the influence of Thomson on Berzelius has been reported (37).

In the system of Berzelius, iridium and rhodium had respectively the symbols I and R because there were no other metals starting with the letter I or R (38). Things changed with the discoveries of iodine in 1811 (39) and ruthenium in 1844 (40).

Since iodine was a metalloid according to Berzelius, it had the priority for the initial letter only. The modification could be read in his work ‘Essai sur la Théorie des Proportions Chimiques et sur l’Influence Chimique de l’Electricité’ of 1819. While the symbol for iridium is still I in the main text, the table at the end of the book was correct: I stands for iodicum (iodine in Latin) and Ir for iridium (41).

Concerning ruthenium and rhodium, Claus followed the rules of Berzelius when he correctly wrote the new symbols Ru and Rh (40, 42).

Conclusion

To conclude, one may say that osmium and iridium were definitely discovered by Smithson Tennant during the summer of 1803 (6–8). The team of French chemists unfortunately did not achieve the separation of iridium and osmium although they described the properties of salts or oxides from both elements. Fourcroy and Vauquelin honestly attributed the discovery to Tennant and no controversies occurred. The name ‘ptène’ was attributed to a mixture of osmium and iridium which joined the list of the “lost elements” recorded by Fontani



et al. (43). See also the website of Peter van der Krogt on the periodic table (44).

Osmium still remains particular because of the strong smell of its volatile oxide but one often forgets its distinctive blue colour (Figure 1). In 1814, Vauquelin wrote:

“As to its colour, if we can judge from certain evidence, I believe that it is blue”(“Quant à la couleur, si l’on peut en juger sur quelques apparences, je crois qu’elle est bleue”) (45).

Acknowledgments

The authors thank Jacques Falquet and Francine Chopard for critical proofreading.

References 1. W. P. Griffith, Platinum Metals Rev., 2004, 48, (4), 182

2. J. R. Partington, “A History of Chemistry”, Vol. 3, Macmillan & Co Ltd, London, UK, 1962, p. 105

3. J. N. Friend, “Man and the Chemical Elements: From Stone-Age Hearth to the Cyclotron”, Charles Griffin & Company Ltd, London, UK, 1951, p. 354

4. W. P. Griffith, Q. Rev. Chem. Soc., 1965, 19, (3), 254

5. J. Wisniak, Indian J. Chem. Technol., 2005, 12, (5), 601

6. D. McDonald, Platinum Metals Rev., 1961, 5, (4), 146

7. D. McDonald and L. B. Hunt, “A History of Platinum and its Allied Metals”, Johnson Matthey, London, UK, 1982, 450 pp

8. M. C. Usselman, “Pure Intelligence: The Life of William Hyde Wollaston”, The University of Chicago Press, Chicago, USA, 2015, 424 pp

9. S. Tennant, Phil. Trans. R. Soc. Lond., 1804, 94, 411

10. S. Tennant, Ann. Chim., 1804, 52, 47

11. H. V. Collet-Descotils, Ann. Chim., 1803, 48, 153

12. A. F. Fourcroy and N. L. Vauquelin, Ann. Chim., 1803, 48, 177



15. M. C. Usselman, Ann. Sci., 1978, 35, (6), 551

16. N. L. Vauquelin, Ann. Chim., 1803, 46, 333


18. A. F. Fourcroy, Ann. Mus. Hist. Nat., 1804, 3, 149

19. A. F. Fourcroy, Ann. Mus. Hist. Nat., 1804, 4, 77

20. H. V. Collet Descotils, J. des Mines, 1805, 18, (105), 185

21. J. L. Howe and H. C. Holz, “Bibliography of the Metals of the Platinum Group 1748-1917”, Bulletin 694, US Geological Survey, Washington, USA, 1919, 558 pp

22. A. F. Fourcroy, “Encyclopédie Méthodique: Chimie et Métallurgie”, Vol. 4, H. Agasse, Paris, France, 1805

23. A. F. Fourcroy, “Encyclopédie Méthodique: Chimie et Métallurgie”, Vol. 5, H. Agasse, Paris, France, 1808

24. A. F. Fourcroy and N. L. Vauquelin, Ann. Mus. Hist. Nat., 1806, 7, 401

25. A. F. Fourcroy and N. L. Vauquelin, Ann. Mus. Hist. Nat., 1806, 8, 248

26. J. A. H. Lucas, “Tableau Méthodique des Espèces Minérales: Première Partie”, D’Hautel, Paris, France, 1806

27. J. Capuron, “Nouveau Dictionnaire de Médecine, de Chirurgie, de Physique, de Chimie et d’Histoire Naturelle”, J. A. Brosson, Paris, France, 1806

28. J. C. Delamétherie, J. Phys. Chim. Hist. Nat., 1806, 62, 32

29. A. F. Fourcroy, “Philosophie Chimique ou Vérités Fondamentales de la Chimie Moderne”, 3rd Edn., Tourneisen Fils, Paris, France, 1806

30. J. A. C. Berzelius, Kongl. Vet. Acad. Handl., 1828, 16, 25; translated into French in Ann. Chim. Phys., 1829, 40, 52

Fig. 1. Blue-grey crystals of osmium (Courtesy of CristalTech Sàrl, Switzerland)



31. W. A. Smeaton, Platinum Metals Rev., 1963, 7, (3), 106

32. M. H. Klaproth and F. Wolff, “Chemisches Wörterbuch”, Vol. 3, Voss, Berlin, Germany, 1808

33. C. Claus, Gorn. Zh., 1845, (7), 157

34. G. B. Kauffman, J. L. Marshall and V. R. Marshall, Chem. Educator, 2014, 19, 106

35. J. Berzelius, Ann. Philos., 1814, 3, 51

36. M. P. Crosland, “Historical Studies in the Language of Chemistry”, Dover Publications, New York, USA, 2004, 448 pp

37. J. R. Partington, J. Chem. Technol. Biotechnol., 1936, 55, (40), 759

38. J. Berzelius, Ann. Philos., 1814, 3, 244

39. M. B. Courtois, Ann. Chim., 1813, 88, 304

40. C. Claus, Bull. Cl. Phys.-Math., 1845, 3, (20), 311

41. J. J. Berzelius, “Essai sur la Théorie des Proportions Chimiques et sur l’Influence Chimique de l’Electricité”, Méquignon-Marvis, Paris, 1819

42. C. Claus, Justus Liebigs Ann. Chem., 1846, 59, (2), 234

43. M. Fontani, M. Costa and M. V. Orna, “The Lost Elements: The Periodic Table’s Shadow Side”, Oxford University Press, New York, USA, 2015, 576 pp

44. P. van der Krogt, “Names That Did Not Make It”, Elementymology & Elements Multidict, The Netherlands, 2010

45. N. L. Vauquelin, Ann. Chim., 1814, 89, 225

The Authors

Rolf Haubrichs is a chemist and co-founder of CristalTech Sàrl, Switzerland, a young start-up involved in the crystallisation of platinum group metals.

Pierre-Léonard Zaffalon received his PhD in bioorganic chemistry from the University of Geneva, Switzerland, in 2012. In 2014, he joined CristalTech Sàrl.




The ‘Nano-to-Nano’ Effect Applied to Organic Synthesis in WaterA remarkable opportunity to use not only water as the reaction medium but very little surfactant and catalyst containing only ppm levels of metal under mild conditions

Bruce H. LipshutzDepartment of Chemistry & Biochemistry, University of California, Santa Barbara, CA 93106, USA


The remarkable benefits associated with the attraction of polyethylene glycol (PEG)-containing nanomicelles to metal nanoparticles in water allows for varying types of important catalysis to be done under very mild and green conditions.

1. Introduction

Aqueous micellar catalysis is far from new (1, 2). Indeed, although a wealth of information on this topic has been accumulated over many decades (3, 4), an appreciation of the potential for this chemistry to replace organic solvents as the reaction medium in many of the most commonly used reactions in catalysis has only recently been advanced (5–8). The explanations behind this surprising state of affairs may lie in the lack of training received in this area and the normal mindset among synthetic organic chemists that the presence of water in a reaction, in other than selected cases (for example hydrolysis), is to be avoided. Hence, its use as the entire reaction medium is rarely a consideration. Simply put, organic chemistry takes place in organic solvents and so why ‘complicate’ an already challenging science?

The short answer is that times have changed and as environmental and human health issues continue to come into focus, so must our attention take note that the chemistry enterprise is creating huge amounts of organic waste, the most egregious component of which is organic solvents (9). Getting them out of organic chemistry should be a goal that chemists strive to achieve, as the way this field is currently practiced is just not sustainable. How can it be that there is not a single key reaction parameter associated with the way catalysis is done today that overlaps with the manner in which nature continues to practice organic chemistry (Figure 1)? Fortunately, there is already strong evidence indicating that by redesigning surfactants for synthetic chemistry (5–8), these form nanomicelles that enable homogeneous catalysis to be efficiently applied to the very same reactions valued by synthetic chemists, but with one major difference: they are done under environmentally responsible conditions.

The two leading nonionic designer surfactants forming micellar arrays in water that accommodate many differing reaction partners, catalysts and additives are DL-α-tocopherol methoxypolyethylene glycol succinate (TPGS-750-M) (10) and β-sitosterol methoxyethyleneglycol succinate (SPGS-550-M) also known as ‘Nok’ (11) (Figure 2). Both form nanomicelles that, unlike the majority of surfactants typically found in catalogues frequented by the synthetic community, are of the ‘right’ size or shape leading to bond formations that are usually as good or better than those observed in organic media. But what had originally not been fully



appreciated is that the methoxy polyethylene glycol (MPEG) (or polyethylene glycol (PEG), in general) present in these 40–60 nm spheres of TPGS-750-M or rods of Nok has a natural tendency to function as a stabilising ligand around metal nanoparticles (NPs) (12, 13) that are also present as catalysts in the water. In other words, generation of metal nanoparticles as catalysts attract the MPEG-containing micelles, which is tantamount to an internal delivery system of the reaction partners housed within the micelles

to the catalyst. This ‘nano-to-nano’ effect offers a remarkable opportunity to use not only water as the reaction medium, but very little surfactant and catalyst containing only ppm levels of metal, and to do such heterogeneous catalysis under atypically very mild conditions (between 22ºC and 45ºC).

That this phenomenon is not only happening but also likely to be responsible for the facile catalysis observed is clear from cryo-transmission electron microscopy (cryo-TEM) analyses. These data show an unequivocal

Solvent/medium Reaction temperature Catalyst

Organic Organic Heating/ 1–5 mol%chemistry solvents cooling (10,000–50,000 ppm)

Nature Water Ambient Trace metalsOverlap: none!

Fig. 1. Extent of overlap as practiced by nature vs. modern organic chemistry: none

Fig. 2. Designer surfactants leading to nanomicelles that participate in ‘nano-to-nano’ effect

TPGS-750-M

Nok

Racemic vitamin E

β-sitosterol

O

O

O

O

PEG portion

H H

HH

O

O

O

Substrates housed inside

Each forms nanomicelles with (M)PEG portion

on outside

(M)PEG portions on outside of micelles

deliver nanomicelles to catalyst

NP catalyst

‘Nano-to-nano’

+

O O17

O O13



preponderance of nanomicelles aggregated around metal NPs, whereas in the absence of such NPs an otherwise even distribution of micelles in the surrounding water is seen. While such an association does not prove that the observed catalysis is taking place as proposed, it does document the ‘nano-to-nano’ effect that localises the high concentration of substrate within the micelle directly at the catalyst surface, potentially accounting for the lack of energy (in the form of heat) needed to enhance interactions in these heterogeneous mixtures that otherwise might be needed in organic solvents where no such formal delivery mechanism exists.

2. The ‘Nano-to-Nano’ Effect: Palladium, Nickel and Copper Nanoparticles 2.1 Palladium

The first observation came unexpectedly when Pd NPs were generated from the combination of palladium acetate (Pd(OAc)2) and sodium borohydride (NaBH4) in aqueous TPGS-750-M at room temperature (14). The resulting heterogeneous aqueous mixture could be used to great advantage, converting a variety of unsymmetrically disubstituted alkynes to the corresponding Z-alkenes, typically with >99:1 Z:E selectivity (Figure 3). Part of the success observed in these net Lindlar-like reductions is the facility with which the reaction mixture could be recycled, including the water, the surfactant therein, and the Pd catalyst. Thus, an ‘in-flask’ extraction with an ethereal solvent (for example methyl tert-butyl ether (MTBE)) afforded the product, leaving behind all other ingredients ready for

introduction of the same or an alternative educt, along with fresh reductant. The overall reliance on organic solvents, therefore, was shown to be at least an order of magnitude lower than amounts often required with similar reactions in the literature (15). Moreover, these differences are to be realised prior to recycling of the aqueous mixtures.

A similar ‘nano-to-nano’ effect was seen with new NPs derived from the reduction of iron(III) chloride (FeCl3), where either the naturally occurring content of Pd within FeCl3 or by externally doping with Pd(OAc)2 at the ppm level sufficed to arrive at active catalysts useful for important cross-couplings (Figure 4) (16). That is, given the threshold presence of ca. 350 ppm Pd, NP formation upon treatment of the mixture (i.e., FeCl3 + 350 ppm Pd) with methylmagnesium chloride (MeMgCl) in tetrahydrofuran (THF) at ambient temperatures affords the desired NP catalysts. When prepared in the presence of SPhos, the resulting NPs mediate Suzuki-Miyaura couplings in aqueous nanomicelles between room temperature and 45ºC. Extensive analyses of this isolable powder, including a cryo-TEM experiment conducted on the reaction medium (TPGS-750-M + water) again confirmed the aggregation of nanomicelles together with the solid iron nanoparticles containing ppm levels of palladium (here designated Fe/ppm Pd NPs).

This newly developed NP platform, consisting of mostly Mg, Cl and THF, with Fe accounting for only ca. 2.5% of the mix, can be altered as a function of the ligand added prior to their preparation. Changing the recipe from inclusion of SPhos to XPhos now allows for efficient ‘nano-to-nano’ catalysis of Sonogashira

Lindlar-like reductions using Pd NPs: alkynes to Z-alkenes:

= NPs

in aqueous TPGS-750-MPreparation: Pd(OAc)2 + NaBH4 OTHP

OH

NH2

BnO

90%, 95:5 Z:E

98%, >99:1 Z:E

99%, >99:1 Z:E

91%, >99:1 Z:E

OHOBn

TBSO

OAc

Fig. 3. Representative Lindlar-like reductions of alkynes to Z-olefins (14)



couplings in the same recyclable aqueous mixtures (Figure 5) (17). Recycling is smoothly orchestrated using very limited amounts of a single and recyclable, organic solvent for 'in flask' extraction.

These NPs derived from FeCl3 can also be prepared in the absence of any ligand, otherwise required for Pd-catalysed cross-couplings. In this case, the ‘nano-to-nano’ effect can be used to effect reductions of aromatic and heteroaromatic nitro groups in water at room temperature (18, 19). The stoichiometric reductant is NaBH4, although as recently updated at Novartis in Basel, Switzerland, the addition of potassium chloride (KCl) or the use of fresh potassium borohydride (KBH4) appears to be the hydride source of choice (20). Only 80 ppm of palladium (as Pd(OAc)2) is required for these NP reductions, again implicating a palladium hydride species (Figure 6). The mild reaction conditions account for the tolerance of many functional

groups. Importantly, use of hydrogen gas in place of a borohydride is totally incompatible with this catalyst and in fact, is detrimental to the overall reduction.

2.2 Nickel

Notwithstanding the reported success of the catalyst (Fe/ppm Pd NPs + BH4

–) applied to nitro group reductions (above) (18, 19), doping of this NP platform with metals other than Pd offers either additional benefits to existing processes, or potentially new opportunities to lower both base and precious metal usage to ppm levels. Part of the incentive to further investigate along these lines is that the amount of residual metal(s) in the desired products has been found to be below tolerance levels as established by the US Food and Drug Administration (FDA). That is, going into these reactions with ppm amounts of transition metal catalysts, rather than the more typical 1–5 mol% range (10,000–50,000 ppm),

Suzuki-Miyaura cross-couplings with Fe/ppm Pd NPs

= NPs

Preparation:FeCl3 + 350 ppm Pd(OAc)2

+ SPhos + MeMgCl in THF

O OO

HN

Cy

N

N

O

Me

F N MeNHN

NN

Boc

26 h, 85% 16 h, 90% 20 h, RT, 94%

O

28 h, 86%

Ar-Br + Ar'-B(OH)2Fe/ppm Pd NPs

aq. TPGS-750-MK3PO4, RT–45ºC

Ar-Ar'

Fig. 4. Fe/ppm Pd NPs that enable Suzuki-Miyaura couplings in aqueous TPGS-750-M NPs based on the ‘nano-to-nano’ effect (16)

93%CF3

F3COTBS

98%

CHO

O

95%

N

Ph TMS

89%

Fig. 5. Fe/ppm Pd NPs used for Sonogashira couplings in aqueous TPGS-750-M (17)



leads to acceptable ppm levels of metal impurities that obviate additional time and cost for their removal, a very common occurrence under traditional conditions in organic solvents. In work soon to appear (21), doping these Fe-based NPs with additional ppm levels of a Ni(II) salt affords a reagent that has been found, likewise, to efficiently reduce nitro group-containing aromatic or heteroaromatic compounds, but often at a far greater rate under otherwise identical conditions of concentration, time and temperature. Figure 7 shows a few comparison cases.

2.3 Copper

Another metal used extensively in organic chemistry is copper and hence, doping the iron nanoparticles with ppm levels with a Cu salt, rather than Pd or Ni (Fe/ppm Cu NPs) might form a potentially useful

reagent, presumably benefiting from the same ‘nano-to-nano’ effect. Indeed, related NPs are formed using Cu(I) admixed with the same FeCl3, followed by standard treatment with MeMgCl in THF (vide supra). Akin to observations with other NPs in this series, the catalyst can be generated and used in situ or isolated for use at a later date. The first type of catalysis examined has been click chemistry between a terminal alkyne and an azide; when performed in aqueous TPGS-750-M at room temperature, cycloadditions to the anticipated triazoles take place quite readily (22). In addition to representative examples shown in Figure 8, products formed upon recycling of the aqueous reaction mixture are suggestive that the catalyst does not lose its activity when handled under an inert atmosphere to prevent autoxidation to the otherwise inactive Cu(II) form.

3. Summary

Micellar catalysis has been made highly effective by virtue of newly engineered nanoreactors in water, offering the synthetic community an environmentally responsible alternative to waste-generating organic solvents as reaction media. The green attributes of this approach to synthesis, however, go well beyond this simple solvent switch. In fact, metal NP catalysts present in such aqueous solutions populated by MPEG-containing nonionic surfactants TPGS-750-M and Nok are active under very mild conditions due to this ‘nano-to-nano’ effect, a phenomenon not found in traditional organic solvents. Applications of metal NPs that can be formed containing either base (for example Ni or Cu) or precious (for example Pd) metals to important reaction types, such as reductions and

RNO2

RNH2

NaBH4

nano-Fe/ppm Pd‘nano-to-nano’

Fig. 6. Ligandless Fe/ppm Pd NPs applied to nitro group reductions (18–20)

NN

O

NO2

Original Fe/ppm Pd NPs 8 h, 90% 12 h, 72% 2 h, 94%

F3C

MeS

NO2

ClCF3

NO2

NO2ArFe/ppm Ni NPs

TPGS-750-M, H2O, RTAr–NH2

New Ni-doped NPs 8 h, 88% 2 h, 88% 30 min, 98%

Fig. 7. Faster reductions with new NPs doped with Ni (21)



cross-couplings, have been demonstrated. Future developments involving other precious metals, such as rhodium and iridium, seem ripe for investigation, furthering the appeal of this new green chemistry.

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15. R. A. Sheldon, Green Chem., 2017, 19, (1), 18 and references therein

16. S. Handa, Y. Wang, F. Gallou and B. H. Lipshutz, Science, 2015, 349, (6252), 1087

17. S. Handa, Y. Wang, F. Gallou and B. H. Lipshutz, manuscript in preparation

18. J. Feng, S. Handa, F. Gallou and B. H. Lipshutz, Angew. Chem., 2016, 128, (31), 9125

19. M. Orlandi, D. Brenna, R. Harms, S. Jost and M. Benaglia, Org. Process Res. Dev., 2016, just accepted manuscript

20. C. M. Gabriel, M. Parmentier, C. Riegert, M. Lanz, S. Handa, B. H. Lipshutz and F. Gallou, Org. Process Res. Dev., 2017, 21, (2), 247

21. H. Pang and B. H. Lipshutz, manuscript in preparation

22. A. Adenot, E. B. Landstrom, F. Gallou and B. H. Lipshutz, Green Chem., 2017, 19, (11), 2506

F

PhNN

N

NN

N

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Cl

Bn

NN

N

R

R’

R + R’-N3Fe/ppm Cu nanoparticles

2 wt% TPGS-750-M, H2O, RTbase

90% 88% 93%

Fig. 8. Representative examples of Fe/ppm Cu NPs applied to click chemistry



The Author

Bruce Lipshutz spent four years at Yale University, USA, (1973–1977) as a graduate student with Harry Wasserman. After a two-year postdoctoral stint with E. J. Corey at Harvard University, USA, as part of the team involved with the total synthesis of the antitumour agent maytansine, he began his academic career at the University of California, Santa Barbara, USA, in 1979, where today he continues as Professor of Chemistry. His programme in synthesis focuses on new reagents and methodologies, mainly in the area of organometallic chemistry. While these contributions tended to fall within the area of ‘traditional’ organic synthesis, more recently his group has shifted in large measure towards the development of new technologies in green chemistry, with the specific goal being to get organic solvents out of organic reactions. To accomplish this, the Lipshutz group has introduced the concept of ‘designer’ surfactants that enable key transition metal-catalysed cross-couplings, and many other reactions, to be carried out in water at room temperature. Most recently, his group has turned its attention to developing new catalysts for key Pd- and Au-catalysed reactions that involve bond formations requiring only parts per million levels of metal, each being conducted in water under very mild conditions. The potential for his group’s work in this field to significantly influence, and in time transform the way in which organic chemistry is practiced in the future, led to a Presidential Green Chemistry Challenge Award in 2011.




“Sustainability Calling: Underpinning Technologies” Pierre Massotte and Patrick Corsi, Innovation, Entrepreneurship and Management Series, ISTE Ltd, London, UK, and John Wiley & Sons, Inc, Hoboken, USA, 2015, 407 pages, ISBN: 978-1-84821-842-0, £104.00, US$130.00, €124.80

Reviewed by Niyati Shukla Johnson Matthey, Orchard Road, Royston, Hertfordshire, SG8 5HE, UK


Massimo PeruffoJohnson Matthey, Lydiard Fields, Great Western Way, Swindon, SN5 8AT, UK


Introduction“Sustainability Calling” is focused on the definition of new paradigms to define a new concept of sustainability. Pierre Massotte has worked for IBM in Quality Assurance and then Advanced Technologies. He spent several years in IBM’s research and development laboratories in the USA, then became Scientific Director in EMEA Manufacturing to improve the competitiveness of IBM’s European manufacturing plants and Development Laboratories. He joined the École des Mines d’Alès, France, as Deputy Director. His research and development topics are related to complexity, self-organisation and issues of business competitiveness and sustainability in global companies. He is the co-author of several books in production systems management. He is now involved, as senior consultant, in various ‘inclusive society’ projects. The second author Patrick Corsi is an international consultant based in Brussels, Belgium, and an Associate Practitioner in intensive innovation at

the Centre de Gestion Scientifique at Mines ParisTech in France. Previously, he had an extensive career with IBM Corporation and the European Commission as well as successful start-up experience in artificial intelligence.

In this book are outlined a set of key concepts and models to support a new notion of sustainability that takes into account the ever increasing complexity of today’s world. Sustainability has been primarily focused on environmental issues, however the authors expand the concept to society, economics, politics, welfare, innovation, competiveness and everyday life (Figure 1). A novel formalism is necessary to redefine this new concept of sustainability and the authors bring the notion of transformative research to apply models already used in different scientific fields to the concept of sustainability.

Resilience and Sustainability

In Part 1, resilience and sustainability are proposed as the main drivers for innovation at a global scale. In Chapter 1 the authors introduce the concepts of scale and time in nature and the law of correspondence. Any system can be divided into levels or subsystems, for example macromolecules, cells, tissues, organs, organism, population, communities and finally biosphere. Each of the subsystems can interact and influence all the others, and the authors propose that to take into account such complexity metamodelling is required. Examples of metamodels are: cross-cutting that focuses on the interactions between lower and upper levels; and the ‘one level method’ in which



generalisations must be applied to create models applicable to each subsystem.

Chapter 2 asks whether globalisation is really new. This chapter characterises globalisation and explains some of its features. It evaluates how big paradigm changes, or disasters, impact human behaviour, influencing our mind and thoughts, conscience and modes of governance. The authors explain that globalisation is similar to economic evolution and any phenomenon in globalisation is always associated with the emergence of spontaneous orders, whose unexpected consequences are far beyond what could be imagined by looking at historical events. They put forward their argument from a geographical point of view and present a map of the trading posts in ancient Rome, as well as describing the economic rise of developing

countries like China, Russia, India, Korea, Indonesia and South Africa. They say that such phenomena are necessary for the evolution of humanity. As soon as a big disturbance occurs in a society, globalisation implies three main factors in the current context and biosphere: the impact of events on human beings; risk management under unpredictable conditions and uncertainties; and modes of governance. The example is given of an earthquake hitting Haiti in January 2010 and how the country showed changes in governance and management levels and achieved extraordinary outcomes. The chapter also classifies the tools and methods used in industries: anticipation and prediction and concludes that cooperation, emergence and self-organisation are three particularly important concepts of the science of complexity.

Sustainable engineeringconvergence theory

Artificial lifecollective thinking &consciousness

Global networks& web sciences

Fractal & chaostheory behaviourstructure

Self-organisationemergenceevolution

Agent Bsd &cellular automata

Nonlineardynamic systemstheory (NLDS)

ComplexitysciencesClt and Meast

AIConnexionismcognitivism

Cybernecticsinformationtheory

Systemstheory

Mathematics &statisticsComputer sciences

Managementbiology, life,psychology &social ecology

Fig. 1. A global and advanced vision for gathering and linking together the different theories and technologies for solving production or sustainability problems (Copyright John Wiley & Sons, Inc)



Chapter 3 unveils the notion of disturbance in the decision-making process and in nature in general. The authors introduce three notions: asymmetry, Coriolis and chirality that have previously been formalised only for physical systems but are applied here in the context of sustainability. Asymmetry is a strong driver in the decision-making process. In a company all the interactions between different entities that bring a disparity of information can lead to an asymmetry of the parts and can lead to the wrong decision; however most of the decisions taken are mostly determined by external pressure. For example political and emotional pressures have a strong effect during the decision process and they are difficult to take into account in a model. Similarly Coriolis forces influence the movement of fluids on the earth’s surface, however to model the effect of the Coriolis forces the model has to use an inertial frame of reference that is not needed when the system under investigation is of a smaller scale. In this chapter the utilisation of fractal theory to model complex systems is proposed, however a simplification similar to the ‘one level method’ has to be made.

Chapter 4 studies aspects of issues raised by project managers related to information, information systems and decision-making, linking the contexts of time, quantum fluctuation and entropy. It first focuses on the concepts of time and space, and then moves to the perception of space and impacts related to these, different antagonisms, time reversibility and entropy to better understand the future challenges humanity will face. The authors explain that the perception of situation involves sensorial organs, the mind, ideas, feelings and time. However perception of time is different for people and perception of event duration is different depending on context. It is also explained that perception of time and space changes as new developments in technology arise. The chapter concludes by saying that failures and crises are not the result of lack of time or the presence of time-irreversible problems, but the result of either lack of skills or societal evolution.

The Notion of Competitiveness

Part 2 revisits the notion of competiveness that in the industrial and financial system is often reduced to profitability. The authors point out that decisions based only on profitability can compromise long-term planning. More examples of transformative research are presented: DNA mutations are presented as

disturbances which increase the survival likelihood of a species by flexibility, however if the mutation rate increases over a threshold dictated by the birth rate the survival rate will be negatively affected. Similarly, disturbances in a competitive world can increase the survival of a business. In a global scale the aging, death and survival of businesses finds correspondence to a biological ecosystem, a quick interchange of individuals and species can increase the survival rate of the ecosystem, while in a business ecosystem it can promote innovation.

In Chapter 9 the authors explain people’s reactions to new emerging technology and how its benefits and weaknesses surface after varying lengths of time. The internet is used as an example: it is an unstable and interactive system that makes communicating and exchanging information very easy, even governments have favoured the emergence of this system although they cannot control it. The chapter highlights that applications such as Snapchat (Snap Inc, USA) and Confide (Confide Inc, USA) can restrain the resilience of information. The notion of temporary data is interesting for the future because it avoids malicious people using confidential or private data against others. It also protects email or social communication in the organisation. The authors conclude that using this concept of social networking on the internet leads to scaling and organisation network problems whereas using the ‘transient web’ can lead to obtaining a sustainable system.

The next chapter is a reminder about the complexity of systems and presents the basic principles required to understand system complexity. Examples are given of biomedical and metabolic pathways in a cell and the Krebs cycle is used to explain the complexity of the system. The chapter also details some advances applicable to the evolution of networks which are relevant to so-called ‘network theory’. In the chapter, a network is considered a complex system and the concept of sustainability is applied to the growth of networks and how their capabilities change over time.

Chapter 11 looks at issues raised by the project managers at the Project Management Institute (PMI). According to the authors, the only current way to measure the sustainability of a system is to measure the ‘entropy generation’ of the system. In the chapter, issues related to information, information systems and decision-making are linked to notions of time, quantum fluctuation and entropy. It is proposed that networking



and self-organisation are contributing factors for reducing entropy generation.

The final chapter is about defining certain terms used throughout the book, like ‘consciousness’. The authors say that “Pre-cognition, self-recognition, reflection, understanding and planning some meanings and actions are fully linked with consciousness”. The chapter discusses the law of accelerating returns, telepathy and telesympathy and differentiates the concepts of telepathy and telesympathy. Two applications are detailed to understand their impact on system sustainability: how to implement sustainable communications; and metadesign of a collaborative development platform.

Conclusions

The book is an interesting source of new concepts to redefine sustainability and how to use it in the decision-making process. The authors give an overview of the complexity of today’s world and provide new ideas and tools to help tackle this complexity. While the book can be of interest to a wide public, a wide range of notions are covered and further details to understand the profound interconnections between all the different concepts are presented in previous publications by Massotte (1–3).

Overall, the book is likely to be interesting for professionals working within industry who wish to maintain the sustainability of their organisations in a changing world. It explains complex systems associated with sustainability and answers questions raised by professionals. For people interested in the subject, the book will provide in-depth knowledge of sustainability on a global level.

References

1. M. Aupetit, P. Couturier and P. Massotte, ‘Function Approximation with Continuous Self-Organizing Maps using Neighbouring Influence Interpolation’, International ICSC Symposium on Neural Computation (NC’2000), Berlin, Germany, 23rd–26th May, 2000, “Proceedings of the Second ICSC Symposium on Neural Computation”, eds. H. Bothe and R. Rojas, ICSC Academic Press, Canada, Switzerland, 2000, p. 247

2. P. Massotte and P. Corsi, “Operationalizing Sustainability”, ISTE Ltd, London, UK, and John Wiley & Sons, Inc, New Jersey, USA, 2015, 438 pp

3. P. Massotte, ‘How Social Innovation is Shaking Business Foundations’, Paris Innovation Review, 13th June, 2013

“Sustainability Calling: Underpinning Technologies”

The Reviewers

Niyati Shukla is a Quality Control Laboratory Technician at Johnson Matthey at Royston, UK. She joined Johnson Matthey in 2015 and her work focuses on analysing samples using a range of techniques and making sure that they meet the customer’s specification.

Massimo Peruffo joined Johnson Matthey in 2015. He is currently a Senior Scientist, Quality Control and Characterisation Laboratory Manager in fuel cells. The main focus of his research is to define and develop new characterisation tools to support the technology department.




Highlights of the Impacts of Green and Sustainable Chemistry on Industry, Academia and Society in the USAImpacts of green and sustainable chemistry on US industries, analysis of green chemistry resources available in academia (higher education) within the USA, and a perspective on the role of green chemistry in US society over the past ten years

Anne Marteel-Parrish*Department of Chemistry, Washington College, Chestertown, MD 21620, USA


Karli M. Newcity**Department of Chemistry, Washington College, Chestertown, MD 21620, USA

**Email: [email protected]

Trends such as population growth, climate change, urbanisation, resource scarcity, conservation of energy and water, and reduction of waste and toxicity have led to the development of sustainable practices in industry, education and society. The desire to improve ways of living, the need for performance materials, and the urgency to close the gap between developed and emerging nations have propelled creative and innovative solutions based on green and sustainable chemistry to the forefront. This article provides an overview of the main impacts of green chemistry on industry, academia and society in the USA in the past ten years, as well as a summary of the drivers and barriers associated with the adoption of green

chemistry practices. It also describes how researchers, policy makers, educators, investors and industries can work together to “build innovative solutions that transform and strengthen the chemical enterprise” (1)

while addressing environmental and social challenges. The goal of this article is to understand why green chemistry is still primarily viewed as Joel Tickner, Director of Green Chemistry and Commerce Council (GC3), University of Massachusetts, Lowell, USA, puts it: as “an environmental activity rather than one that, as experience shows, yields economic benefit, and it has yet to be integrated into the fabric of the chemical enterprise, educational systems, or government programs” (1).

1. Historical Perspective: Paving the Way to Green Chemistry

The practice of green chemistry began in 1990 when the creation of the Pollution Prevention Act was seen as the USA’s initiative to become directly involved in pollution prevention at the source (2). In 1995, former President Bill Clinton introduced the Presidential Green Chemistry Challenge Awards based on five (later changed to six) award categories: Greener Synthetic Pathways, Greener Reaction Conditions, the Design of Greener Chemicals, Small Business, Academic,



and a new category created in 2015 based on a specific environmental benefit: Climate Change (for the reduction of greenhouse gas emissions). These awards are used as a marketing tool to communicate how green chemistry’s contributions have impacted the world.

In 1998, John Warner and Paul Anastas published the book “Green Chemistry: Theory and Practice” providing tools, resources and applications of the 12 Principles of Green Chemistry (3). In 2001, the Green Chemistry Institute decided to join forces with the American Chemical Society (ACS) to become advocates of a more sustainable environment. In 2009, President Obama appointed Paul Anastas to the leadership of the US Environmental Protection Agency (EPA)’s Office of Research and Development. Anastas resigned from this position and chose to pursue his career at the Center for Green Chemistry at Yale University in 2012.

Following the 12 Principles of Green Chemistry provides a way to approach environmental challenges. The 12 Principles of Green Chemistry cover the topics of: pollution prevention; atom economy; less hazardous chemical synthesis; design of safer chemicals; the use of safer solvents and auxiliaries; design for energy efficiency; use of renewable feedstocks; reduction of derivatives; catalysis; design for degradation; real-time analysis for pollution prevention; and inherently safer chemistry for accident prevention, as mentioned in “Green Chemistry: Theory and Practice” (3). The philosophy of green chemistry is to produce substances in a way that does not harm the environment, health and society. A wise way to introduce green chemistry to future generations is to define it from a sustainable development point of view (4).

The concept of sustainable development began during the 1970s when the post-war environmental movement highlighted negative effects such as the direct impacts of pollution on the environment and health. In 1987, the desire to address sustainable development at a global scale became important to the United Nations. Through the Brundtland Commission, sustainable development was defined in the commission’s report entitled ‘Our Common Future’ (5). This report encouraged individuals to become aware of the environmental and social issues. It was influential in discovering new approaches to protect future generations. In 1992, the United Nations Conference on Environment and Development, known as the ‘Earth Summit’ or the ‘Rio Convention’, was held by the United Nations in Rio de

Janeiro, Brazil. Its focus was for the world to commit to a more sustainable development.

In 2002 the World Summit on Sustainable Development (WSSD) in Johannesburg, South Africa, led to a commitment to reduce global greenhouse gas emissions and to a suggestion that all governments around the world become unified in taking action towards sustainable development (5).

More recently it was devised by W. Cecil Steward, the President and CEO of the Joslyn Institute for Sustainable Communities, Lincoln, Nebraska, USA, to represent sustainable development using five domains of sustainability, which include the original three domains (environmental, economic and socio-cultural) and the domains of technology and public policy (Figure 1) (6).

The first domain, environmental sustainability, is based on assuming that the present environmental processes provide a way to keep society as stable as possible based on ideal-seeking behaviour. This domain relies on making the public aware of the limited amount of natural resources. Knowledge of the existence of renewable resources is another crucial tool that the human race must acquire to continue to thrive (6).

Properly harnessing and utilising the earth’s natural resources is a key goal involving economic sustainability. The term ‘economic’ from a business

Environmental

Public policy

Economic Technological

Socio-cultural

Sustainable communities

Fig. 1. Five domains of sustainable development (6). ECOStep: The Five Domains of Sustainability is a concept of W. Cecil Steward, FAIA, © 2017 Joslyn Institute for Sustainable Communities



standpoint takes into account the value of resources (7). Ideally compatibility should emerge between improving the utilisation of natural resources more efficiently and making a profit from the end products. These strategies are defined as economic sustainability, which facilitates responsible usage of natural and manmade resources with no or minimal negative impact on the world. Observing sustainability from an economic perspective allows businesses to capitalise on the positive effects of change within society.

The socio-cultural domain pictures the necessity for a viable and sustainable future due to continued world population growth. Rising consumption levels undesirably impact environmental sustainability. In order to improve the standard of living, implementing strategies to educate society is vital to the foundation of a more sustainable future.

Technological advances have a direct impact on policymaking. Governments use policies to regulate industries and ensure their practices are not detrimental to the environment (6). As a society, implementing fit-for-purpose policies is vital to becoming sustainable.

When these five domains are considered in a harmonious way, the development of a society, a business or a nation willing to take steps towards a more sustainable future should be achieved. These domains provide an ideal platform as to how to structure a sustainable environment. Examples on how these domains have been exploited to impact industry, academia and society in the USA over the past ten years are detailed in the next section. The limitations on an article of this size mean that it focuses on the reduction or elimination of pollution and environmental toxics and on finding ways to reduce the consumption of nonrenewable resources, although this is only one of many areas where green chemistry can have an impact. Additionally, the geographical scope is also specific to the USA due to the limited length of this review.

2. Overview of the Impacts of Green and Sustainable Chemistry Initiatives2.1 In US Industries

Before green chemistry became “a framework to do chemistry” (8), the US Congress passed the Emergency Planning and Community Right-to-Know Act (EPCRA) in 1986, which aimed “to support and promote emergency planning and to provide the public with information about releases of toxic chemicals in their community” (9). One of the outcomes of EPCRA

was the establishment of the Toxics Release Inventory (TRI), which:

“tracks the management of certain toxic chemicals that may pose a threat to human health and the environment. U.S. facilities in different industry sectors must report annually how much of each chemical is released to the environment and/or managed through recycling, energy recovery and treatment”.

(A “release” of a chemical means that it is emitted to the air or water, or placed in some type of land disposal).

As mentioned in the 2015 TRI National Analysis, 21,849 facilities reported to TRI that they managed 27.2 billion pounds (12.2 million tonnes) of toxic chemicals related to production-related wastes through recycling, combustion for energy recovery, treatment or disposal (10). As shown in Figure 2, quantities of toxic chemicals released decreased while quantities of recycled toxic waste increased. As stated in the 2015 TRI National Analysis, “87% of toxic chemical waste managed was not released into the environment due to the use of preferred waste management practices such as recycling, energy recovery, and treatment”.

The 2015 TRI National Analysis also highlights the total quantities of TRI chemicals disposed of or otherwise released by industrial sector (Figure 3).

About 3.4 billion pounds (1.5 million tonnes) of toxic chemicals were released, mostly by three sectors: metal mining (37%), chemical manufacturing (15%) and electrical companies (13%). Unfortunately the chemical manufacturing sector is among the leading sectors in both production-related waste managed (49%) as well as total releases (15%).

Throughout the development of the concept of green chemistry over the past 25 years, there have been many considerations on how green chemistry can help minimise toxic waste production and therefore prevent pollution. One way to manage and control toxic waste production is to continuously enforce a set of rules and regulations in order to keep our society and environment safe. These rules require many businesses and corporations to follow strict guidelines in order to meet environmental safety requirements that include “waste handling, treatment, control, and disposal processes” (11). However, these approaches are a costly factor for many businesses and corporations. Companies spend about $1.00 per pound (approximately 0.45 kg) to manage waste (8), which is a direct cost to the business. The major challenge faced by both industries and societies is to expand technological advances in



order to achieve more sustainable ways to improve the economy and the environment. As Paul Anastas defines it:

“we wanted to begin a shift away from regulation and mandated reduction of industrial emissions, toward the active prevention of pollution through the innovative design of production technologies themselves. And we placed an emphasis on both the environmental and economic value, because we knew the concept would not be viable otherwise.” (8)

The adoption of green chemistry principles could be seen as a wise means to reduce costs. The businesses and corporations that have implemented green chemistry within their design and manufacturing of chemical products and processes have seen major results on lowered environmental costs and increased sales and revenues. Examples of success stories on how some of the main chemical-based industries have benefited from the adoption of green chemistry principles are highlighted below. The examples given here are based on selecting some of the most

Fig. 2. Production-related waste managed by facilities reporting to TRI over 2005–2015 (10). US EPA’s 2015 TRI National Analysis

30000

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All others: 10%

Food: 4%

Paper: 5%

Hazardous waste management: 6%

Primary metals: 10%

Electric utilities: 13%Chemicals: 15%

Metal mining: 37%

Fig. 3. Total disposal or releases by industrial sector in the USA in 2015: 3.36 billion pounds (1.5 million tonnes) (10). US EPA’s 2015 TRI National Analysis



recent winners of the Presidential Green Chemistry and Engineering Challenge Awards, selecting a variety of industrial sectors where a green chemistry alternative was successful, and ensuring that most of the categories of awards are represented. The authors are not affiliated with any of the industries mentioned below, nor did they receive funding from any of these companies.

Chemical giants and other large companies, such as The Dow Chemical Company, (now merged with E. I. du Pont de Nemours and Company (DuPont)), SC Johnson & Son, Shaw Industries Group Inc, Merck & Co Inc and Pfizer Inc have paved the way to define best industrial practices in green chemistry. Smaller companies such as Patagonia Inc, the Warner Babcock Institute for Green Chemistry LLC, Solazyme Inc (now TerraVia Holdings, Inc) and Verdezyne Inc have also engaged in the application of green chemistry principles.

According to the EPA and based on the winning technologies developed by the Presidential Green Chemistry Challenge Awardees (12):

“Through 2016, our 109 winning technologies have made billions of pounds of progress, including:• 826 million pounds [375,000 tonnes] of

hazardous chemicals and solvents eliminated each year – enough to fill almost 3800 railroad tank cars or a train nearly 47 miles [75 km] long

• 21 billion gallons [95 billion litres] of water saved each year – the amount used by 820,000 people annually

• 7.8 billion pounds [3.5 million tonnes] of carbon dioxide equivalents released to air eliminated each year – equal to taking 810,000 automobiles off the road.”

The main industrial sectors where green chemistry has made an impact over the past ten years include but are not limited to: bulk and commodity chemicals, plastics, paints, coatings, pesticides, fuels and pharmaceuticals. Several companies exemplify what green chemistry at work is about. Taking some of the Presidential Green Chemistry and Engineering Challenge Awards winners as examples: • Representing the bulk and commodity chemicals

sector: Solazyme Inc (now TerraVia Holdings, Inc) based in South California developed the production of vegetable oils via the fermentation of microalgae.

After finding out that microalgae have an inherent ability to produce oils, they used genetic engineering to develop an unlimited variety of triglycerides. Using Solazyme’s triglycerides results in lower emissions of volatile organic compounds (VOCs), reduces the quantity of waste produced and lowers the environmental impact compared to traditional petroleum-based oils. Solazyme won the 2014 Presidential Green Chemistry Challenge Award in the Greener Synthetic Pathways category (13).

• In the biodegradable plastics sector: Verdezyne Inc, also based in Southern California, relies on “using the power of biology to make a positive impact on your products”. Verdezyne took advantage of the well-known process of fermentation, using yeast to produce everyday products at a lower cost. Their yeast fermentation process works with renewable feedstocks such as low cost plant-based oils, which act as substitutes for petroleum-based products. Their products, such as adipic acid, are intermediates used in the production of nylons and plastics. Verdezyne won one of the Presidential Green Chemistry Challenge Awards in 2016 in the Small Business Award category (14). They recently diversified their ‘green’ products by partnering with Aceto Corporation to design FerroshieldTM HC, which is a nitrate-free mixture with anti-corrosion properties useful in several applications such as metal cleaners, engine coolants and aqueous hydraulic fluids.

• In 2016, the winner of the new Presidential Green Chemistry Challenge Award in the Specific Environmental Benefit: Climate Change category was Newlight Technologies who developed a low-cost thermoplastic named AirCarbonTM from methane, a potent greenhouse gas. Several well-known companies such as Hewlett-Packard Company, IKEA and Sprint have already adopted AirCarbonTM in the production of their packaging bags, furniture and cell phone cases (15).

• Representing the paint industry: one of the issues in the paint and coatings industry is the emission of large amounts of VOCs when oil-based ‘alkyd’ paints dry and cure. The well-known paint company Sherwin-Williams developed water-based acrylic alkyd paints with low VOCs that can be made from recycled soda bottle plastic (polyethylene terephthalate (PET)), acrylics and soybean oil. These paints exhibit the same properties as alkyd



and acrylic paints but with low VOC content, low odour, and non-yellowing properties. In 2010, Sherwin-Williams claimed that the manufacture of this high-performance paint helped to eliminate over 800,000 pounds (360 tonnes) of VOCs (16). Sherwin-Williams won the 2011 Presidential Green Chemistry Challenge Award in the Designing Greener Chemicals Award category.

• Dow AgroSciences LLC participated in the improvement of many pesticides over almost two decades. In the 1990s they developed a biopesticide called spinosad to repel insect pests on vegetables. However, spinosad was not effective for insect-pest control in tree fruits and tree nuts. In 2008 they received the Presidential Green Chemistry Challenge Award in the Designing Greener Chemicals Award category for the design of spinoteram which is a high-performance insecticide efficient when applied to tree fruits, tree nuts, small fruits and vegetables. Spinetoram exhibits the same environmental benefits as spinosad while being less persistent in the environment compared to traditional organophosphate insecticides. Furthermore the toxicity to non-target species is low as well as its use rate (17).

• Two companies, Albemarle Corporation and CB&I Corporation, have developed a greener solid acid catalyst for the production of alkylate, which is a blending component for motor gasoline. The AlkylClean® technology replaces liquid acid, typically hydrofluoric acid or sulfuric acid, with an optimised zeolite-based catalyst. This catalyst eliminates the production of acid-soluble oils and spent acids and bypasses the need for product post-treatment. These two companies were the recipient of the 2016 Presidential Green Chemistry Challenge Award in the Greener Synthetic Pathways category (18).

• Several collaborators developed a greener synthesis of drugs for the treatment of high cholesterol. The latest to date was a collaboration between Codexis Inc and Professor Yi Tang of the University of California, Los Angeles, who used an engineered enzyme and a natural product to manufacture simvastatin, originally sold by Merck under the trade name Zocor® (19). Their efficient biocatalytic process avoids the use of several hazardous chemicals while eliminating waste and, most importantly, meeting the needs of the customers. Codexis and Professor Tang received

the 2012 Presidential Green Chemistry Challenge Award in the Greener Synthetic Pathways category.

Communicating these success stories to the next generation of scientists, the students of today, and incorporating these real-world case scenarios in the K-12 curriculum and beyond is the key to generate a systemic interest in the field of green and sustainable chemistry (20, 21).

2.2 In Academia

As mentioned by Haack and Hutchison in a review article titled ‘Green Chemistry Education: 25 Years of Progress and 25 Years Ahead’ published in 2016, green chemistry was first depicted as a possible solution to improve laboratory safety, to address issues of inappropriate ventilation in laboratories and obsolete laboratory space, and to modernise the chemistry curriculum (22). Nowadays it seems essential for future citizens and leaders of the 21st century to be educated about the concepts of green and sustainable chemistry to participate in the creation of sustainable societies.

Supporters of green chemistry in academia have followed in the footsteps of leading societies such as the ACS, the US EPA and the Royal Society of Chemistry in the UK, to create reliable educational materials and programmes based on the application of green chemistry (2). Some of the educational green chemistry resources available for educators are textbooks, laboratory experiments, summer programmes, workshops, and more recently, the opportunity to continue training and research in green chemistry by enrolling into specialised Masters and PhD programmes.

The goal of this section is not to present an exhaustive list of all initiatives pursued in the academic world but to highlight the main current resources and to share some of the newest initiatives in academia in the past ten years in the USA. Literature and online resources dedicated to green chemistry have grown during this period, especially targeting undergraduate students.

Ten years ago, to discover how much content related to green chemistry was inserted in chemistry textbooks, two surveys were completed as a baseline by publishers’ representatives (23). The first survey took place in 2006 at the ACS National Meeting and Exposition, and the second survey was in 2007 at the University of Scranton. For the first survey, nine publishers whose focus is the publication



of undergraduate textbooks were chosen. These publishers were Benjamin Cummings, Prentice Hall, Houghton Mifflin Company, McGraw-Hill Publishing Company, W. W. Norton & Company, Thomson Corporation, W. H. Freeman and Company, John Wiley and Sons, and Jones & Bartlett Learning. A list of these publishers’ undergraduate chemistry textbooks for both chemistry majors and non-chemistry majors was compiled. For the second survey, they gathered information from the same publishers above except for W. W. Norton & Company and Jones & Bartlett Learning. After analysing the data from the two surveys, it was determined that only 33 out of 141 textbooks examined from all of the publishers contained a mention of green chemistry.

Ten years later, textbooks dedicated to green chemistry occupy shelves at most college and university libraries (24–27). While these textbooks target science majors, several textbooks incorporating chemistry in the context of sustainability suitable for non-majors were recently published (28, 29). The wide dissemination of textbooks facilitated the development of single green chemistry-based courses as well as the infusion of green chemistry into typical major courses such as general, organic, inorganic, biochemistry, analytical and physical chemistry (30). Courses may be modified by choosing greener alternatives as replacements to traditional examples. For instance, in an organic chemistry laboratory, procedures can use renewable reagents, apply the metrics of atom economy instead of percent yield, limit the amount of organic solvents and use alternative energy sources such as a microwave. For inorganic chemistry, these alternatives can consist in highlighting reusable catalysts and reagents anchored on inorganic solid supports, decreasing the use of heavy metals and of solid acids and bases. For biochemistry, these alternatives can focus on biocatalysis, biosynthesis and the use of raw materials from renewable resources. For analytical chemistry, reducing the use of column chromatography or high-energy distillations is a step in the direction of green chemistry principles. For physical chemistry, a lesson on the thermochemistry of biodiesel, the use of kinetics and catalysis, and the benefits to using computational studies can be introduced.

However the most prominent place for green chemistry to be taught is still in a laboratory setting. The design of green chemistry laboratory exercises, mostly in organic chemistry, created a successful draw to this ‘metadiscipline’ (31). Several organic chemistry

laboratory manuals are being used to ‘green’ the curriculum at many US undergraduate and graduate institutions (32–34).

Articles describing the implementation of green chemistry tools and strategies in the classroom or laboratory have seen exponential growth. Some journals publishing this type of content include the Journal of Chemical Education, Science and Education and Chemistry Education Research and Practice as well as ACS Sustainable Chemistry and Engineering. The number of articles devoted to examples on how to implement green chemistry in education has doubled since 2007 (22).

There are many online teaching resources that have emerged based on collaborations between advocates for green chemistry. The following resources do not represent an exhaustive list of tools and only a few examples are mentioned here. Some examples include: a database called Greener Educational Materials for Chemists (GEMs) which contains laboratory exercises, course syllabi and multimedia content and was created by the University of Oregon (35). The University of Oregon also created the Green Chemistry Education Network, allowing educators to continue their professional development through collaborating and fostering the integration of green chemistry in education. The non-profit organisation Beyond Benign, based in Wilmington, Massachusetts, USA, is “dedicated to providing future and current scientists, educators and citizens with the tools to teach and learn about green chemistry in order to create a sustainable future”. It is focused on K-12 curriculum development and educator training, community outreach and workforce development (36). Another example is the iSUSTAIN™ Green Chemistry Index which is an online tool used to assess the sustainability of products and processes (37).

Mentoring and the creation of a green and sustainable chemistry community of practice is also taking place at conferences and workshops. National and international conferences on sustainability are bringing researchers together from all over the world. Examples of well-known conferences involving presentations of green chemistry educational materials are the national and regional ACS meetings, the Annual Green Chemistry and Engineering Conference and the Biennial Conference on Chemical Education in the USA, as well as international conferences such as the International IUPAC Conference on Green Chemistry, the International Symposium on Green Chemistry and



the International Conference on Green and Sustainable Chemistry.

To foster critical thinking skills and engage students and faculty, workshops and awards are available. Each year the Green Chemistry Institute at the ACS offers workshops designed for students at the Annual Green Chemistry and Engineering Conference; Beyond Benign designed workshops for K-12 teachers’ training as well as online courses for educators; the University of Oregon was one of the pioneers in offering weeklong Green Chemistry Education workshops for educators. Besides the Presidential Green Chemistry and Engineering Challenge Awards for professional chemists, students can also be actively challenged and participate in design competitions such as the People, Prosperity and the Planet (P3) Student Design Competition launched by the EPA in 2002 (38). The goal of this competition is to expand the breadth of participation by involving interdisciplinary teams of students interested in not only chemistry but also engineering, architecture, art and business. The University of Berkeley’s Greener Solutions programme gathers both undergraduate and graduate students with local businesses and governmental agencies to come up with greener chemistry solutions in a real-world context (39).

Students have the opportunity to earn awards such as the Ciba Travel Awards in Green Chemistry, which are used for a student to travel to an ACS conference focused on green chemistry; the Joseph Breen Memorial Fellowship, which is for a student to present research on green chemistry at an international green chemistry conference; and the Kenneth G. Hancock Memorial Award, which recognises “outstanding student contributions to furthering the goals of green chemistry through research and/or studies”.

Finally, it is possible for undergraduate and graduate students to specialise in the study of green chemistry and earn a degree in this discipline. While most institutions endorse some type of green chemistry programming (courses, laboratory curricula focused on green chemistry, workshops), some universities such as the University of Toledo, Ohio, are offering a BS or an MS degree with a minor in green chemistry and engineering, and Chatham University offers an MS in green chemistry focused on entrepreneurial skills. The University of Massachusetts at both Boston and Lowell offer a PhD in Green Chemistry.

Although progress has been made, it is important to keep in mind that the implementation of green chemistry in the curriculum needs to be tailored to the specific mission and type of institutions involved (four-year undergraduate institutions, community colleges, large research universities). One approach does not fit all. It is also essential that all stakeholders from academia and industry are involved in addressing emerging needs for new content related to toxicology as well as for metrics and best educational practices. To attempt to fill in the gaps, a Green Chemistry Education Roadmap Visioning Workshop took place in September 2015 to delineate “the Roadmap Vision and the set of green chemistry core competencies that every student with a bachelor’s degree in chemistry, chemical engineering and allied sciences should attain by graduation” (40). While the roadmap vision is well established as follows: “Chemistry education that equips and inspires chemists to solve the grand challenges of sustainability”, the “transformative potential of green chemistry” on society has not been explored yet since the societal impacts are often not taken into account when assessing the entire life cycle of newly designed green chemicals and processes (40). The next section attempts to give examples of how green chemistry is expected to play a role in addressing environmental and human health issues in a social justice context.

2.3 In Society

Even if the field of green chemistry inspires scientists to tackle sustainability-related issues on a global scale, the limited knowledge about the global risk associated with exposure of the human body to chemical pollution is leading to “an emerging perspective that addresses the confluence of social and environmental injustice, oppression for humans and nature, and ecological degradation” (31). Since the development of chemistry has left unintended marks on humans, especially in non-white and low-income communities, it is essential to consider the social consequences of high levels of environmental pollution by hazardous chemicals.

The US EPA defines ‘environmental justice’ as: “the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income, with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies. EPA has this goal for all communities



and persons across this nation. It will be achieved when everyone enjoys:• The same degree of protection from

environmental and health hazards, and• Equal access to the decision-making process

to have a healthy environment in which to live, learn, and work.” (41)

The EPA recently decided to implement plan EJ 2020 which accounts for “improving the health and environment of overburdened communities”. By 2020, they will:• “Improve on-the-ground results for overburdened

communities through reduced impacts and enhanced benefits

• Institutionalize environmental justice integration in EPA decision-making

• Build robust partnerships with states, tribes, and local governments

• Strengthen our ability to take action on environmental justice and cumulative impacts

• Better address complex national environmental justice issues.” (42)

Environmental justice and social justice are mutually inclusive as demonstrated in the following definitions of social justice as:

“A state or doctrine of egalitarianism (Egalitarianism defined as 1: a belief in human equality especially with respect to social, political, and economic affairs; 2: a social philosophy advocating the removal of inequalities among people)”

according to the Merriam-Webster Dictionary (43).

The National Association of Social Workers states that “Social justice is the view that everyone deserves equal economic, political and social rights and opportunities” (44).

It has been stated that green chemistry “is one of the tools for improving the quality of human life and welfare”. Consequently it seems appropriate to refer to the green chemistry philosophy as the spring board to change the negative perception associated with the chemical enterprise and to “reduce the level of social burden on the personnel and people living nearby” (45).

The successful implementation of green chemistry in industry, the role of green chemistry in increasing public well-being and sustainability leadership across disciplines, sectors, and cultures are essential to promote environmental and social justice. To help achieve this goal, the EPA created an interactive

environmental justice online map across the USA called EJSCREEN which:

“highlights low-income, minority communities across the country that face the greatest health risks from pollution. The analysis combines demographic and environmental data to identify where vulnerable populations face heavy burdens from air pollution, traffic congestion, lead paint, hazardous waste sites and other hazards.” (46)

Applying the 12 principles of Green Chemistry to address social disparities affecting underprivileged populations can lead to many benefits such as the delineation of methodologies to provide:i. cleaner air through decreasing the emission

of hazardous chemicals during use (such as pesticides) or the unintentional release (during manufacturing or disposal) of toxic chemicals leading to health issues but also global warming, ozone depletion and smog formation

ii. cleaner water by preventing the contamination of drinking water with hazardous chemical wastes

iii. increased safety for workers using chemicals as part of their profession so that the use of toxic materials is minimised and the need for personal protective equipment is lessened

iv. safer consumer products such as the production of pharmaceutical drugs with less waste and the replacement of cleaning products and pesticides with safer alternatives

v. safer food based on the reduction of the amount of persistent toxic chemicals present in pesticides or as endocrine disruptors (47).

Aligned with the leadership approach of the EPA, scientists are motivated to determine that chemical exposures fluctuate with social disparities. The following section highlights examples where social injustices stemming from chemical exposure have been the subject of peer-reviewed research. An attempt to demonstrate how green chemistry principles can help address these social disparities is also presented.

2.3.1 Pesticides Exposure and Farmworkers

The population of farmworkers in the USA is severely affected by pesticides exposure. It is estimated that of the 2.5 million farmworkers in the USA, 60% of them and their dependents live in poverty (48). About 88% of all farmworkers are Hispanic and more than 78% of them are foreign-born without legal documentation and no higher education (49).



Issues associated with the language barrier and the lack of health insurance coverage were brought up in a report titled ‘Exposed and Ignored. How Pesticides are Endangering our Nation’s Farmworkers’ in 2013 (48). A study conducted by Washington State Department of Health showed that only 29% of pesticide handlers were able to read in English and to some extent in Spanish. Analysis of the blood work of pesticide handlers who could not read English showed significantly greater pesticide exposure compared to those who could read English to some degree.

Pesticide poisoning or exposure causes farmworkers to suffer more chemical-related injuries and illnesses than any other workforce in the USA (48). Worldwide, 25 million agricultural workers experience pesticide poisonings each year (50). Protective clothing does not provide adequate protection against pesticide exposure, especially when handling organophosphate and N-methyl carbamate pesticides. Since pesticide residues are often invisible and odourless, only a blood test would be useful to monitor exposure to these toxic chemicals.

In a thorough report titled ‘Green Chemistry and Sustainable Agriculture: The Role of Biopesticides’ by Peabody O’Brien et al. in 2009, the role of green chemistry applied to the agricultural world and biopesticides in particular was validated (51). Biopesticides are derived from plants or from microbial pesticides. They are less toxic, more pest specific, they biodegrade more quickly and do not affect the ecological balance.

Another approach is outlined in the Green Chemistry Principle #7: “Chemists should, whenever possible, use raw materials and feedstocks that are renewable”. Green chemists are currently using agricultural waste products as renewable feedstocks and are synthesising biocatalysts to increase the “conversion of agricultural materials into high value products, including novel carbohydrates, polysaccharides, enzymes, fuels and chemicals” (3). As explicitly mentioned in the Peabody O’Brien report:

“Green Chemistry and sustainable agriculture are inherently intertwined; farmers need green chemists to make safe agricultural chemical inputs. Green chemists need farmers practicing sustainable agriculture to provide truly “green” bio-based raw materials to process into new products.” (51)

Additionally, as defined in the Green Chemistry Principle #10: “Chemical products should be designed

so that at the end of their function they break down into innocuous degradation products and do not persist in the environment” (3). The challenge to remove pesticide residues in the soil, water and air has led scientists at Carnegie Mellon University to develop specific TAML® catalysts targeting the degradation of pollutants from water without presenting endocrine disrupting activity (52).

Another example based on the control of pests affecting vineyards, the goal of research conducted by Jocelyn Millar at the University of California at Riverside was to “identify less-toxic pesticides that may be effective alternatives to organophosphates”. Instead of using heavy loads of pesticides, the group developed a pheromone to control the vine mealybug population based on mating disruption. Their pheromone was not only successful in trapping the vine mealybugs but was also beneficial to attract the vine mealybugs’ predators, which was an unexpected benefit to the preservation of the ecological balance and of the natural predator populations (51).

2.3.2 Exposure to Endocrine Disruptor Bisphenol A and Children

Bisphenol A (BPA), a synthetic organic compound used to make plastics and epoxy resins for a variety of common consumer goods, has been under scrutiny since 2008 when several governmental agencies investigated its safety, especially with respect to its use in baby bottles and ‘sippy’ cups. BPA and polyfluoroalkyl chemicals (PFCs) are oestrogen-like chemicals found to “disrupt reproductive development, body weight and metabolic homeostasis, and neurodevelopment, and to cause mammary and prostate cancer.” Many comprehensive reviews regarding the impacts of BPA on health have been published (53–55).

While concerns about the potential hazards of endocrine-disrupting chemicals such as BPA are still debated, and after several countries have banned its use, a study published by Nelson et al. in 2012 addressed the population disparities in exposure to these chemicals. Their findings demonstrated that:

“people with lower incomes, who may be more likely to suffer from other disparities in health and exposures, have a greater burden of exposure to BPA. The results for children are especially troubling. Children overall had higher urinary BPA concentrations than teenagers or adults, but children whose food security was very low or who received emergency food assistance - in



other words, the most vulnerable children - had the highest levels of any demographic group. Their urinary BPA levels were twice as high as adults who did not receive emergency food assistance. Concerns about health effects from BPA exposure are strongest for young children and neonates because they are still undergoing development. Results for BPA by race/ethnicity, adjusting for income, revealed that Non-Hispanic Whites and Blacks had similar urinary levels, and being Mexican American appeared to be highly protective.” (56)

It is thought that: “eating more fresh fruits and vegetables is likely to be associated with eating less canned foods, which may explain the lower urinary BPA levels seen in Mexican Americans compared to other groups.” (57)

Several companies are now selling BPA-free products but do not always inform what substitute is being used. It is even considered that some of the BPA-free alternatives may actually not be safer than their BPA-containing counterparts. Karen Peabody O’Brien, former Executive Director of the scientific foundation Advancing Green Chemistry, and John Peterson Myers, CEO and Chief Scientist at Environmental Health Sciences, both located in Charlottesville, Virginia, have suggested using green chemistry tools to create:

“a new generation of non-petroleum-based materials from scratch, simultaneously protecting public and environmental health while reducing dependence on foreign oil” (58).

In 2014, Richard Wool and his research group at the University of Delaware achieved that by converting lignin fragments, a waste product of the papermaking and other wood-pulping processes, to a compound called bisguaiacol-F (BGF). BGF has the same shape as BPA, but does not interfere with hormones and retains the desirable thermal and mechanical properties of BPA (59).

2.3.3 Contaminated Drinking Water and Air in Poor Communities

The most recent example of social injustice was the water crisis in Flint, Michigan. When the town of Flint switched the source of water for its residents in 2014, corrosion inhibitors were forgotten to be added to the new water source, which caused lead levels to raise to 25 ppb (above the maximum level of 15 ppb set by the EPA). Residents complained numerous times

about the strange taste and colour of the water but no further investigation was conducted. Thousands of children among the majority of the African American population of Flint were exposed to lead without being properly informed since this information was not made public. It was not until January 2016 that a federal state of emergency was declared (60). In March 2017, the EPA awarded US$100 million to the State of Michigan to upgrade Flint water infrastructure, especially lead service lines (61).

While the cause of the increased level of lead in Flint’s potable water was due to corrosion in the lead and iron pipes that distribute water to city residents, green chemistry has been at work to provide environmentally friendly alternatives to chemical water treatment such as the use of nanomaterials (62), the use of ‘green additives’ (63) or the use of photocatalysts (64).

Some green chemistry advocates are concentrating their efforts to address the social and environmental (in)justice of chemical exposure using the concept of sustainable chemistry as framework in their academic research and outreach efforts. This has become a priority at academic institutions such as Bridgewater State University where Professor Ed Brush is starting a Participatory Action Research programme (65). In this programme the community will be involved in research projects targeting social injustice. His research students are interested in assessing the impacts of diesel particulate matter emissions on populations with a high risk of developing asthma such as females, children, people of colour and people of mixed race as well as those living in poverty or with low incomes. The plan is for students to collect data using air collectors and then report their findings related to diesel exhaust pollutants’ impact on health. The ultimate goal is to delineate how green chemistry principles can be put to work to decrease the exposure of minorities to diesel exhaust pollution. It is expected that studies related to biofuels will inspire their green chemistry proposal to reduce social disparities due to exposure to emissions exhaust (66–68).

3. Conclusions

Advances in chemical knowledge and research have brought great progress to the field of green and sustainable chemistry. As mentioned earlier this article was written in the context of attracting attention to problems related to chemical pollution and resource depletion and it also proposes some alternatives related



to the application of green chemistry. The overall goal was to demonstrate that the significant development of green and sustainable chemistry has opened up a new way of performing and teaching chemistry, demonstrating that green chemistry is applicable to all fields of research and that it should not be a tradeoff between cost and environmental impact. In industry, while the implementation of green chemistry is driven by government regulations, consumer awareness and higher demand for more environmentally benign products, the rate of adoption is slow. In 2015, T. Fennelly & Associates, Inc identified some possible accelerators of green chemistry adoption such as (69):• Collaborative efforts relying on establishing price

and performance trade-offs where transparency is addressed and where “open innovation” is welcome. The word “coopetition” has been used “as a model to drive competition and innovation” while simultaneously enabling the growth of green chemistry

• Compromise is a step in the right direction. When companies shift away from regulations and mandated reduction of industrial emissions towards active pollution prevention, continuous improvement of a product will be justified for its economic and environmental value

• Finally, continued and enhanced education in green and sustainable chemistry is crucial among the work force.

Even if the implementation of green chemistry practices in industry face adversity, strategies have been identified to accelerate the adoption of green chemistry such as: continued research and communication among all stakeholders; support for ‘smart’ policies that enhance green chemistry innovation and adoption; fostering collaboration; dissemination of information to the marketplace; and tracking of progress using metrics (1).

With educators passionate about the green and sustainable chemistry field, not only are institutions taking an interest in promoting the ‘green’ concept to their students, there are also plenty of resources available to encourage them to make a difference. The incorporation of green chemistry-based courses and the design of academic degrees in green chemistry is vital to establishing awareness and knowledge of environmentally benign chemistry. Students, who gain insight about how green chemistry can positively impact local communities as well as the entire world, enter the work force with a head start and a sense of ethical

empowerment on how to solve existing challenges using green and sustainable chemistry principles.

Although many educational materials are available, challenges remain for academia, such as (22): • The slow implementation of green chemistry in the

undergraduate and graduate curriculum based on a “lack of uniform demand”, which can be perceived as curricular conservatism from academic and industrial stakeholders

• “The resistance to infuse green chemistry into the main general and organic chemistry textbooks or the ACS standardized exams” which does not motivate departments to make changes in their curriculum

• The lack of expertise and confidence from inexperienced educators to help students learn about green and sustainable chemistry, and

• Finally, the presence of key gaps in terms of content such as the introduction of toxicology and metrics as well as well-defined curricular objectives and assessments.

Through the applications of green chemistry in industry and academia, it has been shown how green chemistry can make a difference in the sustainable development of human civilisation. While this article described some of the efforts undertaken in the USA, the scope of this article could be expanded by highlighting efforts outside the USA such as the commitment of the United Nations to develop 17 sustainable development goals to transform our world (70). Additionally chemical companies around the world such as Dow Chemical Company designed their own set of sustainability goals to help “redefine the role of business in society” (71).

Recognised as a means to aid society to live longer and better, green chemistry’s focus on the humanistic level will drive modern society in the direction of global sustainability.

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55. F. S. vom Saal, B. T. Akingbemi, S. M. Belcher, L. S. Birnbaum, D. A. Crain, M. Eriksen, F. Farabollini, L. J. Guillette Jr., R. Hauser, J. J. Heindel, S.-M. Ho, P. A. Hunt, T. Iguchi, S. Jobling, J. Kanno, R. A. Keri, K. E. Knudsen, H. Laufer, G. A. LeBlanc, M. Marcus, J. A. McLachlan, J. P. Myers, A. Nadal, R. R. Newbold, N. Olea, G. S. Prins, C. A. Richter, B. S. Rubin, C. Sonnenschein, A. M. Soto, C. E. Talsness, J. G. Vandenbergh, L. N. Vandenberg, D. R. Walser-Kuntz, C. S. Watson, W. V. Welshons, Y. Wetherill and R. T. Zoeller, Reprod. Toxicol., 2007, 24, (2), 131

56. ‘NTP-CERHR Monograph on the Potential Human Reproductive and Developmental Effects of



Bisphenol A’, NIH Publication No. 08–5994, CERHR (Center for the Evaluation of Risks to Human Reproduction), US Department of Health and Human Services, National Toxicology Program, Durham, USA, 2008, 395 pp

57. J. W. Nelson, M. Kangsen Scammell, E. E. Hatch and T. F. Webster, Environ. Health, 2012, 11, 10

58. L. Peeples, ‘Toxic Chemical BPA Under Attack, but Alternatives may not be Safer, Experts Say’, TheHuffingtonPost.com, Inc, New York, USA, 23rd February, 2012

59. ‘Potentially Safer, Greener Alternative to BPA could come from Papermaking Waste’, ScienceDaily, Rockville, USA, 16th March, 2014

60. J. Durando, ‘How Water Crisis in Flint, Mich., Became Federal State of Emergency’, USA TODAY, a division of Gannett Satellite Information Network, LLC, USA, 19th January, 2016

61. ‘EPA Awards $100 Million to Michigan for Flint Water Infrastructure Upgrades’, News Releases from Headquarters, US Environmental Protection Agency Media Relations, Washington, DC, USA, 17th March, 2017

62. C. Santhosh, V. Velmurugan, G. Jacob, S. K. Jeong, A. N. Grace and A. Bhatnagar, Chem. Eng. J., 2016, 306, 1116

63. E. Mavredaki, A. Stathoulopoulou, E. Neofotistou and K. D. Demadis, Desalination, 2007, 210, (1–3), 257

64. V. Likodimos, D. D. Dionysiou, and P. Falaras, Rev. Environ. Sci. Biotechnol., 2010, 9, (2), 87

65. E. Brush, ‘Exploring Social and Environmental Justice Through Green Chemistry Education, Research, and Outreach (GCE 119)’, 20th Annual Green Chemistry and Engineering Conference, 14th–16th June, 2016, Portland, USA, online video clip, American Chemical Society, 15th June, 2016

66. D. An, Y. Guo, Y. Zhu and Z. Wang, Chem. Eng. J., 2010, 162, (2), 509

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The AuthorsAnne Marteel-Parrish grew up in the North of France and got her Engineering degree in Materials Science from the Ecole Polytechnique de Lille, France, in 1999. She received a PhD in Chemistry with concentration in Materials Science from the University of Toledo, Ohio, USA, in May 2003. Shortly after, she was hired as Assistant Professor in Chemistry at Washington College in Chestertown, Maryland, USA. Anne received tenure and was promoted to the rank of Associate Professor in 2009. She achieved full professorship in 2016. She was the Chair of the Chemistry Department at Washington College from 2010 to 2016. In 2011 she was invested as the Inaugural Holder of the Frank J. Creegan Chair in Green Chemistry.

Karli Newcity received her BS in Chemistry at Washington College, Maryland, in 2013. Before completing her studies, she took an internship with the Domestic Nuclear Detection Office at the US Department of Homeland Security where she trained in Radiochemistry and Nuclear Forensics. Currently, she is a Chemist supporting the Detection Branch of the Engineering Directorate of the Edgewood Chemical Biological Center, Edgewood, MD, USA, where she performs a wide variety of laboratory operations in a test and evaluation laboratory.

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UK Energy Storage ConferenceResearch progress, economics and policy considerations in the field of energy storage

Reviewed by Jacqueline EdgeEnergy Storage Research Network, Energy Futures Lab, Electrical Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, UK


Introduction

The third UK Energy Storage Conference (UKES2016) was held at the Edgbaston campus of the University of Birmingham, UK, from midday on Wednesday 30th November to midday on Friday 2nd December 2016. The aim of the conference, organised by the Energy Storage Research Network on behalf of the UK Research Council funded Energy SuperStore Hub and chaired by Professor Nigel Brandon (Imperial College London), is to provide an inclusive platform for the UK energy storage community to come together and share their work and views.

The conference was well attended, with a total of 280 delegates, 61 from industry and six from government. The rest were from academia, including 89 students. Most of the delegates were from the UK, but 28 were international. A total of 73 posters were on display throughout the conference, stimulating discussions during refreshment breaks.

Judging by the positive feedback received, the conference appears to have been a success.

Delegates were enthusiastic and highly engaged in the programme, which involved long sessions running until late afternoon. During the breaks, discussion groups formed, either around the highly topical posters or to discuss possible future collaborations.

The presentations reviewed below consist of a selection of those who volunteered their slides for public access. The three winning posters are also reviewed in this article. For a full listing of the talks presented at UKES2016, please go to the conference website. Where permission has been granted, the slides are available to download. The top three posters were selected by a panel of judges. Digital copies of these and a few others, all volunteered by the presenters, are available on the conference website.

The conference presentations were arranged within the following themes:• Demonstration Projects• Policy and Economics of Storage in Energy

Systems• Storage for Transport• Integration of Storage into Energy Networks• Hydrogen for Energy Storage• Flow Batteries• Thermal, Mechanical and Thermochemical

Storage• Electrochemical Energy Storage• Advanced Tools and Diagnostics• Power Management and Control.



Batteries

Dan Rogers (University of Oxford, UK) gave an engineering perspective of grid-scale energy storage in his plenary talk on the second day, explaining his work on power electronics. This field involves using semiconductor devices to control and convert electrical energy. This allows large arrays of cells to be monitored and managed electronically, through carefully constructed algorithms. For large arrays, it is more probable that at least one cell will be significantly weaker than the rest and therefore the construction of simple large arrays becomes challenging. Power electronics can be inserted into the pack to mitigate the influence of the weaker cells and improve overall performance (capacity utilisation and system reliability). Using Markov chain reliability modelling, Rogers was able to show that the reliability of high voltage grid-scale batteries (comprising very large numbers of cells connected in series) can be greatly improved by adding power electronics within the pack (Figure 1), even if the power electronics devices themselves are significantly less reliable than the cells.

These themes were discussed further in a keynote delivered by Joel Sylvester, the Chief Technical Officer for Dukosi Ltd, UK, in the Power Management

and Control session. Battery management systems improve safety, balance the performance of multiple cells and monitor cell degradation to predict failure early on. Embedding this into cells at the time of manufacture can reduce costs, extend lifetimes and validate warranties. Jorn Reniers (University of Oxford) won a prize for his poster in this theme, entitled ‘Offering Multiple Grid Services in Parallel while Minimising Battery Degradation’. The results of a battery pack simulation are presented, showing that the cost benefits of extending the lifetime of the battery through active management outweigh the revenue loss from occasionally missing grid revenue opportunities.

The session on demonstration projects aimed to showcase a range of automotive and grid scale projects currently being developed. Colin Arnold (AGM Batteries Ltd, UK) introduced two new automotive projects that AGM Batteries Ltd are heavily involved in, ‘UK Automotive Battery Supply Chain’, funded by the Advanced Propulsion Centre (APC), UK, and ‘Sodium-Ion Batteries for Electric Vehicles’, funded by Innovate UK. The first requires the development of highly innovative embedded electronics whilst establishing the foundations of a world class UK lithium battery supply chain involving industrialists and academics working together to share insights and expertise. The second project aims to take advantage of exciting sodium-ion chemistry to develop safer and lower cost batteries for electric vehicles and other sectors. During the evening of the first day, the APC hosted a panel session focused on energy storage applications in the automotive industry. Chris May (APC) opened the session with a talk on how the APC is working to identify strategic opportunities for the UK automotive supply chain (Figure 2). Mike Woodcock (APC) and Professor David Greenwood (University of Warwick, UK) then went on to explain how the APC is bringing together the academic and industrial communities to capitalise upon these opportunities.

Xiaohong Li (University of Exeter, UK) delivered one of the keynote addresses in the flow batteries session on a redox flow battery (RFB) system which does not use membranes. In most commercially available RFBs, the ion exchange membrane comprises about a third of the production cost, so removing the need for this membrane will offer opportunities to make RFB technology economically viable for grid-scale applications (Figure 3). Her technique is to develop a zinc-nickel RFB which uses a single electrolyte, eliminating the need to separate two electrolytes with

Power electronics

N modules in a pack

M c

ells

per

mod

ule

Fig. 1. The cells in a battery pack can be divided up into N modules, with each module of M cells controlled by power electronics (Reproduced with permission)



Funding accelerated development of low carbon technologies

Road-mapping low carbon technology

trends

Identifying low carbon technology-led supply

chain opportunities

Developing and linking

industrial and academic

communities

Supporting and

developing SMEs and

supply chain

Strategic technologies

for the UK automotive

industry

Internal combustion

engines

Energy storage

and energy management

Electric machines and power electronics

Lightweight vehicle and powertrain structures

Intelligent mobility

Fig. 2. The ‘hub and spoke’ model of the APC’s strategy for helping the UK automotive industry capitalise on low carbon technologies (Reproduced with permission)

Ion-exchange membrane

Electrolyte tank

Electrolyte Electrolyte

Electrolyte tank

Ele

ctro

de

Electrode

Pump PumpPower/load

Fig. 3. A conventional RFB has two electrolytes, separated by an ion-exchange membrane and requiring duplicate storage and flow mechanisms. A membrane-free system uses a single electrolyte for reactions at both electrodes, eliminating a large proportion of the components (indicated by the faded out sections) (Reproduced with permission)

a membrane. This will also improve performance and greatly simplify device manufacture and operation.

In the session on electrochemistry, Professor Maria-Magda Titirici presented her work on anodes for sodium-ion batteries at Queen Mary University of London, UK. Sodium is cheaper and more abundant than lithium and is therefore an attractive option for making large scale batteries. The research challenge is to find a suitable anode material and Professor Titirici is researching carbon derived from biomaterials

to explore the link between microstructure and performance. One of her PhD students, Pelin Yilmaz, won a prize for her poster, ‘Biomass-Derived Low Cost Negative Electrodes in Na-Ion Batteries’.

Energy Storage

The policy session included a joint talk from Catherine Bale (University of Leeds, UK) and Andrew Pimm (University of Edinburgh, UK), describing the objectives



and progress of the Consortium for Modelling and Analysis of Decentralised Energy Storage (C-MADEnS). Two case studies were presented, one examining the public perception of domestic energy storage and the other exploring the potential for peak demand reduction using Tesla Powerwall installed in 100 homes in the city of Leeds. The first study is still underway, but the second study found that it was possible to reduce peak demand by more than 50%.

Graham Oakes, the Founder and CEO of Upside Energy Ltd, UK, gave a keynote address in the storage integration session, entitled ‘Stimulating Storage Research through Open Innovation’. Upside Energy considers the many uninterrupted power supply batteries around the UK as a distributed storage asset and has developed online control systems to enable these devices to connect to the grid, providing automated demand side flexibility services (Figure 4). Upside Energy was funded by the Innovate UK programme and is an excellent showcase for the benefits of innovation-level funding, demonstrating one way in which the deployment of storage can be encouraged.

A keynote address on the role of storing hydrogen underground was delivered by Professor Bent Sørensen (Roskilde University, Denmark). There are two facilities in operation in Denmark which use underground storage of natural gas: one using a salt cavern and the other using an aquifer store. They could both be converted to hydrogen stores at a low cost and do not require high pressures or low temperatures to store hydrogen in a condensed form. In both cases, hydrogen would be produced using electrolysis,

powered by excess renewable energy. The talk discusses the options for similar installations to be established around the world, mainly in China and the USA. He concluded that renewable energy generation integrated with underground hydrogen storage is the least expensive way to supply 100% of the world’s electrical energy demands.

Pau Farres-Antunez (University of Cambridge, UK) gave a talk on pumped thermal energy storage (PTES), a high energy density thermomechanical form of energy storage having no dependence on nearby geographical features. If liquid reservoirs are used instead of solid, then each tank of liquid can be stored at low pressure and maintain a single temperature, rather than the gradient necessary for solid thermal reservoirs. The design of these enables a greater separation between the hot and cold stores, limiting the opportunities for thermal transfer after the charge has been completed, which is a source of loss in thermal storage systems. The research at Cambridge is exploring ways to improve the efficiency of these systems. Haobai Xue, a PhD student working in the same research group as Pau, presented a winning poster in this theme, comparing compressed air energy storage (CAES) systems with PTES and showing that while the system efficiency for CAES systems tend to be higher than for PTES, PTES achieves a much higher energy density.

Professor Phil Taylor, Director of the new Centre for Energy Systems Integration at Newcastle University, UK, closed the conference on 2nd December with a plenary talk on the broader perspective of how energy storage fits into future energy systems. His talk examined how the apparently disjointed aspects of

Fig. 4. Schematic showing the Upside operation platform and all stakeholders (Reproduced with permission)

Open innovation community

Device manufac-turer and reseller

Device owner

Upside platform

Energy suppliers

System and DNOs

Upside operating company

Develop advanced algorithms

Sells devices and services

Increases value proposition to their customers

Gives device owners an income for shifting demand

Builds and operates Upside Cloud platform

Offers device capacity

Delivers balancing services

Pays for service



energy storage addressed during the conference could be joined up through integration of the technology into an advanced test bed (Figure 5). The new facilities at Newcastle University are part of the Engineering and Physical Sciences Research Council (EPSRC) £30 million programme funding research equipment at several universities around the UK and enable energy storage devices to be integrated into a reconfigurable grid. This will allow testing of many aspects, such as the performance of the devices, ways in which they could be combined to provide multiple grid services or new system operating paradigms to extract the maximum value from the integrated assets.

Conclusions

The conference succeeded in its aim to bring the UK research community together to discuss a wide range of topics in the field of energy storage, spanning economics and policy considerations, through to advanced diagnostics materials and devices. The presentations, both oral and poster, were of a high standard and served to report research progress in these diverse fields, stimulating discussion between people with expertise in diverse research areas, to identify and address the key research challenges for the further deployment of energy storage.

The Reviewer

Jacqueline Edge holds two BSc degrees from the University of Cape Town, South Africa, in Zoology and Computer Science. After a career in online banking development, she returned to academia to study Nanotechnology at University College London (UCL), UK, followed by a PhD in Hydrogen Storage. She now manages the Energy Storage Research Network at Imperial College London, facilitating research collaborations through the running of conferences such as the UK Energy Storage Conference.

Fig. 5. The Newcastle University energy storage testbed (Reproduced with permission)




“Particle Technology and Engineering: An Engineer’s Guide to Particles and Powders: Fundamentals and Computational Approaches”By Jonathan Seville and Chuan-Yu Wu (University of Surrey, UK), Butterworth-Heinemann, an imprint of Elsevier, Oxford, UK, 2016, 294 pages, ISBN: 978-0-08-098337-0, £51.10, US$84.00, €60.16

Reviewed by Domenico Daraio*, Giuseppe Raso and Michele MarigoJohnson Matthey Technology Centre, PO Box 1, Belasis Avenue, Billingham, Cleveland, TS23 1LB, UK


Introduction

The authors of this book, Professor Jonathan Seville and Professor Chuan-Yu Wu, are globally recognised experts in the field of particle technology. Professor Seville has a degree in Chemical Engineering from the Universities of Surrey and Cambridge, UK, with a strong background in the design and manufacturing of products for the pharmaceutical, home care and fast-moving consumer goods industries. Professor Wu has a degree in Chemical Engineering and a PhD from Aston University, UK, in finite element method (FEM) of particle impact problems from which he later moved to discrete element methods (DEM).

The book is intended to provide an initial overview of the field of particle technology by summarising the essential scientific fundamentals of particles and

introducing the basic knowledge required for two computational approaches (DEM and FEM). It gives a wide ranging introduction to the fundamentals of particle mechanics and computational aspects for particulate systems. For more in-depth discussion, the authors refer the readers to other, more extensive, works.

The book is divided into three main sections:• Part one: provides an overview of fundamental

characteristics of particles and powders in bulk form and how they can be determined (Chapters 2 and 3)

• Part two: consists of three chapters and comprises the bulk of the book. This section describes the complexity of a surrounding phase: firstly, as single particle interactions (Chapter 4), then considering multiple particles in the gas phase (Chapter 5) and finally considering multiple particles in liquid (Chapter 6)

• Part three: Chapters 7 and 8 describe the fundamental mechanics of particle systems both at the bulk level and particle level. This provides the basics for an understanding of the last two chapters of the book (Chapters 9 and 10) which introduce two computational methods – DEM and FEM applied to particle technology.



Particle Characterisation

Chapters 2 and 3 examine the fundamental properties of bulk solids such as powder density, flowability, particle size and shape, surface area, compressibility and compactibility and the related experimental techniques which can be used to characterise these properties. The book underlines the importance for particle properties related to final product quality control and process monitoring purposes. Importantly, particle characterisation allows a better understanding of the correlations between bulk behaviour, product quality and process performance. Furthermore, the authors consider particle size measurements and the importance of their physical and statistical representation. Finally, an often overlooked issue in industry is how representative a sample is of a larger quantity. General rules to design and prepare a representative sample to obtain reliable measurements are presented. The general principles in this section should be useful for a new practitioner in the area of particle technology but should be considered golden rules for working in the particle technology field.

Interaction with a Surrounding Phase

The second part of the book focuses on multiphase flow of solids in fluids. Chapter 4 examines the interaction of a single solid particle immersed in a fluid. The analysis of the forces exerted on a single particle by the surrounding fluid and the estimation of the drag force coefficient are presented as a starting point for the calculation of the terminal velocity in either steady-state or under unsteady motion. The value of terminal velocity is one of the key parameters for the design of unit operations such as fluidised beds and solid separation systems.

Systems with multiple solid particles in contact with a continuous gas phase are considered in Chapter 5. Beginning with the gas-solid contact regimes and a list of application examples, the chapter continues with a well-presented description of the equations for pressure drop in packed beds and minimum fluidisation velocity. An entire section is dedicated to fluidisation and fluidisation regimes, with particular focus on bubbling beds and models for the prediction of bubble size and velocity (very important elements in mass and heat transport phenomena involving multiphase flow). Typical fluidisation behaviours are summarised by the established Geldart classification

diagram. Then pneumatic conveying, a few rules of thumb and the most important variables to be considered when designing pneumatic conveying systems are presented.

The last part of Chapter 5 focuses on gas-solid separations and illustrates the operating principles for cyclones and filters. An example of cyclone scale-up (Figure 1) and a brief discussion of multi-cyclone systems are included.

A description of the rheology of suspensions is examined in the first part of Chapter 6. Different rheological behaviours can be exhibited by solid suspensions: this section summarises typical rheological responses and their fitting to models such as power-law types (for example shear thinning and shear thickening). Then a brief touch on pastes is presented by giving useful examples of paste characterisation and a list of common problems associated with paste extrusion. The last part of the chapter gives an outline of the agglomeration process and provides a schematic mechanism for wet agglomeration. This description aids understanding of the influence of several process

Eddy

Vortex finder

Dusty air inlet

Outer vortex

Inner vortex of cleaned air

Disengagement hopper

Dust discharge via flap valve or rotary valve

Fig. 1. An illustration of cyclone scale-up (Reprinted with permission from Elsevier/Butterworth-Heinemann, Copyright © 2016)



variables such as mixing intensity, liquid flow rate and droplet size.

Chapter 7 introduces powder bulk behaviour. Differences between bulk solid and fluid mechanics are illustrated and the concepts of powder failure, internal friction and wall friction are presented. One of the classic problems in bulk solid mechanics is stress analysis in storage vessels and the counterintuitive stress distribution in bulk solid containers is well presented. This analysis together with the Coulomb model for friction are the key elements for silo design. The discharge of storage hoppers is considered in the last part of the chapter. A comparison between flow patterns is provided together with the equations for calculating mass flow under different conditions. Further, transmission of stresses in powders during powder compaction is described with reference to tablet quality density.

Computational Approaches

Chapter 8 illustrates the mathematics required to describe the particle-particle interactions influencing the mechanical behaviour for bulk solids. Both elastic and elastoplastic particles are considered for normal impacts, tangential loading, adhesive forces and capillary forces. This subject is not presented in complete mathematical detail, with full derivations of all the equations. The reader is given a good overview of the complexity of the impact analysis in the case of simple perfectly elastic impacts. In Chapter 9 the numerical DEM (that was originally developed in the field of soil mechanics and further developed for other disciplines) is introduced. The authors give an exhaustive description of the calculation cycle utilised by typical DEM algorithms and they conclude the chapter with a data analysis section. The DEM data post-processing analysis is a key step in the use of this numerical technique where the ultimate goal is to relate the microscopic interparticle phenomena to the macroscopic bulk behaviour of the material. The application of DEM is limited by the amount of plastic deformation that can be reliably represented. In situations where the plastic deformation of the particle is not negligible or for impact problems including contact of irregular shape particles, FEM has been used to model the state of stress inside the particle body. This different computational method is introduced in Chapter 10. Like DEM, this method was

initially developed for other purposes but has more recently found wider application in different engineering disciplines including structural dynamics, heat transfer, fluid dynamics and aerodynamics. The potential and efficacy of the FEM is shown in two representative cases: the analysis of a normal impact between a sphere particle and a substrate and the continuum modelling of powder compaction. For both applications, if high stress levels and deformation are present DEM cannot be used to describe the problem since most of the energy will be dissipated in plastic deformation.

Conclusions

The book gives the reader a full but fairly approachable overview of the fundamentals of particle technology, reporting the current state of this field and providing perspectives on future challenges. A good overview of particle characterisation, the link between the microscopic and macroscopic properties and the future role of computational methods (DEM and FEM) in particle technology is provided in this book.

Particle technology is a broad subject and this text may be sufficient for the interests of a beginner and might awaken a sense of curiosity that will drive the reader to more exhaustive texts such as the Handbook of Powder Technology of which the latest volume was published in 2007 (1).

Reference1. “Particle Breakage”, eds. A. D. Salman, M. Ghadiri and

M. J. Hounslow, Handbook of Powder Technology, Vol. 12, Elsevier BV, Amsterdam, The Netherlands, 2007

“Particle Technology and Engineering: An Engineer’s Guide to Particles and Powders: Fundamentals and Computational Approaches”



The Reviewers

Domenico Daraio is an EngD Student in Formulation Engineering at the University of Birmingham, UK, and he has a degree in Chemical Engineering from the University of Pisa, Italy. He is currently working on DEM modelling of milling systems to better understand how the energy input into the system is transferred at different scales.

Giuseppe Raso is a Marie Curie Early Stage Researcher at the University of Twente, The Netherlands, and the University of Edinburgh, UK. He graduated from the University of Calabria, Italy, in Chemical Engineering. His project involves the rheological study of wet powders and the application of DEM for the simulation of wet granular systems in industrial processes.

Michele Marigo is a Principal Scientist at Johnson Matthey Technology Centre, Chilton, UK. He obtained an undergraduate degree with a master’s in Mechanical Engineering from the University of Padua, Italy, and a doctorate in Chemical Engineering (EngD) from the University of Birmingham. Michele’s expertise includes materials science, particle engineering, discrete element modelling and finite element modelling.




Organometallic Catalysis and Sustainability: From Origin to DateRapid progress towards more sustainable processes for industry

Justin D. SmithDepartment of Chemistry, University of Louisville, Louisville, Kentucky 40292, USA

Fabrice Gallou

Novartis Pharma AG, CH-4057 Basel, Switzerland

Sachin Handa* Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, USA


Organometallic catalysis has its origins in the 18th and 19th centuries. Then, the emphasis was on achieving remarkable chemical transformations, but today the focus is increasingly on sustainability. This article summarises the current promising approaches with special regard to those that have commercial potential, including non-aqueous and water immiscible solvents, modified enzymes, micellar catalysis, catalysis with low loading, metal-free catalysis and catalyst recycling. Environmental metrics, a key evaluation tool for any industrial chemical process, are used in micellar catalysis to demonstrate their usefulness, especially to achieve streamlined protocols, reduce losses and eliminate toxic materials.

Introduction

Nature is the best-developed and largest biochemical reactor, synthesising countless chemical entities in high purity and yield without exhausting itself. Beautifully, its processes exhibit quantitative reaction yield, low E factor, excellent atom economy, absence of toxic metals and solvents, ultra-purity of products, excellent chemoselectivity and outstanding reaction reproducibility throughout billions of years – all accomplished at ambient temperature in water (Figure 1(a)). Conversely, synthetic processes prevail with breadth of substrate scope and reaction kinetics, but only due to availability of powerful organometallic catalysts, which, in combination with other discoveries in chemistry, materials and other disciplines, have enabled synthetic organic chemists to construct almost any desired molecule. Astonishing catalytic transformations have been developed with modified enzymes (1), nanomaterials (2), photoredox chemistry (3) and organocatalysts (4). Asymmetric catalysis has led to independence from chiral auxiliaries and nonracemic starting materials (5). The 18th and 19th century progenitors of organometallic chemistry, Cadet (6), Frankland (7) and Zeise (8), could not have imagined this boom in organometallic catalysis, which continues into the 21st century with milestones including the birth of nanocatalysis (9), the renaissance



of photoredox catalysis (10) and the harnessing of micellar conditions to perform air-sensitive chemistry in water at room temperature (11).

However, in the big picture, in spite of major advances in the development of novel transformations, ligands, catalysts and technologies, the majority of today’s catalytic transformations suffer from many drawbacks in terms of sustainability, as evinced by very high E factors (12), poor atom economy (13), use of hazardous material and toxic organic solvents (12) and the involvement of energy intensive routes (Figure 1(b)). A very simple question must strike any organic chemist’s mind: when has Nature run any reaction in dry tetrahydrofuran (THF) at –78ºC or in any other organic solvent under very harsh conditions? While following Nature and enjoying the wealth of chemical properties of transition metals, one must marvel at how amazingly our processes differ. Are they not responsible for huge chemical waste generation? This issue is somewhat truer with chemistry laboratories in academia where we put much focus on current trends while ignoring sustainability issues, deferring the topic to process chemists. Our preset perceptions sometimes blind us from important innovations, which may be particularly true for sustainability in chemical catalysis. If Nature can perform biochemical catalysis so ideally, why is it not generally possible to perform chemical catalysis in the same fashion? Perhaps this

goal presently seems unrealistic. Due to older beliefs, even gold was considered catalytically inactive (14), leaving Sir Geoffrey C. Bond to remark: “We are at a loss to understand why these catalytic properties of gold have not been reported before, especially since the preparative methods we have used are in no way remarkable”. Today, even gold-assisted photoredox chemistry is possible (15), and for the matter at hand, Frances Arnold’s inspired work on mimicking natural catalytic processes already provides a guiding light (1). Developments helping to save our reserves of threatened metals through the merger of photoredox chemistry with enzymatic, micellar and nanocatalysis are also noteworthy (1–4). Accordingly, endeavours to discover sustainable new catalysts, transformations and technologies that will preserve our beautiful blue planet should be undertaken with careful attention to all aspects of how Nature performs chemistry. Such attention will yield solutions to many current and even untouched problems.

Historical Origins

Organometallic catalysis has a rich history. In 1731, Stahl published a report on the synthesis of Prussian blue, Fe4[Fe(CN)6]3 (16). However, the traditional classification of metalloid complexes as organometallics would date the first synthesis of an organometallic

Practical but sustainable

catalysis

Toxic solvents Toxic

solventsToxic gases

100% chemoselectivity

E factor

Ultra purity

Nature

O2

CO2

N2Man-made

reactorDry

organic solvent

Fig. 1. (a) Nature versus (b) man-made catalytic processes

(a) (b)



compound to 1757, when Cadet encountered the foul smell of cacodyl oxide and tetramethyldiarsine, generated from arsenic-containing cobalt salts while trying to develop new invisible inks (6). The true genesis of organometallic chemistry happened in 1827 when the first p-complex, trichloro(ethene)platinate(II), now known as Zeise’s salt, was reported (Scheme I(a)) (17). Further noteworthy metal alkyl complexes were reported between 1849 and 1863, including diethyl zinc, tetraethyl tin, diethyl mercury and trimethylboron (18, 19). The first metal carbonyl complex, dichlorodicarbonyl platinum, was synthesised in 1868, followed by syntheses of binary metal carbonyl complexes, including tetracarbonyl nickel in 1890 and pentacarbonyl iron in 1891. At the time, catalytic utility was unknown, and the bonding and structure of organometallic complexes was a mystery. Early assumptions held that ligands were aligned in a chain with metal at the terminus. The coordination theory proposed by Werner in 1893 based on his experimental data was the first of many models to more correctly explain the nature of bonding in organometallic complexes (20).

The seminal application of organomagnesium compounds to organic synthesis by Barbier, Grignard and Sabatier occurred in 1900 (21, 22), and the birth of organometallic catalysis was soon to follow. Although concurrent discoveries of organometallic reactions facilitated by unconsumed chemical mediators were rationalised into conceptual unity by Berzelius with his articulation of the concept of catalysis in 1835, the fusion of these two domains into organometallic catalysis did not begin until Ostwald’s work on chemical equilibria and catalysis in 1902. This work initialised homogeneous catalysis and organometallic chemistry with its reports on the first alkyl metal and metal hydride catalysts

(23). Subsequently, Sabatier clearly distinguished homogeneous and heterogeneous catalysis through his method development for hydrogenation of organic compounds in the presence of finely divided metals (24), an achievement that led to a Nobel Prize in Chemistry shared with Grignard in 1912. Important milestones during the next 50 years include the Fischer-Tropsch synthesis of linear hydrocarbons from syngas (25–27), vanadium oxide catalysed oxidation of benzene (28), silver-catalysed epoxidation of ethylene (29), cobalt-catalysed hydroformylation of olefins, the oxo process (30), the Pd-Cu-mediated Wacker process for acetaldehyde formation (31) and the Ziegler-Natta catalysts for olefin polymerisation, which earned their developers the 1963 Nobel Prize in Chemistry. The Wacker process in particular was a bellwether of future directions, being the first useful transformation to employ homogeneous organopalladium catalysis.

The golden period of homogeneous catalysis started in 1962 when Vaska reported a 16-electron iridium complex, now known as Vaska’s complex (Scheme I(b)), having the unusual property of reversible bonding with oxygen; this complex is the basis for the modern iridium complexes used in photoredox chemistry (32). In 1963 Fischer isolated the first metal-carbene complex (33), a tungsten-based complex that later provided a simple and fascinating means of olefin metathesis (34). Another important achievement was the development of the first homogeneous hydrogenation in 1965, independently reported by Wilkinson and Coffey (35, 36). Control on chirality was first accomplished in 1966 by Nazoki and Noyori who reported synthesis of cis- and trans-cyclopropane carboxylate (10% and 6% ee, respectively) from styrene and ethyldiazoacetate using 1 mol% of a chiral Cu(II) complex (Scheme II(a)) (37). This work marked the

(a)

(b)

Pt Pt FeClCl Cl

MeMe

Me

K I CoCOCO

COHH

Zeise salt (1827)

Alkyl metal complex (Pope, 1909)

Metal hydride complex (Hieber, 1931)

– +

Ir Ir IrO

OO2

OCCl

PPh3 PPh3OC PPh3OCCl

ClPh3P Ph3P Ph3PH2

HH

Scheme I Discovery of metal complexes important from catalysis perspective. (a) Early reported examples of metal complexes; (b) unusual properties of the Vaska complex



advent of asymmetric organometallic catalysis. At about the same time, Kagan reported an asymmetric rhodium-catalysed hydrogenation to obtain chiral amino acids using a C-2 symmetric chiral 2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane (DIOP) ligand (38), a discovery that soon led to the synthesis of enantiomerically pure L-3,4-dihydroxyphenylalanine (L-DOPA) by Knowles (Scheme II(b)) (39). Thereafter, asymmetric epoxidation of allylic alcohols was reported by Sharpless (40). Noyori and coworkers finally accomplished the synthesis of the very important 2,2’-bis(diphenylphosphino)-1,1’-binaphthyl (BINAP) ligand in 1976 after two years of method development, paving the way for many similar ligands that are widely used today (41). These many discoveries in asymmetric catalysis by Knowles, Sharpless and Noyori earned them a Nobel Prize in 2001.

The intense scientific interest in organometallic catalysis has not abated in the new millennium with Nobel Prizes being awarded for work in the area in 2005 and 2010. At present, however, it is shocking to observe that we seemingly have yet to fully realise the challenges that will be faced for decades into the foreseeable future. Awareness has begun to take root, thanks to the emergence of the green chemistry concept beginning in 1990 and its promotion of a more sustainable and environmentally responsible practice of chemistry (42). More recently, in the USA, establishment of the ACS Green Chemistry Institute has provided better direction for the community, the US Presidential Green Chemistry Challenge Award is encouraging chemists to focus on innovative sustainable methods and the National Science Foundation (NSF) Sustainable Chemistry, Engineering,

and Materials (SusChEM) programme is likewise a key initiative to attract more chemists in order to attain long-term sustainability goals.

Advances in General Sustainability

Many advancements in organometallic catalysis and synthesis have been achieved and a few of them are summarised here.

Aqueous Reaction Media

When has Nature ever run a reaction in organic solvent? The answer is ‘never’. So if Nature can do chemistry in an aqueous environment, why then do chemists not do the same? Partly, we are not able to perfectly mimic Nature in every aspect, but conducting catalysis in water, even at room temperature, is certainly possible. However, performing chemistry in water and then introducing that water into the waste stream would still adversely impact our environment and be a topic of criticism. The cost of such contaminated water treatment may even be greater than the disposal of organic solvents, and of course, the impact may be more detrimental.

Is it possible to recycle the water if contaminated from catalytic reactions that are conducted in water? Very recently, a micellar technology has been introduced by Lipshutz and co-workers where dissolution of 2% (w/v) of amphiphile named tocopherol methoxypolyethylene glycol succinate (TPGS-750-M) in water forms nanomicelles (43). The hydrophobic interior of nanomicelles has been harnessed for chemical catalysis. Coupling reactions including Suzuki-Miyaura, Buchwald-Hartwig amination, Sonogashira, Hiyama,

N2CHCO2Et+

Ph

1 mol% catalyst Ph

H H

CO2Et +H

Ph H

CO2Et

10% ee 6% ee

Catalyst

Ph

Ph

O

O N

NCu

(a)

(b) MeO

AcO

CO2H

NHAc

(i) Rh catalyst, H2

(ii) H3O+

MeO

AcO

CO2H

NHAcH

Scheme II Asymmetric catalysis at a very early stage. (a) The first reported asymmetric catalysis; (b) Knowles application of asymmetric catalysis in the synthesis of L-DOPA



Heck and C–H activation are well reported under micellar conditions. In addition, asymmetric gold catalysis, aerobic oxidation, ring-closing metathesis (RCM), Cu-H reductions, nitro reductions, trifluoromethylation and many more have been explored (Figure 2) (44). Interestingly, the authors are able to recycle the catalyst and reaction medium many times. Amphiphile TPGS and its components are environmentally benign and do not yield any toxic fragments. Recycling has been performed without any energy intensive procedure. Products of resulting reactions have been extracted by a minimal amount of organic solvent and the aqueous layer is reused for the next catalytic reaction.

Greener Reaction Media

Reaction medium is an important parameter to the success of any catalytic process and the isolation of its resulting product. Large amounts of organic solvents are annually consumed in chemical transformations. Dissolution of all components of a reaction including the resulting product is traditionally considered as beneficial, especially for reaction yield and determining reaction kinetics and mechanism. With the emergence of green chemistry, this parameter has received fresh attention as chemists have begun to seek alternatives

to conventional, oftentimes toxic, organic reaction media. Financial concerns also prompt this renewed consideration, since with conventional reaction media we first pay upfront for toxic solvents and then pay again in the end for their disposal. While a temporary answer is to focus on the use of greener solvents, such as using 2-methyltetrahydrofuran in place of water-soluble THF, alternative reaction media are currently needed that are not only green but also do not lead to the same waste streams.

One class of alternative reaction medium, ionic liquids, has been put forward as a safer choice than organic solvents (45), but despite the limited volatility, inert nature and relative stability of ionic liquids, risk of their post-reaction release into the environment is a significant concern. As Jordan and Gathergood noted: “The parameters of biodegradability, toxicity – and recently mutagenicity – are becoming more significant” (46).

Supercritical carbon dioxide presents a nontoxic, nonflammable alternative, but high pressure and temperatures are required to maintain CO2 in its liquefied state. It has been explored as a reaction medium in many valued reactions such as Pd-catalysed Heck reactions and Rh-catalysed hydroformylation (47).

Traditionally, fluorinated solvents have also been considered to be safer and greener media (48). This class includes perfluorinated hydrocarbons, fluorous amines and ethers. The characteristic supporting their greenness is their immiscibility with water, and thus, inability to contaminate water. However, their miscibility with water is temperature-dependent. Heating the fluorous-bound catalyst in a non-fluorous solvent leads to homogeneity, resulting in catalysis. After reaction completion, cooling provides the separation of phases and ease of product separation from the organic solvent layer. New fluorous solvents, catalysts and reagents are now available that drop the costs associated with bond constructions (49).

‘Switchable solvent’ is another technology assisting organic chemists to move away from using traditional organic solvents (50). Generally, switchable solvents reversibly change their physical properties in response to external stimulus such as a change in external temperature and addition or removal of gases. The ‘switchable’ solvent is also widely recognised for its practical applications to wastewater treatment, CO2 capture and solvent recovery. For example, dimethyl sulfoxide (DMSO) is a high boiling solvent and this property makes product isolation very difficult. Piperylene sulfone (51), a switchable solvent,

Fig. 2. Versatility of micellar approach for catalysis in water

Suzuki-Miyaura

couplings

Buchwald-Hartwig

amination

Sonogashira couplings

Nitro reductions

Many more

Cu–H reduction

C–H activation

Gold catalysis

Aerobic oxidation

Ring closing

metathesis

Water

Reactions take place here

Vitamin E core

TPGS-750-M



has been used to replace DMSO for nucleophilic substitution reactions. It is synthesised by reaction of trans-1,3-pentadiene and sulfur dioxide in the presence of a radical inhibitor. Heating the piperylene sulfone above 110ºC causes thermal decomposition back to the low-boiling starting materials (Scheme III). Thus, it is more convenient to recover the solvent and reaction product.

Modified Enzymes as Biocatalysts

An aqueous environment is also ideal for enzymatic processes, and many known transformations of synthetic utility can be effectively conducted (52). Extension of the repertoire to other valued but unknown organic transformations catalysed by naturally occurring enzymes is the area of directed evolution (Scheme IV) (53). With the aid of protein engineering, enzymatic properties can be fine-tuned through iterative mutagenesis, and then can be utilised as biocatalysts to perform target-oriented synthetic organic chemistry and enantioselective biocatalysis. In a Perspective titled ‘The Nature of Chemical Innovation: New Enzymes by Evolution’, Arnold elaborated on several ‘non-natural’ reactions that can be carried out by modifications of cytochrome P450-derived enzymes (54). Representative transformations using this approach include cyclopropanations (55), aziridinations (56) and regio-divergent aminations (57). Very recently, directed evolution of cytochrome c for carbon–silicon bond formation has been reported (58). Enzymes had not previously been known to catalyse C–Si bond formation. This conjuncture between living systems and synthetic organic chemistry is a stepping stone to mimic Nature. Using a similar approach, the same group were able to achieve enhanced catalytic activity of cytochrome c by a 15-fold increase in turnover rate relative to the state-of-the-art synthetic catalyst for C–Si bond forming reactions. The reaction proceeded with excellent yields and enantioselectivities over a broad substrate range. Such discoveries and developments represent a significant step forward for

mimicry of Nature in catalysis and a move away from scarce metal catalysed processes.

‘In Water’ and ‘On Water’ Catalysis

Notwithstanding, these milestones in exploring enzyme-mediated transformations in water are not the only simpler alternatives to traditional non-sustainable organometallic catalysis and organic solvents. Much better catalytic activities (ee’s, functional group tolerance and yields) have been observed while conducting the reactions with modified enzymes in water. Although reactions ‘on water’ are very well explored (59, 60), further advances are still needed regarding the interactions involved between substrates, catalysts and water (61), this knowledge gap remains atypical within the synthetic community. Nonetheless, recent studies by Kobayashi and co-workers further demonstrate the synthetic potential of water in catalysis (62). In their report, a new nonracemic Cu(II) catalyst leads to asymmetric conjugate additions of the Fleming dimethylphenylsilane (PhMe2Si) residue in enones and enoates as well as unsaturated nitriles and nitro olefins, with ee’s ≥90%. Interestingly, neither the reaction partners nor the copper catalyst is soluble in water. Use of organic solvents including dichloromethane, THF, DMSO, methanol and ethanol provided lesser reaction yields and ee’s. The superior results with water may be due the formation of higher order aggregated states of the catalyst.

Low Catalyst Loadings

Annually, about a billion tonnes of bulk and fine chemicals are produced through metal-catalysed processes. A catalyst is generally used in sub-stoichiometric quantity as it is regenerated after completion of each catalytic cycle. From a pharmaceuticals industry perspective, it is equally important that the resulting product must be free from trace metal impurities which usually come from organometallic catalysts used in the process. Thus, process chemists prefer to use such metal catalysts at early steps of the synthesis. However, sometimes it becomes more challenging to remove trace metal impurities, especially if the product is either an active pharmaceutical ingredient or its intermediate. This problem can be easily solved if there is a provision of more robust catalysts, requiring very low levels of loading in accordance with the notion ‘low in, low out’. Thus, catalyst loading is also a very crucial parameter

Scheme III Switchable solvent approach. Piperylene sulfone as a DMSO equivalent

R = H, Me

RO O

SO2R +

S



for product purity, especially for pharmaceutical and material chemists.

There are many precedents for chemical transformations achieved with a very low catalyst loading (63, 64). However, many of them involve elevated temperature, microwave assistance, toxic organic solvents, dry reaction conditions, no opportunity to recycle the catalyst, limited substrate scope or excessive amounts of reactant. Despite these pitfalls, such contributions are steps toward sustainable catalysis.

Doucet and co-workers reported a low catalyst loading for ligand-free palladium-catalysed direct arylation of furans (Scheme V(a)) (65). Key features of this work include high reaction yield, better atom economy than traditional Suzuki-Miyaura couplings, very low catalyst loading, high turnover number (TON), high reaction yield and greater functional group tolerance with broad substrate scope.

A discovery of an artful RCM reaction by Dider Villemin and its further development through Grubbs and Schrock catalysts provided a new route to synthesise cyclic hydrocarbons (66). With low catalyst loading, it has been explored on many substrates (Scheme V(b)). In his study, Kadyrov observed the efficiency enhancement with volatilisation of byproduct ethylene, leading to an increase in turnover frequency (TOF) up to 4173 per minute at 50 ppm catalyst loading (67). With the catalyst loading between 50 and 1000 ppm, 5- to 16-membered heterocyclic moieties have been synthesised. Key features of this methodology were its high TOF and broad substrate scope. A representative 7-membered cyclic ether was obtained with 86% yield at 100 ppm loading of B. Similarly, 16- and 18-membered lactones were obtained at 100–1000 ppm catalyst loading. However, yield of the 18-membered lactone was poor.

S

SiOEt

O

SiOEt

O

SiOEt

ORepresentative examples:

(a)

(b)

(c)

TON 210, 98% ee TON 630, 99% ee TON 5010, >99% ee

SiR H

+ Rꞌ ORꞌꞌ

O

N2 Rma cyt c V75T M100D M103E

Buffer (pH 7.4), Na2S2O4 RT, 4 h O

Rꞌ ORꞌꞌSiR

H

98–99% ee TON 210–8210

nPr

n-Pr

O OS

N3

Enzyme P411BM3– CIS-T438S-I263F

25ºC, 12 h

O OS NH

Me

nPr+

nPrO OS

NH

Et97% ee 99% ee

Selectivity 95:5

OEt

O

NEt2

OPh

N2

P-450 catalysed cyclopropanation NEt2

O

NH3Cl

PhNEt2

OPh

CO2EtLevomilnacipran

Scheme IV Nature directed enzymatic catalysis. (a) Enantioselective carbon-silicon bond forming reactions; (b) enzyme controlled regiodivergent amination; (c) enantioselective synthesis of levomilnacipran via enzymatic cyclopropanation

+



Catalysis under mild conditions with low catalyst loading along with the opportunity for in-flask recycling of a reaction medium, all in a single package, is well developed by our team (68). A highly valuable and truly general Suzuki-Miyaura cross-coupling catalysed by ppm levels of palladium is just the tip of the iceberg. In one of our reports, a very general, high yielding cross-coupling process with broad substrate scope operating by way of an iron-based nanomaterial containing ppm levels of palladium impurity has been disclosed (Scheme VI) (69). A specific method of nanomaterial generation was crucial for the catalytic activity, namely SPhos as an ancillary ligand, THF as a solvent for formation of nanoparticles, FeCl3 as the iron source, a Grignard reagent as a reductant, and above all, correct stoichiometry of all components. Stability and composition of the nanomaterial was very well established from the physical data including thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy

(XPS), atomic force microscopy (AFM) and transmission electron microscopy (TEM). The reaction medium was also crucial for catalytic activity and TPGS-750-M aqueous solution was the optimal choice with the added benefit of being a greener solvent. Both the catalyst and reaction medium were recycled without any energy intensive separation processes. Extraction of product with a minimum amount of organic solvent usually left the aqueous components containing the active catalyst.

This technology is applicable to a wide range of substrates including a variety of aryl chlorides, bromides and iodides. Different boron nucleophiles such as aryl boronic acids, boronic acid pinacol (Bpin) esters, potassium trifluoroborate salts and N-methyliminodiacetic acid (MIDA) boronate esters are well tolerated. The beauty of this process lies in the participation of earth-abundant metal, the small excess of boron nucleophile needed, mild reaction temperature, no trace metal contamination to the product and the

OR OR+

Br 100–10,000 ppm Pd(OAc)2

KOAc (2.0 equiv.) DMAc, 150ºC, 24 h

(a)

(b)

O O OnBu nBu NC

NC

CHO CHO

100 ppm Pd, 91% 1000 ppm Pd, 70% 1000 ppm Pd, 63%

Catalyst

N NMes Mes

RuCl

ClPCy3

A B

PhN NMes Mes

RuCl

ClPCy3

S

Me Me

O N

OO

O

Representative products:

TOF 130 TOF 26 TOF 1100 86% yield 89% yield 24% yield Cat. loading 100 ppm B Cat. loading 1000 ppm A Cat. loading 100 ppm B

O

O

O

O

Scheme V Transition-metal catalysis at ppm levels of catalyst loading. (a) Direct arylation of furans; (b) ring-closing metathesis



recyclability of the catalyst as well as of the reaction medium. Good functional group tolerance and high reaction yields further lend to its practical application.

Continuing the evolution of sustainable cross-coupling chemistry using ppm levels of palladium, ligand-based technology has also been reported to facilitate low loading levels in water (68). In addition to the salient features of the Fe/ppm palladium approach, this technology includes rational ligand design supported by density functional theory (DFT) calculations, operational simplicity, no elevated reaction temperature and no need for excess of coupling partners. In this methodology, the highly effective ligand HandaPhos combined in a 1:1 ratio with palladium acetate leads to a precatalyst that upon in situ reduction yields a very powerful catalyst to achieve the desired catalysis at room temperature under micellar conditions (Scheme VII).

Although transition-metal free Suzuki-Miyaura cross-couplings have been claimed (70), reassessment of

such microwave assisted reaction conditions confirmed the involvement of palladium species in the catalytic cycle, albeit at parts per billion levels (71). Thus, metal still appears necessary for these processes, but exceptionally low loadings are possible.

Metal-Free Catalysis

Another alternative to strengthen sustainable chemical catalysis is the metal-free platform of organocatalysis (72). However, organocatalyst-promoted reactions suffer from many drawbacks including low catalyst efficiency, long reaction time, difficulty in recycling the catalyst and almost no activity for activation of challenging chemical bonds such as the mC–H bond of an aryl ring. L-proline has been thoroughly explored in asymmetric organocatalysis, especially for conjugate addition reactions (73). The limitation of such transformations is the same as in typical organocatalyst-promoted reactions, and thus, not truly sustainable in

N

N

BnN

N

OMeOHC

OPO(OEt)2OMe

X = Br, Y = Bpin X = I, Y = B(OH)2 X = Br, Y = B(OH)2 X = Cl, Y = B(MIDA), 40 h, 76% 24 h, 77% 24 h, 88% 20 h, RT, 94% X = Br, Y = B(MIDA), 33 h, 85% X = I, Y = B(MIDA), 29 h, 87%

N Me

O

NO

NBoc

X = Cl, Br, I

[B] = B(OH)2, Bpin, BF3K, MIDA

X

[B]

Fe/ppm Pd nanoparticles

Fe/ppm Pd*

K3PO4•H2O (1.5 equiv.) 2 wt% TPGS-750-M 0.5 M, RT–45ºC

COOMe

BnO

OBnTs

N

O

O

X = I, Y = B(OH)2 X = Br, Y = B(MIDA) X = Br, Y = BF3K X = Br, Y = B(OH)2 48 h, RT, 81% 48 h, 80% 20 h, RT, 91% 26 h, 85%

OMe

OMeN

N

OMeOMe

NN

CF3 CF3

F3C CF3

O

O

F

O OO

H N

Cy

+

Scheme VI Fe/ppm-Pd catalysed sustainable and truly general Suzuki-Miyaura couplings. *FeCl3 (5 mol%), SPhos (5 mol%), MeMgCl (6 mol%), K3PO4•H2O



nature. Very cleverly, through mechanistic insights, Wennemers and co-workers achieved catalyst loadings down to 1000 ppm without affecting the ee and overall yield (Scheme VIII) (74). In their study, it was found that the presence of water slowed down the formation of the key enamine intermediate. Therefore, dry reaction conditions are required to achieve this metal-free catalysis at ppm levels. The need for dry conditions is a major problem that chemists usually encounter while designing practical sustainable catalytic methods.

Recent growth in the area of photocatalysis is another step toward mimicry of natural catalysis (75). However, typical involvement of the scarce metal iridium may be an issue in the long run. Fortunately, many metal-free and main group element-promoted photoredox processes have been reported, helping to address this concern (75). Elegant advancement in the area of metal and peroxide-free, scalable and clean photoinduced trifluoromethylation of arenes by C.-J. Li

and co-workers has eased the installation of the highly valuable trifluoromethyl group on various arenes (Scheme IX) (76). So far, this is the most sustainable way to achieve such trifluoromethylation, especially at gram scale under very mild conditions and with good functional group tolerance. However, there is still plenty of room for further advancement as this process is comparatively less efficient for electron-poor arenes.

Catalyst Recycling

By definition, a catalyst facilitates reactivity without being consumed in the process. If it is not consumed, then why is it predominantly treated as waste? Sometimes, in systems where catalyst recycling is not attempted, it survives exactly the length of the process, at which point it is still promptly destroyed as waste! The obvious financial and environmental costs of such an unsustainable approach have long spurred

Scheme VII Ligand-mediated sustainable Suzuki-Miyuara couplings at ppm level of palladium. No organic solvent is used for extraction or purification

N

N

CF3

CF3

F3C

CF3

O

OI

1.0 mmol

+

OB(MIDA)

1.0 mmol (99.9% pure)

Run 0 1 2 3 4Yield, % 90 90 89 91 90

O

CF3

CF3

F3C

CF3

O

N

N

O

1000 ppm [Pd], Et3N (2.0 equiv.)

2 wt% Nok (0.5 M), RT, 18 h

O

O OiPr iPr

iPr

1000 ppm HandaPhos

P

Scheme VIII Asymmetric organocatalysis with ppm level of a catalyst

NH

NH N

NH2O

O

OCO2HCatalyst

O

HR1

R2

R1

R2

+ NO2

0.1 mol% catalyst

CHCl3:iPrOH 9:1, RTNO2

O

H

R1 R2 ee, % Yield, %Et Ph 97 87

nPr Ph 96 98Bn C6H4-2-CF3 92 99



chemists to seek ways to reuse these catalysts across multiple reactions (77). Strategies for catalyst recovery generally involve catalyst immobilisation on separable supports or in biphasic solvent systems (78).

Heterogenisation is a widely-employed technique that often comes at the cost of catalytic activity, selectivity and metal leaching, which can limit the extent of recyclability. A compelling illustration of the potential for this approach to overcome these limitations was recently provided by Tu and co-workers, who reported the development of a robust ruthenium-NHC coordination polymer for solvent-free reductive aminations (79). The solid catalyst could be easily recovered by centrifugation and decanting. It was able to catalyse the synthesis of 5-methyl-2-pyrrolidone from levulinic acid at a 1500 ppm catalyst loading through 37 recycles without significant loss of activity. A second strategy, magnetic-metal nanoparticles, represents an alternative ‘semi-heterogeneous’ system for organometallic catalysts that is easily separable from the bulk reaction medium by use of an external magnet. Catalysts anchored to metal nanoparticles have competitive activities and enantioselectivities compared to their homogeneous analogues (80).

A third strategy, biphasic solvent system, allows for recovery of unmodified homogeneous catalysts by dissolving the products in one layer while retaining the catalyst in another. As noted above, a similar but distinct approach is micellar catalysis. Micellar catalysis has been advanced as a viable strategy to both recover catalysts and minimise solvent waste (12). A key appeal of this strategy is its generality: rather than requiring development of a new immobilised catalyst system for each specific reaction, this approach readily accommodates

existing homogeneous technology into a recyclable gross reaction medium. The extent of the generality is so great that multiple, diverse transformations can be performed sequentially in one pot.

Environmental Metrics

Environmental metrics are important evaluation tools for any chemical process, especially from an industrial point of view (81). Micellar chemistry is an important development in the field of synthetic methods to address issues pertaining to sustainability. Indeed, a most outstanding feature of this chemistry is the overall high mass efficiency. This approach, particularly to novices, appears as counterintuitive, but the micellar environment in which the chemistry occurs possesses some remarkable features.

There are two key components responsible for the efficiency of methods involving micellar chemistry. Firstly, reactions are usually best facilitated by very high concentrations of substrates and catalyst. While transformations in traditional organic solvents tend to proceed at concentrations of 1% to 20% by weight, with 5% being routine after optimisation, corresponding reactions in water under micellar conditions are typically achieved at 10% to 50% by weight, and routine use of 20% is possible with limited effort. The dynamic exchange between the medium and the micelles, a site where actual chemistry takes place whether at the interface or inside the micelles, makes the chemical transformation possible, despite the very minute solubility of reaction partners. Secondly, such transformations typically exhibit very high reactivity and selectivity. Hence, they require very minimal post-reaction processing. Sometimes after the reaction

O O

O

OH

OMeNOMeMeO OMeMeO

CF3CF3CF3

MeMe

MeN

NN

MeOMe

CN CF3

CF3CF3

tButBuN

N N

H N

N H

81%, gram scale 71%, gram scale 71% 65% 75% 65%

Scheme IX Clean, peroxide- and metal-free trifluoromethylation

F3C

R Rhn

Acetone+ CF3SO2Na R

CF3>400 nm

EtOAc:diacetyl (4:1)



completion, only a simple filtration of almost pure solid product is required; otherwise, a simple one-time extraction with a minimum amount of solvent for direct isolation of the product is usually sufficient. Perfect reaction selectivity is possible due to the very mild reaction conditions with almost ideal stoichiometry of reactants. The simple filtration procedure is typically favoured for catalytic transformations where a limited amount of side-products are formed. Due to the very limited excess of reaction partners and very low catalyst loading, this approach requires limited effort in product processing. Extraction is the preferred option for stoichiometric transformations where the amount of side-products formed is still substantial.

Standard catalytic and stoichiometric processes performed on scale in our laboratories and production facilities highlight the performance of the technology, as can be exemplified by Scheme X with standard depiction of the key operations in processes, and their corresponding metric analyses (Table I). Efforts were made to find better practical ways of addressing the safety and environmental impact of the process. Our efforts span over a range of concerns such as the

identification of the most efficient synthesis with regard to atom economy and reaction yields, the use of safe and less hazardous chemicals, the elimination or reduction of waste and the number of operations, all with the additional goal of reduced presence of toxic materials. These basic principles, the foundations of green chemistry, are well known to the scientific community (42). However, practical examples that illustrate their relevance are still scarce. We, therefore, wanted to demonstrate quantitatively the relevance of some of the well-accepted green chemistry metrics.

As a result of this work, it has proven possible to replace commonly used polar aprotic solvents, which suffer from reprotoxicity. The overall cycle time also improved dramatically due to a much-reduced number of operations and streamlined workup protocols. In addition, the new process increased the overall yield, mostly due to reduced mechanical losses (loss of material in the workup and purification steps in the original synthesis and during the isolation and purification operations). Finally, the streamlined synthesis minimised the need to handle potentially toxic material.

Scheme X One-pot double Suzuki-Miyaura couplings

NN N

N

N

CHO

ClCl

B(OH)2

O

Cl

F

B(MIDA)

F

NN

N

H

O1.05 equiv.

PdCl2(dtbpf) (1 mol%) Et3N (3 equiv.)

2 wt% TPGS-750-M/H2O (0.5 M), THF (5%), RT

1.05 equiv.

Et3N (2 equiv.) RT

2 wt% TPGS-750-M/H2O (0.5 M), THF (5%), RT

H

75%

Table I Comparisons of Environmental Metrics for One-Pot Double Suzuki-Miyaura Couplings shown in Scheme X

Metrics Standard process in organic solvents after optimisation Process in surfactant

PMIa 110 72

PMI solvents 57 30

PMI aqueous 38 35

PMI reagents 15 7

E factor 109 71

aPMI = process mass intensity



Conclusion

In concluding remarks, it can be inferred that organometallic catalysis is now a well-developed field. However, in terms of sustainability, considering the looming challenges, it is still in its infancy. Merging of various sub-disciplines has contributed significantly towards the emulation of Nature, but the discovery of new reaction pathways, especially for obtaining desired products from readily available starting materials, lags behind other efforts. Beyond C–H functionalisation, sustainable methods for C–F and C–C functionalisation need to be developed in order to include intensive use of biomass. Weighting curricula to green synthesis at undergraduate and postgraduate levels can help to disseminate more awareness to future generations of chemists. Tremendous discoveries made by our chemical community in the past ten years have made the challenging path forward a little easier, and with focused effort it will become much easier to sustain our blue planet.

Acknowledgments

The authors warmly appreciate the University of Louisville and Kentucky Science & Engineering Foundation for financial support (KSEF-148-502-17-396).

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The Authors

Justin D. Smith studied chemistry at the University of Kansas, USA, where he received a dual BS degree in cooperation with the University of Regensburg, Germany, as part of the Atlantis exchange programme. He is presently pursuing a PhD in chemistry under the direction of Professor Sachin Handa at the University of Louisville, USA.

Fabrice Gallou received his PhD from The Ohio State University, USA, in 2001 in the field of natural products total synthesis. He then joined Chemical Development at Boehringer Ingelheim, USA. He subsequently moved in 2006 to the Chemical Development group at Novartis, Switzerland, where he is now responsible for global scientific activities worldwide, overseeing development and implementation of practical and economical chemical processes for large scale production of active pharmaceutical ingredients (APIs).

Sachin Handa received his PhD in chemistry from Oklahoma State University, USA, in 2013 and subsequently worked as a postdoc at the University of California, Santa Barbara, USA, with Professor Bruce H. Lipshutz. In August 2016, he moved to Louisville, Kentucky, where he is an assistant professor in the Department of Chemistry at the University of Louisville. His research interests include sustainable photoredox chemistry, ligand design and catalyst development.


https://doi.org/10.1595/205651317X695875 Johnson Matthey Technol. Rev., 2017, 61, (3), 246–256


Industrial Low Pressure Hydroformylation: Forty-Five Years of Progress for the LP OxoSM ProcessA long standing collaboration between Johnson Matthey and Dow continues to sustain the high standing of their oxo technology through innovative solutions to address the changing needs of the global oxo alcohol market

By Richard TudorRetired, Reading, UK

Atul Shah*Johnson Matthey, 10 Eastbourne Terrace, London, W2 6LG, UK


Since the mid-1970s when the ‘Low Pressure Oxo’ process (LP OxoSM Process) was first commercialised, it has maintained its global position as the foremost oxo process, offering particular appeal to independent producers of commodity plasticisers facing increasing regulatory pressure. The story of this important industrial process is told from its early beginnings when laboratory discoveries by independent groups of researchers in USA and UK revealed the remarkable ability of organophosphine containing rhodium compounds to catalyse the hydroformylation reaction, and describes how its development, exploitation and continuing industrial relevance came about by collaboration between three companies: The Power-Gas Corporation, which later became Davy Process Technology before becoming part of Johnson Matthey; Union Carbide Corporation, which became a wholly owned subsidiary of The Dow Chemical Company; and Johnson Matthey.

Introduction

The LP OxoSM Process is the rhodium-catalysed hydroformylation process in wide use today in a variety of industrial applications. These applications have been developed, co-marketed and licensed as a cooperation between affiliates of The Dow Chemical Company (‘Dow’) and Johnson Matthey or their predecessors, for over 45 years.

The LP OxoSM Process first made an impact in the 1970s when its technical elegancy, environmental footprint and economics attracted huge attention by the world’s producers of normal butyraldehyde for conversion to the plasticiser alcohol 2-ethylhexanol (2EH).

The Early Dominance of Cobalt Catalysis

Hydroformylation is the reaction of an unsaturated olefinic compound with hydrogen and carbon monoxide to yield an aldehyde. In the case of the widely practised hydroformylation of propylene, the olefin (usually present in chemical or polymer grade propylene) is reacted with a mixture of hydrogen and carbon monoxide (in the form of synthesis gas), to produce two aldehyde isomers (normal butyraldehyde and iso-butyraldehyde) according to Equation (i):

2CH3CH=CH2 + 2CO + 2H2 → CH3CH2CH2CHO + (CH3)2C(H)CHO (i)


https://doi.org/10.1595/205651317X695875 Johnson Matthey Technol. Rev., 2017, 61, (3)

The hydroformylation reaction was first reported by Dr Otto Roelen of Ruhrchemie AG, Germany, in 1938 and was given by German researchers the description of ‘oxo’ synthesis. Alcohols synthesised by the hydrogenation of aldehydes produced from hydroformylation tend therefore to be called oxo alcohols. Roelen’s discovery was to lay the foundation for bulk organometallic chemistry and the application of homogeneous catalysis on an industrial scale. He originally employed as a catalyst a mixture containing cobalt, thorium and magnesium oxide that was commonly used for Fischer-Tropsch synthesis and later speculated that cobalt hydridocarbonyl (HCo(CO)4) was the catalytically active species. He realised that the catalytic mechanism was homogeneous in nature (for example (1, 2)). The Second World War hindered Ruhrchemie’s attempts to complete the construction of a first industrial oxo plant for producing fatty alcohols from Fischer-Tropsch olefins, and in the following years Ruhrchemie commercialised a number of hydroformylation processes using homogeneous cobalt catalyst for use in the production of detergent and plasticiser alcohols. By the end of the 1960s most plants were using the ‘classic’ cobalt process employing HCo(CO)4, operating at very high pressures in the range of 200 to 450 bar and temperatures between 140ºC and 180ºC, although a modification of this catalyst, cobalt hydridocarbonyl trialkylphosphine (HCo(CO)3PR3), had been commercialised enabling the hydroformylation of propylene to occur at about 50 bar. This phosphine modified cobalt catalyst also gave improved selectivity to the preferred normal butyraldehyde, the isomer ratio (normal:branched aldehyde or ‘n:i ratio’) being about 7:1 rather than the 3:1 that was typical of the classic cobalt process. To this day, cobalt catalysts are still being used industrially in some hydroformylation applications, especially in the manufacture of detergent alcohols from long chain olefins produced by ethylene oligomerisation and the production from butene dimers and propylene trimer of the plasticiser alcohols iso-nonyl alcohol (INA) and iso-decyl alcohol (IDA) respectively.

The Beginnings of the LP OxoSM Process

In the 1960s researchers at the chemicals producer Union Carbide Corporation (now a wholly owned subsidiary of The Dow Chemical Company, USA) in Charleston, West Virginia, USA, and a group led by the late Professor Sir Geoffrey Wilkinson (later to

become a winner of the Nobel Prize for Chemistry) at Imperial College London, UK, found independently that rhodium compounds containing organophosphines could catalyse the hydroformylation reaction at mild temperatures and pressures and with high selectivity to linear aldehydes (2, 3). Wilkinson’s research was supported by the precious metal refiner and processor Johnson Matthey who supplied rhodium through a loan scheme inaugurated in 1955 that did much to foster university research in platinum group metals chemistry in the UK and overseas. Wilkinson later proposed that the rhodium complex responsible for catalysing hydroformylation reactions was tris(triphenylphosphine)rhodium(I) carbonyl hydride (RhH(CO)(PPh3)3) and that high selectivities to normal aldehyde could be achieved using a large excess of phosphine ligand (for example (4, 5)). In the late 1960s Johnson Matthey and The Power-Gas Corporation decided to seek worthwhile opportunities to collaborate in research projects. The Power-Gas Corporation was a full services engineering and construction contractor of considerable international repute with a strong process engineering base, and had recently restructured its research and development activities meaning it was looking for process development projects. By early 1970, The Power-Gas Corporation had broadly confirmed in its Stockton-on-Tees laboratory Wilkinson’s proposition that high n:i ratios can be obtained with a large excess of phosphine. Further encouraged by preliminary process engineering evaluation work, The Power-Gas Corporation concluded in a 1970 letter to Johnson Matthey that a proposition for a low pressure propylene hydroformylation process using a homogeneous rhodium based catalyst would be “economically attractive when compared with what we currently know of processes as they are operated today”. By the middle of the year, Johnson Matthey and The Power-Gas Corporation had entered into a new, but far more wide-reaching collaboration aimed at developing a commercial, licensable hydroformylation process initially directed at the conversion of propylene to 2EH. The agreement was followed by co-ordinated programmes of further research, testing and studies of reaction kinetics in the laboratories of both companies. The Power-Gas Corporation did process scale-up work and process designs based on predicted optimum reaction conditions. Johnson Matthey investigated how it would manufacture commercial quantities of a suitable rhodium catalyst precursor and also economically manage the recovery of rhodium



from used catalyst. Based on information describing Union Carbide Corporation’s activity found in literature searches, Johnson Matthey and The Power-Gas Corporation decided to visit Union Carbide Corporation in the USA in October 1970. It became evident from early discussions that Union Carbide Corporation had made significant progress on the experimental front but also that Wilkinson’s results complemented the Union Carbide Corporation findings. After confidential disclosures had been made between them, three independent companies in different, but overlapping, fields found they had mutual and complementary interests and contributions to make in developing potentially revolutionary chemical technology:• Union Carbide Corporation: A chemicals producer

having experience in the operation of cobalt oxo systems with their huge shortcomings. Union Carbide Corporation regarded the potential for rhodium with guarded excitement and in the early 1970s was awaiting market conditions to improve before deciding whether or not to develop a commercial rhodium process for its own use in a new oxo plant

• Johnson Matthey: A precious metal refiner and processor seeking opportunities to increase its product range and market reach

• The Power-Gas Corporation: A process engineering contractor with wide experience in chemical projects, international sales and marketing, which saw the potential relationship between oxo synthesis chemistry and the design and supply of plants for producing gases, notably hydrogen and carbon monoxide, on which it had a long history.

In August 1971, the parties agreed to collaborate to develop and market low pressure rhodium catalysed oxo technology for use with certain olefinic feeds.

Commercialisation and Start of Licensing

A collaborative process engineering and plant design exercise by Power-Gas Ltd (the new name of The Power-Gas Corporation) and Union Carbide Corporation resulted in even better economics of the propylene LP OxoSM Process than previous studies. An upturn in the market was followed by a decision by Union Carbide Corporation to build a plant at Ponce, Puerto Rico having a nameplate capacity of 136,000 tonnes per year of normal and iso-butyraldehydes to replace a cobalt catalysed plant. The new plant would use the homogeneous triphenylphosphine (TPP)

modified rhodium catalyst discovered by Union Carbide Corporation and proposed by Wilkinson. Union Carbide Corporation took the precaution of building a pilot plant at Ponce so that operating data could be available during the construction of the main plant. The choice of location meant the catalyst could be tested using the commercial feedstocks that were to be used in full-scale operations. Data from the pilot plant tests calibrated the process engineering design of the commercial plant that was being carried out by Davy Powergas (another name change!) in London. Following its decision to build a butyraldehyde plant, Union Carbide Corporation decided to fast-track an ethylene hydroformylation project at Texas City, USA. The plant started operations in April 1975 ahead of the Ponce plant, which started in January 1976. The commissioning of both plants went smoothly and plant performance was better than expected. At Ponce, the rhodium catalyst operated at less than 20 bar and at a temperature between 90ºC and 100ºC, much milder conditions compared to cobalt. The isomer ratio, comfortably above 10, showed a more than threefold improvement and the lower reaction temperature resulted in significantly less byproduct formation. The product aldehyde was much ‘cleaner’, resulting in cost savings in product work-up and eliminating the effluent treatment measures that were needed during cobalt operations (6). With the Ponce plant continuing to operate well and very reliably, uncertainties about the robustness of the rhodium catalyst and the reliability of kinetic models developed in the laboratory abated. Projections of catalyst life and rhodium related costs were looking much more favourable than had been assumed. The expected large improvements in yield to desired product normal butyraldehyde, utility costs and environmental impact were confirmed. A new propylene oxo process was heralded that was far superior to the cobalt process Union Carbide Corporation had built and operated at Ponce – which shared many of the characteristics of the cobalt technology then being used by most of the world’s 2EH producers. The investment capital needed for a LP OxoSM Process plant was less than for a cobalt plant equivalent because of a simpler flow-sheet, cleaner product and other factors. The lower operating pressure meant in most cases expensive compression of the incoming synthesis gas could be avoided.

In 1977, Union Carbide Corporation, Davy Powergas Ltd and Johnson Matthey won the prestigious Kirkpatrick Chemical Engineering Achievement



Award “for outstanding group effort in new chemical engineering technology commercialised in the last two years”. In its dissertation the award sponsor, Chemical Engineering, stated the new LP OxoSM Process “yields a better product mix and also features low capital needs, effective use of feed, and negligible environmental impact” (7). With such a testimonial the Ponce plant became the target of numerous client visits and by the end of 1978 several companies had committed to build LP OxoSM process plants under licences granted by Davy Powergas in conjunction with Union Carbide Corporation.

Behind the successful commercialisation of the LP OxoSM Process, both Union Carbide Corporation and Davy had intensified their development work in laboratories in the UK and the USA. This was initially aimed at improving the LP OxoSM Process for propylene applications, then the single focus of market interest. An early effort was made in the laboratory by Union Carbide Corporation to find a way to mitigate the negative cost impact of what was termed ‘intrinsic’ catalyst deactivation. This was predictable deactivation attributable to the formation of clusters of monomeric rhodium species, as distinct from deactivation caused by external causes such as the presence of poisons in the feedstocks (6). Union Carbide Corporation’s efforts were to pay dividends (see later). Away from the laboratory, Davy process engineers had visited Union Carbide Corporation plants to gather design and operating data on the industrial scale conversion of butyraldehydes to alcohol end products. This led to the two companies agreeing the process basis of alcohol technology offerings sought by licensees wishing to use ‘Union Carbide Corporation and Davy’ technology for both the propylene hydroformylation step and the conversion of butyraldehydes to 2EH and possibly normal and iso-butanols. See Figure 1.

The Early Licensed PlantsIn May 1980, the first two licensed plants to be completed went into operation – in Sweden and in the Federal Republic of Germany (Figures 2 and 3). These had a combined nameplate capacity of over 300,000 tonnes per year of butyraldehydes. Ten years on, nine further plants had started: three in Japan, two in China and plants in the Republic of Korea, the USA, Poland and France. By 1990, the LP OxoSM process was producing about 1.5 million tonnes per year of butyraldehydes, about half of this from seven cobalt ‘conversion’ projects. By 2000, no butyraldehyde was being produced by cobalt technology anywhere except in Russia, which remains so today. All the licensed plants used the TPP-modified rhodium catalyst giving typical n:i ratios of circa 10:1 to 12:1. The catalyst existed in the same medium as the feedstocks and liquid reaction products in stirred, back-mixed reactors. The plants used the ‘gas recycle flow-sheet’ employing in situ gas stripping to separate reaction products from catalyst to provide a simple and affordable process design. In Part I of a two-part article (6), Tudor and Ashley explained the thinking behind this choice of flowsheet. Central to this was uncertainty and concerns regarding catalyst deactivation and the containment or loss of expensive rhodium. Union Carbide Corporation operators found it easy to operate gas recycle reactors to achieve smooth, stable and dependable plant performance without undue concerns about the life or security of the rhodium catalyst, and gas stripping was accordingly adopted as the norm for all of the first generation of plants using the LP OxoSM Process. Laboratory work by Union Carbide Corporation on intrinsic deactivation had led to the discovery of a catalyst reactivation technique that could in effect reverse in days the effect of months of progressive activity decline because of rhodium clustering (6). Most of the early licensees

PropyleneSyngas

LP OxoSM

n-Butyraldehyde

n- + iso-Butyraldehyde

Aldolisation Hydrogenation

Hydrogenation

Hydrogen

Hydrogen

Product refining

Product refining

2-Ethylhexanol

n-Butanoliso-Butanol

Fig. 1. Schematic showing the production of oxo alcohols from propylene by the LP OxoSM Process



Fig. 2. Butyraldehyde plant built by Chemische Werke Huels at Marl, Federal Republic of Germany, taken in 1980

Fig. 3. The Davy, Union Carbide Corporation and Johnson Matthey start-up advisory team at the Marl plant, taken in 1980

included in their plants the equipment needed to achieve such catalyst reactivation and used it to good effect to carry out repeated reactivations on what was essentially a single rhodium catalyst charge. This drastically reduced the need for off-site rhodium recovery and the reprocessing of recovered rhodium to the catalyst precursor.

Liquid Recycle Opens Up New HorizonsIn the first half of the 1980s, with original concerns about catalyst life and security largely behind them, Union Carbide Corporation and Davy turned their attention to a new flowsheet concept employing the ‘liquid recycle’ principle. This involved separating the reaction products from the catalyst solution in equipment outside the oxo reactor, using a proprietary design of vaporiser (8). By decoupling the hydroformylation reaction step from the physical process of product and catalyst separation, it became possible to choose a reaction regime to optimise the reaction conditions without, for example, having to use temperatures high enough to ensure effective product removal by gas stripping. Liquid recycle would also enable designers to significantly reduce the size of reactors, which for gas recycle had to be large enough to accommodate expansion of the liquid phase by the entrainment of bubbles from a large recycle gas flow. Such were its benefits that nearly all plants designed after the late 1980s used liquid recycle. Several of the earlier licensees, eager to exploit freed-up reactor volume, switched from gas to liquid recycle operation, in some cases nearly doubling the outputs of their oxo units from the same reactors.

Liquid recycle technology is today extensively used with enormous success across all applications of the LP OxoSM Process. It has provided designers greater scope for chemical engineering creativity when evaluating flow-sheet options for catalyst innovations and new non-propylene developments.

Polyorganophosphite-Modified Rhodium

The early 1990s saw the emergence of a more advanced polyorganophosphite-modified catalyst that would offer considerable appeal over its TPP counterpart, giving a much improved n:i ratio and other benefits (8). Polyorganophosphite-modified rhodium catalysts are very reactive and show good regioselectivity (selectivity to the straight chain aldehyde) in comparison with phosphine-modified catalysts such as TPP. Union Carbide Corporation overcame a major limitation of these new ligands, namely their instability in the presence of aldehydes, through the discovery and development of ligand stabilisation systems. Union Carbide Corporation first used the new ligand in 1995 in a new butanol plant at St Charles, Louisiana, USA, in the anticipation it would deliver an n:i ratio of about 30:1. The design of this plant, with certain improvements and



accumulated operating know-how became the basis of an advanced propylene LP OxoSM Process using polyorganophosphite-modified catalyst. Compared to TPP, it offered significant improvements to feedstock utilisation efficiency, selectivity to normal butyraldehyde, rhodium inventory and catalyst life. The success of technology, design and operating measures that Union Carbide Corporation had developed in the laboratory to overcome concerns about the stability of the polyorganophosphite-modified catalysts had pleased Union Carbide Corporation enormously, the catalyst at St Charles showing remarkable robustness and no signs of activity loss over a prolonged period, with hardly any rhodium usage. A significant gain (by about 7%) in yield to normal butyraldeyde and the reduced operator attention and plant down-time needed to operate the polyorganophosphite catalyst and manage its life cycle stood out as particular cost benefits compared to TPP.

Today, two Union Carbide Corporation owned butanol plants use the polyorganophosphite-modified catalyst using ‘LP OxoSM SELECTORSM 30’ technology, so named to reflect its proven capability of achieving an n:i ratio of at least 30:1. Seven of nine propylene plants so far licensed to use SELECTORSM 30 are in operation, including two examples of where existing licensees elected to retrofit the technology into TPP plants originally built many years earlier to use (retrospectively called) ‘SELECTORSM 10’ technology. Some of these plants now achieve n:i ratios greater than 30:1.

The Propylene LP OxoSM Process Today

The introduction of the polyorganophosphite-modified catalyst system in place of TPP has boosted propylene efficiencies and cut costs needed for seeing out the complete rhodium life cycle. In addition, various patented process enhancements have been introduced and the economics of practically all areas of the flow-sheet improved. Today the process is the source of about 70% of the world’s butyraldehyde and about 90% of licensed-in propylene oxo technology. Nearly all licensees convert butyraldehyde products to 2EH or butanols, and the aldehyde to alcohols part of the flow-sheet has been progressively improved through studies, development projects and catalyst programmes. These have improved the aldol condensation step, and for hydrogenation introduced improved catalysts and reactor designs. On the latter, major capital savings have been made by making more

use of liquid phase hydrogenation in place of vapour phase which was used in earlier designs, eliminating the need for a cycle compressor and simplifying the reactors.

Non-Propylene Applications of the LP OxoSM

Technology

By the early 1990s, shifts in markets and client enquiries called for a broader reach of possible applications for the LP OxoSM technology. In response, Union Carbide Corporation and Davy set new development trajectories that eventually resulted in new licence offerings for several non-propylene applications.

C7 and Longer Chain Alpha Olefins

The first non-propylene applications were two plants licensed and built by Sasol at Secunda in South Africa. Both of them produced alcohols from alpha olefins sourced from fuel product streams from Sasol’s coal based ‘Synthol’ Fischer Tropsch operations. The first started production in 2002 of C12–C13 ‘Safol®’ detergent alcohols using a C11–C12 olefin fraction as feed (Figure 4). The second was commissioned in 2008 for producing octanol from a 1-heptene fraction for subsequent conversion to co-monomer grade 1-octene. The designs of both plants resulted from development programmes by Davy at their Technology Centre in Teesside, UK, tightly tailored to Sasol’s requirements.

Fig. 4. Surfactant alcohol plant built by Sasol at Secunda, Republic of South Africa



The detergent alcohol development, being the first, was the most demanding and at the outset two areas stood out as being crucial to a successful outcome. Both stemmed from the characteristics of the designated Sasol C11–C12 alpha olefins feed. Firstly, Davy’s lack of familiarity with such feeds and the uncertainty of how the Sasol feed would perform over time under hydroformylation conditions suggested innovative techniques would be needed to identify and remove impurities that could harm the rhodium catalyst. Secondly, there would be a need for continuous purging of high boiling ultra-heavy reaction byproducts and this could be a source of significant rhodium ‘loss’ placing an undue burden on the economics of the process. This could be so despite Sasol engaging a third party precious metal refiner to recover and reprocess that rhodium off-site.

In the commercial plant, the feed was to be separated as a C11–C12 cut in a fractionation system before being treated primarily to remove impurities known to be detrimental to the oxo catalyst. Early screening tests done by Davy on the reactivity of representative samples of the pre-treated C11–C12 cut were promising, but it became evident that amongst the huge number of chemical constituents of the feed was at least one ‘bad actor’, possibly several, affecting the rhodium catalyst. It took considerable experimentation – some of it very conjectural – and then further testing in the mini-plant proving run (see below) to develop and prove a further pretreatment step for removing suspected offenders from the feed to acceptable levels. A need to address the extent of rhodium loss in the ultra-heavies’ purge stemmed from the high molecular weights of aldehyde products and the very high boiling, undesirable byproducts formed from aldol condensation and other reactions. This meant that whatever operating regime was adopted to effect the physical separation of desired aldehyde product from catalyst and reaction byproducts, rhodium catalyst would be present in the necessary ultra-heavies’ purge. This too got much attention during the mini-plant run and data collected on the extent of purging needed provided the basis of projections of the economic implications for the commercial plant.

Davy custom built a ‘mini-plant’ that was configured to simulate the entire olefin to alcohol processing scheme proposed by Davy when fed with Sasol supplied C11–C12 feed. This was used for a four-month demonstration run of the process, at the end of which Davy had done all the testing and evaluation considered necessary

and had assembled sufficient data to provide a platform for the design of the commercial plant as well as projections of its performance, including the expected rhodium usage. Davy subsequently used data on reaction kinetics and other information obtained from the proving run to do the process design of a commercial plant with a throughput about 20,000 times greater.

Before the start-up of the Safol plant, Davy and Sasol discussed the potential benefits of a patented proprietary rhodium recovery process that was being developed by Davy. The proposition was a process that would remove and recover most of the largely deactivated rhodium present in the ultra-heavies purge stream before recycling that rhodium for reuse in the reaction system as active catalyst. Tests done by Davy later confirmed the effectiveness of the patented technology and a compelling economic case emerged for it being adopted by Sasol. Its use would eliminate much of the cost burden of having to engage a precious metal refiner to extract the rhodium in the purge. Sasol built the rhodium recovery process to work in conjunction with both the Safol plant and the new octanol plant, which have shared its large benefits since.

Normal Butenes to 2PH

In the 1980s the phthalate ester of the ‘workhorse’ C8 plasticiser alcohol 2EH – the ‘C8’ plasticiser di-octyl phthalate (DOP) (or di-2-ethylhexyl phthalate (DEHP)) – was coming under increasing regulatory pressure and polyvinyl chloride (PVC) plasticiser producers were paying increasing attention to higher molecular weight ‘C9’ and ‘C10’ phthalate plasticisers produced from C9 and C10 alcohols. These phthalates, containing 9 and 10 carbon atoms in each ester chain respectively, had better migration and volatility (fogging) properties and were seen as being more suitable for PVC uses where these and other properties, such as their good weathering behaviour, were especially required. A few oxo operators were manufacturing INA or IDA from butene dimers and propylene trimers – produced by oligomerisation of refinery light olefins – respectively. Market outlets for their corresponding phthalate plasticisers, diisononyl phthalate (DINP) and diisodecyl phthlate (DIDP), had been established, and some of them were niche applications that could bear a price premium compared to DOP. Overall however, their usages were small compared to DOP partly because of the wide availability of the latter. DOP was also



cheaper, largely because of the low production cost of 2EH compared to INA and IDA. With market interest in these higher molecular weight plasticisers increasing because of their perceived environmental, health and safety performance advantages, several companies, most of them 2EH producers, contacted Union Carbide Corporation and Davy with an interest in the production from normal butenes of 2-propylheptanol (2PH), a C10 alcohol. No 2PH was then being made industrially but Union Carbide Corporation and Davy saw the results of tests from a number of sources showing the promise of the phthalate ester of 2PH, DPHP, as a PVC plasticiser. DPHP displayed some of the performance characteristics of DINP and DIDP and was also seen as a potential substitute for DOP in some PVC applications.

Before these early signs of market interest, Union Carbide Corporation and Davy had anticipated the potential attractions of a 2PH process and had conducted hydroformylation trials in the laboratory with 1-butene using TPP-modified rhodium catalyst. The proposed 2PH process was similar to the 2EH process Davy had already licensed with a notable exception. Experimental work had shown the ratio of normal to branched valeraldehyde product achievable with TPP was about 20:1 compared to the 10:1 to 12:1 typical of propylene. The expensive aldehyde isomer separation step needed for 2EH production was therefore omitted before aldol condensation and hydrogenation steps and product 2PH refining. This meant the commercial 2PH product would actually contain 2-propylheptanol as the principal component (meaning >85%) in an isomeric mixture of C10 alcohols. And with butene feeds other than higher value co-monomer grade 1-butene then having transfer prices typically between 55 and 70% of the price of purchased propylene, early studies had indicated that 2PH produced from a refinery sourced raffinate-2 stream could be produced with a significant cost advantage over 2EH. This TPP based technical platform formed the basis of the responses to early market interest in 2PH, but later on it was further enhanced following the introduction of more advanced proprietary ligands. Potential 2PH producers tabled C4 feed-stream specifications with significant concentrations of 1-butene and 2-butene (both cis- and trans-) as well as non-reactive butanes. The use of the much more reactive proprietary ligand in place of TPP meant the less reactive 2-butene component was now able to contribute significantly to product yield. It could therefore convert a much larger

slice of the C4 feed-stream to 2PH, meaning higher normal butene conversion efficiencies while preserving relative isomer selectivities. Eventually, as the pull from PVC producers seeking greater versatility and improved long-term property retention in plasticisers intensified, several oxo producers instigated projects to build the first 2PH plants. In 2007, and after Davy Process Technology had become part of Johnson Matthey, Dow and Johnson Matthey licensed a normal butenes hydroformylation facility in Europe using a proprietary ligand modified rhodium catalyst system to produce mixed valeraldehyde from a C4 raffinate feed for conversion to 2PH. Following the successful start of this plant in 2009, a second licensed plant started in Asia in 2012. Soon afterwards two Chinese companies launched 2PH projects, both incorporating Dow and Johnson Matthey hydroformylation, aldol and hydrogenation technology. The first of these, with a capacity of 60,000 tonnes per year, successfully started operations in 2014. The second is being built by a licensee in the Shaanxi Yanchang Petroleum group for producing 80,000 tonnes per year of 2PH in tandem with butanols.

Since 2008, the global use of 2PH has increased more strongly than either of the other higher plasticiser alcohols INA and IDA. Its C10 phthalate ester has been widely accepted as a PVC plasticiser in Europe, the USA and China. By 2019, the global annual production of 2PH is expected to exceed 500,000 tonnes, of which over two thirds will be made using a butene fed LP OxoSM facility. Commercial C4 streams suitable for feeding to plants utilising the Dow and Johnson Matthey 2PH technology include raffinate streams from steam naphtha crackers: either raffinate 2 largely depleted of iso-butene, such as streams available from methyl tert-butyl ether (MTBE) plants or raffinate 3 rich in 2-butene, the latter being raffinate 2 after its more highly valued 1-butene component has been removed. Another possible C4 source is the waste 2-butene stream from a methanol to olefins plant. The very fact that a 2-butene stream can be an economically viable feed is proof of the high activity and versatility of the Dow and Johnson Matthey catalyst, especially when one considers the reactivity in hydroformylation of 2-butene (cis- and trans-) is as low as one fiftieth that of 1-butene. Other potential feed sources could conceivably be C4 olefinic fractions from Fischer-Tropsch plants. All of the above sources are likely to be cheaper than the olefins feeding 2EH, INA or IDA plants.



Where there is interest from a 2EH or butanols producer in making 2PH if market conditions suit, Johnson Matthey can design cost effective flexible LP OxoSM plants capable of using propylene and butene as separate feedstocks either continuously or intermittently.

The Alcohol Products from C3 and C4 Hydroformylation and their Uses

Butyraldehyde is mainly used in the production of 2EH and butanols. Of the two isomers, normal butyraldehyde is the more valuable, because unlike iso-butyraldehyde, it can be used to produce 2EH. Also, normal butanol usually offers solvent and derivative value superior to that of iso-butanol. A small outlet for normal butyraldehyde is trimethylolpropane used as a building block in the polymer industry.

Large quantities of 2EH are esterified with phthalic anhydride to produce the PVC plasticiser DEHP, often referred to as DOP. While strong demand for DEHP in Asia has sustained a global growth rate of about 2.5%, regulatory pressures have meant Western Europe and the USA now together account for less than 5% of world usage, with demand in the former practically zero. In recent years increasing amounts of 2EH have been used to produce di(2-ethylhexyl) terephthalate (DEHTP) or dioctyl terephthalate (DOTP), using dimethyl terephthalate or purified terephthalic acid as the other primary input. Not being an ortho-phthalate plasticiser like DEHP, DOTP has a growing use as a replacement for DEHP, in particular, without any negative regulatory pressure. Increasing amounts of 2EH are being esterified with acrylic acid to produce 2-ethylhexylacrylate, used in the production of homopolymers, copolymers for caulks, coatings and pressure-sensitive adhesives, paints, leather finishing and textile and paper coatings. 2EH is also used to produce 2-ethylhexyl nitrate, a diesel fuel additive and also lubricant additives.

Normal butanol is used industrially for its solvent properties, but by far its largest use is as an industrial intermediate. Butyl acrylate is widely used in the production of homopolymers and copolymers for use in water-based industrial and architectural paints, enamels, adhesives, caulks and sealants, and textile finishes. Butyl methacrylate’s uses include the manufacture of acrylic sheet, clear plastics, automotive coatings and other lacquers. n-Butyl acetate is an industrial solvent and artificial flavourant and is used

in various coatings, floor polishes, textiles and as a gasoline additive.

Iso-butyraldehyde has a multitude of uses as an intermediate – to name a few, pharmaceuticals, crop protection products and pesticides. A key outlet is neopentylglycol (NPG) or 2,2-dimethyl-1,3-propanediol, produced by the aldol condensation of iso-butyraldehyde and formaldehyde. NPG is mainly used as a building block in polyester resins for coatings, unsaturated polyesters, lubricants and plasticisers. Iso-butanol has similar properties to normal butanol and may be used as a supplement or replacement for it in some applications. More specific uses include industrial coatings and cleaners, de-icing fluids, flotation agents, textiles and as a gasoline additive. It is also an intermediate for agricultural chemicals and for glycol ethers and esters. An outlet for iso-butyric acid, the oxidation product from iso-butyraldehyde, is a monoester of trimethyl pentanediol which has a use as a coalescing agent for latex paints.

The main component of commercially produced 2PH is 2-propylheptane-1-ol derived from the normal valeraldehyde present in the product from the hydroformylation of normal butenes. Other lesser components are 4-methyl 2-propyl 1-hexanol and 5-methyl 2-propyl 1-hexanol, derived from branched aldehyde isomers in the aldol condensation feed. The phthalate ester of 2PH is di-(2-propylheptyl) phthalate as its principal component, giving the plasticiser the generic name DPHP. It is a versatile PVC plasticiser with impressive weathering and low fogging properties making it particularly suitable for tough outdoor uses such as roofing membranes and tarpaulins, automotive, wires and cables and cable ducts.

LP OxoSM Technology Today

In 2001 Union Carbide Corporation became a wholly owned subsidiary of The Dow Chemical Company. In 2006 Davy Process Technology became part of Johnson Matthey. The process development and marketing collaboration today between Johnson Matthey and Dow Global Technologies, Inc, has its roots in the historic 1971 agreement between Union Carbide Corporation, Johnson Matthey and The Power-Gas Corporation, but now spans more olefins giving it a broader market reach. To date, 53 LP OxoSM technology projects have now been licensed, six of them for non-propylene applications. The collaboration is as close and focused as it ever was, and the resolve



of Dow and Johnson Matthey is to sustain the place for LP OxoSM Technology as the premier oxo technology in the world through safe, innovative, low environmental impact and cost advantaged technical solutions, forever pushing the boundaries of the technology even further. Germane to many further developments will be the role for advanced ligand systems that have already boosted propylene and butene efficiencies and cut costs needed for seeing out the complete rhodium life cycle. Some new developments are already at the stage where they can be licensed for commercial use.

Examples of New DevelopmentsPropylene n:i Ratio Flexibility

In those instances where operators are seeking a wide flexibility in the butyraldehyde isomer ratio, ‘Variable SELECTORSM’ Technology has been developed that enables the n:i ratio to be adjusted on-line within the range of 2:1 and 30:1 to suit market conditions by adjusting operating parameters.

INA from Butene Dimer and, the “All Singing, All Dancing” Oxo Plant?

The global plasticiser market is currently about 8 million tonnes per year and is growing at around 3 to 4% per year. The market share of the C9 phthalate DINP has increased in recent years and the consequential growing global demand for INA, currently about 1.4 million tonnes per year, is being met by new projects announced for Asia. A first INA plant in China started production in 2015. The superior migration and fogging properties and more favourable toxicological profiles of C9 and C10 phthalate plasticisers compared to DEHP should ensure sustained growth in the use of both DINP and DPHP.

To meet the growing demand for INA, Dow and Johnson Matthey have developed a new low pressure rhodium catalysed INA process in pilot plants at Dow and Johnson Matthey (see Figure 5) using commercially produced butene dimer feedstock. One of its key attributes is it can be retrofitted to existing 2EH or butanol plants built by licensees of the LP OxoSM Process, creating for them and for new licensees the opportunity to run flexible product oxo plants to best exploit market conditions. And with the 2PH process being similarly retrofittable, one can now envisage an oxo producer having flexible access to say, refinery

sourced C3 and C4 olefins, building a single, highly flexible, LP OxoSM facility using advanced, dependable technologies to selectively deliver any and all of 2EH, INA and 2PH – as well as butanols. Collectively, the three higher alcohols supply more than two thirds of a very diverse plasticiser market.

LP OxoSM and SELECTORSM are service marks of The Dow Chemical Company (“Dow”) or an affiliate of Dow.

Acknowledgements

The photographs taken at the Chemische Werke Huels plant and of the Safol plant are included with the kind permissions of Evonik Industries (Figures 2 and 3) and Sasol Ltd (Figure 4) respectively.

References1. G. Frey, ‘75 Years of Oxo Synthesis’, Speciality

Chemicals Magazine, 8th October, 2013

2. F. J. Smith, Platinum Metals Rev., 1975, 19, (3), 93

3. M. J. H. Russell, Platinum Metals Rev., 1988, 32, (4), 179

4. G. Wilkinson, Platinum Metals Rev., 1968, 12, (4), 135

5. M. L. H. Green and W. P. Griffith, Platinum Metals Rev., 1998, 42, (4), 168

6. R. Tudor and M. Ashley, Platinum Metals Rev., 2007, 51, (3), 116

7. ‘Low-Pressure Oxo Process Yields a Better Product Mix’, Chemical Engineering (New York), 5th December, 1977, 110

8. R. Tudor and M. Ashley, Platinum Metals Rev., 2007, 51, (4), 164

Fig. 5. Johnson Matthey oxo pilot plant for INA process development at Stockton-on-Tees, UK



The Authors

Richard Tudor retired from Davy Process Technology in 2011 as Vice President, Oxo Business following an involvement of over 35 years in the company’s oxo licensing activities, initially in a technical capacity becoming Process Manager. His first commercial role was a broad remit as the company’s Licensing Manager, following which he ran the oxo business for over 20 years. He graduated in Chemical Engineering from the University of Manchester, UK, and is a Fellow of the Institution of Chemical Engineers and a former member of the Licensing Executives Society. Between 2011 and 2016 he continued working for Johnson Matthey as licensing consultant.

Atul Shah is Licensing Development Director at Johnson Matthey, London, UK. He has worked on many oxo alcohol projects globally and has played a leading role in Johnson Matthey’s oxo alcohols licensing business for over 30 years, both in technology and business development. Atul graduated from the University of London with a BSc (Eng) in Chemical Engineering and joined Davy in 1984, which became part of Johnson Matthey in 2006. He holds an MBA and is a Fellow of the Institution of Chemical Engineers.


https://doi.org/10.1595/205651317X695884 Johnson Matthey Technol. Rev., 2017, 61, (3), 257–261


W. P. GriffithDepartment of Chemistry, Imperial College, London SW7 2AZ, UK


The story of the first 200 years of Johnson Matthey is told. The firm was started in 1817 by Percival Johnson, but in 1851 George Matthey became a partner and the present name was derived from these two partners. A number of milestones in its illustrious history are reviewed, and some of the current activities of the company are brought up to date, in this short article.

Introduction

Thirty-five years ago a magisterial volume was published by Johnson Matthey on “A History of Platinum and its Allied Metals”, but despite its title that book is also a history of the firm itself from 1817 to 1982 (1). The present account marks Johnson Matthey’s bicentenary, and is much indebted to that volume; many aspects of the story have also been chronicled by Platinum Metals Review and its 2014 successor, the Johnson Matthey Technology Review. Appropriate references to these journals are given wherever possible. A Platinum Metals Review paper marking the firm’s sesquicentenary was published in 1967 (2), and a recent paper notes that Johnson Matthey is one of the oldest British chemical firms still in existence (3). In this survey we concentrate on the firm’s formative years and, while highlighting its activities with platinum group metals (pgms), include

some of Johnson Matthey’s considerable recent non-pgm activities.

The Johnsons of Maiden Lane

The forebears of Percival Norton Johnson, who in 1817 became the founder of the precursor of Johnson Matthey, came from a family well acquainted with metal assaying and refining (4, 5). His grandfather John Johnson (1737–1786) had since 1777 been an assayer of ores and metals, mostly silver, gold and some base metals, at No. 7, Maiden Lane (now part of Gresham Street between Wood Street and Foster Lane, London EC2). His son, also John Johnson (1765–1831) was apprenticed to him in 1779, and on his father’s death took over his business, becoming the only commercial assayer in London. Around 1800 he became involved with the rapidly developing platinum metals industry, using crude ‘platina’ smuggled to Britain via Jamaica from what is now Colombia. His biggest early customer was probably William Hyde Wollaston (1766–1826) (6), who made many purchases of platina between 1802–1819 from Johnson. Wollaston developed a secret process for isolating platinum so pure that it could be fashioned into crucibles, chalices and other vessels and drawn into wires much thinner than a human hair; this business made him wealthy. In addition to isolating rhodium and palladium in 1802 (6, 7), he sold to his friend and partner Smithson Tennant some ore from which Tennant in 1804 isolated iridium and osmium (8, 9).

Percival Norton Johnson (1792–1866), was born on 29th September 1792 at 6–7 Maiden Lane and was

Two Hundred Proud Years – the Bicentenary of Johnson MattheyOrigins of the company and of today’s research activities in science and technology



apprenticed to his father John Johnson. In 1812, aged only 19, he established his scientific credentials in a paper showing that platinum alloyed with silver and gold would dissolve in nitric acid (10, 11).

The Early Years of Percival Johnson’s New Firm

The date of foundation of what 34 years later would be called Johnson Matthey is established as January 1st 1817 (1, 2). On that day Percival Johnson left his father’s business and set up his own business as an ‘Assayer and Practical Mineralogist’ with his brother John Frederick as assistant, although he would later collaborate with his father (2). The year 1817 was also that in which Humphry Davy showed that a platinum wire (almost certainly provided by Johnson) would catalyse the combination of oxygen and hydrogen – the first demonstration of heterogeneous catalysis (12, 13).

In 1818 Percival moved to 8 Maiden Lane and in 1822 to 79 Hatton Garden, the latter being expanded in 1850. In 1826 he brought in another talented assayer, John Stokes, renaming the firm Johnson and Stokes in 1832. When Stokes died in 1835, William John Cock (1813–1892), like Percival Johnson a founder member of the Chemical Society in 1841 (14), joined Percival in the firm which was now called Johnson and Cock. William was the son of Thomas Cock (1782–1842), Percival’s brother-in-law, also an assayer.

William Cock was a considerable chemist and metallurgist, devising a new procedure for increasing the malleability of platinum, and published ‘On Palladium – Its Extraction, Alloys &c.’ (15, 16) in one of the earliest of the Chemical Society’s papers. Johnson and Cock produced a platinum medal for Queen Victoria’s coronation in 1838, and in 1844 made the platinum from which the standard pound weight was made. Cock resigned in 1845 from ill-health, but continued collaboration; Johnson’s firm was now called P. N. Johnson & Co (1).

Johnson’s Firm Renamed Johnson and Matthey

In 1838 Johnson and Cock apprenticed the second person commemorated in the present firm’s name, George Matthey (1825–1913) (17). Just thirteen when they first employed him, he quickly became interested in platinum and Cock took him under his wing. Matthey had a shrewd business mind as well as an excellent knowledge of chemistry and metallurgy, and he

persuaded a reluctant Johnson to exhibit samples of platinum, palladium, rhodium and iridium at the Great Exhibition of 1851, for which they were awarded a prize. Johnson took him into partnership in the same year and renamed the firm Johnson and Matthey. In 1846 Percival Johnson was elected a Fellow of the Royal Society (FRS), his election being supported by Michael Faraday (to whom the firm had given an ingot of platinum and some platinum wire for a famous Royal Institution discourse).

In 1852 Johnson Matthey was appointed official assayer to the Bank of England followed by official refiner in 1861. A key event in the firm’s history was Matthey’s collaboration with Jules Henri Debray (1827–1888) for melting platinum on a large scale (18). At the Paris Exhibition of 1867, Johnson Matthey was awarded two gold medals for its fine display of some 15,000 ounces of pgms in many forms, and as a result George Matthey became a Chevalier of the Légion d’Honneur, one of France’s highest honours. In 1874 the firm made the first standard metre and standard kilogram in 10% iridium-90% platinum alloy for the International Metric Commission. This kilogram is still the standard measure and will be so until late 2018 when it will be defined using a more modern technique. It is now held in the the Bureau international des poids et mesures in Sèvres (19). In a rare departure at the time from pgms, Johnson Matthey almost certainly provided the high purity aluminium for the statue known as Eros, erected in 1892 in Piccadilly Circus (20).

In 1879 Matthey was awarded an FRS: like Johnson and Cock he had published several papers, including an important one on the removal of rhodium and iridium from platinum, and the preparation of a platinum-iridium alloy (21). Both he and Johnson are commemorated in the new “Oxford Dictionary of National Biography” (22, 23). Like Johnson, George Matthey was a great supporter of the Chemical Society, thus continuing a long and still current association between the Society (now the Royal Society of Chemistry) and Johnson Matthey (14).

In 1860 George Matthey’s brother Edward (1836–1918) was appointed a junior partner: he had studied under Hofmann at the Royal College of Chemistry. Another partner was John Scudamore Sellon (1836–1918), a nephew of Johnson’s wife, who had commercial experience; the firm was now renamed Johnson Matthey and Co (1). On 1st June 1866 Percival Johnson died (22); George Matthey wrote an obituary (published in the Anniversary meeting



of the Chemical Society, March 30th, 1867, page 392 (24)). George Matthey retired in 1909 after a 70-year career; and died on 14th February 1913 (23, 25). John Sellon replaced him as chairman, but died in 1918 as did Edward Matthey. The Matthey succession on the company’s board was secured by George’s son Percy St. Clair Matthey (1862–1928) and, from 1928, by Edward Matthey’s son Hay Whitworth Pierre Matthey (1876–1957), chairman until 1957 (1).

Johnson Matthey became a limited company in 1891 and its ordinary shares were first listed on the London Stock Exchange in 1942. It subsequently opened businesses in the USA (1927); Australia and New Zealand (1948); across Europe (in the 1950s); India (1964); Japan (1969); Mexico and Malaysia (1995) and in China (2001). There are now Johnson Matthey operations in over 30 countries.

Sources of Platinum Group Metals

John and Percival Johnson used platina smuggled into Britain by speculators from the Choco district of what is now Colombia from ca. 1780–1830. After Colombia became independent of Spain less platina found its way to Europe and Johnson Matthey seems to have used Russian supplies from around 1850 (1) and, early in the 20th century, Canadian sources from Ontario (2). Everything changed though with the discovery of huge reserves of pgm-bearing ore in South Africa, first found there in 1906 (26). In 1925 the huge South African Merensky Reef which contains some 80% of the world’s reserves of pgms was discovered, and by 1931 Johnson Matthey took and continued to take pgms from the mines in the Rustenburg region, 100 km west of Pretoria (27), for many years. In 1925 the ground-breaking Powell-Deering smelting and refining process for Rustenburg ore was developed by Johnson Matthey. A refinery was set up in Brimsdown, near Enfield, UK, in 1928. This is still in use, though primary refining of South African pgm-containing ores is done in South Africa. Some primary refining is carried out by Johnson Matthey. However the company remains the world’s largest secondary refiner of pgms, with refineries in Royston and Brimsdown in the UK, West Deptford in the USA and in China.

Johnson Matthey in the 20th and 21st Centuries

Until the late 19th century Johnson Matthey was mainly concerned with relatively small-scale applications

of platinum and other pgms, and though admired, particularly in France, was relatively little known abroad. It is now a major international company dealing with many aspects of pgm and non-pgm technologies. Major factors leading to this were the establishment of a plentiful source of pgms, the foundation of an outstanding research department, and its later diversification with non-pgm technology.

Johnson Matthey’s Research Department, and Collaboration with Academic Institutions

In 1918 Alan Richard Powell (1894–1975) established a research department at Johnson Matthey and was for 36 years its Research Manager; he was awarded an FRS in 1953 (28). The department initially occupied two rooms at Hatton Garden but in 1938 moved to Wembley, and then in 1976 to its present location at Sonning Common, near Reading (29). Powell wrote an account of the first fifty years of his department (30).

Early in the 20th century Johnson Matthey launched an unusual initiative, later called the Johnson Matthey Loan Scheme, of which the author was for many years a beneficiary, as were many others in university and other departments worldwide. Compounds of rare materials, mainly pgms, were given, without charge, to bona fide researchers for work on innovative science. Researchers were free to publish their material, the only stipulation being that the residues of material used were returned to Johnson Matthey (31). Much useful work resulted from this; a good example being that of the late Sir Geoffrey Wilkinson (FRS and Nobel laureate) whose extensive work on synthesis and homogeneous catalysis by pgm complexes would have been impossible without the scheme (32, 33). The scheme has been replaced by one in which Johnson Matthey continues to collaborate with universities and others, and often provides research materials.

In 1957 the quarterly Platinum Metals Review was founded by Johnson Matthey; after 58 years of production it became the Johnson Matthey Technology Review in mid-2014, partly to signal that much of the company’s current research and applications are no longer pgm-based. Volume numbers remain as for Platinum Metals Review.

Areas of Prime Development in Johnson Matthey

The company is actively involved with many areas



including automotive emission control catalysts, homogeneous and heterogeneous catalysis for petroleum refining, oxidation of ammonia to nitric acid, manufacture of active pharmaceutical ingredients, components for glass manufacture, thermocouples and advanced battery materials, fuel cells and water purification, and much more. Johnson Matthey states that its focus today as it celebrates its 200th year is on the global priorities of cleaner air, the efficient use of natural resources and improved health (34, 35). Here we briefly note some aspects of Johnson Matthey’s research and production in these areas.

Clean Air: Automotive

Johnson Matthey was and is a leader since the 1960s in conversion of the toxic components of vehicle exhaust gases – hydrocarbons, carbon monoxide and oxides of nitrogen (NOx) – to carbon dioxide, water and nitrogen; there has also been much progress with diesel emissions and particulates (36–38) and with removal of alkenes and alkynes from automotive emissions. In 1977 Johnson Matthey was presented with the Queen’s Award for Technological Achievement for its pioneering work in emissions control (39). The company now accounts for one in three of the catalysts on cars around the world.

A non-pgm area of research and production is the design and manufacture of low-power low-capacity batteries for industrial and leisure uses and high-power high-capacity batteries for automotive applications, such as high performance hybrid and plug-in hybrid vehicles. Most of these are lithium-ion based. The first themed issue of Johnson Matthey Technology Review in 2015 was devoted to battery technologies (40, 41).

Efficient Use of Natural Resources

In 2002 ICI sold its Synetix process catalysts business along with its Tracerco subsidiary to Johnson Matthey. The process catalysts business provided Johnson Matthey with a strong global position in non-precious metal catalysts used in a wide range of major chemical manufacturing processes, an area that has been strengthened by further acquisitions. In 2006 Johnson Matthey bought Davy Process Technology (DPT), thus strengthening its position as a catalyst and technology supplier to the world’s chemical and energy industries. Some of the many processes involved include the catalysed conversion of syngas (carbon monoxide,

carbon dioxide and hydrogen) to methanol; oxo alcohols from hydroformylation reactions involving alkene oxidations with syngas; and the production of biodiesel.

Health: Chemotherapy

Another area in which Johnson Matthey played an important early and continuing part was the use of pgm complexes, particularly of platinum, in the treatment of malignant cancers, starting in 1983. First-generation (cisplatin), and many second- and third-generation drugs have been made and investigated by the company, and very recently reviewed (42). In 1993 Johnson Matthey bought Meconic, a holding company for the pharmaceutical company MacFarlan Smith, and this became part of Johnson Matthey; a major interest now is the synthesis of pharmaceuticals often without pgm-based technology.

Conclusions

The origins of Johnson Matthey – founded in 1817 by Percival Johnson and later strengthened by the appointment of George Matthey – have been described with some of its principal achievements over the last two centuries. The focus of the company in the 21st century which has grown to include many non-pgm technologies has been highlighted.

Acknowledgement

The author thanks Dan Carter and Ian Godwin for their help in providing information on some of the latest initiatives at Johnson Matthey.

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The Author

Bill Griffith is an Emeritus Professor of Chemistry at Imperial College, London, UK. He has much experience with the platinum group metals, particularly ruthenium and osmium. He has published over 270 research papers, many describing complexes of these metals as catalysts for specific organic oxidations. He has written eight books on the platinum metals, and has published, with Hannah Gay, a history of the 170-year old chemistry department at Imperial College (33). He is responsible for Membership at the Historical Group of the Royal Society of Chemistry.

Structural Changes in Cartilage and Collagen Studied by High Temperature Raman SpectroscopyM. Fields, N. Spencer, J. Dudhia and P. F. McMillan, Biopolymers, 2017, 107, (6), e23017

High temperature Raman spectra for freeze-dried cartilage samples which demonstrate a rise in laser-excited fluorescence interpreted as conformational changes corresponding to denaturation above 140ºC are reported. Spectra for separated collagen and proteoglycan fractions extracted from cartilage show the changes are linked with collagen. At high temperature peptide hydrolysis occurs suggesting that molecular H2O is retained within the freeze-dried tissue as shown by the Raman data. Thermogravimetric analysis supports this hypothesis and shows 5–7 wt% H2O remaining within freeze-dried cartilage that is gradually released upon heating up to 200ºC. The capacity of the denatured collagen to re-absorb water is diminished and is shown by the spectra attained after exposure to high temperature and re-hydration following recovery.

Tailoring the Physical and Catalytic Properties of Lanthanum Oxycarbonate NanoparticlesC. Estruch Bosch, M. P. Copley, T. Eralp, E. Bilbé, J. W. Thybaut, G. B. Marin and P. Collier, Appl. Catal. A: Gen., 2017, 536, 104

Lanthanum oxide and its carbonate analogues were synthesised by flame spray pyrolysis (FSP). Two different feeds were investigated: an organic solution and an aqueous organic microemulsion. The properties of the materials prepared are effected by a key experimental parameter of FSP, the O2 dispersion i.e. the flow rate of the dispersing gas in the FSP nozzle. When a lanthanum containing organic solution was used as FSP feed, a rise in the level of O2 dispersion led to a rise in surface area and a reduction in mean particle size and basicity. Lanthanum can form different phases, for example, oxides, hydroxides, oxycarbonates and carbonates. The rise of O2 dispersion also initiated a phase change, going from a mixture of type Ia and type II La2O2CO3 and La2O3 to pure La2O3. Using an aqueous or organic microemulsion feed which had a higher viscosity compared to the organic feed, produced materials with a lower surface area and a

higher mean particle size than those prepared using the organic solution at the same O2 dispersion. In this case a mixture of type II La2O2CO3 and La2O3 was attained. The materials were assessed for oxidative coupling of methane (OCM) and the authors were able to show that by changing the synthesis parameters, the OCM performance of the materials could be altered.

Reforming Biomass Derived Pyrolysis Bio-oil Aqueous Phase to FuelsC. Mukarakate, R. J. Evans, S. Deutch, T. Evans, A. K. Starace, J. ten Dam, M. J. Watson and K. Magrini, Energy Fuels, 2017, 31, (2), 1600

The catalytic conversion of the biogenic carbon in pyrolysis aqueous phase streams to produce hydrocarbons using a vertical microreactor coupled to a molecular beam mass spectrometer (MBMS) was investigated. Real-time analysis of products and tracking catalyst deactivation are provided by the MBMS. The HZSM-5 catalyst was used in this work, which improved the oxygenated organics in the aqueous fraction from noncatalytic fast pyrolysis of oak wood to fuels containing small olefins and aromatic hydrocarbons. The HZSM-5 catalyst showed higher activity and coke resistance during processing of the aqueous bio-oil fraction compared to similar experiments using biomass or whole bio-oils. Decreased coking was possible due to a release of coke precursors from the catalyst pores that was improved by excess process water available for steam stripping.

Lithium and Boron as Interstitial Palladium Dopants for Catalytic Partial Hydrogenation of AcetyleneI. T. Ellis, E. H. Wolf, G. Jones, B. Lo, M. M.-J. Li, A. P. E. York and S. C. E. Tsang, Chem. Commun., 2017, 53, (3), 601

It has been shown that light elements, including lithium and boron atoms, can reside in the octahedral (interstitial) site of a Pd lattice by altering the electronic properties of the metal nanoparticles, and therefore the adsorptive strength of a reactant. The obstruction of the sub-surface sites to H in the altered materials resulted in substantially increased selectivity for the partial catalytic hydrogenation of acetylene to ethylene.

Johnson Matthey HighlightsA selection of recent publications by Johnson Matthey R&D staff and collaborators






Structure–Activity Relationship of Different Cu–Zeolite Catalysts for NH3–SCRM. P. Ruggeri, I. Nova, E. Tronconi, J. E. Collier and A. P. E. York, Top. Catal., 2016, 59, (10–12), 875

Three different catalytic materials for NH3-SCR applications were investigated and its activities and selectivities towards undesired products (for example, N2O and NH4NO3) were compared. The selected materials included a large pore Cu-BETA catalyst and two small pore structures: a Cu-CHA and a Cu-SAPO material, and were characterised by the same Cu loading. The objective was to study the potential impact of the microporous structure of the catalyst on the SCR performances.

Effect of Graphene Support on Large Pt NanoparticlesL. G. Verga, J. Aarons, M. Sarwar, D. Thompsett, A. E. Russell and C.-K. Skylaris, Phys. Chem. Chem. Phys., 2016, 18, (48), 32713

Pt clusters with up to 309 atoms interacting with single graphene supports with up to 880 carbon atoms were simulated by large-scale DFT calculations. The adsorption, cohesion and formation energies of two and three-dimensional Pt clusters interacting with the support, including dispersion interactions via a semi-empirical dispersion correction and a vdW functional were computed. When interacting with the support, three-dimensional Pt clusters are more stable than the two-dimensional and the difference between their stabilities increases with the system size. As the nanoparticle size is increased, the dispersion interactions are more pronounced and this is crucial to a reliable description of larger systems. The overall charge is transferred from the Pt clusters to the support as interatomic expansion (contraction) on the closest (farthest) Pt facets from the graphene sheet and charge redistribution were observed.

STA-20: An ABC-6 Zeotype Structure Prepared by Co-Templating and Solved via a Hypothetical Structure Database and STEM-ADF ImagingA. Turrina, R. Garcia, A. E. Watts, H. F. Greer, J. Bradley, W. Zhou, P. A. Cox, M. D. Shannon, A. Mayoral, J. L. Casci and P. A. Wright, Chem. Mater., 2017, 29, (5), 2180

Dual templating by diDABCO-C6A and trimethylamine was used to prepare a novel microporous silicoaluminophosphate with topology STA-20 (see Figure). A hypothetical zeolite database and ADF-STEM with Rietveld refinement were used to resolve its structure. The zeotype structure STA-20 is a member of the ABC-6 family and it has trigonal symmetry, P-31c, with a = 13.15497(18) Å and c = 30.5833(4) Å in the calcined form. The stacking sequence is 12 layers of 6-rings (6Rs), AABAABAACAAC(A), containing single and double 6R units. STA-20 has a 3D-connected pore system limited by 8R windows and the longest cage

observed in an ordered ABC-6 material. Elemental analysis, 13C MAS NMR, computer modelling and Rietveld refinement were combined to obtain models for the location of the templates within cages of the framework.

Enhancing the Thermoelectric Properties of Single and Double Filled p-Type Skutterudites Synthesized by an Up-Scaled Ball-Milling ProcessJ. Prado-Gonjal, P. Vaqueiro, C. Nuttall, R. Potter and A. V. Powell, J. Alloy. Compd., 2017, 695, 3598

Mechanical alloying was used to prepare single and double filled p-type skutterudites Ce0.8Fe3CoSb12 and Ce0.5Yb0.5Fe3.25Co0.75Sb12. It is a rapid method for preparing skutterudites that could be scaled up to industrial level. Enhanced figures of merit ZT were found for large-scale samples prepared by ball-milling compared with those prepared by conventional solid-state reaction. ZT rises ca. 19% at room temperature due to reduced grain size leading to reduced thermal conductivity. Effect of microstructure on thermoelectric properties, stability in air and performance after multiple heating and cooling cycles are presented. Improved resistance to oxidation are found in the densified samples prepared by ball-milling starting at 694 K for Ce0.8Fe3CoSb12 and at 783 K for Ce0.5Yb0.5Fe3.25Co0.75Sb12.

A New Type of Scaling Relations to Assess the Accuracy of Computational Predictions of Catalytic Activities Applied to the Oxygen Evolution ReactionL. G. V. Briquet, M. Sarwar, J. Mugo, G. Jones and F. Calle-Vallejo, ChemCatChem, 2017, 9, (7), 1261 Explicit water solvation and functionals that account for van der Waals interactions were used to modify the adsorption energies included in a DFT model to improve predictions for the overpotentials for the oxygen evolution reaction (OER) on RuO2 and IrO2. These are known experimentally to be similar and quite low but

Reprinted with permission from (A. Turrina, R. Garcia, A. E. Watts, H. F. Greer, J. Bradley, W. Zhou, P. A. Cox, M. D. Shannon, A. Mayoral, J. L. Casci and P. A. Wright, Chem. Mater., 2017, 29, (5), 2180). Copyright (2017) American Chemical Society



widely used computational electrochemistry models based on adsorption thermodynamics do not show this. In such models IrO2 is usually predicted to have low overpotentials while RuO2 is predicted to have large overpotentials. The results of the present study explain the discrepancy and successfully predicted both oxides to be highly active.

On the Motion of Linked Spheres in a Stokes FlowF. Box, E. Han, C. R. Tipton and T. Mullin, Exp. Fluids, 2017, 58, (4), 29

Inspired by the mechanics of swimming microorganisms, the motion of linked spheres at low Reynolds number is being investigated. In the present study small permanent magnets were embedded in the spheres and an external magnetic field was applied to generate torques. Pairs of neutrally buoyant spheres connected by glass rods or thin elastic struts were found to move in a reciprocal orbit driven by an oscillatory field. Three spheres linked by elastic struts were observed to buckle in a periodic, non-reciprocal fashion. This effect propels the elemental swimmer with swimming direction determined by the geometrical asymmetry of the device. The technique may be suitable for miniaturisation.

A New Class of Cu/ZnO Catalysts Derived from Zincian Georgeite Precursors Prepared by Co-PrecipitationP. J. Smith, S. A. Kondrat, P. A. Chater, B. R. Yeo, G. M. Shaw, L. Lu, J. K. Bartley, S. H. Taylor, M. S. Spencer, C. J. Kiely, G. J. Kelly, C. W. Park and G. J. Hutchings, Chem. Sci., 2017, 8, (3), 2436

A Cu/ZnO catalyst was prepared from a zincian georgeite precursor synthesised by co-precipitation from acetate salts and ammonium carbonate. The presence of Zn plus mild ageing conditions inhibits crystallisation into zincian malachite or aurichalcite. The catalyst exhibits better performance for methanol synthesis and low temperature water-gas shift (LTS) reaction than a zincian malachite derived catalyst. It is suggested that alumina may not need to be added as a stabiliser. Alkali metals, which are known to act as catalyst poisons, are excluded from the synthesis procedure which is thought to account for the improved performance.

Harvesting Renewable Energy for Carbon Dioxide CatalysisA. Navarrete, G. Centi, A. Bogaerts, Á. Martín, A. York and G. D. Stefanidis, Energy Technol., 2017, 5, (6), 796

Renewable energy can be used to transform carbon dioxide into commodities (CO2 valorisation). Technological advances in the field are reviewed along with socioeconomic implications and the chemical basis of the transformation. Use of microwaves, plasmas and light to activate CO2 are introduced and their fundamental phenomena discussed. The present state-of-the-art has inherent limitations. To solve these, the current catalytic concepts will need to be redesigned and a new conceptual approach for an energy-harvesting device is proposed. The future challenges in efficient conversion of CO2 using renewable energy sources are described.

Johnson Matthey Technology Review is Johnson Matthey’s international journal of research exploring science and technology in industrial applications


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