Acetic AcidBy

Hamad ShaabiReyan Rutherford

Shaun LynnAndrew Pollock

Marketing

Asia60%

North America22%

South America

2%

Europe11%

Middle East2%

Rest of the World3%

Acetic Acid Demand Major Region

Asia57%

North America

4%

South America

2%

Europe14%

Middle East23%

Acetic Acid Supply Major Region

Region Demand Supply Import Export

Asia 37 57 - 20

North America 22 4 18 -

South America 2 2 - -

Europe 11 14 - 3

Middles East 2 23 - 20

Marketing

Vinyl Ac-etate

Monomer37%

Terephthalic Acid17%

Acetate Es-ters11%

Acetic Anhy-dride8%

Others27%

Global Acetic Acid Derivatives

Acetic acid Derivatives Uses

Vinyl Acetate Monomer Paints, adhesives, coating, textiles, wire and cable polyethylene compounds

Terephthalic Acid Bottles, textiles, polyester fibers

Acetate EstersPaints, coating, inks formulation, sealants, adhesives in pharmaceutical applications

Acetic Anhydride Cellulose acetate fibers, plastics, pharmaceutical such as aspirin

Others Chemical reagent

Method

Ethylene via acetaldehydeMethanol by carbonylationButane by liquid-phase oxidationCativa Process

Ethylene via acetaldehyde

Reactor 106 °C 10 ATM

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CO2 Removal OFF Gas

BFW

Steam

EthyleneOxygenNitrogenwater

H2O

stm stm

Acetaldehyde Acetic Acid Product

[PdCl4]²ˉ C2H4 + H2O + ½O2 CH3CHO + H2O CuCl2 CH3CHO + H2O CH3COOH + H2

Estimating plant capital costs

Major Process Step Special Requirements Score

Reaction 10 atm (0.3), Temp 160 °C(0.3),H.G Stainless steel (0.6)

2.2

Scrubber High grade s.s. (0.6) 1.6

CO2 Removal High grade s.s. (0.6) 1.6

Acetic Column High grade s.s. (0.6) 1.6

Acetaldehyde Column

High grade s.s. (0.6) 1.6

Acetic Finishing High grade s.s. (0.6) , entrainment (0.3)

1.9

Total process complexity factor 10.5

Methanol Carbonylation

Methanol Carbonylation

Most used process for production of Acetic acid.

Developed by Henry Dreyfus at British Celanese, pilot plant opened in 1925.

Uses a metal catalyst, usually Rhodium.CH3OH + CO CH3COOH

Methanol Carbonylation

1. CH3OH + HI CH3I + H2O

2. CH3I + CO + [Metal Catalyst] CH3COI

3. CH3COI + H2O CH3COOH + HI

CH3OHHI

CH3I

H2OCO + [Metal Catalyst]

CH3COI CH3COOHH2OHI

Reaction carried out at a minimum of 200atm.

Methanol Carbonylation

• Methanol and carbon monoxide are the raw materials.

• Bi-products are separated using distillation.

Methanol Carbonylation Flow Diagram

Methanol Carbonylation Complexity Factor

Major Process Step Special Requirements Score

Reaction200 atm (0.9)

Temp 200 °C(0.3)High Grade Stainless steel (0.6)

2.8

Scrubber High Grade Stainless steel (0.6) 1.6

CO2 Removal High Grade Stainless steel (0.6) 1.6

Acetic Column High Grade Stainless steel (0.6) 1.6

Acetaldehyde Column High Grade Stainless steel (0.6) 1.6

Acetic Finishing Entrainment (0.3)High Grade Stainless steel (0.6) 1.9

Total process complexity factor 11.1

Cativa Process

Cativa

• Developed in 1996 by BP.

• Uses Iridium catalyst.

• Requires Catalytic Promoter – Ruthenium

• Increase in“active anionic” species Ir(CO2)I3Me]-

Mechanism of Iridium Catalysed Reaction

Cativa Process

• First step is no longer the rate determining step

• Cativa Process 150x faster than Monosanto

• Rate = [catalyst] x [CO]

[I-]

• Very high yield 95-98% at 99% purity

Cativa Flow diagram

Advantages of the Cativa process• Iridium is much cheaper than rhodium • Less iridium is needed because it is so stable that all the

catalyst is recycled in the plant • The reaction is faster and the quantities of by-products are

much lower, reducing the purification costs. For example steam is used to heat the distillation columns and there is a 30% saving of steam over the Monsanto process

• Some conversion of CO to CO2 still occurs but at a much lower rate

• CO utilisation is increased from about 85% to over 94% • Overall the Cativa process releases about 30% less CO2 per

tonne of product than does the rhodium process

Butane by liquid-phase oxidation

Acetic Acid by Butane Oxidation• When butane is heated with air in the presence of a metal catalysts acetic acid is produced.

C4H10 + 2½ O2 → 2 CH3COOH + H2O

• Suitanle metal catalysts are manganese, cobalt and chromium.

• Conditions are run at a combination of temperature and pressure designed to be as hot as possible while keeping the butane in a liquid phase. Typical conditions are 150°C an 55 atm.

• The reaction produces side products such as ethyl acetate, butanone and formic acid which are commercially valuable.

• Reaction conditions can be altered to produce either of these as the major product if this is economically useful.

• Before methanol carbonylation became commercialised in the 1980s, Butane oxidation was the major source of acetic acid

• Now produces less than 10% of acetic acid supply annually.

Thank you any question ?

References: G. James, chemical process and design hand book, USA 2001 A. John & Encyclopedia of chemical technology ullmann’s & encyclopedia of industrial chemistry