Acetic Acid

1. Acetic Acid By HamadShaabi Reyan Rutherford Shaun Lynn Andrew Pollock

2. Marketing

3. Marketing

5. Method • Ethylene via acetaldehyde • Methanol by carbonylation • Butane by liquid-phase oxidation • Cativa Process

6. Ethylene via acetaldehyde

7. CO2 Removal OFF Gas Steam Reactor 106 °C 10 ATM H2O Flash tank Acetic Acid scrubber Acetaldehyde Acetic Acid Product BFW Acetic Acid Column Acetaldehyde Column Acetic acid Extractor Extraction System Ethylene Oxygen Nitrogen water stm stm • [PdCl4]²ˉ • C2H4 + H2O + ½O2 CH3CHO + H2O • CuCl2 • CH3CHO + H2O CH3COOH + H2

8. Estimating plant capital costs

9. Methanol Carbonylation

10. 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

11. Methanol Carbonylation • CH3OH + HI  CH3I + H2O • CH3I + CO + [Metal Catalyst]  CH3COI • CH3COI + H2O  CH3COOH + HI CO + [Metal Catalyst] H2O HI HI H2O CH3COOH CH3OH CH3I CH3COI Reaction carried out at a minimum of 200atm.

12. Methanol Carbonylation • Methanol and carbon monoxide are the raw materials. • Bi-products are separated using distillation.

13. Methanol Carbonylation Flow Diagram

14. Methanol Carbonylation Complexity Factor

15. Cativa Process

16. Cativa • Developed in 1996 by BP. • Uses Iridium catalyst. • Requires Catalytic Promoter – Ruthenium • Increase in“active anionic” species Ir(CO2)I3Me]-

17. Mechanism of Iridium Catalysed Reaction

18. 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

19. Cativa Flow diagram

20. 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

21. Butane by liquid-phase oxidation

22. 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.

23. Thank you any question ?

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