Propanoic Acid - Production

Production

In industry, propanoic acid is mainly produced by the hydrocarboxylation of ethylene using nickel carbonyl as the catalyst:

H₂C=CH₂ + H₂O + CO → CH₃CH₂CO₂H

It is also produced by the aerobic oxidation of propionaldehyde. In the presence of cobalt or manganese ions, this reaction proceeds rapidly at temperatures as mild as 40–50 °C:

CH₃CH₂CHO + ½ O₂ → CH₃CH₂COOH.

Large amounts of propanoic acid were once produced as a byproduct of acetic acid manufacture. Currently the world's largest producer of propanoic acid is BASF, with approximately 80 kt/a production capacity.

Propanoic acid is produced biologically as its coenzyme A ester, propionyl-CoA, from the metabolic breakdown of fatty acids containing odd numbers of carbon atoms, and also from the breakdown of some amino acids. Bacteria of the genus Propionibacterium produce propanoic acid as the end product of their anaerobic metabolism. This class of bacteria is commonly found in the stomachs of ruminants and the sweat glands of humans, and their activity is partially responsible for the odor of both Swiss cheese and sweat.