Greener Industry - Ethanoic Acid

Production Method

Future developments
Ethanol and ethanoic acid may be produced by biotechnological processes from renewable biomass and recycled waste resources. More details on production of ethanol from biomass can be found in the section on ethanol.

At present, these processes cannot compete economically with existing industrial processes for the production of ethanoic acid, which are already very energy efficient and produce relatively little waste.

George Stahl, a German chemist, first isolated ethanoic acid, from vinegar in 1700. Vinegar is produced by the air oxidation of ethanol. The concentrated acid is often referred to as 'glacial acetic acid' because it freezes solid just below room temperature.

Production was originally by air oxidation of ethanol (common alcohol) to produce 'vin aigre' (literally "sour wine") or vinegar, a weak aqueous solution of ethanoic acid. Wine vinegar for cooking is still produced using this method.

Up to the 1970s, ethanoic acid was produced industrially by the direct oxidation of naptha or butane, and this process is still in operation in some countries. It produces a wide range of by-products, useful in small quantities. Click here for more.

Ethanoic acid was also made by the oxidation of ethene via the Wacker process. Ethene is oxidised to ethanal in the presence of a palladium (II) chloride catalyst in water. This reaction is still used today to make ethanal. Further oxidation of ethanal to ethanoic acid is then carried out.

Monsanto and Cativa
From about 1970, ethanoic acid was mainly produced by the Monsanto process. This involves the carbonylation of methanol using a rhodium metal iodide complex ion as catalyst. Click to find out more

Since 1997, ethanoic acid is increasingly being produced by the BP Cativa process, also involving the carbonylation of methanol. The difference is that it uses an iridium metal iodide complex ion as a catalyst, with promoters. This Green Chemistry Award-winning process is likely to become the major production method in the near future. Click here to find out more.