A clear viscous liquid or glassy solid carboxylic acid, CH3COOH, with a characteristically sharp odour of vinegar; r.d. 1.049; m.p. 16.6°C; b.p. 117.9°C. The pure compound is called glacial ethanoic acid. It is manufactured by the oxidation of ethanol or by the oxidation of butane in the presence of dissolved manganese(II) or cobalt(II) ethanoates at 200°C, and is used in making ethanoic anhydride for producing cellulose ethanoates. It is also used in making ethenyl ethanoate (for polyvinylacetate). The compound is formed by the fermentation of alcohol and is present in vinegar, which is made by fermenting beer or wine. ‘Vinegar’ made from ethanoic acid with added colouring matter is called ‘nonbrewed condiment’. In living organisms it combines with coenzyme A to form acetyl coenzyme A, which plays a crucial role in energy metabolism.