Acetic acid (also called methyl carboxylic acid or ethanic acid) can take the form of an acetate ion. It is found in vinegar and is primarily responsible for its sour taste and smell. Its formula is CH3-COOH (C2H4O2). According to the IUPAC, it is systematically called ethanic acid.


It is produced by synthesis and bacterial fermentation. Today, the organic route supplies about 10% of world production, but remains important in the production of vinegar, since the laws on global food purity establish that the vinegar for food use must be of biological origin. About 75% of the acetic acid produced in the chemical industry is prepared by carbonylation of methanol, explained below. Alternative methods (such as isomerization of ethyl formate, conversion of synthesis gas, oxidation of ethylene and ethanol) provide the rest.

In several reactions, acetic acid is a secondary product. For example, in the synthesis of acrylic acid from propane, propylene and acrolein, acetic acid is also produced with selectivity between 1 and 15%. The fermentative production of lactic acid also produces acetic acid. Total world production of virgin acetic acid is estimated at 5 Mt / a (millions of tons per year) and about half is produced in the United States. Production in Europe is around 1 Mt / a and is falling and Japan produces 0.7 Mt / a. Another 1.5 Mt are recycled every year, for a total of 6.5 Mt / year on the world market.