Ethanoic Acid

Ethanoic Acid, (traditionally known as acetic acid) a colourless liquid, CH₃ COOH, with a sharp, irritating odour and sour taste. In aqueous solution, it functions as a weak acid. Pure ethanoic acid, because it freezes at slightly below ordinary room temperature, is called glacial ethanoic acid; mixtures with water solidify at much lower temperatures. Ethanoic acid is miscible (mixable) with water and with many organic solvents.

Ethanoic acid can be prepared by the action of air on solutions of alcohol in the presence of certain strains of bacteria, such as Bacterium aceti. Dilute solutions (4-8 per cent) prepared in this way from wine, cider, or malt are called vinegar. Concentrated ethanoic acid is prepared industrially by several synthetic processes, such as the reaction of methanol (methyl alcohol) and carbon monoxide (CO) in the presence of a catalyst, or the oxidation of ethanal (acetaldehyde).

Ethanoic acid is used in the production of acetate rayon, plastics, photographic film, paint solvents, and pharmaceuticals such as aspirin. Ethanoic acid boils at 118° C (245° F) and melts at 17° C (62° F).