ACETIC ACID

also called ethanoic acid (CH3COOH) the most important of the carboxylic acids. A dilute solution of acetic acid produced by fermentation and oxidation of natural carbohydrates is called vinegar (q.v.); a salt, ester, or acylal of acetic acid is called acetate. Industrially, acetic acid is used in the preparation of metal acetates, used in some printing processes; vinyl acetate, employed in the production of plastics; cellulose acetate, a major ingredient in photographic films and textiles; and volatile organic esters (such as ethyl and butyl acetates), which are widely used as solvents for resins, paints, and lacquers. Biologically, acetic acid is an important metabolic intermediate, and it occurs naturally in body fluids and plant juices. Besides that produced as vinegar, vast amounts of acetic acid are prepared synthetically. In one common process acetylene is hydrated to acetaldehyde, which is then oxidized to acetic acid. Ethyl alcohol also is converted industrially to acetic acid by oxidation. Pure acetic acid, often called glacial acetic acid, is a corrosive, colourless liquid (boiling point 117.9 C; melting point 16.6 C), completely miscible with water.