Acetic acid, pronounced uh SEE tihk, is an
important organic acid and industrial chemical. It gives vinegar its sour taste. Vinegar
used in the home contains about 5 percent of the acid. Pure acetic acid is called glacial
acetic acid because it solidifies at 62 °F (17 °C), the temperature of a cool room. When
diluted with water, it is known simply as acetic acid.
Georg Stahl, a German chemist, first isolated glacial acetic acid from vinegar in 1700.
Commercially, the acid is usually produced by such chemical processes as the oxidation of
acetaldehyde with air in the presence of catalysts. Acetaldehyde is itself formed from the
oxidation of ethylene obtained from petroleum.
One of the chief uses of acetic acid is as an intermediate for making other chemicals.
Manufacturers convert it into acetic anhydride and acetate esters. Acetic anhydride is
used to make acetate fibers and cellulose acetate, a plastic. Ethyl acetate is an
important ester used as a solvent for varnishes and in nail polish remover. As a reagent,
acetic acid is used to make synthetics, rubber, and aspirin and other pharmaceuticals. It
is also widely used as an acid and solvent.
Acetic acid is a colorless liquid with a sharp, irritating odor. It is a caustic
substance, and concentrated forms of it can cause severe burns. Acetic acid mixes readily
Contributor: Robert J. Ouellette, Ph.D., Prof. of Chemistry, Ohio State Univ.