butyric acid

butyric acid or butanoic acid , CH 3 CH 2 CH 2 CO 2 H, viscous, foul-smelling, liquid carboxylic acid; m.p. about -5°C; b.p. 163.5°C. It is miscible with water, ethanol, and ether. It is a low molecular weight fatty acid that is present in butter as an ester of glycerol; the odor of rancid butter is due largely to the presence of free butyric acid. Butyric acid is used in the manufacture of plastics. Isobutyric acid, or 2-methylpropanoic acid, (CH 3 ) 2 CHCO 2 H, is a geometric isomer of the butyric acid described above; it has different physical properties but similar chemical properties