Title: Isobutyric Acid

CAS Registry Number: 79-31-2

CAS Name: 2-Methylpropanoic acid

Additional Names: isopropylformic acid

Molecular Formula: C4H8O2

Molecular Weight: 88.11

Percent Composition: C 54.53%, H 9.15%, O 36.32%

Line Formula: (CH3)2CHCOOH

Literature References: Prepn from 1-nitroisobutane: Lippincott, Hass, Ind. Eng. Chem. 31, 118 (1939); from methallyl chloride: Towle, Hall, US 2667508 (1954 to Standard Oil Co. of Indiana); from propylene: Alderson, US 3020314 (1962 to du Pont); from 2-methylpropane + CO with HF catalyst: Friedman, Cotton, J. Org. Chem. 27, 481 (1962).

Properties: Liquid; pungent odor like that of butyric acid, but not as unpleasant. bp760 152-155°. mp -47°. d420 0.950. nD20 1.3930. Flash pt, open cup: 170°F (77°C). Sol in 6 parts of water; misc with alcohol, chloroform, ether.

Melting point: mp -47°

Boiling point: bp760 152-155°

Flash point: Flash pt, open cup: 170°F (77°C)

Index of refraction: nD20 1.3930

Density: d420 0.950

CAUTION: Mild irritant.