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.   |