Isobutyric Acid (CAS 79-31-2)

Isobutyric Acid (CAS 79-31-2)

Isobutyric acid, also known as 2-methylpropanoic acid or isobutanoic acid, is a carboxylic acid with structural formula (CH3)2CHCOOH. It is an isomer of n-butyric acid. It is classified as a short-chain fatty acid. Deprotonation or esterification gives derivatives called isobutyrates.

Isobutyric acid is a colorless liquid with a somewhat unpleasant odor. It is soluble in water and organic solvents. It is found naturally in carobs (Ceratonia siliqua), in vanilla, and in the root of Arnica dulcis, and as an ethyl ester in croton oil.

Production
Isobutyric acid is manufactured by the oxidation of isobutyraldehyde, which is a byproduct of the hydroformylation of propylene.

It can also be prepared by the high pressure hydrocarboxylation (Koch reaction) from propylene: CH3CH=CH2 + CO + H2O → (CH3)2CHCO2H