Isobutyric acid
Isobutyric acid, also known as 2-methylpropanoic acid or isobutanoic acid, is a carboxylic acid with structural formula 2CHCOOH. It is an isomer of n-butyric 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 in the free state in carobs, in vanilla, and in the root of Arnica dulcis, and as an ethyl ester in croton oil.Production
Isobutyric acid is prepared by the oxidation of isobutyraldehyde, which is a byproduct of the hydroformylation of propylene.
It can also be prepared by the high pressure hydrocarboxylation from propylene:Niche methods
Many routes are known including the hydrolysis of isobutyronitrile with alkalis and the oxidation of isobutanol with potassium dichromate in the presence of sulfuric acid, In the presence of proton donors, the action of sodium amalgam on methacrylic acid also gives isobutyric acid.
Isobutyric acid can also be manufactured commercially using engineered bacteria using a sugar feedstock.Reactions
When heated with a chromic acid solution it is oxidized to acetone. Alkaline potassium permanganate oxidizes it to α-hydroxyisobutyric acid, 2C-CO2H.
Isobutyric acid is a retained trivial name under the IUPAC rules.
