Preparation of Carboxylic Acids: Hydrolysis of Nitriles

Nitriles (R–CN) can be converted into carboxylic acids (R–COOH) upon treatment with aqueous acids, i.e., upon hydrolysis of nitriles. Under base-catalyzed conditions, carboxylate anions (R–COO⁻) are formed.

The reaction facilitates a two-step conversion of haloalkanes to carboxylic acids. Here, haloalkanes are first converted to nitriles using sodium cyanide via an S_N2 reaction. The resultant nitrile is then hydrolyzed to yield carboxylic acids bearing one more carbon than the haloalkane used. The reaction uses dimethyl sulfoxide, alcohols, or water as solvents. As the process involves the S_N2 mechanism, tertiary alkyl halides are seldom used.