Electroreduction of benzonitrile

Benzylamine is used as a photographic fixing agent, as a corrosion inhibitor and also as a raw material for the preparation of powerful explosives which are easy to handle. The conventional method adopted for the preparation of benzylamine is the catalytic hydrogenation of benzonitrile in absolute ethanol under high pressure. In the present communication, a novel electrolytic reduction technique for the conversion of benzonitrile to benzylamine, using a palladium black deposited on graphite cathode, is described. Galvanostatic polarization studies, using both a stationary and a rotating cylindrical palladium black deposited cathode, revealed that there is considerable depolarization only in a very low current density regions. The identity of benzylamine has been confirmed by NMR, mass spectral and infrared data. Carbon, hydrogen and nitrogen analysis also support the identity of benzylamine. This simple electrochemical reduction technique opens up a new route for the reduction of cyanide groups to the primary amine groups.