Benzyl chloride

Benzyl chloride, or α-chlorotoluene, is an organic compound with the formula C₆H₅CH₂Cl. This colourless liquid is a reactive organochlorine compound that is a widely used chemical building block.

Preparation

Benzyl chloride is prepared industrially by the gas-phase photochemical reaction of toluene with chlorine:

In this way, approximately 100,000 tonnes are produced annually. The reaction proceeds via free radical, involving the intermediacy of the chlorine atoms. Side products of the reaction include benzal chloride and benzotrichloride.

Other methods exist, such as the Blanc chloromethylation of benzene. Benzyl chloride was first prepared from treatment of benzyl alcohol with hydrochloric acid.

Uses and reactions

Industrially, benzyl chloride is the precursor to benzyl esters which are used as plasticizer, flavorants, and perfumes. Phenylacetic acid, a precursor to pharmaceuticals, arises via benzyl cyanide, which is generated by treatment of benzyl chloride with sodium cyanide. Quaternary ammonium salts, used as surfactants, are readily formed by alkylation of tertiary amines with benzyl chloride.