Benzyl chloride, or α-chlorotoluene, is a reactive organochlorine compound that is a widely used chemical building block. Industrially, benzyl chloride is the precursor to benzyl esters which are used as plasticizers, flavorants, and perfumes. Phenylacetic acid, a precursor to pharmaceuticals, is produced from 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. Benzyl chloride is an alkylating agent with very irritating properties to the skin. Indicative of its high reactivity (relative to alkyl chlorides), benzyl chloride reacts with water in a hydrolysis reaction to form benzyl alcohol and hydrochloric acid. In contact with mucous membranes, hydrolysis produces hydrochloric acid. Thus, benzyl chloride is a lachrymator and has been used in chemical warfare.