Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula . It is a colourless, fuming liquid with an irritating odour, and consists of a benzene ring () with an acyl chloride () substituent. It is mainly useful for the production of peroxides but is generally useful in other areas such as in the preparation of dyes, perfumes, pharmaceuticals, and resins. Preparation Benzoyl chloride is produced from benzotrichloride using either water or benzoic acid: C6H5CCl3 + H2O -> C6H5COCl + 2 HCl C6H5CCl3 + C6H5CO2H -> 2 C6H5COCl + HCl As with other acyl chlorides, it can be generated from the parent acid and standard chlorinating agents such as phosphorus pentachloride, thionyl chloride, and oxalyl chloride. It was first prepared by treatment of benzaldehyde with chlorine. An early method for production of benzoyl chloride involved chlorination of benzyl alcohol. Reactions It reacts with water to produce hydrochloric acid and benzoic acid: C6H5COCl + H2O -> C6H5COOH + HCl Benzoyl chloride is a typical acyl chloride. It reacts with alcohols to give the corresponding esters. Similarly, it reacts with amines to give the amide. It undergoes the Friedel-Crafts acylation with aromatic compounds to give the corresponding benzophenones and related derivatives. With carbanions, it serves again as a source of the benzoyl cation synthon, . Benzoyl peroxide, a common reagent in polymer chemistry, is produced industrially by treating benzoyl chloride with hydrogen peroxide and sodium hydroxide: 2 C6H5COCl + H2O2 + 2 NaOH -> (C6H5CO)2O2 + 2 NaCl + 2 H2O References External links International Chemical Safety Card 1015 Acyl chlorides Benzene derivatives IARC Group 2A carcinogens