Chloromethyl-benzoyl chloride derivs. prepn. - by chlorinating methyl-benzoyl chloride cpds. with less than the stoichiometric amt. of chlorine and recycling unreacted starting material

摘要

Prepn. of o-, m- and/or p-chloromethylbenzoyl chloride (I) by chlorination of the Me gp. of the corresp. methylbenzoyl chloride (II), comprises reacting (II) at elevated temp. with 10-35% of the stoichiometric amt. of chlorine, sepg. the (I) by distn. and recycling the unreacted (II). (I) are intermediates in the pharmaceutical industry e.g. as in DT2447385 or in the prepn. of Ketoprofen (US 3641123). Almost complete conversion of (II) is obtd. and the formation of side-prods., esp. dichlormethyl benzoyl chlorides, is reduced. the chlorine is completely utilised (I) is obtd. in purity 99%. The process can be carried out continuously or discontinuously, as can the distillative sepn. of (I).