A method for the production of 2, 4 - to - (chloromethyl) - toluene, in addition to mono chlorine methyl toluene or 2, 5 - to - (chloromethyl) - p - xylene

摘要

Bis-(chlormethyl) derivatives of monoalkylor dialkyl-benzenes are produced by reacting the appropriate alkyl benzene with formaldehyde (paraformaldehyde or trioxymethylene), zinc chloride and hydrochloric acid, the reaction being carried out in the presence of an inert organic diluent, such as an aliphatic or alicyclic hydrocarbon or a chlorinated derivative thereof. Specified diluents are: carbon tetrachloride, chloroform, methylene dichloride, sym-tetrachloroethane, and cyclohexane. Examples 1 and 2 relate to the preparation of 2,4-bis-(chlormethyl) -toluene by adding toluene to a mixture of trioxymethylene, zinc chloride, carbon tetrachloride and hydrogen chloride, which had been heated at 60 DEG C. to bring about depolymerization of all the trioxymethylene. The organic components of the reaction-products are separated by standard methods, and are submitted to distillation to remove the solvent and the unreacted toluene. The mixture is then submitted to fractional distillation under reduced pressure, when monochlormethyltoluene distils over first, and is followed by 2,4-bis-(chlormethyl) toluene. The latter is purified by crystallisation from petroleum ether, n-hexane or n-pentane. Example 1 also describes the chlormethylation of the byproduct, viz. monochlormethyltoluene, to give further amounts of 2,4-bis-(chlormethyl) toluene. Example 3 describes the preparation of 2,5-bis-(chlormethyl)-p-xylene by the chlormethylation of p-xylene using carbon tetrachloride as diluent.