GB824878A - Improvements in the production of dibenzylbenzenes and substitution derivatives thereof - Google Patents

Abstract

In a process for the production of dibenzyl benzenes and substitution derivatives thereof from diphenylmethanes and benzyl chlorides in the presence of a Friedel-Crafts catalyst diphenyl-methane or a homologue thereof or a diphenyl methane nuclearly-substituted with at least one halogen, nitro, hydroxy or alkoxy group is reacted with benzyl chloride or a homologue thereof or a benzyl chloride nuclearly substituted with at least one halogen, nitro, hydroxy or alkoxy group in the presence of benzene or a homologue thereof or a benzene hydrocarbon nuclearly substituted with at least one halogen, nitro, hydroxy or alkoxy group. Benzyl chlorides specified include benzyl, xylyl, polymethyl benzyl chlorides and their nuclearly-substituted derivatives, e.g. chloro-, nitro-, hydroxy- and methoxybenzyl chlorides and chloroxylyl chloride. Diphenylmethanes specified include diphenyl-, ditolyl-, dixylyl-, dimesityl-, phenyl-tolyl- and phenyl-mesityl-methanes and their halogen, nitro and alkoxy derivatives. Substitution derivatives of benzene specified include toluene, xylene, mesitylene, chlorotoluene, nitrotoluene, xylenol and anisole. Catalysts specified include aluminium chloride, boron fluoride, concentrated sulphuric acid and anhydrous hydrofluoric acid. Preferably the diphenylmethane is formed during the reaction from the benzyl chloride and benzene or the substitution derivative thereof. Advantageously the benzyl chloride employed as starting material may be prepared by chlorination of a methyl substituted benzene, e.g. toluene or xylene, at elevated temperature, whilst irradiating with ultra-violet light and reacting the product with a diphenylmethane, both steps being optionally carried out continuously. In examples: dixylylxylene is obtained by reacting xylylxylene in the presence of aluminium chloride with a mixture of xylyl chloride and xylene obtained by chlorinating xylene in a lead vessel (1); di-(chlorobenzyl)-chlortoluene is obtained by reacting chlortoluene, chlorbenzylchlortoluene and chlorbenzyl chloride in the presence of an iron chloride catalyst (2); and dibenzyltoluene is obtained in a continuous process in which a mixture of toluene and benzyl chloride, obtained by chlorinating toluene is reacted with benzyl toluene in the presence of an oily aluminium chloride complex formed by adding anhydrous aluminium chloride to the reaction mixture at 60-70 DEG C. (3).