Production of 4,4'-di:halo-di:phenyl-sulphone

摘要

A process for the production of 4,4'-dihalo-diphenyl- sulphones (DHDPSO) comprises reacting chloro-, bromo- or fluoro- benzenes with 4-halophenylsulphonyl chlorides of formula (I); in which X = chlorine, bromine or fluorine. The reaction is carried out in the liquid phase at elevated temperature in presence of solid catalysts with acid centres, comprising (K1) layer silicates with negative layer charges neutralised by protons and essentially not doped with Lewis acids, (K2) zeolites in the acidic H-form, or (K3) mixed oxides with acid centres, consisting of a combination of (a) oxides of titanium, zirconium, hafnium, tin, iron or chromium(III) with (b) oxides of vanadium, chromium(VI), molybdenum, tungsten or scandium, or sulphated or phosphatised oxides of group (a), such mixed oxides having been calcined at 450-800 deg C after combination. Preferably type (K1) comprises aluminium silicate in which part of the silicon is replaced by aluminium and/or part of the Al is replaced by magnesium, especially a montmorillonite. Type (K2) comprises zeolites of structural types MFI, MEL, BOG, BEA, EMT, MOR, FAU, MTW, LTL, NES, CON or MCM 22, especially 12-ring zeolites of the BETA, Y, EMT or mordenite type, or 10-ring zeolites of the pentasil type. Type (K3) may be super-acid mixed oxides, preferably with group (a) oxides and group (b) oxides in a mol ratio of (70:30)-(98:2). The process comprises reacting chlorobenzene (PhCl) with 4-chlorophenyl-sulphonyl chloride (ClPhSOCl) in a mol ratio of 1-100, preferably using excess PhCl, at 100-250 deg C and 1-50 bar, preferably at boiling pt. under normal or autogenous pressure. The catalyst is in the form of a solid bed, and the reaction may be carried out as a continuous process in which excess PhCl is returned to the reactor.