Chlorination of aromatic compounds and catalystst therefor

摘要

A process for the chlorination of an aromatic compound of the following formula (A) : wherein R is H or C1 to C12 alkyl, cycloalkyl, aryl, alkaryl, aralkyl or carboxyalkyl, the or each R is selected from H, C1-C4 alkyl (especially methyl), C1-C4 haloalkyl or polyhaloalkyl, e.g. C1-C4 perfluoroalkyl, C1-C4 alkoxy, C5-C12 aryl (e.g. phenyl), alkaryl or aralkyl, or halogen, and n is an integer which is 0, 1 or 2, and the or each R, if present, may independently be attached at the ortho or the meta position (preferably at the meta position), which process comprises reacting (preferably in heterogeneous liquid/solid phase below 35 DEG C) the aromatic compound (which is preferably phenol) with a chlorinating agent (preferably sulphuryl chloride) in the presence of a sulphur-containing catalyst, optionally also in the presence of a Lewis acid co-catalyst, characterised in that the sulphur-containing catalyst is an organic compound according to the following formula (I) or formula (II) : in which: PS represents a polymeric backbone preferably selected from polystyrene or a polysiloxane, e.g. a polyalkylsiloxane or a polyalkylarylsiloxane; x is an integer which is 0 or from 1 to 12; R<1>, R<2>, R<3> and R<4> are each independently selected from the group consisting of: optionally substituted straight or branched chain alkyl or alkanediyl having from 1 to 20 (preferably 1 to 10) carbon atoms, optionally substituted straight or branched chain alkaryl or aralkyl having from 5 to 20 carbon atoms, and optionally substituted aryl having from 5 to 20 carbon atoms; X<1> and X<2> are each independently selected from the group consisting of halogen (preferably Cl, Br or I), thiol, dialkylsulphonium halide and R5, where R5 is selected from the group consisting of: optionally substituted straight or branched chain alkyl or alkanediyl having from 1 to 20 (preferably 1 to 10) carbon atoms, optionally substituted straight or branched chain alkaryl or arallkyl having from 5 to 20 carbon atoms, and optionally substituted aryl having from 5 to 20 carbon atoms; y is a number (which may be integral or non-integral) greater than zero, preferably up to about 10000, more preferably in the range from about 1 to about 1000, particularly from about 1 to about 500 and especially from about 2 to about 100; wherein in the above definitions of R<1>, R<2>, R<3>, R<4> and R<5> the optional substituents may be independently selected from the following: halogen (e.g. F, Cl), hydroxy, amino, cyano, nitro, C1-C4 alkyl, C1-C4 haloalkyl e.g. C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 alkoxycarbonyl.