GB840405A - Improvements in or relating to preparation of phenyl halomethyl thioethers - Google Patents

Abstract

The process of making a phenyl halomethyl thioether of the general formula R-SCH2X, wherein R is a phenyl radical optionally substituted by one or more radicals R1 which may be the same or different, R1 being a halogen atom, a nitro group or an organic radical such as CH3-, OCH3, CH3CONH- or -COOH and X is chlorine or bromine comprises forming a mixture of formaldehyde or a source of formaldehyde and hydrochloric or hydrobromic acid and slowly adding thereto a thiophenol optionally substituted by one or more appropriate radicals R1 as defined above to maintain an excess of acidic material relative to the thiophenyl or substituted thiophenol in the reaction mixture so formed whereby a relatively pure phenyl or substituted phenyl halomethyl thioether reaction product is obtained, the molar ratio of free formaldehyde to thiophenol or substituted thiophenol in said reaction mixture being at least 1.1 : 1 and the molar ratio of the acid to thiophenol or substituted thiophenol in said reaction mixture being at least 7 : 1. Examples relate to the preparation of p-chloro-, p-bromo-, o-methyl-p-methoxy-, 3-chloro-4-methyl- and 2,5-dichlorophenyl chloromethyl sulphides and p-chlorophenyl bromoethyl sulphide. Other products of the given general formula specified are those in which R is phenyl, o - chlorophenyl, m - chlorophenyl, p - bromophenyl, m - methyl phenyl, p - methyl phenyl, p - ethoxyphenyl, 2,4 - dichlorophenyl, 2,5 - dimethoxyphenyl, 2,4 - dimethyl phenyl, 2,4,5-trichlorophenyl and b -naphthyl.