GB281290A - The manufacture of phenylthioglycollic acids, containing halogen and alkylgroups in the nucleus - Google Patents

Abstract

281,290. I. G. Farbenindustrie Akt.- Ges. Nov. 24, 1926, [Convention date]. Halogenalkylbenzene -sulphochlorides, mercaptans, and -thioglycollic acids.-Halogenalkylbenzenes are converted into sulphochlorides by treatment with chlorsulphonic acid at temperatures below 100‹ C.; a single sulphochloride is usually obtained the sulphochloride group entering in the p.position to a halogen atom. By reduction there are obtained the corresponding mercaptans which yield the corresponding thioglycollic acids on condensation with chloracetic acid. As parent materials trisubstituted benzenes contain two halogen atoms and one alkyl group, or one halogen atom and two alkyl groups are particularly suitable. According to examples, the following compounds are obtained :- (1) 1-methyl-5-chlorbenzene-2-sulphochloride, -2- mercaptan, and -2-thioglycollic acid from mchlortoluene ; (2) 1-methyl-2 : 4-dichlorbenzene- 5-sulphochloride, -5-mercaptan, and -5-thioglycollic acid from 1-methyl-2 : 4-dichlorbenzene : (3) 1-methyl-2 : 6-dichlorbenzene-3-sulphochloride, - 3-mercaptan, and -3-thioglycollic acid from 1-methyl-2 : 6-dichlorbenzene : (4) 1 : 4-dimethyl- 2 - chlorbenzene - 5-sulphochloride, -5-mercaptan, and -5-thioglycollic acid from 1: 4-dimethyl-2- chlorbenzene. Reduction of the sulphochlorides is effected by means of zinc dust and sulphuricacid and condensation of the mercaptans with sodium chloracetate in aqueous caustic soda solution, thioglycollic acids being isolated as free acids or as their sodium or calcium salts.