GB647214A - Improvements in or relating to methane sulphonic acids and derivatives thereof - Google Patents

Abstract

Substituted methane sulphonic acids of the general formula R(X.CH2SO3H)n and alkali metal or alkali earth metal salts thereof are prepared by a process which includes the step of heating a salt of chloro-, bromo- or iodomethane sulphonic acid with an alkali metal or alkaline earth metal aryloxide or the corresponding thio compound containing the radical R. In the above formula X is an oxygen or sulphur atom, n is an integer not greater than 3, and R is an aryl radicle which may be substituted by one or more groups stable under the process conditions or, when X is a sulphur atom and n is 1, is also an aralkyl radicle. Normally the compound obtained is a metal salt of the above acid, the metal being that of the methane sulphuric acid salt used, and the free acid may be obtained in the conventional fashion via the barium salt. The stable substituent groups of R may be chemically converted to other groupings since the group -O.CH2SO3H is quite stable to such reagents as oxidizing, reducing and hydrolytic reagents. Thus the compounds may be nitrated and nuclear methyl groups oxidized, e.g. with permanganate, to carboxy groups. Hence 4-carboxy-phenoxymethane sulphonic acid may be prepared either by condensing 4-hydroxy benzoic acid or p-cresol with the halomethane sulphonic acid except that in the latter case the nuclear methyl group must be oxidized. Temperatures instanced are about 170 DEG to 240 DEG C., e.g. 200 DEG C., an excess of the free phenol or mercaptan often being employed as a flux and recovered by such methods as distillation, steam distillation or solvent extraction. The alkali metal salts of the required product are usually soluble in water but insoluble in organic solvents and hence can be recovered by solvent extraction or via the insoluble barium salt. If the phenol or mercaptan is high-boiling or a poor solvent the reaction may be carried out in an aqueous medium in a pressure reactor in which case the chloro-methane sulphonate is preferred. In examples, iodo-methane sulphonic acid sodium salt in the presence of copper bronze, other than in (5) or in (2) when copper acetate is used instead, is reacted with (1), (2), (3), (4) and (5) sodium 2 : 4-dichlorphenate; (6) sodium 4-chlorphenate, 4-methoxyphenate and 4-methylphenate; (7) sodium 4-cyanophenate; (8) and (9) sodium phenate; (10) sodium 4-bromphenate; (11) sodium carbethoxyphenate; (14) sodium 2 : 5-dichlorphenate, 2 : 4 : 5-trichlorphenate and 2 : 4 : 6-trichlorphenate; and (16) the sodium salt of benzyl-mercaptan to give, if necessary after treatment with barium chloride, (1) and (3) sodium 2 : 4-dichlorphenoxymethane sulphonate; (2), (4) and (5) barium 2 : 4 - dichlorphenoxymethane sulphonate; (6) sodium 4-chlor-, 4-methoxy- and 4 - methylphenoxymethane sulphonate; (7) sodium 4-cyanophenoxymethane sulphonate; (8) and (9) barium phenoxymethane sulphonate; (10) sodium 4 - bromophenoxymethane sulphonate; (11) sodium 4-carbethoxyphenoxymethane sulphonate; (14) barium 2 : 5-dichlor-2 : 4 : 5-trichlor- and 2 : 4 : 6-trichlor-phenoxymethane sulphonate; and (16) barium thiobenzyl-methane sulphonate; in (12) potassium 2 : 4-dichlorphenate is heated with potassium chloromethane sulphonate in the presence of copper bronze to give potassium 2 : 4-dichlorophenoxymethane sulphonate; in (13) sodium 2 : 4-dichlorphenate is reacted with sodium bromo-methane sulphonate to give barium 2 : 4-dichlorophenoxymethane sulphonate on treatment with barium chloride solution; and in (15) sodium 2 : 4-dichlorphenate is heated with chlormethane sodium sulphonate in aqueous solution under pressure to give barium 2 : 4 dichlorophenoxymethane sulphonate after treatment with barium chloride. The S-benzyl-iso-thiouronium salts of the free acids corresponding to the above salts obtained in the examples except that of 2 : 5-dichlorphenoxymethane sulphonic acid are described and in (3) the S-benzyl-iso-thiouronium salt of 2 : 4-dichlorphenoxymethane sulphonic acid is obtained by adding S-benzylisothiourea hydrochloride to a solution of the sodium salt of the acid. Specification 647,215 is referred to. Samples have been furnished under Sect. 2 (5) of sodium b -naphthoxymethane sulphonate prepared by heating iodomethane sodium sulphonate and the sodium salt of b -naphthol, barium phenylene 1 : 4-bis (oxymethane sulphonate) by heating chlormethane sodium sulphonate and hydroquinone in aqueous caustic soda solution with subsequent barium chloride treatment, sodium 4-methylphenyl thiomethane sulphonate by heating 4-thiocresol with chloromethane sodium sulphonate in aqueous caustic soda solution, and barium and sodium 4 : 6-dichlorophenylene-1 : 3-bis (thiomethane sulphonate) by heating 1 : 3-dithiol-4 : 6-dichlorobenzene and chloromethane sodium sulphonate in aqueous caustic soda solution with subsequent barium chloride and sodium carbonate treatment.