GB753735A - Process for the manufacture of n-alkyl anthranilic acid-sulphonic acids and of derivatives of these sulphonic acids - Google Patents

Abstract

A process of manufacturing N-alkyl anthranilic acid-sulphonic acids and derivatives of these sulphonic acids of the general formula <FORM:0753735/IV(a)/1> wherein R is OH or the radical of an aminoalkyl-sulphonic acid the nitrogen atom of which is linked to the said SO2-group, comprises heating the dry acid alkali metal salts of compounds of the general formula <FORM:0753735/IV(a)/2> wherein R has the above meaning, with a water-free aliphatic or cycloaliphatic primary amine, in the presence of metallic copper or a copper salt. The halogen in the formula is preferably chlorine and the -SO2R group in the 5-position with respect to the -COOH group. The products of the invention may be employed as stabilizers in preparing diazoamino compounds. In examples: an acid sodium salt is obtained by heating anhydrous isopropylamine with the dried monosodium salt of 5-sulpho-2-chlorobenzoic acid in the presence of cuprous chloride in an autoclave, adding caustic soda solution to the product, removing excess amine and copper oxide and adding hydrochloric acid and sodium chloride to the residue (1); a disodium salt is obtained by salting out the product obtained in a similar process in which the dried monosodium salt of 2 - chlorobenzoic acid - 5 - sulpho - N - methyltauride is employed instead of that of 5-sulpho-2-chlorobenzoic acid (2); and a disodium salt is obtained in a similar process using anhydrous cyclohexylamine instead of isopropylamine (3). The monosodium salt of 2 - chlorobenzoic - 5 - sulpho - N - methyltauride is obtained by adding hydrochloric acid and sodium chloride to a solution of the condensation product of 2-chlorobenzoic acid-5-sulphochloride and N-methyltaurine. U.S.A. Specification 1,960,644 is referred to.