GB576619A - Intermediate products for the preparation of dyestuffs, process of making them and their application - Google Patents

Abstract

Diazoamino compounds of the general formula <FORM:0576619/IV/1> wherein R represents the residue of a primary aromatic amine R-NH2, or an amine behaving as such on diazotization, but which is incapable of coupling with diazo compounds, and Me represents a monovalent metal, are obtained by condensing a salt of a 2-cycloalkylamino-5-sulphobenzoic acid with the diazotized amine R-NH2 in neutral solution. Specified cycloalkyl groups are cyclohexyl and o- and p-methylcyclohexyl. The products are suitable for use in the production of insoluble azo dyes on the fibre, especially in printing. Examples relate to the production of the diazoamino compounds from diazotized (1) 2-nitroaniline, (2) 2 - chloro - 5 - trifluoromethyl - aniline, (3) 2-chloro-4-aminoxanthone, and 2-cyclohexylamino-5-sulphobenzoic acid. In an example of the use of the compounds, a cotton fabric is printed with an aqueous paste containing the product of (2) above, the o-toluidide of 2 : 3-hydroxynaphthoic acid, caustic soda, thiodiglycol and starch tragacanth thickener and the print is dried, steamed in acetic acid vapour, rinsed, soaped and rinsed to obtain a fast red pattern. Specifications 320,324 and 324,041, [both in Class 2 (iii)], are referred to. 2 - Cyclohexylamino - 5 - sulphobenzoic acid and the corresponding o- and p-methylcyclohexyl compounds are obtained by condensation of cyclohexylamine and its o- and p-methyl derivatives respectively with a salt of 2-chloro-5-sulphobenzoic acid in presence, if necessary, of a condensing agent such as copper powder.