GB987467A - Process for the production of 2:1-chromium complex dyestuffs - Google Patents

Abstract

2:1-Chromium complexes of monoazo dyes are prepared by reacting a 1:1-chromium complex with a metal-free metallizable dye at elevated temperature in the presence of formamide or an N-substitution product thereof, the metal-free dye being an o,o1-dihydroxyazo or o-hydroxy-o1-carboxyazo dye and the 1:1-chromium complex being of a different o,o1-dihydroxyazo dye or o-hydroxy-o1-alkoxyazo dye. In Example (1) the monoazo dye 2-amino-4-sulphamyl-phenol --> 1-phenyl-3-methyl-5-pyrazoline is heated with chromic chloride in ethylene glycol to form the 1:1-complex, the mixture is cooled to 100 DEG C., the monoazo dye anthranilic acid --> 1-(21-chlorophenyl)-3-methyl-5-pyrazolone and formamide added, the mixture maintained at 100 DEG C. for 1 hour, added to water and the dye complex salted out. In further examples the following additional dyes are specified:-2 - amino - 4 - sulphamyl-phenol --> 2-naphthol and 2-amino-4-sulphamyl-phenol --> acetoacetanilide; 2-amino-4-nitrophenol --> 1-methylsulphonylamino-7-naphthol; 2 - amino - 4 - chloro - 5 - sulphamylphenol --> 41 - hydroxynaphtha - (21,11:4,5)-oxathiol - s - dioxide; anthranilic acid --> acetoacetanilide; 2,5 - dimethoxy - 4 - sulphamyl - aniline --> 1 - methylsulphonylamino-7 - naphthol; 2 - amino - 4 - sulphamylbenzoic acid --> acetoacetic acid 2-methylanilide and 1-amino-2,5-dimethoxy-4-chlorobenzene --> 8 - methylsulphonyl - amino - 2-naphthol.