CS260947B1 - Black 1: 2 chromocomplex azo dye and method of preparation - Google Patents

Abstract

Black 1:2 chromium complex azo dye of formula I for dyeing wool, PAD and silk from neutral to weakly acidic baths and for printing these materials is prepared by the mutual reaction of 2-(2-hydroxynaphthyl-1-azo)-4-chloro-5-nitrophenol and 1:1 chromium complex of 3-(2-hydroxynaphthyl-1-azo)-4-hydroxy-7-nitronaphthalenesulfonic acid in an aqueous medium at a temperature of 70 to 95 °C and at a pH of 8 to 11.

Description

The object of the invention is a 1: 2 chromium complex azo dye of structural formula I which dyes wool, PAD and silk from a neutral to slightly acid bath with a black tint and can also be used for printing these materials.

Until now, 1: 2 chromium complexes of o, o'-dihydroxyazo dyes containing a single sulfo group in its molecule are preferably used for dyeing and printing wool, PAD and silk.

These dyes are characterized by good leveling, solubility, stability and universal use. The present domestic assortment of these dyes lacks the brand coloring these materials with a black tint.

Now a black 1: 2 chromocomplex dye of structural formula I has been found,

(1) which is prepared by the interaction of 2- (2-hydroxy-naphthyl-1-azo) -4-chloro-5-nitrophenol and a 1: 1 chromium complex of 3- (2-hydroxy-naphthyl-1-azo) -4-hydroxy -7-nitronaphthalenesulfonic acid in aqueous medium at 70-95 ° C and at pH 8-11. The dye stains wool, PAD and silk from a neutral to slightly acid bath with a black tint.

Example

24.5 parts (0.05 mol) of a 1: 1 chromium complex of 3- (2-hydroxy-naphthyl-1-azo) -4-hydroxy-7-nitronaphthalenesulfoacid are added to a suspension prepared from 17.2 parts (0.05 molu)

2- (2-hydroxynaphthyl-1-azo) -4-chloro-6-nitrophenol and 500 parts water 70 ° C, the pH of the reaction mixture is maintained at 8 to 11 with 2.5 N NaOH. The reaction mixture is heated to 85 ° C. to 95 ° C and the reaction is complete after several hours. The dye is isolated from the reaction mixture by salting and filtering under suction. The filter cake is dried at 100 ° C. The reaction yielded 42.5 parts of PAD wool dye and silk from a weakly acid to neutral black bath.

Claims (2)

(AND) 2. A process for preparing a black 1: 2 chromium complex dye according to claim 1, which comprises reacting 2- (2-hydroxynaphthyl-1-azo) -4-chloro-5-nitrophenol with a 1: 1 chromium complex of 3- (2). -hydroxy-naphthyl-1-azo) -4-hydroxy-7-nitrophenolsulfonic acid in an aqueous medium at a temperature of 70 to 95 ° C and a pH of 8 to 11.