GB406168A - Improvements in or relating to the manufacture of azo dyes - Google Patents

Abstract

Yellow to orange dyes for silk and vegetable fibres are prepared by coupling a diazotized aminobenzamide in an alkaline medium with a 2 - benzoylaminobenzoylamino - 5 - naphthol - 7-sulphonic acid. The aminobenzamide may be substituted on the nitrogen atom of the amide group with one or two alkyl or aryl radicles, and the benzene nuclei in the diazo compound or the coupling component may also be substituted, otherwise than by a free sulpho, carboxyl, hydroxyl or amino group. In the examples, the diazo compound from (1) p-aminobenzamide, or (2) m-aminobenzamide, or (3) p-aminobenzmethylamide, or (4) p-aminobenzdimethylamide, or (5) p-aminobenzanilide, is coupled with benzoyl-p-aminobenzoyl-2-amino-5-naphthol-7-sulphonic acid; (6) the diazo compound from p-aminobenzamide is coupled with o-chlorobenzoyl-p-aminobenzoyl-2-amino-5-naphthol-7-sulphonic acid or (7) with p-toluyl-p-aminobenzoyl-2-amino-5-naphthol-7-sulphonic acid or (8) with benzoyl-m-aminobenzoyl - 2 - amino - 5 - naphthol - 7 - sulphonic acid; coupling is effected in a medium made alkaline with sodium bicarbonate. Other diazo compounds specified as suitable are those from aminobenzmono- or -di-ethylamides, the corresponding butyl derivatives, and aminobenztoluidides; other specified coupling components are anisoyl-and nitrobenzoyl-p-aminobenzoyl-2-amino-5-naphthol-7-sulphonic acid. The coupling components specified may be prepared by condensing 2-amino-5-naphthol-7-sulphonic acid with m- or p-nitrobenzoyl chloride, reducing the nitro group with hydrosulphite, and aroylating the product. The aminobenzamides specified may be prepared by condensing m- or p-nitrobenzoyl chloride with the appropriate base, and reducing the products with hydrosulphite.