Patent GB-462913-A (GB)
Title: Manufacture of dyestuffs and intermediate products therefor
IPC: C09B31/08
Filed: 1935-09-20
Abstract: Azo dyes; azo dyes, forming on the material; acylaminonaphtholsulphonic acids.--Intermediates for azo dyes, are obtained by acylating 1 : 3-diamino-8-naphthol-6-sulphonic and 1 : 3-diamino-5-naphthol-7-sulphonic acids.  They are applicable as coupling components or, if the acylation is effected with an aroylating agent carrying a nitro group and the latter is subsequently reduced, as either diazo or coupling components.  The following examples are specified: (1) an aqueous suspension of 1 : 3-diamino - 8 - naphthol - 6 - sulphonic or 1 : 3-diamino - 5 - naphthol - 7 - sulphonic acid is neutralized with sodium carbonate and acylated with acetic anhydride or benzoyl chloride; the products may be coupled, without isolation, with diazotized aniline to obtain acid wool dyes; (2) an aqueous suspension of 1 : 3-diamino - 8 - naphthol - 6 - sulphonic acid is neutralized as in (1), acylated with m- or p-nitrobenzoyl chloride in presence of calcium carbonate, the calcium salt is filtered off, stirred with hot water, treated with anhydrous sodium carbonate to convert it into the soluble sodium salt of the acylation product, the whole being filtered hot and the sodium salt salted out from the filtrate and the nitro groups are then reduced with iron and acetic acid; the products may be coupled with diazotized aniline or o-toluidine to obtain dyes having affinity for natural or regenerated cellulose, the dyeings being capable of diazotization on the fibre and development, e.g. with b -naphthol; if the aminoaroylated compounds are diacylated the products are substantive and may be converted into azo dyestuffs on the fibre as well as in substance; (3) the dyestuff, 1-amino-8-p-toluenesulphoxynaphthalene - 3 : 6 - disulphonic acid --> 1-naphthylamine, is diazotized and coupled with 4<1> : 4<11>-diaminodibenzoyl-1 : 3-diamino-8-naphthol-6-sulphonic acid and the toluenesulpho group is removed from the disazo product by saponification; the product gives on cotton blue dyeings which may be diazotized and developed with 1-phenyl-3-methyl-5-pyrazolone to a green, fast to washing; the 1-naphthylamine may be replaced by its 2-methoxy derivative or p  cresidine and the 4<1> : 4<11>-diamino derivative by the corresponding 3<1> : 3<11>-diamino- or 2<1> : 2<11>-diamino-3<1> : 3<11>-dimethyl derivative; (4) the dyestuff, 2 - aminonaphthalene-4 : 8-disulphonic acid --> 1-naphthylamine, is diazotized and coupled with 3<1> : 3<11>-diaminodibenzoyl-1 : 3-diamino-8-naphthol-6-sulphonic acid; the product gives on cotton blue dyeings which may be diazotized and developed as in (3); the 1-naphthylamine may be replaced by its 2-methoxy derivative, cresidine or p - xylidine; (5) the dyestuff, 1-amino-8-p-toluenesulphoxynaphthalene-3 : 6-disulphonic acid --> 1-naphthylamine --> Cleve's acid, is diazotized and coupled with 3<1> : 3<11>- or 4<1> : 4<1> - diaminodibenzoyl - 1 : 3-diamino-8-naphthol-6-sulphonic acid and the toluenesulpho group is removed from the trisazo product by saponification; the product gives on cotton blue dyeings which may be diazotized and developed as in (3).  Other initial and middle components may be used as described in Specification 399,097.  Samples furnished under Sect. 2 (5) are of the sodium salts and complex copper compounds of the monoazo dyestuffs obtainable by coupling diazotized anthranilic acid, 4-chloro- and 5 - nitro - 2 - aminophenols and 4 - chloro- and 4 - nitro - 2 - aminophenol - 6 - sulphonic acids with dibenzoyl - 1 : 3 - diamino - 8 - naphthol-6-sulphonic acid and by coupling diazotized 5 - nitro - 2 - aminophenol with diacetyl - 1 : 3-diamino-8-naphthol-6-sulphonic acid.