GB281410A - Improvements in or relating to dyeing with azo dyes - Google Patents

Abstract

281,410. British Dyestuffs Corporation, Ltd., Baddiley, J., Chorley, P., and Brightman, R. Sept. 7, 1926. Azo dyes.-Regenerated cellulose materials, e.g. viscose silk, are dyed in level shades with the dyes obtained by coupling diazotized aromatic amines and their derivatives, including sulphonic and carboxylic acids, wth 2-amino-8-naphthol sulphonic acids or with their N-substituted derivatives. other than those described in Specifications 270,446 and 270,883. In addition to monoazo dyes, the disazo dyes obtained by coupling one molecular proportion of a diazo compound with a sulphonic acid of 2-amino-8- naphthol or its N-substituted derivatives in acid solution, and then coupling the product in alkaline solution with a further molecular proportion of the same or a different diazo compound, may be used. For example the disazo dye obtained by coupling 2-phenylamino-8- naphthol-6-sulphonic acid with p-nitraniline-osulphonic acid (acid) and a-naphthylamine (alkaline) dyes viscose silk a blue violet shade, while the corresponding disazo dye from 8-oxy-2 : 2<1>-dinaphthylamine-6-sulphonic acid gives a blue shade. In an example of the dyeing process, the dyebath is made up with the dyestuff from diazotized dehydrothio-p-toluidine sulphonic acid and 2-phenylamino-8-naphthol-6-sulphonic acid (alkaline coupling), soap and glauber's salt are added, and the regenerated cellulose silk goods are dyed nearly at the boiling point; after rinsing and drying a level deep brown shade is obtained. The shades obtained on viscose silk with the following monoazo dyes are tabulated.- the dyes obtained by coupling 2 : 8 : 6-acid in alkaline solution with the diazo compounds of p-chloraniline and o-anisidine ; those obtained by coupling 2-phenylamino-8-naphthol-6-sulphonic acid in alkaline solution with the diazo compounds of 2 : 5-dichloraniline, 2-chlor-4-toluidine- 5-sulphonic acid, and dianisidineoxamic acid, and in acid solution with the diazo compounds of 5-nitro-2-amisidine and naphthionic acid; the dye obtained by coupling 8-oxy-2: 1<1>-dinaphthylamine-6-sulphonic acid with diazotized aniline in alkaline solution: the dyes obtained by coupling 8-oxy-2 : 2<1>-dinaphthylamine-6-sulphonic acid with the diazo compounds of m-aminobenzoic acid and dehydrothio-p-toluidine sulphonic acid in alkaline solution; those obtained by coupling 8 - oxy - 2 : 2'-dinaphthylamine-3 : 6-disulphonic acid with diazotized 2: 5-dichloraniline in acid solution and with 4-chlor-2-anisidine and 4: 4<1>- nitroaminodiphenyl sulphide in alkaline solution: the dyes obtained by coupling diazotized dehydrothio-p-toluidine sulphonic acid (alkaline) with 2-o-anisoylamino-8-naphthol-6-sulphonic acid and with 2-2<1> : 4<1>-dinitrophenylamino-8-naphthol- 6-sulphonic acid; the dye obtained by coupling dia,zotized p-chloraniline (alkaline) with 2-pchlorphenylamino-8-naphthol-6-sulphonic acid: and the dye obtained by coupling diazotized p-aminoacetanilide (alkaline)with 2-ethylamino-8- naphthol-6-sulphonic acid. 8-Oxy-2 : 1<1>-and - 2 : 2<1>-dinaphthylamine-6-sulphonic acids are obtained by heating 2 : 8 : 6-acid with sodium bisulphite and a- or #-naphthylamine. 8-Oxy-2 : 2<1>-dinaphthylamine-3 : 6 - disulphonic acid is obtained by heating 2-amino-8-naphthol- 3 : 6-disulphonic; acid with sodium bisulphite and #-naphthylamine. 2 - p-chlorphenylamino-8-naphthol-6-sulphonic acid is obtained by heating 2 : 8 : 6-acid with sodium bisulphite and p-chloraniline.