GB422317A - The manufacture of azo-dyestuffs insoluble in water - Google Patents

Abstract

Azo dyes insoluble in water are made by diazotizing an amine of the general formula <FORM:0422317/IV/1> (in which one X = H, alkyl or phenyl, and the other X = alkyl or phenyl-) and coupling with an arylide of 2 : 3-oxynaphthoic acid. They may be produced in substance, on a substratum or on the fibre. They yield clear fast yellow to golden-orange shades. In an example the following dyestuff is produced on cotton 1 - amino - 2 - benzylsulphone - 4 - methyl-sulphone - benzene --> 1 - (2<1> - oxy - 3<1> - naphthoylamino)-2-methyl-4-chlorobenzene. In a table the shades obtained by use of the following additional components are given: 1-amino-2-benzylsulphone-4-ethylsulphone-benzene, 1 - amino - 2 - methylsulphone - 4 - benzylsulphone - benzene, 1 - amino - 2 : 4 - dibenzylsulphone - benzene; the anilide, o-toluidide and p-chloranilide of 2 : 3 - oxynaphthoic acid. Specifications 6379/12, [Class 2 (iii)], and 17279/13, [Class 15 (ii)], are referred to. Aminobenzenedisulphones are made as follows: aniline is converted into 2-amino-6-thiocyanobenzothiazole by the action of an excess of ammonium thiocyanate and bromine in the presence of glacial acetic acid with the intermediate formation of 2 : 4 - dithiocyanoaniline. The 6-thiocyano group is then saponified to the mercapto group which is alkylated or aralkylated. The 2-aminobenzothiazole-6-thioethers are converted according to Specification 306,590, [Class 2 (iii)], into 1-amino-benzene-2-mercapto-4-thioethers which are then further alkylated or aralkylated on the free mercapto group. In this way unsymmetrically substituted dithioethers can be obtained. The symmetrical substituted dithioethers may be obtained by converting the 2-amino-6-thiocyanobenzthiazole into 1 - amino - 2:4 - dimercaptobenzene (cf. Specification 306,590) which is then dialkylated or diaralkylated. The dithioethers are converted into the disulphones by acetylation of the amino group, oxidation with hydrogen peroxide in glacial acetic acid and saponification. Specifications 257,619 and 295,295, [both in Class 2 (iii)], also are referred to.