Patent GB-330607-A (GB)
Title: New azo dyes and their application to the dyeing of regenerated cellulose rayon
IPC: C09B35/35
Filed: 1929-03-13
Abstract: 330,607. Imperial Chemical Industries, Ltd., and Brightman, R. March 13, 1929. Azo dyes.-Trisazo dyes containing at least two sulphonic groups or two carboxylic groups or one of each, and suitable for dyeing regenerated cellulose materials, are obtained by tetrazotizing 3 : 4<1> - diaminoazobenzene, or a substitution product thereof provided that the substituent is not an amino or substituted amino group, and coupling with two molecular proportions of the same or different coupling components other than naphtholaryl ketones or arylides of 2 : 3- oxynaphthoic acid. Certain of the products are also obtainable by diazotizing 3-nitro-4<1>-aminoazobenzene or a suitable derivative thereof, coupling with a sulphonic or carboxylic derivatve of a phenol, a naphthol, an N-substituted naphthylamine or aminonaphthol, reducing the nitro group, diazotizing the resulting amino group, and coupling with a suitable component. 3 : 4<1>. Diaminoazobenzene and substitution products thereof are obtainable by coupling diazotized m-nitraniline or derivatives thereof with amines of the benzene series coupling in p-position to the amino group, and thereafter reducing the nitro group. The following examples are specified : (1) The monoazo product m-nitraniline # aniline -#-sulphonic acid is hydrolyzed to remove the sulphonic group, the product is diazotized and coupled with salicylic acid, the nitro group is reduced, and the aminodisazo dyestuff is diazotized and coupled (alkaline) with 2 : 8 : 6-acid; the product dyes viscose silk reddish brown; if phenyl-2:5: 7-acid is used as second coupling component the dyeing is red; if 1 : 5-naphtholsulphonic acid is used as first coupling component and phenyl-2 : 8: 6-acid as second coupling component the dyeing is brown. (2) The monoazo product m-nitraniline # cresidine is diazotized and coupled with 2:6-naphtholsulphonic acid, the nitro group is reduced, and the aminodisazo dyestuff is diazotized and coupled (alkaline) with 1 : 8-aminonaphthol-2 : 4-disulphonic acid; the product dyes viscose silk blue ; if 4- nitro anisidine # cresidine is used as initial monoazo product and 1 : 4-naphtholsulphonic acid as first coupling component greener dyeings are obtained. (3) The monoazo product 4-nitro-2-anisidine # aniline-w-sulphonic acid is hydrolyzed to remove the sulphonic group, the product is diazotised and coupled with o-cresotinic acid, the nitro group is reduced, and the aminodisazo dyestuff is diazotized and coupled (alkaline) with phenyl-2 : 8 6-acid; the product dyes viscose silk yellowish brown; if 4-nitro-2-toluidine is used as initial diazo component a similar dyestuff is obtained. (4) The monoazo product m-nitraniline # o-toluidine is diazotized and coupled with salicylic acid, the nitro group is reduced, and the aminodisazo dyestuff is diazotized and coupled (alkaline) with 2 : 8 : 6-acid; the product dyes viscose silk yellowish brown. (5) The nitro group of the monoazo product m-nitraniline # cresidine is reduced, the reduction product is tetrazotized and coupled (alkaline) with 1 mol. of 2 :8 : 6-acid and 1 mol. of 2-methylaminonaphthalene-7-sulphonic acid or 2 : 8-aminonaphthol- 3 : 6-disulphonic acid; the products dye viscose silk brownish black. (6) The coupling components in (5) are replaced by 1 mol. of benzoyl- 2 : 8 : 6-acid and 1 mol. of 1 : 5 : 7-acid; the product dyes viscose silk violet-blue. Specifications 2953/92, 19743/92, 9972/93, 5636/94; 27630/03, [Class 15, Bleaching &c.], and 6814/07 are referred to. '