GB560842A - Manufacture of azo dyestuffs capable of development on the fibre - Google Patents

Abstract

Trisazo dyes, capable of development on the fibre with diazotised 4-nitroaniline, are obtained by tetrazotising an azo dyestuff of the general formula <FORM:0560842/IV/1> , wherein -R- represents a 1 : 4-phenylene residue, which may be further substituted and coupling with resorcinol (2 mols.) or m-aminophenol (2 mols.) or 1 mol. of each. In an example the product of saponification of the dyestuff, 4-acetylaminoaniline --> (alkaline) 1 : 5 : 7-aminonaphtholsulphonic acid, is tetrazotized and coupled with resorcinol (2 mols.); the dyeing on cotton may be developed with diazotised 4-nitroaniline to a readily dischargeable olive-black, very fast to washing; the first component may be replaced by its 3-methyl, 3-methoxy or 2-chloro-5-methoxy derivative, by 4-oxalylamino-aniline or by 4 - nitroaniline (nitro group subsequently reduced) and the resorcinol by m-aminophenol. A table is also given showing the shades of the direct and developed dyeings on cotton obtainable with the trisazo dyes from various combinations of components, additional 1 : 4-diaminobenzene components being the 2 : 5-dimethyl, 2 : 5-dichloro and 2 : 5-dimethoxy derivatives. An example of the dyeing process is also given. Specifications 20278/97, [Class 2], and 523,918 are referred to.