GB435249A - Improvements in or relating to the production of water soluble basic azo dyestuffs - Google Patents

Abstract

Water-soluble basic azo dyes are made by coupling a diazo compound which contains no water solubility promoting radicle of acid character such as sulphonic or carboxyl groups but which may contain a quaternary ammonium group with an arylide of a b -keto carboxylic acid having a quaternary ammonium group in the arylide residue. Specified diazo components are the salts of trimethyl - (m - or p - aminophenyl-) ammonium and of the m<1>-or p<1>-aminobenzoyl derivatives of these or of o-, m-or paminobenzyl-pyridiniums, aminoazo compounds containing quaternary ammonium groups e.g. the salts of trimethyl - (p<1> - aminobenzene azo-phenyl-) ammonium and the aminoazo compounds from diazotized aromatic amino ammonium compounds and m-toluidine, a -naphthylamine or other middle component. The dyestuffs are fast to light and are capable of fixing substantive and mordant dyestuffs of acid character on to cellulose fibres, e.g. cotton and viscose. If the basic dye is applied first, it can also act as a mordant for non-substantive acid dyes or the dyeing can be after-treated with tanning agents, especially those of the pyrogallol or ellagene class. The tanning agent may also be applied prior to the dyeing. The dyeings may be after-treated with metal salts. In examples the following yellow dyestuffs are described: (1) tetrazotized benzidine or (2) diazotized trimethyl-(p<1>-aminobenzoyl-m-aminophenyl-) ammonium methosulphate (obtained by condensing m-aminodimethylaniline with p-nitrobenzoylchloride, condensing with dimethyl sulphate and reducing) is coupled with trimethyl - p - acetoacetylaminophenylammonium methosulphate (obtained by condensing acetoacetic ester with p-aminodimethylaniline in xylol and the product obtained with dimethylsulphate). The Specification as open to inspection under Sect. 91 refers to the use of the corresponding chloride as diazo component in p example 2 above (the dyestuff being precipitated with calcium iodide) and to the corresponding secondary disazo dyes with m-toluidine and a -naphthylamine respectively as middle components. This subject-matter does not appear in the Specification as accepted.