Patent GB-493463-A (GB)
Title: Manufacture of derivatives of azo-dyestuffs
Filed: 1937-04-09
Abstract: Mono-, dis- or poly-azo dyes characterized by the general grouping R-N=N-R1 wherein R is the residue of an end component and stands for a phenyl radical containing in only one o-position to the azo linkage a hydroxyl group and which may be further substituted, and R1 is the residue of an end or middle component and stands for a phenyl or naphthyl radical which does not contain a hydroxy group in an o-position to an azo linkage but which may be further substituted are esterified by treating with an agent introducing an SO3-radical into a hydroxy group in the presence of a tertiary base.  The terms "end component" and "middle component" refer only to the position of the residues in question in the dyestuff molecule.  The esterification consists in treating the parent dyestuff with chlorsulphonic acid or a derivative thereof, such as an ester or amide or other agent introducing an SO3 radical into an OH group, in presence of a tertiary base.  The products may be treated in substance or on a substratum such as on the fibre with an acid saponifying agent to reform the sparingly soluble parent dyestuff.  The dyestuffs may be converted into complex metal compounds during or after the conversion.  Diazo components specified are amines of the benzene, naphthalene, diphenyl, di- and triphenylmethane series, e.g. aniline and naphthylamine derivatives, o-aminodiphenylethers, acylated m- or p-phenylenediamines, such as monobenzoylated-, cinnamoylated- or phenoxyacetylated diamino-hydroquinone-dimethyl- or diethyl ether, 4 - methoxy - 4 - aminodiphenylamine; benzidines, 4-41-diaminodiphenylureas, aminoazo compounds and heterocyclic compounds such as dehydrothiotoluidine.  Coupling components specified are phenol, cresols and arylides of phenol carboxylic acids.  In the examples: (1) 4-amino-3 : 21-dimethylazobenzene --> p-cresol is treated with a mixture of pyridine and chlorsulphonic acid, the dyes (2) dehydrothiotoluidine --> p-cresol; (3) 4 : 41-diamino - 2 - methyl - 5 - methoxyazobenzene \sQ p-cresol,; (4) p-chloraniline --> 1 - amino - 2 - methoxynaphthalene --> 1 - oxy - 4 - chlor - 3 - methylbenzene and 4 - amino - 3 - methoxyazobenzene --> p-cresol are similarly treated; (5) cotton is printed with a paste containing the product of (1), water, resorcinol, triethanolamine and starch tragacanth, dried, treated in an acid bath and rinsed; (6) similar to (5) using the product of (3) but no triethanolamine; (6) cotton is dyed in a bath containing the product of (3), and sodium carbonate and sulphate and the dyeing fixed by treating in a sulphuric acid bath.  Specification 282,107, [Class 2 (iii)], is referred to.  The Specification as open to inspection under Sect. 91 comprises the manufacture of ester-like derivatives of azo dyes wherein an azo dye containing at least one phenolic hydroxy group or at least one group behaving as a phenolic hydroxy group and in which at most one such group is contained in the adjacent position to the azo group, is treated by a method which will convert such hydroxy group or groups into acid esters of sulphuric acid.  The starting materials may contain one or more metals in complex union or these metals may be introduced in the esterification products.  Diazo components of the carbazole, urea, diazine and triazine series are specified: p-amino-salicylic acid is also mentioned.  Additional coupling components are a -naphthol, 8-oxyquinoline, oxycarbazoles and barbituric acid.  According to further examples the following dyes are esterified as above: 4-amino-3 : 21-dimethylazobenzene --> p-oxybenzoic acid o-anisidide, 4-amino - N - phenylazimidobenzene --> p-cresol, the dyes from diazotized aniline, 2 : 5-dichloraniline, 2 - methoxy - 5 - methyl - 1 - aminobenzene, p - anisidine, 4 - chlor - 2 - amino - 1 : 1-diphenyl ether and p-cresol, 4-chlor-3-methyl-1-phenol, the anilide of p-cresotinic acid, a -naphthol or 8-oxyquinoline. The dye 4 - amino - 3 - methoxyazobenzene --> p - cresol is treated with the reaction product of chlorsulphonic acid ethyl ester and pyridine.  The dye 2-methoxy - 5-methyl-1-aminobenzene --> p-cresol is esterified with the reaction product of pyrosulphuryl chloride and pyridine and the dye 4 - amino - 3 : 21 - dimethylazobenzene --> p-cresol with aminosulphonic acid and pyridine.  The products may be applied to silk, regenerated cellulose, wool or mixtures thereof or also cotton. This subject-matter does not appear in the Specification as accepted.