Patent GB-604921-A (GB)
Title: Manufacture of azo-dyestuffs
IPC: C09B39/00
Filed: 1945-03-27
Abstract: Azo dyestuffs containing twice the atomic grouping <FORM:0604921/IV (c)/1> wherein x represents a sulphonic acid group or a sulphonamide group (which may contain substituents attached to the nitrogen atom) and Py represents the residue of a 3-methyl-5-pyrazolone linked to the azo-group in the 4-position and containing a salicylic grouping in a benzene nucleus which may contain further substituents and which is attached to the 1-position of the pyrazolone ring either directly or through a bridge member, are manufactured (a) by coupling a tetrazo compound of a diamine of substantive character, free from azo- and azoxy-groups but containing a sulphonic acid or sulphonamide group in o-position to each amino-group and containing an -HN-CO-NH-or <FORM:0604921/IV (c)/2> group, with two molecular proportions of a pyrazolone of the said kind, or (b) by coupling a diazo-monoazo compound of substantive character, containing once the said atomic group and free from azoxy-groups or further azo-groups but containing a sulphonic acid or sulphonamide group in o-position to the diazo group and containing an -HN-CO-NH-or <FORM:0604921/IV (c)/3> group, with an equimolecular proportion of a pyrazolone of the said kind, or (c) by treating an amino-monoazo dyestuff containing the said atomic grouping (especially one containing the residue of a (41-aminobenzoylamino)-1-amino-benzene-2-sulphonic acid or a 4 : 41-diamino-diphenyl-3-sulphonic acid), or an equimolecular mixture of two such amino-monoazo dyestuffs, with phosgene, or with cyanuric chloride in the proportion of one molecular proportion thereof to two of amino-monoazo dyestuff or dyestuffs, and, in the latter case, if desired, condensing the product with an amine.  As diamines suitable for use in method (a) are specified, the symmetrical ureas of mono-(aminobenzoyl)-p-phenylenediamino-o- or o1-sulphonic acids, of 4 : 41 - diaminodiphenyl - 3 - sulphonic acid or p-phenylenediaminesulphonamide, mixed ureas such as <FORM:0604921/IV (c)/4> and the ternary condensation product of 1 mol. of cyannic chloride with 2 mols. of 4 : 41-diaminodiphenyl-3-sulphonic acid and 1 mol. of aniline.  The amino-monoazo dyestuffs used in method (c) may be made by diazotizing an amine of the benzene or naphthalene series, containing a sulphonic acid or sulphonamide group in o-position to the amino-group and, as a further substituent, e.g. in p-position to the amino-group, a group convertible to an amino group (e.g. a nitro or acetylamine group), coupling with a pyrazolone of the kind defined and converting to an amino group the substituent so convertible.  The products may be used for dyeing or printing cellulosic fibres (e.g. cotton, flax and artificial silk or staple fibres of regenerated cellulose) and also animal fibres (e.g. wool or leather).  They may be treated in substance, in the dyebath or on the fibre with agents yielding metal (e.g. iron, chromium or especially copper).  Examples are given of the production of symmetrical dyestuffs by methods (a) and (c) and of asymmetrical dyestuffs by method (c), the coupling components employed being 1 - (41 - hydroxy - 31 - carboxyphenyl) - 3 -methyl-5-pyrazolone and 1-(41-carboxyphenyl)-3-methyl-5-pyrazolone 411-hydroxy-311-carboxyanilide.  In a further example, cotton is dyed with one of the products from a bath containing sodium carbonate and sodium sulphate and treated in the same bath with complex copper tartrate.  Specification 455,274 is referred to.  Samples have been furnished under Sect. 2 (5) of a dyestuff proposed by both methods (c) and (a) using as coupling component 1-(51-chloro-41 - hydroxy - 31 - carboxy) - phenyl - 3 - methyl - 5 - pyrazolone.  The Specification as open to inspection under Sect. 91 comprises also the manufacture of other azo dyestuffs from amines of substantive character containing a sulphonic acid group (or group easily convertible thereto, such as a sulphonic ester group) or a sulphonamide group in o-position to at least one diazotizable amino group and pyrazolones containing a lake-forming group.  The amines may have a p-diamine structure, as in the case of benzidine and p-phenylenediamine derivatives, or may contain groups or residues imparting substantive properties, such as acid amide, azo or azoxy groups or residues of dehydrothiotoluidine, carbazole, stilbene or 2-amino-5-naphthol-7-sulphonic acid. Further methods building up the substantive residues after coupling are: conversion of an amino group into an acid amide group or an azo group, condensation of an acid group (e.g. a carboxyl group) with a further amine, and reduction of a nitro group to an azo or azoxy group by means of a mild reducing agent (e.g. dextrose in alkaline medium).  An example is given of this p  last method, and also examples of the production of dyestuffs from 4 : 41-diaminodiphenyl-3 : 31-disulphonic acid and its 5 : 51-dichloro derivative, and from 4-amino-41-hydroxy-31-carboxy - 1 : 11 - azobenzene - 3 - sulphonic acid.  This subject-matter does not appear in the Specification as accepted.