Patent GB-619688-A (GB)
Title: Manufacture of trisazo-dyestuffs
IPC: C09B43/16
Filed: 1946-06-12
Abstract: Trisazo dyestuffs are manufactured by coupling a condensation product of the general formula <FORM:0619688/IV (c)/1> (wherein R4 represents an aromatic nucleus of the benzene series, R5 represents hydrogen or alkyl and R6 represents a halogen atom or the grouping <FORM:0619688/IV (c)/2> wherein R7 represents hydrogen or alkyl and R8 an aromatic residue of the benzene series, R4 and R8 being free from the characteristic grouping of salicylic acid and being incapable of taking an active part in the formation of dyestuffs by coupling or diazotization) with a diazo compound of a disazo dyestuff containing at least one sulpho group and of the general formula <FORM:0619688/IV (c)/3> (in which R1 represents a benzene nucleus containing a hydroxy group in p-position to the azo linkage and a carboxyl group in o-position to the hydroxy group, and R2 and R3 represent 1 : 4-naphthylene residues) and so selecting the starting materials that the trisazo dyestuff contains from 2 to 4 (preferably 3) sulphonic acid groups; or by coupling a diazo compound of such a disazo dyestuff with 2 : 5 : 7-aminonaphtholsulphonic acid in neutral or alkaline medium so that coupling occurs in the 6-position, and then reacting 1 mol. of the resulting trisazo dyestuff with 1 mol. of a cyanuric halide and the product with 1 mol. of an amine NHR4R5 and, if desired, simultaneously or subsequently with 1 mol. of an amine NHR7R8 which may be the same as or different from NHR4R5.  The products yield after-coppered dyeings on cellulose, e.g. cotton or regenerated cellulose, and may also be used for dyeing mixed fabrics, e.g. mixtures of wool and viscose staple fibre, preferably in a neutral bath in the presence of sodium or potassium chromate. Examples describe the preparation of the following dyestuffs: (1) 1-amino-3-carboxy - 4 - hydroxybenzene --> 1 - naphthylamine - 7 - sulphonic acid --> 1 - naphthylamine --> the tertiary condensation product from cyanuric chloride, 2 : 5 : 7-acid, metanilic acid and aniline; (2) 1-amino-3-carboxy-4-hydroxybenzene --> 1 - naphthylamine - 7 - sulphonic acid --> 1-naphthylamine-7-sulphonic acid --> the secondary condensation product from cyanuric chloride, 2 : 5 : 7-acid and aniline.  Various alternative components are specified. In example (3), cotton is dyed with the product of (1) from a bath containing sodium acetate and sodium sulphate and after-treated in the same bath with a solution of copper sulphate and tartaric acid neutralized with caustic soda, yielding a grey tint. Specifications 209,723, (Class 2 (iii)], 517,335 and 580,175 are referred to. Samples have been furnished under Sect. 2 (5) of: (I) the dyestuff obtained by replacing the end component in (1) above by the tertiary condensation product from cyanuric chloride, 2 : 5 : 7-acid, metanilic acid and N-monomethylaniline; (II) the dyestuff obtained by replacing the end component in (2) above by that of (1) above; (III) the product obtained by condensing 1 mol. of the trisazo dye 1-amino-3-carboxy-4-hydroxybenzene --> 1 - naphthylamine - 7 - sulphonic acid --> 1-naphthylamine --> (alkaline) 2 : 5 : 7-acid with 1 mol. of cyanuric chloride and condensing the product with 1 mol. of metanilic acid and then with 1 mol. of aniline.