GB575437A - Manufacture of new disazo dyestuffs containing copper - Google Patents

Abstract

Copper complexes of unsymmetrical disazo dyes are made by tetrazotising 1 mol. of benzidine carrying methoxy or ethoxy groups in the 3- and 31-positions and optionally a methyl or ethyl group in each of the phenyl nuclei, coupling with 1 mol. of a 1.8- or 2.8-aminonaphthol which carries, in a pair of the positions 3, 4, 5, 6 and (unless occupied by an amino group) 2, not being ortho or peri to each other, two sulphonic acid groups, and with 1 mol. of a 1- or 2-naphthol disulphonic acid, wherein the sulphonic acid groups may occupy any non-adjacent pair of the positions 3, 6, 7 and 8, provided that at least one of the positions 2 and 3 is occupied, and subsequently heating in an aqueous solution of a water-soluble copper salt. In the examples: 1-naphthol-3 : 8- or 3 : 6-disulphonic acid \sM 3 : 31-dimethoxybenzidine --> 1 : 8-aminonaphthol-2 : 4-disulphonic acid is heated with copper sulphate or acetate in an aqueous solution containing ammonium hydroxide or an organic base, e.g. pyridine, piperidine or morpholine. In a table, the copper compounds of the following dyes are specified: 2-naphthol-3 : 6- or 6 : 8-disulphonic acid \sM 3 : 31-dimethoxybenzidine --> 1 : 8-aminonaphthol-2 : 4-disulphonic acid, 1-naphthol-3 : 8-disulphonic acid \sM 3 : 31-dimethoxybenzidine --> 1 : 8-aminonaphthol-3 : 6-, 3 : 5- or 4 : 6-disulphonic acid.or 2 : 8-aminonaphthol - 3 : 6 - disulphonic acid. 2 : 21 - Di-methyl-5 : 51-dimethoxybenzidine is also specified as tetrazo component. The products dye silk and cellulosic fibres, e.g. cotton and regenerated cellulose, blue shades, the after-treatment of which dyeings with crease-proofing resinous condensation products such as a urea-formaldehyde condensation product is described. Specification 366,580 is referred to.