GB1028918A - Improvements relating to cobalt-containing formazane dyestuffs and their use - Google Patents

Abstract

The invention comprises cobalt-containing formazane compounds which contain no salt-forming groups which dissociate acid in water and no sulphamide groups, except arylsulphamide groups and which correspond to the general formula <FORM:1028918/C4-C5/1> wherein A1 and A2 are each an aromatic radical, B1 and B2 are each an aromatic radical containing no metallizable groups in the o-positions to the nitrogen bond, Q1 and Q2 are each a bridging member, Z1 and Z2 are each an optionally substituted aliphatic hydrocarbon group having at most four carbon atoms, W1 and W2 are each an optionally substituted, saturated or unsaturated aliphatic hydrocarbon radical, an optionally saturated cycloaliphatic hydrocarbon radical or an optionally substituted aromatic hydrocarbon radical or a heterocyclic radical containing no ring nitrogen atoms or the nitro or the cyano group, X11 and X12 represent -O- in o-position to the nitrogen linkage to A1 or A2, Y+ represents an equivalent of a cation and n1, n2, m1 and m2 each represen the whole numbers 1 or 2. The dyes are prepared by reacting one mole of an appropriate formazane compound or a mixture of such compounds with an agent providing less than 1 mol of cobalt to form a compound which contains the residues of two molecules of formazane dyestuff to one cobalt atom. The formazane compounds employed as starting materials are prepared by methods known per se, e.g. an aldehyde is coupled with the hydrazine from an amine A-NH2 and the hydrazone is coupled with a diazonium compound from an amine B-NH2 or a hydrazine from an amine B-NH2 is condensed with an aldehyde and the hydrazone is coupled with a diazonium compound from an amine A-NH2. Many examples are furnished and alternative starting materials listed. The dyes are suitable for colouring synthetic polyamides, silk, leather and wool.