GB785084A - Polyazo dyestuffs - Google Patents

Abstract

The invention comprises dyestuffs of formula <FORM:0785084/IV (b)/1> where Z is H, Me or phenyl and Ar1 and Ar2 are the same or different aryl residues, each of which has at least one further azo group and both together have at least 2 SO3H groups, and their copper, cobalt and chromium complex compounds. The dyestuffs are made by tetrazolizing appropriate 4,41-diamino-diphenylmethane derivatives and coupling with the required aromatic compounds with subsequent metallization if desired. The metal-free dyestuffs may also be made by coupling one mol. of the tetrazotized diphenylmethane derivative first with an aromatic compound which is free of azo groups but contains at least 2 coupling-directing hydroxy and/or amino groups, and one mol. of the diazo dyestuff thus obtained is coupled with 2 mols. of an aromatic compound which provides the azo component if the disazo dyestuff is free of amino groups but is otherwise the coupling component. Indicated and specified components which may be coupled with the tetrazotized diphenylmethane are resorcinol, 1,3 - diaminobenzene, 1,8 - dihydroxynaphthalene mono- and di-sulphonic acids, 1,6-dihydroxynaphthalene - 3 - sulphonic acid, 3-aminophenol, 3 - hydroxydiphenylamine and 1-amino-8-naphthol and their sulphonic acids. Diazo components indicated for coupling with the disazo dyestuff are aniline, nitroanilines and toluidines, 2,5-dichloroaniline, sulphanilic and metanilic acids, 4-chloroaniline-3- and aniline-2,5- and 4-aminoazobenzene-3,41-di-sulphonic acids, naphthylamines and 1-naphthylamine-4-and 2-naphthylamine-4,8-di-sulphonic acids. Components indicated for coupling with the tetrazolized disazo dyestuff components are naphthols, naphthylamines, aminonaphthols and their sulphonic acids and 1,3-dihydroxy-, -diamino- and -hydroxyamino-benzenes and their N-alkyl or -aryl derivatives. Dyestuffs specified for coupling with the tetrazotized diphenylmethane derivatives are p-nitraniline --> H acid and H acid \sM benzidine --> 2-naphthol-3,6-disulphonic acid. The dyestuffs dye leather in dark brown to black shades. In examples which illustrate the preparation of the dyestuffs, their copper, cobalt and chromium complexes and their use in dyeing leather apart from certain of the above indicated or specified reactants, aniline-2,4-disulphonic acid and 2-naphthylamine - 5,7 - disulphonic acid --> 1-naphthylamine are used as additional azo components for coupling with a disazo dyestuff.