GB644883A - Manufacture of meta iliferous azo-dyestuffs - Google Patents

Abstract

Metalliferous azo dyestuffs are manufactured by treating an o-alkoxy-o1-hydroxyazo dyestuff, which contains at least one sulphonic acid group and at least two azo groups, in the presence of an aliphatic amine containing a hydroxy group (e.g. mono-, di- or tri-ethanolamine), with an agent yielding metal (preferably of atomic number 24-30, especially 27-29) until the alkoxy group or groups is or are split up. Suitable starting materials are obtainable by coupling a tetrazotized 4 : 41-diamino - 3 : 31 - dialkoxydiphenyl (especially tetrazotized diamisidine) with a coupling component or components coupling in o-position to a hydroxy group, e.g. with 2 molecular proportions (identical or different) of a naphthol-or aminonaphthol-, mono- or di-sulphonic acid or acids (of which many are specified), or with one molecular proportion of such a component and one of a different type of component coupling in o-position to a hydroxy group (e.g. a 1 - sulphophenyl - 3 - methyl - 5-pyrazolone), or by coupling any diazo compound with a middle component coupling in p-position to an amine group and having an alkoxy group in o-position thereto (e.g. 2-methoxy-5-methylaniline), diazotizing the product and coupling with an end component coupling in o-position to a hydroxy group. The products are suitable for the substantive dyeing of cellulosic fibres such as cotton, linen, and artificial silk and staple fibres of regenerated cellulose. The zinc compounds can be converted to metal-free o : o1-dihydroxyazo dyestuffs. Examples describe the preparation of copper and nickel compounds of dyestuffs of the types mentioned above, and the dyeing of cotton in greenish-blue tints with the copper compound of the dyestuff dianisidine \sQ H-acid (2 mols.) from a bath containing sodium carbonate and sodium sulphate. Specification 575,437 is referred to.