GB606731A - Manufacture of new azo-dyestuffs - Google Patents

Abstract

Azo dyestuffs are manufactured by coupling a 1-naphthol containing as a substituent in the 4-position an alkyl radical of more than one carbon atom or a cycloalkyl radial, with an o-hydroxylated and sulphonated diazo compound. The products may be used for dyeing by the after-chroming process or by the process in which the chroming agent is present in the dye bath from the outset, and they may also be treated in substance with agents yielding metal, e.g. compounds of copper, nickel, cobalt or especially chromium, or mixtures of such compounds, producing metalliferous dyestuffs suitable for dyeing animal fibres or other fibres having an affinity for acid dyestuffs. Examples describe the preparation of the following dyestuffs: (1) 1-hydroxy-2-amino-4-nitro- or -4-chloro-benzene-6-sulphonic acid --> 4-n-butyl-1-hydroxynaphthalene; (2) 1-amino-2-naphthol --> 4-ethyl- or 4-n-butyl-1-hydroxynaphthalene; and the dyeing of wool with the products of (1) with simultaneous or subsequent chroming. Lists of additional components are given. The Specification as open to inspection under Sect. 91 comprises also the use of diazo compounds containing, in o-position to the diazo group, a substituent convertible into or exchangeable for a hydroxy group, and the metallization of the resulting dyestuffs under such conditions that this substituent is hydrolysed to or replaced by a hydroxy group. Reference is also made to the replacement of the coupling component in example (1) by 4-ethyl-1-hydroxynaphthalene. This subject-matter does not appear in the Specification as accepted.