Patent GB-649656-A (GB)
Title: Process for the manufacture of new azo-dyestuffs and complex metal compounds thereof
IPC: C09B45/14
Filed: 1948-06-18
Abstract: Compounds of the general formula <FORM:0649656/IV (b)/1> (wherein R represents an alkyl or aryl residue free from o-hydroxycarboxylic acid groupings) are prepared by reduction, e.g. catalytic reduction, of the corresponding nitro compounds.ALSO:Azo dyestuffs containing at least one o : o1-dihydroxyazo grouping are manufactured by coupling a diazo compound of an amine of the general formula <FORM:0649656/IV (c)/1> wherein R represents an alkyl or aryl residue free from o-hydroxycarboxylic acid groupings (e.g. 3-amino-4-hydroxyacetophenone, 3-amino-4-hydroxyphenyl n-propyl, n-butyl or n-amyl ketone, or 3 - amino - 4 - hydroxy - 21 - carboxydiphenyl ketone) with a coupling component which couples in a position vicinal to a hydroxy group, i.e. one which owes its p capacity for coupling to an aromatic hydroxy group or a reactive keto-methylene group.  Coupling is generally carried out in an alkaline medium, e.g. in a medium rendered alkaline with alkali carbonate or hydroxide, if desired in the presence of a solvent such as alcohol or pyridine.  The products may be treated in substance or on the fibre with an agent yielding metal (e.g. iron, nickel, cobalt, aluminium, manganese, copper or especially chromium).  Dyestuffs sparingly soluble or insoluble in water but soluble in cellulose ester lacquers are obtained with non-sulphonated components such as o-coupling phenols or naphthols, 5-pyrazolones or open-chain keto-methylene compounds (all of which are exemplified) or 2 : 4-dihydroxyquinoline.  These products are advantageously metallized in substance by the process of Specification 637,404 (but the treatment by this method of non-sulphonated dyestuffs derived from 3-amino-4-hydroxyacetophenone is disclaimed).  Sulphonated monoazo dyestuffs suitable for dyeing animal fibres (e.g. silk, leather and especially wool) are obtained with o-coupling naphtholsulphonic acids or N-acyl or N-aryl aminonaphtholsulphonic acids, or 1-sulphoaryl-5-pyrazolones, of which examples are given. These products are advantageously treated on the fibre by the after-chroming process, preferably with trivalent chromium salts. Dyestuffs particularly suitable for dyeing cellulosic materials are obtained with components capable of imparting or enhancing substantivity, such as derivatives of 2 : 5 : 7-aminonaphtholsulphonic acid, especially 5 : 51-dihydroxy-2 : 21-dinaphthylamine- or -dinaphthylurea-7 : 71-disulphonic acid or condensation products in which two molecules of 2 : 5 : 7-acid are connected by a heterocyclic bridge (e.g. a cyanuric or quinazoline residue), which compounds may be coupled (advantageously in a medium containing calcium hydroxide) with two molecular proportions of a diazo compound of an amine of the general formula above or with one of such a diazo compound and one of another diazo compound preferably containing a metal-complex-forming group in a vicinal position to the diazo group (e.g. diazotized 2 - aminophenol - 4 - sulphonic acid, 6 - chloro - 2 - aminophenol - 4 - sulphonic acid, 2 - aminophenol-4-carboxylic acid anilide or n-butylamide, anthranilic acid and its nuclear substitution products, or 2-amino-1-methoxybenzene-4-sulphonic acid).  These products are advantageously coppered by the process of Specification 619,969 or French Specification 809,893.  Examples illustrate the various features of the invention.  The Specification as open to inspection under Sect. 91 comprises also an alternative process for preparing the diazo dyestuffs of the invention, which consists in coupling a diazo compound of an amine of the general formula above with 2 : 5 : 7-acid, linking 2 mols. of the aminoazo dyestuff simultaneously or successively with 1 mol. of a heterocyclic bridge member, and, if desired, when a free halogen atom is still present, reacting this with, for example, aniline.  It further includes the disclaimed subject-matter above, of which two examples are given.  This subject-matter does not appear in the Specification as accepted.