Patent GB-648364-A (GB)
Title: Process for the manufacture of metalliferous monoazo-dyestuffs
IPC: C09B45/14
Filed: 1948-03-05
Abstract: 1 - Amino - 2 - hydroxy - 6 - alkoxynaphthalene - 4 - sulphonic acids are manufactured by treating a 2-hydroxy-6-alkoxynaphthalene with a nitrosating agent (e.g. an alkali nitrite and mineral acid), treating the resulting 1-nitroso derivative with a solution of alkali bisulphite to form a 2-hydroxy-6-alkoxy-1-naphthylhydroxylamine sulphonic acid, and heating this in a medium rendered acid with mineral acid.  An example describes the preparation of the 6-methoxy compound.  Diazo compounds of the foregoing amines are obtainable by treating them with sodium nitrite in the absence of free mineral acid and in the presence of an equivalent quantity of a zinc salt or a small quantity of copper sulphate, and may be separated in stable form by addition of a mineral acid or sodium chloride.  1 - Amino - 2 : 6 - dialkoxynaphthalene - 4-suphonic acids are obtainable from 2 : 6-dialkoxynaphthalenes (e.g. 2 : 6 - dimethoxynaphthalene) by nitration, reduction and sulphonation.ALSO:Metalliferous monoazo dyestuffs are manufactured by the action of agents yielding metal or monoazo dyestuffs of the general formula <FORM:0648364/IV (c)/1> wherein R represents the residue of a hydroxynaphthalene bound to the azo group in a position vicinal to a hydroxy group, or the residue of a 5-pyrazolone bound to the azo group in the 4-position, and X represents hydrogen or an alkyl group, the treatment in the latter case being conducted under such conditions that the said alkyl group is split off.  Starting materials in which X is hydrogen are obtainable by coupling a diazotized 1-amino-2-hydroxy-6-alkoxynaphthalene-4-sulphonic acid with, for example, a - or b -naphthol, 1 : 3-, 2 : 3-, 2 : 6- or 2 : 7-dihydroxynaphthalene, 2-hydroxy-6- or - 7 - methoxynaphthalene, 1 - acetylamino - 7 - hydroxynaphthalene 5-chloro-, 5,8-dichloro-, 4-methyl- or 4-n-butyl-1-naphthol, 1-naphthol-4-, -5- or -8- sulphonamide or -sulphonic acid, 3-methyl-5-pyrazolone or its 1-phenyl-, 1-(21-chloro- or 31-sulpho)-phenyl- or 1-(21-naphthyl)-derivative, 1-phenyl- or 1-(41-sulpho)-phenyl-5-pyrazolone-3-carboxylic acid or 1 : 3-diphenyl-5-pyrazolone, advantageously in an alkaline with an alkali carbonate to alkaline with caustic soda), if desired, in the presence of a solvent assisting coupling (e.g. alcohol or pyridine) or of an agent yielding metal (e.g. an agent yielding copper or zinc, such as zinc chloride, the metal being removed after coupling if a complex with a different metal is desired). These starting materials may be treated with agents yielding iron, nickel, cobalt, aluminium, copper or especially chromium, e.g. with chromium acetate, formate, fluoride or sulphate, advantageously in an alkaline, neutral or acid aqueous medium, in the presence or absence of an organic solvent (e.g. alcohol or pyridine), if desired with the addition of a substance capable of forming complexes (e.g. an aliphatic or aromatic hydroxy carboxylic acid), preferably using at least one atomic proportion of chromium for each molecular proportion of dyestuff.  Starting materials in which X is alkyl are obtainable by coupling a diazotized 1-amino-2 : 6-dialkoxynaphthalene-4-sulphonic acid with the coupling components specified above or with components which do not couple readily with o-hydroxydiazo compounds, e.g. 2 - naphthol - 8 - sulphonic or -6 : 8 - disulphonic acid.  They may be treated with, for example, a copper tetramine salt under energetic conditions, or especially with chromium sulphate or formate at 110-140 DEG  C.  The products are suitable for dyeing or printing materials of animal origin (e.g. wool, silk, or leather), casein artificial wool, animalized cellulose artificial silk, or fibres of superpolyamides or superpolyethanes.  Examples describe the use of 1-amino-2-hydroxy-6-methoxy- and 1-amino-2 : 6 - dimethoxy - naphthalene - 4 - sulphonic acid as diazo components, with certain of the coupling components and chroming agents specified above, and the dyeing of wool greenish-blue with one of the products from a bath containing sulphuric acid.  The Specification as open to inspection under Sect. 91 comprises also the metallization of monoazo dyes of the general formula above in which R represents the residue of any coupling component bound to the azo linkage in a position vicinal to a hydroxy group (e.g. resorcinol, perinaphthindandione, acetoacetic anilide, barbituric acid, N-phenyl-4-hydroxy-2-quinolone, 2 : 4 - dihydroxyquinoline, m - phenylenediamine (sic), m-aminophenol, 1-methyl-2-amino-4-hydroxybenzene or 2-hydroxyanthracene), and of diazo dyes obtained by coupling 1 mol. of a coupling component capable of coupling twice (e.g. resorcinol) with 2 mols. of a diazotized 1 - amino - 2 - hydroxy - 6 - alkoxynaphthalene - 4 - sulphonic acid or with 1 mol. of such a diazo compound and 1 mol. of another diazo compound, or by coupling a diazotized 1-amino-2-hydroxy-6-alkoxynaphthalene-4-sulphonic acid with a middle component (e.g. 1-hydroxy-3-amino - 4 - methylbenzene), rediazotizing and coupling with an end component (e.g. a pyrazolone).  This subject-matter does not appear in the Specification as accepted.