GB879321A - Mono-azo dyestuffs of the benzene-azo-naphthalene series and metal complexes thereof - Google Patents

Abstract

The monomaleamide of 1-amino-7-naphthol is obtained by heating, e.g. at 70-75 DEG C., an approximately equimolecular mixture of 1-amino-7-naphthol and maleic anhydride. A solvent for the reactants, e.g. isopropyl alcohol, may be present.ALSO:The invention comprises azo dyes of the general formula:-<FORM:879321/IV(c)/1> wherein X is a hydroxyl group and the benzene nucleus A may be substituted by non-acid substituents, and metalliferous complexes of these dyes. The nucleus A may contain chlorine, bromine, nitro, alkoxy, alkyl, acylamino, sulphonamido, alkylsulphonamido, hydroxyalkylor alkoxyalkyl-sulphonamido, morpholysulphonamido, or alkylsulphonyl groups as non-acid substituents. The dyes may be obtained by coupling the diazo compound of an appropriate aminophenol with the monomaleamide of 1amino- 7-naphthol. They may be reacted with chromium compounds in the presence of amides or ammonium salts of carboxylic acids, alkali metal salts of aliphatic or aromatic o-hydroxy carboxylic acids or aminocarboxylic acids, or in presence of an organic liquid such as ethylene glycol to form complex compounds. They may be heated in alkaline media with salts of chromium, cobalt, nickel, copper, iron, or manganese. The unmetallized dye may be reacted with a metallizing agent in presence of another metallizable dye, or with a metallized dye containing one atom of metal per molecule of dye. Complexes of chromium or cobalt containing less than one atom of metal per molecule of dye are preferred for the dyeing of animal fibres or fibres of polyamides or polyurethanes. Examples describe the production of dyes of the stated formula using diazo components obtained from 4-isopropylsulphonamido-, 4-nitro-, 5-nitro-, 4chloro- 5-nitro-, 4-sulphonamido-, 4-chloro- 5sulphonamido-, and 4-methylsulphonyl-2-aminophenol, and the production of metal complexes of these dyes using sodium chromo-salicylate or sodium cobalt tartrate as metallizing agent. In one example, a solution containing the sodium salt of the dye 2-amino- 4-isopropyl-sulphonamido-phenol --> 7-naphthol- 1-maleamic acid and the sodium salt of the dye 2-amino- 5-nitrophenol --> b -naphthol is heated with a solution of sodium chromosalicylate to form a metal complex which dyes wool a blue-grey shade from neutral or weakly acid baths. Similar complexes in which the second component dye is 2-amino4-nitro-phenol --> b -naphthol, 2-amino- 4-nitrophenol --> 1-phenyl- 3-methyl- 5-pyrazolone, or 4-chloro- 2-amino- 5-sulphonamido-phenol --> 1-(31-trifluoromethyl-phenyl)- 3-methyl- 5-pyrazolone, are specified.