GB349304A - Manufacture of metalliferous dyestuffs - Google Patents

Abstract

Azo dyes and soluble metal compounds thereof; substantive and acid wool dyes, dyeing with; regenerated celluloses, dyeing.-Azo dyestuffs containing metal are produced by treating with one or more agents yielding metal and with a nitrosating agent, in either order, an azo dyestuff obtainable by coupling in an alkaline medium an o-oxydiazo or o-carboxydiazo compound with an N-substituted 2 : 5 : 7-aminonaphtholsulphonic acid. The nitrosation of the metal compounds of the dyestuffs may be effected in the dyebath or on the fibre. Dyeings are obtainable on animal, vegetable, and regenerated cellulose fibres. The following examples are specified: (1) To an alkaline solution of the chromium compound of the dyestuff 5-nitro-2-aminophenol --> (alkaline) phenyl-2 : 5 : 7-acid is added at 4-6 DEG C. sodium nitrite and the mixture is slowly acidified with sulphuric acid while maintaining the temperature below 10 DEG C.; after neutralization with sodium carbonate the dyestuff is salted out; it dyes cotton or regenerated cellulose silk from a neutral or alkaline Glauber's salt bath, or animal fibre from an acid bath, level steel blue tints; the coupling component may be replaced by a tolyl-2 : 5 : 7-acid. (2) To an aqueous solution of the dyestuff 5-nitro - 2 - aminophenol --> (alkaline) phenyl-2 : 5 : 7-acid is added sodium nitrite, the mixture is slowly acidified with sulphuric acid at 4-10 DEG C., and the dyestuff is salted out; this nitrosated compound is boiled for several hours with a chromic salt; the product has properties similar to those of the corresponding dyestuff in (1). (3) The intermediate nitrosated compound in (2) is converted into the copper compound by treatment with copper sulphate or cupric ammonium sulphate; the product dyes vegetable fibres blue-violet tints from an alkaline p Glauber's salt bath. (4) To a solution, neutralized with caustic soda, of the chromium compound of the dyestuff 4-nitro-2-aminophenol-6-sulphonic acid (2 mols.) \sQ (alkaline) 5 : 51-dioxy-2 : 21-dinaphthylamine-7 : 71 disulphonic acid is added sodium nitrite, and the mixture is slowly acidified with sulphuric acid at 5-10 DEG C.; after neutralization with sodium carbonate and concentrating, the dyestuff is salted out; the product dyes cotton or regenerated cellulose silk level grey-blue tints from a neutral Glauber's salt bath. (5) To a solution, neutralized with caustic soda, of the copper compound of the dyestuff 2 - aminophenol - 4-sulphamide \sQ (alkaline) 5 : 51-dioxy-2 : 21-dinaphthylamine-7 : 71-disulphonic acid is added sodium nitrite, and the mixture is slowly acidified with sulphuric acid at 5-10 DEG C.; after neutralizing and concentrating the dyestuff is salted out; the product dyes vegetable fibre or regenerated cellulose silk red-violet tints from a neutral or alkaline Glauber's salt bath. (6) To a feebly alkaline solution of the dyestuff containing copper and chromium obtainable from the dyestuff 5-nitro-2-aminophenol-4-sulphamide --> (alkaline) phenyl 2 : 5 : 7-acid is added sodium nitrite, and the mixture is slowly acidified with sulphuric acid at 4-6 DEG C.; after neutralization with sodium carbonate the dyestuff is salted out; the product dyes vegetable fibres or regenerated cellulose silk level blue tints from a neutral or alkaline Glauber's salt bath. Examples are also given of the dyeing processes for cotton, viscose silk, and ordinary or weighted silk.