GB395027A - The manufacture of new azo dyestuffs - Google Patents

Abstract

Dizazo dyes containing copper are made by treating with an agent yielding copper a disazo dyestuff obtainable by coupling in alkaline solution one mol. of a tetrazotized aromatic diamine, containing an alkoxy group in o-position to each diazo group, with two mols. of 2-amino-5-naphthol-1 : 7-disulphonic acid or an N-acyl derivative thereof, or with one mol. of the above acid or an N-acyl derivative thereof and one mol. of a naphthol sulphonic acid, the coppering being formed under such conditions that the alkoxy groups are split up. In the case of urea dyestuffs, a corresponding aminoalkoxy monoazo dye may first be prepared, converted into the urea and finally coppered. They dye silk, cotton and viscose violet to blue shades of good fastness to light. In examples: (1) the dyestuff dianisidine \sQ 2 - acetylamino - 5 - naphthol - 1 : 7-disulphonic acid is treated with ammoniacal copper sulphate; (2) the dyestuff 2-amino-5-naphthol-1 : 7-disulphonic acid \sM dianisidine --> 1-naphthol - 4 - sulphonic is treated with copper sulphate; (3) the dyestuff 4 : 4<1>-diamino-3 : 3<1>-dimethoxydiphenylurea \sQ 2 - acetylamino - 5 - naphthol - 1 : 7 - disulphonic acid is coppered as in (1); the same dyestuff is obtained by reducing the dyestuff 5-nitro-2-aminoanisole --> 2-acetylamino - 5 - naphthol-1 : 7-disulphonic acid, phosgenating and coppering. Specifications 113,141, [Class 2 (iii), Dyes &c.], and 352,956 are referred to.