Verfahren zur Herstellung von Disazofarbstoffen

1,162,144. Disazo dyes and metal complexes. FARBWERKE HOECHST A.G. 30 Aug., 1966 [28 Aug., 1965; 7 Jan., 1966], No. 38649/66. Heading C4P. The invention comprises disazo dyes of formulµ and the metal complexes of wherein D is the radical of a phenyl or naphthyl diazo component having T and T 1 in orthoposition to -N =N-, T being H, OH or alkoxy and T 1 being OH or COOH, m is 0 or 1, K is a pyrazolone coupling component residue, X is a group -(N-alkyl) n SO 2 -CH = CH 2 or -(N-R) n -SO 2 -CH 2 -CH 2 -Z wherein R is H or alkyl, n is 0 or 1, Z is an organic or inorganic radical which can be split off by an alkaline agent, p 1 and p 2 are 0 or 1 and P 1 +P 2 is at least 1 and -N=N-K-(X)p 1 is linked at a or a1. The dyes are made by the usual coupling processes using a 6- or 7-amino- 1- naphthol-3-sulphonic acid as middle component and if desired metallizing with, for example, a Co, Cv or Cr yielding agent at the final or intermediate stage of preparation of an appropriate disazo dye. The dyes may also be demetallized. The X groups are present in the starting materials or may be introduced into the disazo dye. Thus, the group -(N-alkyl) n -SO 2 -CH= CH 2 where n is 0 may be reacted with a thiosulphate or a dialkylamine to form a #-thiosulphato- or -dialkylamino-ethyl-sulphone group and the group -(N-R) n -SO 2 CH 2 CH 2 OH esterified with H 2 SO 4 . The dyes may be used to colour natural and synthetic polyamide materials and, in particular, to colour cellulosic materials by reactive dye processes in brown and grey shades. Specifications 913,517, 999,877, 1,015,789 and 1,019,454 are referred to.