GB340243A - Improvements in the manufacture and production of azo dyestuffs containing chromium - Google Patents

Abstract

Azo dyes, soluble chromium compounds of; lakes.-Azo dyestuffs containing chromium are obtained by treating with agents yielding chromium azo dyes of the type, aromatic amine of the benzene series containing no hydroxy or carboxy group in oosition to the diazotized amino group --> a 1-phenyl-3-methyl-5-pyrazolone carrying an o-hydroxy-carboxylic grouping in the phenyl residue. The products dye wool usually pure yellow to orange shades, fast to light, and have good equalizing properties, and are applicable also for printing on cotton and for the preparation of lakes. The following examples are specified. (1) The dyestuff m-aminobenzoic acid --> 1-(2'-hydroxy-3'-carboxy-5'-sulpho) phenyl-3-methyl-5-pyrazolone is boiled in aqueous solution for 3 hrs. under reflux with a chromium hydrate paste containing formic acid; the product dyes wool level greenish yellow shades fast to washing and fulling; similar products are obtainable by the use as diazo components of aniline and m-chloraniline. (2) The dyestuff sulphanilic acid --> 1-(2'-hydroxy-3'-carboxy-5'-sulpho) phenyl-3-methyl-5-pyrazolone is heated in aqueous solution for 1 hr. under pressure at 110 DEG C. with a similar chromium hydrate paste; the product dyes leather yellow shades fast to light; the chromium compound, similarly prepared, of the dyestuff sulphanilic acid --> 1-(2'-hydroxy-3'-carboxy) phenyl-3-methyl-5-pyrazolone is similar; chroming may also be effected with a salt of hexavalent chromium, e.g. sodium chromate. (3) The dyestuff 4-aminosalicylic acid --> 1-(2'-hydroxy-3'-carboxy-5'-sulpho) phenyl-3-methyl-5-pyrazolone is heated for 3 hrs. on the water bath with a chromium hydrate paste containing formic acid; the product dyes leather fast orange shades and is applicable also for dyeing cotton. (4) The dyestuff 2-chloro-4-toluidine --> 1-(2'-hydroxy-3'-carboxy-5'-sulpho) phenyl-3-methyl-5-pyrazolone is chromed as in (1); the product dyes wool yellow shades fast to light and washing. (5) The dyestuff metanilic acid --> (2'-hydroxy-3'-carboxy-5'-sulpho) phenyl-3-methyl-5-pyrazolone is chromed as in (1); the product dyes wool greenish yellow shades fast to light. Specification 26460/12 is referred to. 1-(2'-Hydroxy-3'-carboxy) phenyl-3-methyl-5-pyrazolone is prepared by condensing the hydrazine from 1-amino-2-hydroxybenzene-3-carboxylic acid with acetoacetic ester.