GB438437A - Manufacture of acid dyestuffs - Google Patents

Abstract

Acid dyestuffs are manufactured by condensing a 4-halogenbenzophenone or a 4-alkoxybenzophenone, which is free from nitrogen and contains no halogen or alkoxy-group in the 4<1>-position, or a dichloride thereof, with an a -substituted indole unsubstituted in the b -position, causing the halogen atom or alkoxygroup in the 4-position to react with a primary aromatic amine containing in the p-position to the amino - group an alkoxy - group, and sulphonating the product. Alternatively, the initial condensation product is sulphonated and the sulphonation product is condensed with the primary aromatic amine. Instead of the a -substituted indole a sulphonic acid thereof may be used. In examples: (1) 4-chloro-2<1> : 5<1>-dimethylbenzophenone dichloride (obtainable by the action of phosphorus pentachloride on the ketone obtainable by condensing p-chlorobenzoyl chloride with p-xylene by the Friedel-Craft method) is condensed with N-methyl-a -phenylindole by the action of phosphorus oxychloride in benzene solution, and the product is melted with p-phenetidine and then sulphonated with oleum to produce a dyestuff of the probable formula <FORM:0438437/IV/1> which dyes wool and silk bluish-green tints; (2) the initial condensation product of (1) is sulphonated and then condensed with p-anisidine; the product dyes wool and silk somewhat more yellowish tints than that of (1); (3) the indole in (1) is replaced by 1 : 4 : 7-trimethyl-2-phenylindole; the product dyes wool and silk yellowish green tints; (4) 4-methoxybenzophenone dichloride is condensed in toluene, by the action of zinc chloride, with N -methyl - a - phenylindolemonosulphonic acid (obtainable by sulphonating N -methyl-a -phenylindole) and the product is melted with p-phenetidine and then sulphonated; the product dyes wool and silk bluish green tints.