Improvements in or relating to the manufacture of new dyestuffs of the triarylmethane series

Abstract

Abstract Triarylmethane dyes are prepared by the introduction of the group -CH2-CH2-SO3H into the primary or secondary amino groups of a triarylmethane compound according to known methods. Thus the triarylmethane compounds may be condensed with a halogenethanesulphonic acid, or an aromatic aminosulphonic acid of the formula <FORM:0387956/IV/1> wherein R represents hydrogen, alkyl, aralkyl or aryl, may be condensed with the customary components and the leuco-dyestuffs oxidized. The products have an increased solubility in water, and dye wool and silk in clear reddish-violet to blue to green shades. In examples (1) p-diethylaminobenzaldehyde is condensed with 2 mols. of o-tolyltaurine in weak sulphuric acid solution, and the leuco-product oxidized, for example by adding lead peroxide: (2) ethylphenyltaurine is condensed with formaldehyde and the diphenylmethane oxidized with diethylaniline in acid bichromate; alternatively this dyestuff is prepared by condensing p-diethylaminobenzaldehyde with 2 mols. of ethylphenyltaurine and oxidizing the product: (3) tetramethyldiaminodiphenylmethane-hydrol is heated with m-tolylethyltaurine in weakly acid solution and the product oxidized by lead peroxide: (4) tetraethyl-4,4<1>-diamino-3<11>-triphenylmethane is heated with sodium chlorethanesulphonic acid. The aromatic aminosulphonic acids employed as starting materials are prepared by condensing the appropriate aromatic primary or secondary amine with chlorethanesulphonic acid in presence of an acid binding agent.

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