Process for the preparation of cationic dyestuffs

Abstract

Cationic dyestuffs of the general formula ##STR1## wherein R.sub.1 represents hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 - to C.sub.4 -alkoxy, nitro or halogen, R.sub.2 represents hydrogen, C.sub.1 - to C.sub.4 -alkyl, C.sub.1 - to C.sub.4 -alkoxy, halogen or phenylazo, R.sub.3 represents C.sub.1 - to C.sub.3 -alkyl and A.sup..crclbar. represents an anion, are prepared by reacting azo bases of the general formula ##STR2## wherein R.sub.1 and R.sub.2 have the abovementioned meaning, or the salts thereof with inorganic or organic acids, with dialkyl sulphates of the general formula (R.sub.3 --O--).sub.2 SO.sub.2 III wherein R.sub.3 has the abovementioned meaning, in the absence of organic solvents and in the presence of water, the weight ratio of azo base to water being 100:20-300 and the molar ratio of azo base to dialkyl sulphate being 1:3.5-5.0, and, if desired, by replacing the alkyl-sulphate anion with another anion.

Dependencies are inferred from the claim text.