Preparation of cationic azo or hydrazone dyes in which the alkylation and the separation of the cationic dye are carried out continuously

摘要

The invention relates to a continuous process for the preparation of cationic azo or hydrazone dyes from heterocyclic diazo components and coupling components. The diazo component is diazotised in water and an acid, the diazo solution is coupled with the coupling component and continuously alkylated, preferably using sufficient acid that, after the alkylation, a two-phase system forms, consisting of an aqueous solution which is substantially free from dye and a highly concentrated oil phase or solid dye.