Process for the conversion of sparingly soluble inorganic salts of cationic dyes or optical brighteners into easily soluble salts of organic acids

摘要

A process is described for converting sparingly soluble inorganic salts of cationic dyes and brighteners into more soluble salts of organic acids without intermediate isolation of the free base, wherein the counter-ion of the dye or brightener cation is replaced by the anion of a cyclic or acyclic organic acid by means of Donnan dialysis. Dye or brightener solutions obtained in this way are stable and can be directly used for dyeing or printing textile materials.