Process for the preparation of concentrated solutions of anionic dyestuffs

Abstract

Stable, concentrated solutions of anionic dyestuffs are prepared by reacting the alkali metal or ammonium salts of anionic dyestuffs and brighteners, which are usually obtained from the industrial preparation process, in water-soluble organic solvents, optionally in the presence of water, with salts of nitrogen bases which impart hydrophilic properties, in accordance with the reaction equation Me.sub.n F + nB.multidot.A.fwdarw.Bn.multidot.F + nMeA in which Me denotes an alkali metal or ammonium ion, B denotes a protonated or quaternized nitrogen base, A denotes the anion of an acid, N denotes an integer from 1 to 4 and F denotes the anion of a dyestuff acid, And separating the resulting solutions from the salt n.multidot.MeA, which is insoluble in the reaction mass.

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