Concentrated storage-stable aqueous solutions of yellow to greenish yellow stilbene azo or stilbene azoxy dyes

摘要

1. A process for the preparation of a concentrated storage-stable aqueous dye solution which contains a mixture of yellow to greenish yellow stilbeneazo(xy) dyes obtained by base-catalyzed self-condensation of 4-nitrotoluene -2- sulfonic acid under heat over several hours, which process comprises carrying out the condensation in the presence of 0,2 to 0,8 mol of a C2 -C4 monoalkanolamine and 0,8 to 1,5 mol of a C2 -C4 dialkan olamine or C2 -C4 trialkanolamine, each based on 1 mol of 4-nitrotoluene -2- sulfonic acid, and alkali, and, after the reaction mixture has been neutralised or at the same time, removing inorganic salts or alkali metal ions from the dye solution.