Sodium → H acid

Reaction equation

[Na].[NH2:2][C:3]1[C:12]2[C:7](=[CH:8][C:9]([S:14]([OH:17])(=[O:16])=[O:15])=[CH:10][C:11]=2[OH:13])[CH:6]=[C:5]([S:18]([OH:21])(=[O:20])=[O:19])[C:4]=1N=[N:23][C:24]1[CH:29]=[C:28]([S:30]([OH:33])(=[O:32])=[O:31])[CH:27]=[CH:26][C:25]=1[S:34]([OH:37])(=[O:36])=[O:35]>O>[NH2:23][C:24]1[C:25]([S:34]([OH:37])(=[O:36])=[O:35])=[CH:26][CH:27]=[C:28]([S:30]([OH:33])(=[O:32])=[O:31])[CH:29]=1.[NH2:2][C:3]1[C:12]2[C:7](=[CH:8][C:9]([S:14]([OH:17])(=[O:16])=[O:15])=[CH:10][C:11]=2[OH:13])[CH:6]=[C:5]([S:18]([OH:21])(=[O:20])=[O:19])[CH:4]=1

Participants

Procedure

The suspension of the diazonium betaine was run into a precooled solution of the sodium salt of 28 g of 1-amino-8-hydroxy-2-(2',5'-dihydroxysulfonylphenylazo)naphthalene-3,6-disulfonic acid (obtained by strongly acid coupling of diazotized aniline-2,5-disulfonic acid to 1-amino-8-hydroxynaphthalene-3,6-disulfonic acid) in 300 ml of water, and the pH was brought to 5 with 25% strength by weight aqueous sodium acetate solution. After stirring had been carried out for two hours at from 10° to 15° C., the resulting dye of the formula ##STR15## was precipitated by saturation with potassium chloride, filtered off under suction and reacted further as a water-moist filter residue.