Sodium → H acid

Beteiligte Stoffe

Reaktionsschritte

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.

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