sodium 4-hydroxy-3-[(2-hydroxy-1-naphthyl)azo]-5-nitrobenzenesulphonate

Preparation

3-Amino-4-hydroxy-5-nitrobenzenesulfonic acid diazotization, and Naphthalen-2-ol coupling.

Properties and Applications

red light navy blue to black. Soluble in water for purple to black, right amount soluble in ethanol for red light purple, slightly soluble in Acetone. In concentrated sulfuric acid to red light purple, after dilution to orange, red precipitation. Dye aqueous solution to join concentrated hydrochloric acid for orange; Join concentrated sodium hydroxide solution for bordeaux red.