disodium 8,8'-[[1,1'-biphenyl]-4,4'-diylbis(azo)]bis(7-hydroxynaphthalene-1-sulphonate)

4-(4-Aminophenyl)benzenamine double nitriding, and 7-Hydroxynaphthalene-1-sulfonic acid (2 Moore) coupled.

dark red to blue light red violet. Soluble in water for product red to red light purple, slightly soluble in alcohol. The strong sulfuric acid for purple, diluted with light purple (a red); In nitric acid in red orange for solution. The dye solution to join strong hydrochloric acid for navy, precipitation; Add thick sodium hydroxide solution for red light brown, have precipitation.