4-(4-Aminophenyl)benzenamine double nitriding, first and 6-Aminonaphthalene-2-sulfonic acid and 7-Aminonaphthalene-2-sulfonic acid coupling, and then in alkaline conditions and 7-Amino-4-hydroxynaphthalene-2-sulfonic acid coupling.
Properties and Applications
blue-ray red. Soluble in water for red jujube, and adequate soluble in ethanol in red. The strong sulfuric acid in blue, diluted red for sauce. The dye solution to join strong hydrochloric acid for Red sauce, precipitation; Add thick sodium hydroxide solution for orange brown.