disodium 7-amino-4-hydroxy-3-[[5-hydroxy-6-(phenylazo)-7-sulphonato-2-naphthyl]azo]naphthalene-2-sulphonate

2-Aminobenzenesulfonic acid diazo, and?2,5-Dimethylbenzenamine coupling, its product to diazo, and 2-Amino-5-hydroxynaphthalene-1,7-disulfonic acid coupling.

red light purple. Soluble in water and ethanol for product red. The strong sulfuric acid for green light blue, for purple diluted. The dye solution to join strong hydrochloric acid have purplish red precipitate; Add thick sodium hydroxide solution for Red sauce.