4,5-Dihydroxy-3-[[4'-[(2-hydroxy-6-sodiosulfo-1-naphthalenyl)azo]-1,1'-biphenyl-4-yl]azo]naphthalene-2,7-disulfonic acid disodium salt

4-(4-Aminophenyl)benzenamine double nitriding, First coupling with?4,5-Dihydroxynaphthalene-2,7-disulfonic acid coupling, again with 6-Hydroxynaphthalene-2-sulfonic acid?coupling.

dark red light blue. Soluble in water for purple. The strong sulfuric acid in blue, diluted into purple solution, then a red light purple precipitation. The dye solution to join hydrochloric acid have red light purple precipitation; Sodium hydroxide solution to a red solution.

Standard	Acid Resistance	Alkali Resistance	Light Fastness	Soaping		Water
				Fading	Stain	Fading	Stain
ISO	2	2	2-3	1-2		1-2