tetrasodium 4,4'-[carbonylbis(imino-4,1-phenyleneazo)]bis[3-amino-5-hydroxynaphthalene-2,7-disulphonate]

4-Nitrobenzenamine diazo, in acid conditions and 3-Amino-5-hydroxynaphthalene-2,7-disulfonic acid?coupling, and then will the nitro reduction, again will create the amino nitrogen compounds for light accidentally gasification.

blue light pink. Soluble in water for product red, soluble in ethanol. In the dark for the strong sulfuric acid, diluted Red sauce for. The dye solution to join strong hydrochloric acid for purple, have precipitation; Add thick sodium hydroxide solution for red, have precipitation.

Standard	Acid Resistance	Alkali Resistance	Light Fastness	Soaping		Water
				Fading	Stain	Fading	Stain
ISO	2-3	5	2			2