2-Naphthalenesulfonic acid, 7-amino-4-hydroxy-3-[[4-[[6(or 7)-sulfo-4-[(3-sulfophenyl)azo]-1-naphthalenyl]azo]-1-naphthalenyl]azo]-, trisodium salt

Preparation

3-Aminobenzenesulfonic acid diazo, and 5-Aminonaphthalene-2-sulfonic acid and 8-Aminonaphthalene-2-sulfonic acid?coupling, again diazo, and Naphthalen-1-amine?coupling, product to diazo, in alkaline conditions and 7-Amino-4-hydroxynaphthalene-2-sulfonic acid coupling.

Properties and Applications

dark blue to the navy. Soluble in water for violet black, slightly soluble in alcohol. The strong sulfuric acid for dark purple to black, diluted for purple. The dye solution to join strong hydrochloric acid have precipitation of dark; Add thick sodium hydroxide solution have dark purple precipitation.

Standard	Acid Resistance	Alkali Resistance	Light Fastness	Soaping		Water
				Fading	Stain	Fading	Stain
ISO	4-5	4-5	5	2-3		3