Benzoic acid, 2-hydroxy-3(or 5)-[[4-[(1-hydroxy-5-sulfo-2-naphthalenyl)azo]-1-naphthalenyl]azo]-, disodium salt

Preparation

3-Amino-2-hydroxybenzoic acid and 5-Amino-2-hydroxybenzoic acid diazotization, and Naphthalen-1-amine coupling, product to diazotization, and 5-Hydroxynaphthalene-1-sulfonic acid coupling.

Properties and Applications

black. Soluble in water for dark purple, right amount soluble in ethanol. In concentrated sulfuric acid to blue light green, dilution for shallow sauce red. Dye aqueous solution to join concentrated hydrochloric acid for sauce red; Join concentrated sodium hydroxide solution for navy blue.

Standard	Ironing Fastness	Light Fastness	Fulling		Persperation Fastness	Soaping	Water
			Alkali	Acid
ISO	5	5	4	4	4-5	5	5