sodium 6-hydroxy-5-[(2-hydroxy-5-nitrophenyl)azo]naphthalene-2-sulphonate

2-Amino-4-nitrophenol diazotization, and 6-Hydroxynaphthalene-2-sulfonic acid coupling.

blue light red. Soluble in water for orange brown, right amount soluble in ethanol. In concentrated sulfuric acid for red, to orange after diluted. Dye aqueous solution to join concentrated hydrochloric acid for orange; With strong caustic for orange brown.

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