2-Naphthalenesulfonic acid, 3,3'-[carbonylbis(imino-3,1-phenyleneazo)]bis[7-amino-4-hydroxy-, disodium salt

Preparation

N,N’-bis(3-aminophenyl)urea double nitriding, in alkaline conditions and 7-Amino-4-hydroxynaphthalene-2-sulfonic acid (2 Moore) coupled.

Properties and Applications

Claret. Soluble in water for orange brown, soluble in ethanol for orange. In the strong sulfuric acid to red, shallow orange for diluted. The dye solution to join strong hydrochloric acid for red orange brown, have precipitation; Add thick sodium hydroxide solution for orange brown, have precipitation; Add 10% sodium hydroxide solution color micro become yellow.

Standard	Acid Resistance	Alkali Resistance	Light Fastness	Soaping		Water
				Fading	Stain	Fading	Stain
ISO	4	5	1	4		3-4
AATCC	5	5	1-2	3		4