2429-72-3

3,3′-Dimethylbenzidine double nitriding, first in alkaline conditions and 7-Amino-4-hydroxynaphthalene-2-sulfonic acid coupling, and then and 4-Hydroxynaphthalene-1-sulfonic acid coupling.

dark red light blue. Soluble in water for violet black, slightly soluble in ethanol for red light purple. The strong sulfuric acid for green light blue, diluted red for purple, have precipitation; In nitric acid for dark purple, and then into a red light purple. Dye with strong hydrochloric acid solution for purple, have precipitation; Add thick sodium hydroxide solution for purplish red color, have precipitation.

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