C.I. Direct Black 13

4-Nitrobenzenamine diazo, in acid conditions and 4-Amino-5-hydroxynaphthalene-2,7-disulfonic acid?coupling, 4-Nitrobenzenamine diazo, in alkaline conditions and the synthesis product matches, will be one of the nitro reduction, again diazo, and Benzene-1,3-diamine coupling.

black. The strong sulfuric acid for green light gray, brown after dilute the precipitation; In nitric acid solution for brown. The dye solution to join hydrochloric acid solution for dark purple, precipitation; Sodium hydroxide solution to join the same color.

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