C.I. Direct blue 38, trisodium salt

6-Amino-4-hydroxynaphthalene-2-sulfonic acid acid diazo, in acid conditions coupled with Benzene-1,3-diamine, 4-(4-Aminophenyl)benzenamine double nitriding, first in alkaline conditions and 4-Amino-5-hydroxynaphthalene-2,7-disulfonic acidcoupling, again in alkaline conditions and accidentally coupled nitrogen compounds.

dark blue. For a blue-black soluble in water, soluble in ethanol is shallow purple. The strong sulfuric acid for blue, shallow purple for diluted. The dye solution to join strong hydrochloric acid have violet and precipitation; With strong sodium hydroxide solution for dark purple.

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