C.I. Direct Blue 33

N-(4-aminophenyl)acetamide diazo, coupled with the 4-Hydroxynaphthalene-1-sulfonic acid, and then hydrolysis amino acylation again diazo, and 5-Aminonaphthalene-2-sulfonic acid and 8-Aminonaphthalene-2-sulfonic acid coupling, again diazo, in alkaline conditions and 7-Amino-4-hydroxynaphthalene-2-sulfonic acid coupling. And if 5-Aminonaphthalene-2-sulfonic acid?and?8-Aminonaphthalene-2-sulfonic acid?mixture coupling is C.I. 31635, if just and 5-Aminonaphthalene-2-sulfonic acidcoupling is C.I.316351, if just and 8-Aminonaphthalene-2-sulfonic acid coupling is C.I. 316352.

red light navy blue. Soluble in water for the navy, slightly soluble in alcohol. The strong sulfuric acid for dark blue-green, diluted into purple. The dye solution to join strong hydrochloric acid for dark purple, have precipitation; Add thick sodium hydroxide solution into a dark.

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