Direct Blue 78

Chemical Properties

Yellowish gray powder. Aqueous solution is blue, adding concentrated hydrochloric acid is reddish blue, adding concentrated sodium hydroxide solution is reddish purple. Soluble in ethylene glycol ether, slightly soluble in ethanol, insoluble in other organic solvents. In concentrated sulfuric acid it is purple sauce to black, after dilution it is sauce red; in concentrated nitric acid it is brownish gray. After dyeing, it is basically unchanged when encountering copper and iron ions.

Uses

Direct Blue 78 is a good dyeing agent for cotton fabrics.

Preparation

2-Aminobenzene-1,4-disulfonic acid diazo, and 8-Aminonaphthalene-2-sulfonic acid first coupling, its product to diazo, and Naphthalen-1-amine second coupling, again diazo, in alkaline conditions and 4-Hydroxy-7-(phenylamino)naphthalene-2-sulfonic acid third coupling.

Flammability and Explosibility

Not classified

Properties and Applications

blue. Soluble in water for blue, solubility of 15 g/L (60 ℃), 30 g/L (97 ℃), soluble in soluble fiber element, slightly soluble in alcohol, insoluble in other organic solvents. The strong sulfuric acid in Red sauce for galleries to, diluted Red sauce for; In the light of nitric acid for palm gray. The dye solution to join strong hydrochloric acid for red light blue; Add thick sodium hydroxide solution for red light purple. Water-soluble good, colored light to blue. Dye in bath of copper, iron ion colored light basic unchanged. SDC classification for class B. Neutral white is very good, alkaline white. Mainly used for cotton or viscose dyeing and printing directly, and disperse dyestuffs with bath dyeing polyester/cotton blended fabric. Can also be used for paper, leather and biological dyeing.

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

References

[1] Sawada K, Ueda M. Adsorption behavior of direct dye on cotton in non-aqueous media[J]. Dyes and pigments, 2003, 58(1): 37-40.