Eriochrome Black A

Preparation

4-Amino-3-hydroxy-7-nitronaphthalene-1-sulfonic acid diazotization, and Naphthalen-2-ol coupling.

Properties and Applications

blue light gray to black. Black powder. Soluble in water for navy blue, in the water solubility 60 g/l (80 ℃), slightly soluble in ethanol and Acetone. In concentrated sulfuric acid for blue, yellow after diluted into light brown; In concentrated nitric acid for red orange. Its aqueous solution for navy blue, join concentrated hydrochloric acid to pale yellow light brown; Join strong caustic into orange brown. Dyeing wool in nitric acid into black light purple, and have a slight white streaks. Mainly used for wool fabric dyeing, also can be used for silk and nylon dyeing, also can be used for wool and a variety of fiber blended fabric dyeing, can be in acetic acid chromium pretreatment of wool fabric direct printing. Also used in the leather dyeing.