C.I.NO: Acid black 2

Alias: C.I. Acid Black 2; Nigrosine; C.I. 50420; Nigrosin water soluble; nigrosin cell culture tested; Nigrosin Acid black; Acid Black 5 (50420); Nigrosin; Nigrosine Water Soluble

Physical and chemical properties: The appearance is black granular with glitter, easily soluble in water and blue-purple, and blue when soluble in ethanol. The dye is blue in concentrated sulfuric acid and becomes purple when diluted to form a precipitate; the aqueous solution is blue-violet, and sodium hydroxide is added to form a dark purple precipitate.

Uses: Mainly used for leather dyeing (generally chromium mordant dyeing). It is also suitable for the dyeing of paper, wood, soap, anodized aluminum, wool, and silk fabrics. It can also be used to make ink.