Direct Brown 25

Preparation

4-(4-Aminophenyl)benzenamine double nitriding, first coupled with 2-Hydroxybenzoic acid, and then and 5-Aminonaphthalene-2-sulfonic acid and 8-Aminonaphthalene-2-sulfonic acid coupling, its product to diazo, and C.I. Basic Brown (C.I. 21000) coupled.

Properties and Applications

brown to red light brown. Soluble in water for yellow brown to olive brown, slightly soluble in ethanol, acetone, soluble fiber element, insoluble in other organic solvents. The strong sulfuric acid for purple to blue-black, diluted is shallow brown; In nitric acid of for olive completely dissolved. The dye solution to join strong hydrochloric acid with olives brown precipitation; Add thick sodium hydroxide solution have yellow brown to orange brown precipitation.