Direct Blue 11

Preparation

2,5-Dichlorobenzenamine diazo, in acid conditions and 4-Amino-5-hydroxynaphthalene-2,7-disulfonic acid?coupling, 4-(4-Aminophenyl)benzenamine double nitriding, first in alkaline conditions and accidentally coupled nitrogen compounds, and then in alkaline conditions and 4-Amino-5-hydroxynaphthalene-2,7-disulfonic acidcoupling.

Properties and Applications

dark blue. Soluble in water for dark green light blue, soluble in ethanol, insoluble in acetone and other organic solvents. The concentrated sulfuric acid is light to dark gray light blue, diluted dark red light for blue, precipitation. The dye solution to join a little red sulfuric acid 10%; Add thick sodium hydroxide solution to become red become colourful.