2,7-Naphthalenedisulfonic acid, 5-amino-4-hydroxy-3-[[4'-[[1-hydroxy-6-(phenylamino)-3-sulfo-2-naphthalenyl]azo]-3,3'-dimethoxy[1,1'-biphenyl]-4-yl]azo]-, trisodium salt

Preparation

3,3′-Dimethoxylbenzidine double nitriding, first in alkaline conditions and 4-Amino-5-hydroxynaphthalene-2,7-disulfonic acid, and then in three alkaline conditions and 4-Hydroxy-7-(phenylamino)naphthalene-2-sulfonic acid coupling.

Properties and Applications

blue. Soluble in water for blue, soluble in soluble fiber element, slightly soluble in ethanol as a pale red purple, insoluble in other organic solvents. The strong sulfuric acid for green light blue, diluted red to blue for purple. The dye solution to join strong hydrochloric acid for dark purple, have precipitation; Add thick sodium hydroxide solution for dark purple, have precipitation.