CI 50325

Preparation

6,8-Bis(phenylamino)naphthalene-1-sulfonic acid?and 2,5-Diamino-4-methoxybenzenesulfonic acid condensation, and then product (add) ammonia in the cuprous oxide catalyst for the air oxidation.

Synthesis

Wool Fast Violet B 21, C.I. 50 325 [6837-46- 3], from 1,3-bis(phenylamino)naphthalene-8- sulfonic acid and 2-methoxy-1,4-phenylenediamine- 5-sulfonic acid proceeds differently. In the cyclization step the methoxyl group is split off as methanol. Therefore, the dye can also be synthesized from 1,4-phenylenediamine-2-sulfonic acid.

Properties and Applications

blue purple. Soluble in water and ethanol for red light purple. The strong sulfuric acid for green, purple for red after diluted. In water solution is a deep red to join sodium hydroxide, and precipitation.