Blue-gray crystals. Soluble in alkali, insoluble in organic solvent. 4-Hydroxy-7-phenylaminonaphthalene-2- sulfonic acid [119-40-4] N-phenyl J acid, is produced by reaction of J acid with aniline in aqueous sodium bisulfite at reflux for 40 h (yield 85 %). It is used to produce C.I. Direct Violet 7, C.I. Direct Violet 9, C.I. Direct Violet 51, C.I. Direct Blue 78, and C.I. Direct Blue 168.
7-Anilino-4-hydroxy-2-naphthalenesulfonic acid is a dye intermediate, which is used to synthesize azo dyes such as direct copper salt green BTL, copper salt blue FBGL and copper salt purple BBL.
