Abstract: An azo-compound, free acid form of which is represented by the following formula (I): wherein A and B represent, independently with each other, a phenyl having one or two groups selected from sulfo and carboxyl or a naphthyl having 1 to 3 sulfos; R1, R2, R3, R4, R5 and R6 represent, independently with each other, hydrogen, lower alkyl or lower alkoxy; and X represents —N═N— or —NHCO—, and a dye polarizing film containing the azo-compound in a polarizing film base, which exhibits a high polarizing performance and is excellent in durability and light fastness, are provided.

Abstract: An azo-compound, free acid form of which is represented by the following formula (I): 1

Abstract: A process for producing 1,4-diaminoanthraquinone-2,3-disulfonic acid or a salt thereof which comprises reacting a 1,4-diamino-2,3-dihalogenoanthraquinone with a sulfonating agent in an aqueous medium in the presence of at least one of a quaternary ammonium compound and a quaternary phosphonium compound and optionally, in the presence of an inert organic solvent is disclosed. A process for producing 1,4-diamino-2,3-dicyanoanthraquinone which comprises further reacting the thus obtained 1,4-diaminoanthraquinone-2,3-disulfonic acid or salt thereof with a cyanogenation agent is also disclosed.

Abstract: A process for the production of 1,4-diaminoanthraquinone-2-sulfonic acid or a salt thereof is disclosed, comprising reacting 1-amino-4-bromoanthraquinone-2-sulfonic acid or its salt with liquid ammonia in the presence of a copper catalyst wherein the reaction is carried out in the presence of an inert organic solvent, e.g., n-heptane and cyclohexane. In this process, crystals of the desired product do not substantially deposit on reactor walls, and distillation recovery of ammonia can be performed easily without causing deterioration of the desired product. 1,4-Diaminoanthraquinone-2-sulfonic acid or salt thereof is a useful intermediate for the preparation of, e.g., anthraquinone dyes.