4- (5-amino-6-hydroxy-benzoxazol-2-yl) ammonium benzoate, and preparation and use thereof

摘要

The present invention is 4- (5-amino-6-hydroxy-benzoxazol-2-yl) ammonium benzoate of the formula (I), and published their preparation and use. Formula (II) of 4- (5-amino-6-hydroxy-benzoxazol-2-yl) benzoic acid or the formula (III) 4- (5- amino-6-hydroxy-benzoxazol-2-yl) carboxamide benzoate the salts as the raw material, allowed to sufficiently react with ammonia in an aqueous solvent, and heating the resulting reaction mixture directly to remove excess ammonia, 4- (5-amino-6-hydroxy-benzoxazol-2-yl) -benzoic give the acid ammonium. Was prepared 4- (5-amino-6-hydroxy-benzoxazol-2-yl) Quality of ammonium benzoate is Chijimigokyu (purity of 99.5% or higher, containing a metal ion content of 200ppm or less, and DMF condensation preventing impurities will not), it is possible to manufacture the PBO and a modified PBO fiber in the AB type alone, PBO and a modified PBO that has been produced, have a molecular weight of high, tensile performance is excellent. [Formula 1]