Effect of initiation conditions on the direct polycondensation reaction using triphenyl phosphite and pyridine

In a model reaction of terephthalic acid with aniline by using triphenyl phosphite in a mixed solvent of pyridine and N‐methylpyrrolidone (NMP), mono‐ and dianilides were produced with relative yields varying with the content of pyridine in the solvent. The polycondensation of terephthalic acid with aromatic diamines was found to proceed more favorably via monoamidation, and highmolecular‐weight polyterephthalamides were prepared by controlling initiation conditions (selective activation of carboxylic groups), such as initial solvent systems, including the amount and kind of pyridines and initiation temperatures.