Reaction Mechanism of Direct Polycondensation with Triphenylphosphine and Hexachloroethane

The reaction mechanism of direct polycondensation with triphenylphosphine and hexachloroethane was investigated by gas chromatography, infrared and NMR spectroscopic analyses. It was found that pyridine participated in the reaction process of the direct polycondensation of dicarboxylic acid and diamine in the presence of triphenylphosphine and hexachloroethane in addition to serving as solvent and acid acceptor. The polyamide formation passed through an active acyl intermediate of carboxylic acid formed from triphenylphosphine and hexachloroethane in the presence of pyridine, followed by an aminolysis reaction with amine to form an amide linkage.