Elementary stages in polycondensation

Abstract

A spectroscopic and kinetic investigation has been made of the reaction between m-phenylenediamine and pyromellitic and dichloropyromellitic dianhydrides in THF; closely agreeing values of the rate constants and activation energies for the reaction have been found when using measurements from IR spectroscopy (from the change in intensity of the bands of the reagents and the product) and electron spectroscopy (from the change in intensity of the charge-transfer bands). Photo- and thermo-electron transfer has been studied in model systems containing primary and substituted aromatic diamines and electron acceptors; natural and catalytic electron transfer have been compared. On the basis of the data obtained, a mechanism for the elementary stage in the polycondensation reaction is presented as the successive transfer of an electron and a proton in the electron-excited state of a complex formed by molecules of the reagents and solvent.