SPECTROSCOPIC STUDY ON THE ELEMENTARY REACTIONS OF OXIDATIVE POLYMERIZATION.

In the reported study the catalytic cycle of the Cu-pyridine complex catalyzed polymerization of 2,6-xylenol was divided into four elementary processes: the coordination of the substrate, the electron transfer from the substrate to the cupric ion, the dissociation of the activated substrate, and the reoxidation of the catalyst. Rate constants of each elementary reaction, k//1, k//e, k//d, and k//o, were determined spectroscopically by the stopped-flow method. The approximate magnitudes of each rate constant were k//1:10(1 multiplied by (times) mole** minus **1 multiplied by (times) min** minus **1), k//e:10** minus **2(min** minus **1), and k//o:10**2(min** minus **1), respectively. Thus, it was considered that the k//e or the k//d process was the rate-determining step, but the latter could not be measured in this procedure. The rate constants were affected by the species of the solvent. With a few exceptions of the solvent which had coordinating ability, k//1 and k//e increased and k//o decreased with the polarity of the solvent. The effects of the polymer-ligand on each elementary reaction were also studied in the polymerization catalyzed by the Cu-partially-quaternized poly(vinylpyridine) complex.