REACTIONS OF NITROXYL RADICALS WITH PHENOLS IN A POLYMERIC MATRIX

The kinetics of the reactions of 2,2,6,6-tetramethylpiperidine-1-oxyl and 2,2,6,6-tetramethyl-4-benzoyloxypiperidine-1-oxyl with phenol, p-c hlorophenol, p-methylphenol, and p-nitrophenol is studied in a liquid phase and in polypropylene by using EPR spectroscopy. The rate constan ts and activation energies are measured. It is shown that these reacti ons are bimolecular and proceed in the kinetic regime, both in benzene and polypropylene. In a polymeric matrix, the reaction rates are lowe r; in this case, the bigger the molecular volume of reactants, the hig her the additional Gibbs energy typical of solid phase.