ROTATING-RING-DISK ELECTRODE STUDIES OF REACTION OF STABLE RADICAL CATIONS WITH STYRENE AND ISOBUTYL VINYL ETHER

In the reported experiments, an electroanalytical technique has been utilized in a new method for the study of reactive intermediates in polymerization reactions. A ring-disk electrode system generated persistent carbocation radicals whose stability decreased in the order: 1,3,6,8-tetraphenylpyrene (TPP), rubrene (Ru), 9,10-diphenylanthracene (DPA), and 9,10-dimethylanthracene (DMA). Radical cations from these parent compounds flowed to a collecting ring which was controlled potentiostatically to reduce unreacted cations. When styrene or isobutyl vinyl ether was added to the solution, the concentration of carbocation radicals reaching the electrode was reduced. Current collection efficiencies N were determined as a function of rotation speed for each monomer concentration. The rate constants show a trend in cation reactivities which is in agreement with that obtained by other methods.