A NEW OSCILLATORY ELECTROCHEMICAL PHENOMENON OBSERVED IN THE ELECTROPOLYMERIZATION OF PYRROLE IN MECN-DISK-ELECTRODE TECHNIQUE(N(BU)(4)PF6 ON AN IRON ELECTRODE STUDIED BY THE RING)

A regular oscillatory behavior was observed during the electropolymeri zation of pyrrole on an iron electrode in aqueous acetonitrile contain ing tetrabutylammonium hexafluorophosphate. The periodicity, the ampli tude, and the shape of the oscillations depend on the concentrations o f the electrolyte species. In order to elucidate the mechanism of this oscillatory phenomenon, the ring-disk-electrode technique was used. A mechanism involving a catalytic oxidation of pyrrole by Fe3+ ions pro duced during iron oxidation is proposed and discussed.