KINETICS OF COMPROPORTIONATION - A SPECTROELECTROCHEMICAL APPROACH

A general spectroelectrochemical approach to the kinetics of the comproportionation reaction Y + Y2- --> 2Y- is presented which combines both rotating-disc double-step chronoamperometry and quantitative in situ electrochemical ESR spectroscopy. It is shown that when the electroreduction of Y to Y2- proceeds via two separate one-electron waves and Y.- is ESR active, the combination of the two techniques allows the unambiguous determination of the kinetics together with the diffusion coefficients of the three species involved. The method is applied to the case where Y = p-chloranil (tetrachloro-p-benzoquinone), and good agreement between theory and experiment is found.