The Electrochemical Oxidation of I− in a Nonpolar Solvent Consisting of Al2Br6 and KBr in an Aromatic Hydrocarbon

Abstract

The mechanism of oxidation of I− in a nonpolar solvent consisting of 1.0MAl2Br6 and 0.80MnormalKBr in an aromatic hydrocarbon was studied. A chemical step following charge transfer, in which I− is regenerated, was observed. It was postulated that bromination of the solvent occurred. Oxidation of Br−by I2 to normalIBr or Br2 is possible in this system since the standard potentials for different redox couples are much closer than in aqueous solutions. Qualitative mechanistic information obtained from analysis of cyclic voltammograms was consistent with the mechanism derived on the basis of steady‐state current/potential measurements. It was observed that iodine is reduced rapidly in this system if mesitylene is used as the solvent and much more slowly in benzene. The half‐wave potential for the oxidation of I− is about 1.10V vs.RAlE, compared to about 2.2V in aqueous solutions.