Kinetic Analysis of the Electrochemical Oxidation of 2-methylthiophene via Cyclic Voltammetry

Abstract

Elucidating the kinetic parameters for the oxidation of thiophenes can aid in the design of future solar fuel technologies. After being oxidized, these thiophene compounds undergo homocoupling and form a new carbon-carbon bond. Quantitative data on the kinetics of substituted thiophene homocoupling reactions is underreported. This study investigates the electrochemical oxidation of 2-methylthiophene in 0.1 M TBAPF6 in acetonitrile using cyclic voltammetry (CV). CV data was simulated using a kinetic mechanism where the initial oxidation of 2-methylthiophene is followed by the dimerization of the radical cation. The simulations best match the experimental data when the initial rate constant is smaller than 1 x 10-8 Ms-1. This small rate constant for reduction implies that the rate of oxidation is inversely large. The findings of this study will help identify the reaction mechanism and provide a framework for optimizing and controlling other carbon-carbon bond forming reactions.