In the current study, effects of thermodynamic on the reaction mechanisms of the electrochemical oxidation of hydroquinone and catechol in the presence of various nucleophiles have been investigated both experimentally and theoretically, using cyclic voltammetry, controlled-potential coulometry, and density functional theory. The theoretical results were calculated at DFT (B3LYP) level of theory and 6-311?G(p,d) basis set. Calculated DGtot of the oxidation of the intermediates and products indicated that thermodynamic is one of the important parameters on the reaction mechanisms. The results of this work show that depending on the DGtot of electrochemical oxidation, the intermediates which are produced on the surface of electrode will participate in the electrochemical or chemical following reactions.
