Electrochemical oxidation of catechol was studied in the presence of piperidine as a nucleophile in water/acetonitril mixture solvents using cyclic voltammetry and square wave voltammetry methods. The results indicate that the o-benzoquinone derived from the anodic oxidation of catechol participates in Michael addition reaction with piperidine to form the corresponding catechol-piperidine adducts according to an ECE mechanism. Digital simulation of cyclic voltammograms was used to prove the proposed mechanism. Taking into account the solution electron transfer between o-benzoquinone and oxidized catechol-piperidine adduct, the values of α, k and the following chemical reaction rate constant were determined.