Electrochemical oxidation of o-tolidine has been assessed in a mixture (70/30) of buffer/acetonitrile and various pHs. The electrochemical results corroborate that the mechanism of electrooxidation of o-tolidine acidic, neutral, and alkaline solutions are different, and three pH zones with different oxidation mechanisms were obtained: in the first region, a reversible oxidation reaction under the E mechanism, in the second region, observing the two one-electron oxidation–reduction under the ECDispE mechanism, and observation of the evidence of the ECE mechanism in the third region. In the continuation, electrosynthesis of a new azo compound has been reported in the third region. This process involves the electrochemical oxidation of o-tolidine in an aqueous phosphate buffer (pH = 7.2) in a divided cell using a carbon anode.
