Electrochemical oxidation of catechol ( 1) has been studied in the presence of morpholine ( 2a), dimethylamine ( 2b) and diethylamine ( 2c) as nucleophile in aqueous solution, using cyclic voltammetry and controlled-potential coulometry. The results indicate that the participation of catechol ( 1) in Michael reaction with 2 to form the corresponding aminoquinone derivatives ( 5a– 5c). Based on ECE mechanism, the homogeneous rate constants were estimated by comparing the experimental cyclic voltammetric responses with the digital simulated results.