On the electrochemical oxidation of enamines
The electrochemical oxidation properties of enamines of the cyclic ketones cyclo-pentanone, -hexanone, -heptanone, and -octanone with the cyclic amines pyrrolidine, piperidine, 1-methylpiperazine (1-MP), morpholine (MO), hexa-, and hepta-methyleneimine are investigated with the aid of cyclic voltammetry. The oxidations are totally irreversible. The lifetime of the intermediate cation radicals are shorter than 0.2 ms as determined by double potential step chronoamperometry. The anodic peak potentials depend on the amine component in the order of ring sizes 5 < 7; 8 < 6 < 1-MP < MO. The variation of the ketone component shows no significant influence on the peak potentials. The ionization potentials of the enamines were measured and correlated with the anodic peak potentials.