Collect. Czech. Chem. Commun. 1991, 56, 68-77

Competitive chemical reactions in DC polarography: Influence of fast protonation equilibria on CE and ECE mechanisms

Eulogia Muñoz, José L. Avila, Juan J. Ruiz and Luis Camacho*

Department of Physical Chemistry and Applied Thermodynamics, Faculty of Sciences, University of Córdoba, 14004 Córdoba, Spain


We carried out a DC polarographic study of the limiting current for CE and ECE processes with chemical stages subject to potential catalytic effects and in direct competition with protonation reactions in quasi-equilibrium. The aforesaid competition may result in the appearance of maxima in the limiting current vs pH plots for CE mechanisms. We established the conditions required for the rise of such maxima, and developed methods for the calculation of kinetic parameters. The competition did not result in any maxima in the above-mentioned plots for ECE mechanisms; however, we established criteria for their potential identification.