INFLUENCE OF SOLUTION ACIDITY ON THE ADSORPTION AND CHARGE-TRANSFER KINETICS OF PARABANIC ACID REDUCTION

Parabanic acid reduction has been studied in the -1.4 less than or equ al to H-0 less than or equal to 0.9 acidity range by the ac impedance technique. Changes in the adsorption of reactant and products with sol ution acidity lead to protonation equilibrium constants that differ fr om their bulk values. The observed pK(a) shifts were consistent with i nterfacial dielectric saturation. Variation of the charge transfer par ameters with potential and proton activity allows a detailed analysis of the reduction mechanism to be performed in terms of the scheme of s quares.