Abstract
Polarographic and cyclic voltammetric reduction of N|-(benzenesulfonyl)-3-methyl-4-(2|-substituted-aryl hydrazono)-pyrazolin-5-ones was carried out in 40% (v/v) dimethylformamide in Britton-Robinson buffer solutions of pH 1.1-10.1. Thermodynamic parameters i.e. enthalpy of activation ‘ΔH*p’, heat of activation at constant volume ‘ΔH*v’ and entropy of activation ‘ΔS*’ were evaluated. The reduction was found to be diffusion controlled and irreversible at all temperatures. The compound exhibits two polarographic waves in the entire pH range of study. The results obtained in polarography were compared with the results obtained in cyclic voltammetry and a mechanism for the electrode process was proposed in acidic and basic media.