Effect of temperature on the Polarographic behaviour of aromatic dinitro compounds vis-a-vis the kinetics of the electrode reaction

Abstract

The polarographic reduction of some aromatic dinitro compounds, viz., 1,2- and 1,3-dinitrobenzenes, 2,4-dinitrotoluene, ,2,4-dinitrophenol and 3,4- and 3,5-dinitrobenzoic acids in aqueous ethanolic (10%, v/v) medium has been studied at <em>p</em>H 7 (BR buffer) at different temperatures (25 - 55°C). The reduction has been found to be diffusion-controlled and irreversible. The potential-dependent rate constant <em>k</em>_f,h at different temperatures has been calculated by Koutecky's method. The study reveals that the irreversible electrode reactions of aromatic dinitro compounds tend to become increasingly more irreversible at elevated temperatures as indicated by a negative shift in <em>E</em>_1/2 values with increase in temperature. The results have been explained in the light of correlation between electrode kinetics and double layer structure.