EFFECT OF TEMPERATURE AND EVALUATION OF THERMODYNAMIC PARAMETERS FOR THE POLAROGRAPHIC-BEHAVIOR OF 3-METHYL-4-(2'-SUBSTITUTED BENZENEAZO)-2-ISOXAZOLIN-5-ONES

The polarographic behavior of 3-methyl-4-(2'-substituted benzeneazo)-2 -isoxazolin-5-ones has been studied in 50% v/v dimethylformamide solut ion in Britton-Robinson buffer of pH 4.1 at different temperatures (30 3.15-333.15 K). The reduction is diffusion-controlled and becomes irre versible at higher temperatures. The shift of E1/2 values toward more negative potentials and a decrease in the values alphan(a) and k(f,h)o suggests that the electrode reaction becomes more irreversible at ele vated temperatures. Thermodynamic parameters were evaluated at the dif ferent temperatures studied. The results can be explained in the light of a correlation between electrode kinetics and double-layer structur e.