The determination of the activation parameters of reaction between iron carbon nitride and potassium cobalt (HEDTA) nitrite.

摘要

The kinetics of the oxidation of [Fe(CN)6]-4 by K[Co(HEDTA)NO2] was studied in order to get the mechanism and the activation parameters of the reaction. Using a freshly-made Na3PO 4 solution as the reaction medium with a pH of 6.00 the ionic strength was maintained at 0.10 M and the buffer molarity was 0.001 M.;The rate constant (kobs) of the reaction between [Fe(CN) 6]-4 and K[Co(HEDTA)NO2] was determined at temperatures of 25.0°C, 27.5°C, 30.0°C, 35.0°, and 40.0°C. We explored this reaction by monitoring the evolution of ferricyanide, [Fe(CN) 6]-3, spectroscopically for which e420 = 1023 cm-1 M-1 by recording the absorbance as a function of time at 420 nm wavelength. The data were plotted and results analyzed to give activation parameters, energy of activation (Ea), entropy of activation (DeltaS‡), and enthalpy of activation (DeltaH ‡) for the two reacting complexes under the specified reaction conditions. Based on previous results, an outer-sphere electron-transfer pathway and a first order rate of reaction for each of the reacting species 1 have been proposed.