Comparative kinetic analysis of silent and ultrasound-assisted catalytic wet peroxide oxidation of phenol

Abstract

The kinetic study of silent and ultrasound-assisted catalytic wet peroxide oxidation of phenol in water was performed to qualitatively assess the effect of ultrasound on the process kinetics. Various kinetic parameters such as the apparent kinetic rate constants, the surface utilization coefficient and activation energy of phenol oxidation over RuI 3 catalyst were investigated. Comparative analysis revealed that the use of ultrasound irradiation reduced the energy barrier of the reaction but had no impact on the reaction pathway. The activation energy for the oxidation of phenol over RuI 3 catalyst in the presence of ultrasound was found to be 13 kJ mol −1, which was four times smaller in comparison to the silent oxidation process (57 kJ mol −1). Finally, ‘figures-of-merit’ was utilized to assess different experimental strategies such as sonolysis alone, H 2O 2-enhanced sonolysis and sono-catalytic oxidation of phenol in order to estimate the electric energy consumption based on the kinetic rate constants of the oxidation process.