Kinetics of liquid phase oxidation of benzyl alcohol with hydrogen peroxide over bio-reduced Au/TS-1 catalysts

In this paper, the kinetics and mechanism of oxidation of benzyl alcohol with H2O2 over heterogeneous bio-reduced Au/TS-1 catalysts have been reported after eliminating mass transfer resistances. Langmuir-Hinshelwood and power-law kinetic models are applied to describe the experimental results of the catalytic oxidation. By fitting the kinetic data using the power-rate law model, the orders of the reaction with respect to benzyl alcohol, H2O2, benzaldehyde and catalyst were found to be 0.55, 0.22, -0.35 and 1.06, respectively, with an activation energy of 38.2 kJ mol(-1) from an Arrhenius plot. These fractional orders indicate that the species were adsorbed on the catalyst surface leading to the product, benzaldehyde. Furthermore, the reaction mechanism derived from the Langmuir-Hinshelwood model is proposed; it gives a reasonable description of the oxidation rate, following a rate expression:. r = 0.0119 x [BzOH][H2O2]/(1 + 2.222 x [BzOH] + 2.330 x [H2O2] + 4.769 x [BzH])(2) (mol L-1 g(cat)(-1) s(-1)). (c) 2012 Elsevier B.V. All rights reserved.