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×[BzOH][H2O2](1+2.222×[BzOH]+2.330×[H2O2]+4.769×[BzH])2   (mol L−1 gcat−1 s−1).

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► A detailed kinetic study of benzyl alcohol oxidation with H2O2 has been reported.
► Mass transfer resistances were eliminated for estimating true kinetic parameters.
► The kinetic data was modeled using the power law rate expression.
► Reaction mechanism derived from Langmuir–Hinshelwood model was proposed.
► Rate expression describes satisfactorily the kinetic behavior of the reaction.