Kinetic modeling of partial oxidation of benzyl alcohol in water by means of Fe(III)/O2/UV–solar simulated process

• Fe(III) photo-assisted selective oxidation of benzyl alcohol to benzaldehyde.
• Identification of some involved radical species by ESR analysis.
• Reaction mechanism of the investigated homogeneous photo-catalytic process.
• Kinetic modeling and numerical simulation of the partial oxidation process.
• Estimation of unknown kinetic parameters of reaction.

The mechanism of selective oxidation of benzyl alcohol to benzaldehyde and of benzaldehyde to benzoic acid by means of ferric ions in water under simulated UV–solar radiation is investigated through the development of a new kinetic model, also based on the results of Electron Spin Resonance (ESR) experiments, not previously reported in the literature. A value of pH = 0.5 is chosen with the aim to minimize the contribution of the undesired hydroxylation reactions.The mathematical model is constituted by of a set of mass balance equations for the chemical species involved in the homogeneous photocatalytic oxidation process.The experimental concentration–time profiles, collected at different starting substrates concentrations, are satisfactorily predicted by the model under deaerated and aerated conditions.The values of different rate constants of the reactions, taken into account for the adopted mechanism, not available in the literature, are estimated by a proper optimizing procedure.The model may be used for the prediction of the performance of the homogeneous Fe(III)-photo-catalytic partial conversion of aromatic alcohols to the corresponding aldehydes in water at room temperature and very acidic pH.

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