Kinetic modeling of the quasi‐homogeneous oxidation of glycerol over unsupported gold particles in the liquid phase

Abstract

In the present study, kinetic analysis and modelling of the glycerol oxidation reaction over unsupported Au particles were performed. The reaction pathways, which were determined in agreement with the experimental results, comprise two types of reactions, namely oxidation and C–C cleavage. A homogeneous catalytic reaction model was proposed by considering the occurrence of the non‐catalytic reaction, the effect of the temperature, as well as NaOH and catalyst concentrations. The proposed kinetic model could adequately describe the data. The reaction under basic conditions but in the absence of a catalyst favoured the formation of C–C cleavage products (glycolic and formic acids), while in the presence of unsupported Au particles the oxidation to glyceric acid and the direct oxidation of glycerol to formic acid were promoted. Finally, it was observed that the formation of tartronic acid was not promoted by the catalyst and followed the non‐catalytic route.Practical applications: The building of a kinetic model for glycerol oxidation in liquid phase using gold‐based catalyst allows to better understand the mechanism leading to oxidation and C–C cleavage responsible to some change of selectivities in the process. The model parameters obtained in this study would be used to scale an industrial unit in a reactor modeling.The present work describes a homogeneous catalytic kinetic model of the glycerol (GLY) oxidation, by using unsupported Au nanoparticles. The proposed model includes the occurrence of the non‐catalysed reaction in basic media and the effect of the reaction temperature, NaOH/GLY ratio and GLY/Au ratio. The model predicted well the experimental results. Unsupported Au nanoparticles were selective to glyceric acid and C–C cleavage products like formic and glycolic acids.