Glycerol Oxidation in the Liquid Phase over a Gold-Supported Catalyst: Kinetic Analysis and Modelling

The present work deals with the kinetic analysis and modelling of glycerol (GLY) oxidation in the liquid phase over a supported gold catalyst. A Langmuir-Hinshelwood model was proposed, after considering the effect of the reaction temperature, the NaOH/GLY ratio and the initial concentrations of GLY and GLY-Product mixtures. The proposed model effectively predicted the experimental results, and both the global model and the individual parameters were statistically significant. The results revealed that the C-C cleavage to form glycolic and formic acids was the most important reaction without a catalyst. On the other hand, the supported Au catalyst promoted the GLY oxidation to glyceric acid and its further conversion to tartronic and oxalic acids. Regarding the adsorption terms, glyceric acid showed the highest constant value at 60 degrees C, whereas those of GLY and OH- were also significant. Indeed, this adsorption role of OH- seems to be the reason why the higher NaOH/GLY ratio did not lead to higher GLY conversion in the Au-catalysed reaction.