Title : Kinetic modelling of glycerol oxidation on metallic supported catalysts
Abstract:
Due to the growing interest in the use of renewable energy sources, glycerol has become an important bio-building block. Catalytic oxidation of glycerol in liquid phase lead to add-value products such as glyceric, glycolic or tartronic acids, which can be used in food, cosmetics, and textile industries. Regarding the catalysts, Au and Pt have been proven to be good active phases: the first one is stable in the reaction media, whereas the second one is very active and selective to glyceric and tartonic acids. On the other hand, the use of Ag has been seldom studied, but it has some advantages: it is selective to C-C cleavage products, and much cheaper than Pt and Au. The aim of this work is to give a quantitative comparison of Au, Pt and Ag as active phases in glycerol oxidation using a kinetic modelling including if necessary deactivation. Based on a simplify reaction scheme, we can determine the effect of the metal nature on selectivity. Inhibition of glycerol and products have been investigated through a pseudo Hougen-Watson-Langmuir-Hinshelwood approach indicating that some acidic species could strongly limited the reaction in line with recent works dealing with DFT calculations. Finally, we have also contributed to try to better understand glyceraldehyde formation in neutral/acidic conditions with Pt catalysts where a quasi-irreversible inhibition similar to a deactivation behavior, has been identified increasing when pH is decreasing. Current work is focused on the determination of a detailed mechanism to build a more accurate kinetic model specially to incorporate the effect of Ph in kinetic constants.
