Selective oxidation of Glycerol using Pt and Pd Catalysts supported on ZSM-11 zeolites

Abstract

Microporous zeolites of the type ZSM-11, with MEL structure, were synthesized by hydrothermal crystallization. These materials were modified with the incorporation of noble metals such as Au, Pt and Pd, by impregnation in incipient humidity at 80 ° C. Then, a Bismuth promoter (1% w / w) was added by the co-impregnation method. On the other hand also, Au (2% w / w) was incorporated by simultaneous impregnation, to the supported Pt and Pd mono metal catalysts, to evaluate the combined effect of these metals. After this, heat treatments of desorption and calcination were performed to remove the remains of precursor salts. Finally, all the catalysts were characterized by X-ray Diffraction (DRX), BET surface area, and by FTIR with pyridine adsorption to study their acid strength. All synthesized and modified materials were evaluated in the catalytic oxidation of glycerol (GLY). Of the different alternatives existing in the revaluation of GLY, we have focused on the selective oxidation in liquid phase, in order to obtain products with greater added value. In this work, the mono and bimetallic ZSM-11 zeolites are evaluated in the selective oxidation of GLY using pure O2 as oxidant, obtaining conversion values of the order of 64% mol, with a mono-metallic catalyst of Pt-ZSM-11, and a Lactic Acid (LA) selectivity of 21% mol. This result was improved using bimetallic catalysts of AuPt-ZSM-11 obtaining selectivities at LA of 45% mol.