Platinum supported on H-Mordenite: A highly efficient catalyst for selective hydrogenolysis of glycerol to 1,3-PDO

The selective production of 1,3-propanediol from glycerol under mild reaction conditions is of high interest. The current work describes the use of a highly selective catalyst consisting of platinum supported on mordenite zeolite employed for the first time for vapor phase hydrogenolysis of glycerol to 1,3-propanediol under atmospheric pressure. The catalysts with varying Pt content (0.5-3wt%) were prepared by wet impregnation method and thoroughly characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Temperature Programmed Desorption of Ammonia (NH3-TPD), CO chemisorptions, FTIR of adsorbed pyridine, BET surface area. The influence of metal loading, reaction temperature, hydrogen flow rate, contact time and weight hourly space velocity (WHSV) has been studied to unveil the optimized reaction conditions. A high 1,3-propanediol selectivity (48.6%) was obtained over 2 wt% Pt/HM catalyst at 94.9% glycerol conversion under the conditions of 10% glycerol content, 225 °C reaction temperature and normal atmospheric pressure. According to the obtained results, the glycerol hydrogenolysis efficiency is influenced by the Pt dispersion and acidity of the support. Selectivity to 1,3-propanediol was directly dependent on the concentration of Bronsted acid sites in the catalyst. It has also been shown that a longer reaction time and a low H2 pressure have the positive effects on the glycerol hydrogenolysis efficiency of the enhanced Pt/HM. A plausible reaction mechanism has been presented. The spent catalyst exhibited consistent activity and selectivity towards desired product during glycerol hydrogenolysis reaction.