Hydrogenolysis of glycerol with external h2 supply as value-added liquid chemicals source

The hydrogenolysis process of glycerol with external H2 supply has been studied using Ni-exchanged zeolites (FAU, LTA, ZSM-5). The reaction temperature and the oxidation state of the active phase were investigated in this work. Ni/zeolite catalysts were tested for 3 hours in a batch reactor, at different temperatures between 200 and 250 ºC and at 33 bar of initial H2 pressure. A water solution of 5 wt.% glycerol was used as a feedstock. The liquid products collected were analyzed afterwards by GC-MS and GC-FID. Several catalyst characterization techniques were performed: N2 physisorption, XRD, AAS, NH3-TPD and FTIR of adsorbed probe molecule (pyridine or NH3). The relevance of the metallic function for the hydrogenation reaction was proved. In most cases, the increase of the reaction temperature between 200 and 250 ºC implies a steady increase in the glycerol conversion and in the carbon conversion to liquid products, both for the reduced and non-reduced catalysts. The temperature also influences the selectivity to liquid products. Moreover, some temperatures were proposed as optimal for the production of certain liquids under these conditions.