Preparation of Al2O3/AlF3-Supported Ruthenium Catalysts for the Hydrogenolysis of Biodiesel-Derived Crude Glycerol

Hydrogenolysis of biodiesel-derived glycerol to value-added chemicals has emerged as an innovative approach to biowaste valorization for a more sustainable society. In the present work, Ru catalysts on Al2O3/AlF3 supports with different AlF3 content were prepared by the aqueous incipient wetness method and tested in the reaction of glycerol hydrogenolysis for the first time. The prepared catalysts were characterized by neutron activation analysis, N-2 physisorption, and H-2 chemisorption techniques. The catalytic hydrogenation of crude glycerol was performed at a temperature of 473 K and a hydrogen pressure of 4.0 MPa, using a 5 wt % glycerol aqueous solution for 4 h with comprehensive characterization of liquid- and gas-phase products. Texture, structure, and activity of the prepared catalysts were significantly affected by the fluoridation. To understand the mechanism of possible reactions for glycerol hydrogenolysis better, the effects of pH and individual hydrogenolysis of most of the products of the glycerol reaction were investigated.