Hydrogenolysis through catalytic transfer hydrogenation: Glycerol conversion to 1,2-propanediol

Important biorefinery processes imply hydrogenolysis reactions where high hydrogen pressures are required. As most of the nowadays available hydrogen gas is produced from fossil fuels there are great incentives to develop alternative technologies able to both substitute non-renewable reactants and operate at lower severity conditions. The use of hydrogen donor molecules from renewable origin can be a promising alternative to tackle simultaneously with both objectives. In the present study the use of methanol, 2-propanol and formic acid in the glycerol hydrogenolysis process to obtain 1,2-propanediol was investigated using a Ni–Cu/Al2O3 catalyst, prepared by sol–gel method, and under N2 atmosphere. A semi-continuous set-up was designed in which the donor solution was continuously fed into the autoclave reactor containing the glycerol aqueous phase. The best results in terms of glycerol conversion and 1,2-propanediol selectivity were obtained with formic acid.