Exploring the catalytic properties of supported palladium catalysts in the transfer hydrogenolysis of glycerol

The transfer hydrogenolysis of glycerol promoted by palladium based catalysts is reported. The reactions were carried out under mild conditions (453 K and 5 bar of N2) in absence of added hydrogen by using the reaction solvent, 2-propanol, as hydrogen source. The catalytic results were interpreted in terms of metal (Pd)-metal (Co or Fe) interaction that modifies the electronic properties of palladium and affords bimetallic PdM sites (M = Co or Fe), thus enhancing the catalytic properties of the systems in the conversion of glycerol as well as in the selectivity to 1,2-propanediol and 1-propanol. The transfer hydrogenolysis mechanism is here elucidated and involves the glycerol dehydration to 1-hydroxyacetone and the subsequent hydrogenation of 1-hydroxyacetone to propylene glycol.