On the effect of Alkaline Earth Metal Cations in the Hydrogenolysis of Glycerol over Pt/C - an Experimental and Theoretical Study

Glycerol can be converted to propylene glycol via metal and base catalyzed hydrogenolysis. The nature of the base has a profound influence on the outcome of the reaction. We have tested a range of alkaline (LiOH, NaOH and CsOH) and alkaline earth (Mg(OH)(2), Ca(OH)(2), Sr(OH)(2) and Ba(OH)(2)) metal hydroxides in combination with Pt/C. The data reveal that alkaline earth metal hydroxides exhibit a much higher activity and improved selectivity. DFT calculations confirm that the coordination of reactive intermediates to divalent cations is responsible for the observed behavior. In the study, the effect of the cation on hydrogenolysis was elucidated for the first time.