Catalytic performance of Rh/SiO₂ in glycerol reaction under hydrogen

Glycerol is a main byproduct in the biodiesel production process, and the effective utilization of glycerol can contribute to biodiesel promotion. One of the possible methods is the catalytic conversion of glycerol to valuable chemicals, and this can also agree with the concept of green chemistry in terms of the utilization of renewable resources. Catalytic performance of supported metal catalysts (metal: Rh, Ru, Pt, Pd support: active carbon, SiO₂, Al₂O₃) was evaluated in the reaction of glycerol aqueous solution under H₂. It is found that Rh/SiO₂ exhibited higher activity and higher selectivity to hydrogenolysis products such as propanediols and propanols than Ru/C catalysts at low temperature (393 K). We also investigated the additive effect of ion-exchange resin (Amberlyst). Regarding the reaction route in the reaction of glycerol, it is suggested that the consecutive hydrogenolysis of propanediols to propanols on Rh/SiO₂ can proceed via 1,2-propanediol, while it can proceed on Ru/C via 1,3-propanediol.