Deoxydehydration of glycerol to allyl alcohol catalysed by ceria-supported rhenium oxide

The Deoxydehydration (DODH) of glycerol to allyl alcohol was studied over ceria-supported rhenium oxide catalyst. Mesoporous ceria materials were synthetized via a nanocasting process using SiO2 and activated carbon as hard templates. The as-obtained ceria supports were impregnated with 2.5-10 wt.% ReOx. and applied in the DODH reaction of glycerol to allyl alcohol at 175C in batch conditions using 2-hexanol as solvent and hydrogen donor. As the characterisations revealed that the template removal was a critical step in the synthesis of the mesostructured ceria via the nanocasting method, the influence of the presence of the hard template was studied in detail by comparison to commercial ceria supports. The catalyst based on the nanocasting ceria showed higher performance of up to 88% yield in allyl alcohol and was reusable for 3 cycles without reactivation step. No evidence of leaching was observed via hot filtration test. The characterisation of the catalyst by XPS revealed the presence of Re4+ species after test, which led us propose that two redox couples, namely Re7+/Re5+ and Re6+/Re4+, are involved during DODH of glycerol to allyl alcohol, which was further confirmed by DFT calculations.

Automated summary

The Deoxydehydration (DODH) of glycerol to allyl alcohol was studied over a ceria-supported rhenium oxide catalyst. Mesoporous ceria materials were synthesized using a nanocasting process. The catalyst based on nanocasting ceria showed higher performance with up to 88% yield in allyl alcohol and was reusable for 3 cycles without reactivation step. XPS characterization of the catalyst revealed the presence of Re4+ species after the reaction, which suggested the involvement of two redox couples, Re7+/Re5+ and Re6+/Re4+, during the DODH reaction.