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

• Published in: Molecular catalysis 2023-01, Vol.535, p.112856, Article 112856
• Main Authors: Vargas, Karen Silva, Zaffran, Jeremie, Araque, Marcia, Sadakane, Masahiro, Katryniok, Benjamin
• Format: Article
• Language: English
• Subjects: Chemical Sciences
• ISSN: 2468-8231; 2468-8231
• DOI: 10.1016/j.mcat.2022.112856

•A reusable ceria-supported rhenium oxide catalyst was successfully applied in DODH of glycerol, giving excellent yields of up to 86% in allyl alcohol using a secondary alcohol as a hydrogen donor.•A mesoporous ceria support was successfully prepared by nano casting method. The sequential hard template removal had negative impact on the catalytic performance due to the reduction of the ceria.•XPS and DFT calculations showed that two redox couples are involved in the DODH reaction, namely Re7+/Re5+and Re6+/Re4+. The redox couple Re6+/Re4+ was enabled by the presence of O-vacancies. 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 175°C 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. [Display omitted]