Aqueous-phase hydrogenative ring-rearrangement of biomass-derived furfural over Pd catalysts by tuning property of hydrotalcite support

The conversion of biomass-based compounds into highly value-added chemicals has received extensive attention in recent years. This work reports the liquid-phase selective hydrogenation and furan ring-rearrangement of furfural (FFL) into cyclopentanone (CPO) and cyclopentanol (CPL) over Pd/Co₄Al₁-HTs catalysts and water as the solvent. The specific reaction rate of the optimal catalyst at 160 °C reaches 538 h^–1, and the selectivity of CPO/CPL is 77.5 %. By adopting the ion-exchange and formamide treatment methods, the type of the interlayer anions and interlayer spacing for the CoAl-HTs supports can be regulated, which can affect the state of the supported Pd sites and their catalytic activity and selectivity towards the ring-rearrangement products. Furthermore, the H₂/D₂ exchange experimental results demonstrate that the presence of the interlayer NO₃ ^– anions of CoAl-HTs support promotes the activation and dissociation of H₂, thereby accelerating the hydrogenation of FFL to cyclic compounds.