(476b) Optimization of Aqueous Phase Furfural Hydrogenation Using Pd1Ni Dilute Limit Alloy Catalysts

Simultaneous strong electrostatic (SEA) adsorption is pushed to the limit of metal dilution to prepare single-atom sites on a supported cluster of another metal. Silica-supported nickel prepared by SEA shows very low activity in aqueous-phase furfural (FAL) hydrogenation reaction (T=150 °C, P=430 psig). Adding a small amount of palladium to form Pd₁Ni dilute limit alloy (DLA) shows a 90-fold increase in activity at 10% furfural conversion. However, FAL hydrogenation in the presence of water follows two competing pathways of ring-opening without rearrangement (4-oxopentanal) and with rearrangement (cyclopentanone). Hronec et al. (2016) confirmed the important role of hydrogen in the liquid phase on the selectivity toward cyclopentanone. In a separate study by Mironenko et al. (2019), carbon nanoglobules supported palladium shows selectivity towards 4-oxopentanal at any hydrogen pressure. Our hypothesis is that hydrogen spillover by Pd promotes formation of 4-oxopentanal. Hence, If our single-atom Pd on Ni over silica support is coupled with lower hydrogen pressure, the hydrogen spillover can be reduced and result in improved selectivity towards cyclopentanone. This study investigates the effect of reaction conditions such as temperature and hydrogen pressure on aqueous phase furfural hydrogenation using palladium-nickel DLA on a 100—mL autoclave reactor in batch operation.

References:

• Hronec, M.; Fulajtárová, K.; Vávra, I.; Soták, T.; Dobročka, E.; Mičušík, M. Carbon Supported Pd-Cu Catalysts for Highly Selective Rearrangement of Furfural to Cyclopentanone. Catal. B Environ. 2016, 181, 210–219. https://doi.org/10.1016/j.apcatb.2015.07.046.
• Mironenko, R. M.; Belskaya, O. B. Effect of the Conditions for the Aqueous-Phase Hydrogenation of Furfural over Pd/C Catalysts on the Reaction Routes. AIP Conf. Proc. 2019, 2141 (August). https://doi.org/10.1063/1.5122029.