Pd-Decorated CePO4 Catalyst for the One-Pot, Two-Step Cascade Reaction to Transform Biomass-Derived Furanic Aldehydes into Fuel Intermediates

Production of fuel range chemicals from biomass-derived carbonyls is a viable strategy to overcome the dependency on nonrenewable fossil fuels. Acid-base catalytic processes play a vital role in producing liquid fuel range chemicals and intermediates derived from renewable biomass. Aldol condensation is one of the simplest ways to convert biomass-derived carbonyls to C8-C15 range fuels. Herein, CePO4 possessing acidic and basic sites is synthesized under basic pH and used as catalyst support to decorate Pd nanoparticles to fabricate a Pd/CePO4 catalyst. Pd/CePO4 facilitates aldol condensation to form a highly selective alpha,beta-unsaturated methyl ketone in the first step, followed by the selective reduction of C = C to form a C-C coupled hydrogenated product containing a C = O functional group in a one-pot cascade protocol. Many biomass and non-biomass-derived aldehydes are reacted with acetone and methyl isobutyl ketone (MIBK) for the selective production of fuel precursors. Pyridine Fourier transform infrared (FT-IR) and NH3/CO2 temperature-programmed desorption (TPD) measurements are employed to probe the acidity and basicity of the catalyst. The influence of different Pd loadings on the reducibility of these catalysts is studied by H-2 temperature-programmed reduction (TPR) analysis. The activation energy (E-a) for aldol condensation between furfural and acetone is estimated to be 55.3 kJ/mol. The present catalytic system offers a higher furfural conversion (99.0%) with a higher selectivity (93.6%) of the desired hydrogenated product. Production of furan-based higher-carbon-containing compounds having carbonyl functionality using a simple and robust metal phosphate-based catalyst would be highly interesting from industrial and academic perspectives for fuel/chemical production.

Automated summary

The production of fuel range chemicals from biomass-derived carbonyls using acid-base catalytic processes is a feasible strategy to reduce dependency on nonrenewable fossil fuels. The use of CePO4 as a catalyst support for Pd nanoparticles in aldol condensation reactions allows for the selective production of C8-C15 range fuels. The catalytic system shows high furfural conversion and selectivity for the desired hydrogenated product, making it a promising approach for fuel and chemical production.