Cascade Engineered Synthesis of γ-Valerolactone, 1,4-Pentanediol, and 2-Methyltetrahydrofuran from Levulinic Acid Using Pd-Cu/ZrO2Catalyst in Water as Solvent

Synthesis of chemicals derived from biomass using heterogeneous catalysts with water as a solvent elegantly fits into the realm of sustainable chemistry. In this work, a novel heterogeneous palladium copper bimetallic catalyst supported on zirconia was synthesized and fully characterized. This catalyst was used in one-pot synthesis of gamma-valerolactone, 1,4-pentanediol, and 2-methyl tetrahydrofuran from levulinic acid and hydrogen using water as a solvent. The catalyst consists of 1% palladium and 29% copper supported on zirconia and is characterized per se and after reuse by using elemental analysis, FTIR, NH3-TPD, XRD, and BET surface area, XPS, SEM, and TEM analysis. This is the first ever report on the direct synthesis of 1,4-pentanediol and 2-methyl tetrahydrofuran using water as a solvent. Reaction mechanism and kinetic modeling was done to validate the experimental results. The results reported are thus a combination of synthesis of a novel catalyst with its full characterization, its application in a novel synthesis route, description of the synthesis mechanism and kinetic modeling, and proof of the robustness of the developed catalyst by reusing it for four catalytic cycles.