Bifunctional acid-base zirconium phosphonate for catalytic transfer hydrogenation of levulinic acid and cascade transformation of furfural to biofuel molecules

Abstract

The production of biofuels, such as furfural ether and γ-valerolactone (GVL) from biomass platform chemicals furfural (FFA) and Levulinic acid (LA) is of significant interest. In this study, a nanoporous inorganic-organic Zr−phosphonate catalyst (ZrNPO3) was synthesized and employed in the selective production of GVL (98.2 %) via catalytic transfer hydrogenation of LA. The catalyst containing acid-base sites was further used to produce biofuel molecules like GVL and furfuryl ether under a mild reaction condition via cascade furfural transformation. The GVL selectivity was further improved using phosphotungstic acid@ZrNPO3. The catalytic optimization studies were combined with poisoning studies and the detailed physicochemical characterization to acquire insight into the structure-activity correlation and reaction mechanism. The synergistic presence of the Lewis acidity and basicity on the catalyst was responsible for its remarkable activity. Designing a single catalyst for the one-pot tandem transformation of FFA to GVL would be highly motivating for catalysis researchers and industrialists.