Interplay Between Metallicity and Acidity in the Hydrogenation of Levulinic Acid

Abstract

The one-pot transformations of biomass-derived levulinic acid (LA) to gamma-valerolactone (GVL), 2-methyltetrahydrofuran (2-MTHF), and pentanoic acid (PA) are some of the most favorable reactions due to the various potentials of these products as a green fuel alternative, platform chemical, and solvent. Here, a non-noble Co-promoted NiCu catalyst supported on CeO2-doped alumina was deployed for the direct solvent-free hydrogenation of LA. The significant influence of various Al2O3 morphologies, CeO2 doping, and Co-promotion was investigated to identify the interplay of active metal sites, morphology, and acidity on the product selectivity and corresponding reaction pathway. The synergy between tunable acidity and metallicity was crucial to achieving high catalytic activity and controlling product selectivity in the multifunctional catalysts. Under the optimum reaction conditions, the Co-NiCu/CeO2-Al2O3 (hollow flower spheres) catalyst attained complete LA conversion and a 2-MTHF yield of 84%. Postcharacterization techniques confirmed recyclability up to five cycles, showing that the catalyst morphology and metallicity are intact with considerably high catalytic activity.