Levulinic Acid Derived Reusable Cobalt-Nanoparticles-Catalyzed Sustainable Synthesis of γ-Valerolactone

The effective utilization of levulinic acid, a renewable feedstock derived from sugar biomass, is of central importance for the preparation of value-added chemicals as well as catalytic materials. Specifically, the production of gamma-valerolactone, a key platform molecule, from levulinic acid represents one of the pivotal processes in converting lignocellulose-based biomass into renewable fuels and chemicals. Compared to synthetic valorization, the use of levulinic acid for the preparation of catalytically active nanomaterials is scarcely explored. Here, we report the use of levulinic acid for the preparation of cobalt-based nanocatalysts as well as for the synthesis of gamma-valerolactone. The template synthesis of cobalt-levulinic acid on commercial silica and subsequent pyrolysis resulted in the formation of cobalt nanoparticles as highly active and selective catalysts for the hydrogenation of levulinic acid to gamma-valerolactone under industrially viable and scalable conditions. Applying this optimal catalyst, other lactones starting from different oxo carboxylic acids have also been prepared in good to excellent yields. Synthetic and practical utility of this Co-based valerolactone synthesis protocol has been demonstrated by performing synthesis on the scale of 20 g and recycling of catalyst.