Minimizing Energy Demand in the Conversion of Levulinic Acid to γ‑Valerolactone via Photothermal Catalysis Using Raney Ni

Abstract The valorization of lignocellulosic wastes emerges as a prime strategy to mitigate the global carbon footprint. Among the multiple biomass derivatives, γ‐valerolactone is particularly attractive as precursor of high‐value chemicals, biofuel, green solvent or perfumery. γ‐Valerolactone can be synthesized through a hydrogenation reaction from levulinic acid, obtained from cellulose. However, the high energy requirements of this synthetic pathway have hindered its industrial viability. To drastically reduce the reaction energy requirements, here a novel synthetic strategy, based on solvothermal‐photothermal processes using cost‐effective Raney‐Ni as photothermal catalyst, is proposed. First, the use of hydrogen gas is avoided by selecting isopropanol as a safer and greener H‐source. Second, a photothermocatalytic process is used to minimize the reaction temperature and time with respect to conventional reactions. This approach exploits the broadband optical absorption of the Raney®‐Ni, due to its highly damped plasmonic behavior, to achieve fast and efficient catalyst heating inside the reactor. The photothermal reaction required less than 2 h and just 132 °C to reach over 95% conversion, thereby drastically reducing the reaction time and energy consumption compared to conventional reactions. Importantly, these conditions granted high catalyst reusability. This solvothermal‐photothermal approach could offer a sustainable alternative for the industrial production of γ‐valerolactone.