Continuous‐Flow Hydrogenation of Levulinic Acid to γ‐Valerolactone in Water Using Platinum on Nitrogen‐Doped Carbon Pellets

The conversion of levulinic acid (LA) to γ-valerolactone (GVL) is studied in a continuous-flow process. For this purpose, a Pt-based hydrogenation catalyst supported on hierarchically porous nitrogen-doped carbon pellets (NDC) was used. Owing to their large surface area of 756 m2 g−1 and mesopore volume of 0.49 cm3 g−1, the extruded cylindrical pellets are suitable as support material to be loaded with Pt0 and to be used in fixed-bed reactors. From a sustainable processes perspective, water was used as a solvent. For the H2-assisted hydrogenation of LA to GVL in water at 160°C, the prepared 2.7 wt% Pt/NDC provides 96.4% GVL yield (99% LA conversion) and a Pt time yield of 54.7 molGVL h−1 molPt−1 (66.2% LA conversion). Using the same catalyst, that is, 2.7 wt% Pt/NDC catalyst at 220°C and formic acid (FA) as a renewable reducing agent, it provided enhanced GVL selectivity of 98.7% with LA conversion (65.3%) and a 92.6% GVL yield at high LA conversion (97.7%). The high activity and remarkable selectivity of the FA-assisted hydrogenation demonstrated its potential for a sustainable and self-sufficient integrated refining strategy of sugars to GVL, in which in situ formed FA can be employed as a bioderived reducing agent.