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

ABSTRACT

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 m ² g ⁻¹ and mesopore volume of 0.49 cm ³ g ⁻¹ , the extruded cylindrical pellets are suitable as support material to be loaded with Pt ⁰ and to be used in fixed‐bed reactors. From a sustainable processes perspective, water was used as a solvent. For the H ₂ ‐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 mol _GVL h ⁻¹ mol _Pt ⁻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.