Conversion of ethyl levulinate to γ-valerolactone catalyzed by Pd/UiO-66-NH2

Conversion of ethyl levulinate to GVL was proposed using Pd 4 /UiO-66-NH 2 . • Pd 4 /UiO-66-NH 2 was constructed via a post-synthetic modification strategy. • Synergistic effects between Pd species and acidic sites drive superior performance. • GVL yield of 90% with 98.9% selectivity was achieved under 170 ℃ and 1.0 MPa H 2 . • The catalyst shows good recyclability, and can be reused for at least five runs. An efficient strategy is proposed for direct hydrogenation of ethyl levulinate (EL) to γ-valerolactone (GVL) using a highly dispersed palladium nanoparticles supported on the UiO-66-NH 2 framework (Pd/UiO-66-NH 2 ), which was prepared via a facile post-synthetic modification by anchoring palladium (Pd) nanoparticles on the framework's native -NH 2 groups. Under optimized conditions (170 °C, 1.0 MPa H 2 ), 90% yield and 98.9% selectivity of GVL were shown when the reaction was catalyzed by Pd 4 /UiO-66-NH 2 in cyclohexane. Catalyst characterization using XRD, N 2 adsorption-desorption, FT-IR, TEM, TGA, XPS and H 2 -TPR, confirmed that an intensive synergistic effect existed between the Pd and the acidic sites, which is responsible for the superior performance of Pd@UiO-66-NH 2 . The solvent effect and the feedstock adaptability were also investigated. Furthermore, the catalyst of Pd 4 /UiO-66-NH 2 demonstrated good stability and reusability, where no significant activity loss was shown even after five consecutive cycles. Therefore, this study provides new insights for efficient upgrading biochemical. Download: Download high-res image (188KB) Download: Download full-size image