An effective strategy is proposed here for transfer hydrogenation of alkyl levulinate to γ-valerolactone (GVL) using a UiO-66 framework modified with phosphotungstate ionic liquid (UiO-66@IL(HPW)). Due to the intensive influence of ionic liquid fragment, the modification significantly enhances the catalytic activity of UiO-66@IL(HPW), leading to a complete conversion of ethyl levulinate with over 93.1% selectivity for GVL. Characterizations techniques, including XRD, N 2 absorption/desorption, SEM, FT-IR, pyridine FT-IR, NH 3 -TPD and CO 2 -TPD, confirm that while the basic structure of UiO-66-NH 2 is insignificantly changed, the introduction of the ionic liquid greatly improves the acidic/base properties of the catalyst. XAFS and XPS results reveal an intensive interaction between the N and W species in UiO-66@IL(HPW), and the formed W-N/O moiety is responsible for the enhanced catalytic activity. In addition, a plausible catalytic mechanism is proposed based upon in situ DRIFTS and density functional theory (DFT) calculations, highlighting the crucial role of ionic liquid fraction within the UiO-66 ligand. Therefore, this work would contribute to the valorization of biochemicals.
Gong Chen,Wei Junnan,Tang Xing,Zeng Xianhai,Sun Yong,Lin Lu
Biomass-derived levulinic acid (LA) and its esters are currently envisaged as versatile, renewable platform chemicals. In this study, cellulosic pulp derived from the cooking of lignocellulosic biomass with active oxygen and solid alkali was employed as raw material for the formation of LA or ethyl levulinate (EL). This pretreatment process is highly effective for the delignification and deconstruction of lignocellulose matrix, making a facile degradation of the resulting cellulosic pulp to LA or EL. At this point, the acid-catalyzed hydrolysis or ethanolysis of cellulosic pulp was optimized by response surface methodology (RSM), offering desirable LA yield of 65.3% or EL yield of 62.7%, which is significantly higher than those obtained from raw biomass. More importantly, coking behavior on the inwall of the reactor was eliminated during the hydrolysis or ethanolysis of cellulosic pulp, which is one of the top challenges for the acid-catalyzed conversion of biomass in an industrial scale.
危险品化学品经营许可证（带存储）