Yafei Li,Boyang Liu,Yu Wang,Shiqing Wang,Xiaocheng Lan,Tiefeng Wang
It is important but challenging to develop non-noble metal catalysts with high activity and selectivity for biomass conversion. The activation of C═O bond is a crucial step in biomass upgradation. Herein, a series of Ni-xP/Al2O3 catalysts with different P/Ni molar ratios were prepared for the conversion of ethyl levulinate to γ-valerolactone. The developed Ni-0.38P/Al2O3 catalyst was 5.4 times more active than conventional Ni/Al2O3 based on turnover frequency and significantly outperformed the state-of-the-art non-noble metal catalysts. The unique catalytic performance was ascribed to the formation of Ni3P phase, which was identified by several characterizations. The results of DFT calculation and characterization by XPS and CO-FTIR revealed that electron was transferred from Ni to P with the formation of Niδ+ sites. In situ FTIR for the surface reaction indicated that Niδ+ acted as a new active site to activate the C═O bond, which rendered the high intrinsic activity of Ni3P for the C═O hydrogenation of EL.
The catalytic ethanolysis of microcrystalline cellulose in supercritical ethanol is examined over a sulfonated hydrothermal carbon catalyst (SHTC). SHTC is amorphous carbon containing −OH, −COOH and −SO 3 H groups with total acidity of 7.15 mmol/g and −SO 3 H acidity of 1.72 mmol/g. SHTC shows high catalytic activity towards the ethanolysis of cellulose in supercritical ethanol. Complete conversion of microcrystalline cellulose with high yields of ethyl levulinate and ethyl glucoside is obtained. The reaction temperature, time and catalyst amount have significant effects on the catalytic performances of SHTC. Appropriate reaction time and less catalyst amount are favorable for the production of ethyl glucoside, while prolonged reaction time and appropriate catalyst amount favor the production of ethyl levulinate. The highest yield of ethyl glucoside as 420.9 mg/g cellulose is obtained over 0.1 g SHTC at 245 ºC for 1 h. The highest yield of ethyl levulinate as 817.6 mg/g cellulose is achieved over 0.3 g SHTC at 245 ºC for 1 h. SHTC shows good stability in the recycle experiments with slight loss of catalytic activity.
He Xiangyan,Liu Huai,Wang Yue,Peng Lincai,Zhang Junhua
Effective structural design can make the catalyst have higher specific surface area and dispersed active sites, thus endowing the catalyst higher catalytic efficiency. In this work, magnetic nitrogen-doped carbon nanotube (CNT) was introduced as the support to immobilize the zirconium-based biomass-derived hybrid (Zr-FDCA) through solvothermal method, in which specific surface area had significantly increased to improve the dispersibility of zirconium, thus improving the adsorption over the catalyst to ethyl levulinate (EL). In addition, the introduced nitrogen served as the basic sites to boost the proton transfer in catalytic transfer hydrogenation (CTH) reaction. As a result, the prepared Zr-FDCA@CNT exhibited an ideal catalytic performance in CTH of EL into γ-valerolactone. Gratifyingly, Zr-FDCA@CNT also showed magnetism and good reusability, which could be easily separated from the reaction mixture and no significant loss in the activity after reuse for four runs. Graphical Abstract
Schematic for CTH of EL over Zr-FDCA@CNT
Xing Tang,Huawei Chen,Lei Hu,Weiwei Hao,Yong Sun,Xianhai Zeng,Lu Lin,Shijie Liu
A series of low-cost readily-assembled eco-friendly metal hydroxides were examined as catalysts in the synthesis of a novel platform molecule, γ-valerolactone (GVL), from biomass-derived ethyl levulinate (EL) via hydrogen transfer reaction. Among these catalysts, ZrO(OH) 2 · x H 2 O was found to be most active. EL conversion of 93.6% and GVL selectivity of 94.5% were achieved when 2-propanol was used as a hydrogen donor at 473 K with a reaction time of only 1 h. The complete reaction pathway and the probable main by-products for the conversion of EL to GVL were clearly deduced for the first time. The ZrO(OH) 2 · x H 2 O catalyst could be reused at least ten times without any significant loss of catalytic activity. Furthermore, characterizations were carried out on the fresh and spent ZrO(OH) 2 · x H 2 O catalysts with XRD, FT-IR, BET, TGA-DTA. Combined with the results of poisoning experiments, a plausible mechanism for catalytic transfer hydrogenation (CTH) of EL to GVL was proposed to be consisted of a catalytic cycle involving a six member ring transition state.
危险品化学品经营许可证（带存储）