Ying Duan,Chi Zhang,Dongsheng Deng,Dong Sui,Xiaohan Gao,Yanliang Yang
The rearrangement of furan rings for valuable chemicals is an important topic for biomass conversion. In this study, 2,5-di(hydroxymethyl)furan (BHMF) was selectively converted to 6-methyldihydro-2H-pyran-3(4H)-one (MDPO) and 1-hydroxy-2,5-hexanedione (HHD) under atmospheric H2 pressure in water. The selectivity to MDPO or HHD could be regulated by a catalyst. The parameters (temperature, pH, catalyst loading, and BHMF concentration) for the transformation of BHMF were studied. The selectivity for the transformation of BHMF was very sensitive to the reaction conditions, especially for the conversion of BHMF to MDPO. 68% selectivity to MDPO on Pd/C and 72% selectivity to HHD on Rh/C were achieved under the optimized conditions. Both Pd/C and Rh/C could be reused at least 5 times without the loss of activity. The fresh and used Pd/C and Rh/C were characterized by XRD, XPS, SEM, TEM, EDS mappings and ICP-OES to study the changes during the reaction. The reaction process was studied through controlled experiments, and 6-methylene-2H-pyran-3(6H)-one (MEPO) and 6-hydroxy-6-methyl-2H-pyran-3(6H)-one (HMPO) were identified as intermediates. A reasonable reaction mechanism was proposed and the different selectivity to MDPO and HHD was well explained based on the controlled experiments and DFT calculations. The conditional sensitivity for the selectivity to MDPO and HHD could also be interpreted by the proposed reaction pathway.
Graphical In the reaction zone : Benefiting from the presence of the secondary porosity and the appropriately acidity, the hierarchically structured ZSM-5 (HSZ) catalysts exhibited the excellent catalytic performance for the conversion of 2,5-bis(hydroxymethyl)furan (BHMF) to 2,5-bis(ethoxymethyl)furan (BEMF) in a continuous fixed bed reactor. The highest yield of BEMF (90.46 %) was obtained over the HSZ-150 catalyst under the reaction condition of 140 °C, 2.0 MPa of H 2 , and 0.3 h −1 of WHSV. The selective conversion of 2,5-bis(hydroxymethyl)furan (BHMF) to 2,5-bis(ethoxymethyl)furan (BEMF) was investigated in a fixed bed reactor over several heterogeneous solid acid catalysts, including Amberlyst-15, ZSM-5, Mordenite, and a series of hierarchically structured ZSM-5 zeolites (HSZ). The HSZ catalysts exhibited superior catalytic performance to other three commercial catalysts. The highest yield of BEMF (90.46 %) was obtained over the HSZ-150 catalyst under the reaction condition of 140 °C, 2.0 MPa of H 2 , and 0.3 h −1 of WHSV. Moreover, the HSZ-150 catalyst displayed an extremely good stability in the etherification reaction, maintaining more than 80 % yield of BEMF for about 80 h. The outstanding catalytic performance of the HSZ-150 catalyst could be ascribed to that the presence of mesopores enhanced the etherification activity by alleviating the diffusion limitation, and the appropriate acidity improved the BEMF selectivity via suppressing the side reactions.
Wang Huiqiang,Fang Shengqiong,Zuo Miao,Li Zheng,Yu Xin,Tang Xing,Sun Yong,Yang Shuliang,Zeng Xianhai,Lin Lu
Removal of copper ions (Cu(II)) efficiently from water is crucial for water environment security. We use sustainable, low-cost, renewable cellulose derivatives (carboxymethylcellulose sodium (CMC-Na)) and polyvinyl alcohol (PVA) as the matrix, and cellulose nanocrystals (CNCs) as the functional addition. The CNC/CMC-Na/PVA hydrogel was prepared by the physical cross-linking method. Static adsorption experiments proved that CNC/CMC-Na/PVA hydrogel has a greater adsorption potential (108 mg/g) towards Cu(II). At the same time, the adsorption of Cu(II) on CNC/CMC-Na/PVA hydrogels is spontaneous and endothermic, and obeys the pseudo-second-order model with intra-particle diffusion. Furthermore, the primary adsorption mechanisms had been electrostatic attraction and surface complexation. Importantly, CNC/CMC-Na/PVA hydrogel has efficient absorbability and preferable reusability in actual water samples. Furthermore, the copper nanoparticles (Cu NPs) adsorbed on the surface of CNC/CMC-Na/PVA hydrogels were reduced with NaBH 4 in situ to realize the secondary utilization in CNC/CMC-Na/PVA hydrogels supported by Cu NPs. It is found that the material can be used as a catalyst to efficiently catalyze the conversion of HMF to BHMF (99%). Consequently, we provide insights into the hydrogel preparation that would possibly be promising novel adsorbents for the elimination of heavy-ion from sustainable water purification. Graphical abstract
危险品化学品经营许可证（带存储）