Carbon dioxide as both a selective agent and reaction media in the palladium-catalyzed Ullmann-type coupling has been described. The results showed that aryl chlorides could be easily activated in the presence of carb...Carbon dioxide as both a selective agent and reaction media in the palladium-catalyzed Ullmann-type coupling has been described. The results showed that aryl chlorides could be easily activated in the presence of carbon diox-ide and the chemoselectivity shifted toward the palladium-catalyzed Ullmann-type coupling reaction. In liquid car-bon dioxide, homocoupling reactions of aryl halides, including less reactive aryl chlorides, were carried out smoothly in moderate to good yields using Pd/C, zinc, and H2O as the catalytic system at room temperature.展开更多
A series of H-SAPO-34 zeolites were synthesized by a hydrothermal method in fluoride media.The as-synthesized H-SAPO-34 zeolites were characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,N_2 p...A series of H-SAPO-34 zeolites were synthesized by a hydrothermal method in fluoride media.The as-synthesized H-SAPO-34 zeolites were characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,N_2 physisorption,temperature-programmed desorption of NH_3（NH_3-TPD） and nuclear magnetic resonance（NMR） measurements.The results showed that a certain concentration of F- anions promoted the nucleation and crystallization of H-SAPO-34.The H-SAPO-34 synthesized in the fluoride media showed high crystallinity,uniform particle size distribution,large specific surface area and pore volume,and enhanced acidity.Therefore,Cu/SAPO-34 based on the fluoride-assisted zeolite showed a broadened temperature window for the selective catalytic reduction of NO by NH_3（NH_3-SCR） reaction due to the enhanced acidity of the zeolite and the improved dispersion of copper species.展开更多
基金the National Natural Science Foundation of China (No. 20202002), Hunan Province Department of Education (No. 02C211) and Hunan Normal University (2001).
文摘Carbon dioxide as both a selective agent and reaction media in the palladium-catalyzed Ullmann-type coupling has been described. The results showed that aryl chlorides could be easily activated in the presence of carbon diox-ide and the chemoselectivity shifted toward the palladium-catalyzed Ullmann-type coupling reaction. In liquid car-bon dioxide, homocoupling reactions of aryl halides, including less reactive aryl chlorides, were carried out smoothly in moderate to good yields using Pd/C, zinc, and H2O as the catalytic system at room temperature.
基金financial support by the Ministry of Science and Technology,China(No.2013AA065302)the National Natural Science Foundation of China(No.51372137)+1 种基金the State Key Laboratory of Solid Waste Reuse for Building Materials(No.SWR-2013-003)the financial support from the Strategic Emerging Industry Development Funds of Shenzhen(No.JCYJ20140417115840287)
文摘A series of H-SAPO-34 zeolites were synthesized by a hydrothermal method in fluoride media.The as-synthesized H-SAPO-34 zeolites were characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,N_2 physisorption,temperature-programmed desorption of NH_3（NH_3-TPD） and nuclear magnetic resonance（NMR） measurements.The results showed that a certain concentration of F- anions promoted the nucleation and crystallization of H-SAPO-34.The H-SAPO-34 synthesized in the fluoride media showed high crystallinity,uniform particle size distribution,large specific surface area and pore volume,and enhanced acidity.Therefore,Cu/SAPO-34 based on the fluoride-assisted zeolite showed a broadened temperature window for the selective catalytic reduction of NO by NH_3（NH_3-SCR） reaction due to the enhanced acidity of the zeolite and the improved dispersion of copper species.
