It was proved by ICP, fluorescence spectra and N 2 adsorption that the rare earth complex [C 5H 5NC 16H 33] [Eu(TTA) 4] is in the channel of Si-MCM-41 in the course of assembly. The rare earth complex of 67.9% is in t...It was proved by ICP, fluorescence spectra and N 2 adsorption that the rare earth complex [C 5H 5NC 16H 33] [Eu(TTA) 4] is in the channel of Si-MCM-41 in the course of assembly. The rare earth complex of 67.9% is in the channel, suggesting that the assembly of the complex molecular on the mesoporous MCM-41 was carried out mainly in the channel.展开更多
The nV‐MCM‐41 catalysts were prepared by one‐step hydrothermal synthesis and applied to the oxidative dehydrogenation of propane（ODHP） in the presence of CO2. Several state‐of‐the‐art char‐acterization method...The nV‐MCM‐41 catalysts were prepared by one‐step hydrothermal synthesis and applied to the oxidative dehydrogenation of propane（ODHP） in the presence of CO2. Several state‐of‐the‐art char‐acterization methods were performed to explore the correlation between catalytic performance and the physicochemical characterizations of the catalysts. Because moderate amounts of V species were introduced into the framework of MCM‐41, the catalyst maintained a large specific surface area, a highly ordered mesoporous structure, and highly dispersed V active sites（monomeric and dimeric V oxide species）, while the high‐vanadium‐doping catalysts caused an enhancement in the number of acidic sites and V2O5 crystallites. The ODHP reaction showed that the 6.8 V‐MCM‐41（V content 6.8 wt%） catalyst exhibits high activity and stability, and the C3H8/CO2 molar ratio（1：4） was suitable. The promoting effect of CO2 on the oxidative dehydrogenation of ODHP was demonstrated as the reaction coupling mechanism and ＂lattice oxygen＂ mechanism.展开更多
Surface organometallic chemistry (SOMC) is a recently developing research field. It is of great significance for the quantitative modification, restoration of solid surface, identification of the physical and chemical...Surface organometallic chemistry (SOMC) is a recently developing research field. It is of great significance for the quantitative modification, restoration of solid surface, identification of the physical and chemical nature of surface and the preparation of new catalyst. The production of R 3 Sn-O-MCM-41 (R 3 SnM) was obtained by heating tributyltin chloride and Al-MCM-41 mixture at 170 °C for 5 h under stirring in nitrogen atmosphere. The composition, structure and surface physical and chemical properties of the samples were characterized by inductively coupled plasma mass spectrometry (ICP-MS), 13 C, 119 Sn, 29 Si and 27 Al solid state NMR (nuclear magnetic resonance) spectra, in-situ pyridine infrared spectroscopy (Py-IR), N 2 adsorption-desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), etc. The results of ICP and organic elemental analysis shows that the grafting yield w Sn was 6.46% for R 3 SnM. H 0 (the negative logarithm of the acid concentration)and the number of acid sites for R 3 SnM respectively were 2.77-0.99 and 4.8 mmol·g-1 by the Hammett method. N 2 adsorption-desorption, XRD, TEM analysis showed that R 3 SnM with ordered hexagonal mesopore structure, resulted in the decease of surface areas and pore size as well as the increase of mesoporous volume and surface acidity, as compared to Al-MCM-41. R 3 SnM was used in the synthesis of isoamyl acetate. The yield of isoamyl acetate was 96% when n(isoamyl alcohol)︰n(acetic acid) 1.0︰1.0, 3 R SnM w 5%, 138 °C for 5 h. The catalyst can be reused and the yield of 86% can be attained when catalyst was reused five times at the same catalytic conditions.展开更多
文摘It was proved by ICP, fluorescence spectra and N 2 adsorption that the rare earth complex [C 5H 5NC 16H 33] [Eu(TTA) 4] is in the channel of Si-MCM-41 in the course of assembly. The rare earth complex of 67.9% is in the channel, suggesting that the assembly of the complex molecular on the mesoporous MCM-41 was carried out mainly in the channel.
文摘The nV‐MCM‐41 catalysts were prepared by one‐step hydrothermal synthesis and applied to the oxidative dehydrogenation of propane（ODHP） in the presence of CO2. Several state‐of‐the‐art char‐acterization methods were performed to explore the correlation between catalytic performance and the physicochemical characterizations of the catalysts. Because moderate amounts of V species were introduced into the framework of MCM‐41, the catalyst maintained a large specific surface area, a highly ordered mesoporous structure, and highly dispersed V active sites（monomeric and dimeric V oxide species）, while the high‐vanadium‐doping catalysts caused an enhancement in the number of acidic sites and V2O5 crystallites. The ODHP reaction showed that the 6.8 V‐MCM‐41（V content 6.8 wt%） catalyst exhibits high activity and stability, and the C3H8/CO2 molar ratio（1：4） was suitable. The promoting effect of CO2 on the oxidative dehydrogenation of ODHP was demonstrated as the reaction coupling mechanism and ＂lattice oxygen＂ mechanism.
基金Supported by the National Science Foundation of Heilongjiang Province (B201010)the Education Department of Heilongjiang Province (12511595)
文摘Surface organometallic chemistry (SOMC) is a recently developing research field. It is of great significance for the quantitative modification, restoration of solid surface, identification of the physical and chemical nature of surface and the preparation of new catalyst. The production of R 3 Sn-O-MCM-41 (R 3 SnM) was obtained by heating tributyltin chloride and Al-MCM-41 mixture at 170 °C for 5 h under stirring in nitrogen atmosphere. The composition, structure and surface physical and chemical properties of the samples were characterized by inductively coupled plasma mass spectrometry (ICP-MS), 13 C, 119 Sn, 29 Si and 27 Al solid state NMR (nuclear magnetic resonance) spectra, in-situ pyridine infrared spectroscopy (Py-IR), N 2 adsorption-desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), etc. The results of ICP and organic elemental analysis shows that the grafting yield w Sn was 6.46% for R 3 SnM. H 0 (the negative logarithm of the acid concentration)and the number of acid sites for R 3 SnM respectively were 2.77-0.99 and 4.8 mmol·g-1 by the Hammett method. N 2 adsorption-desorption, XRD, TEM analysis showed that R 3 SnM with ordered hexagonal mesopore structure, resulted in the decease of surface areas and pore size as well as the increase of mesoporous volume and surface acidity, as compared to Al-MCM-41. R 3 SnM was used in the synthesis of isoamyl acetate. The yield of isoamyl acetate was 96% when n(isoamyl alcohol)︰n(acetic acid) 1.0︰1.0, 3 R SnM w 5%, 138 °C for 5 h. The catalyst can be reused and the yield of 86% can be attained when catalyst was reused five times at the same catalytic conditions.
