The Zn-Cu(I)/HMCM-41 catalysts were successfully prepared in laboratory scale by solid-state ion exchange with CuCl salt, together with introduction of Zn to improve the dispersion degree of the active component Cu(I)...The Zn-Cu(I)/HMCM-41 catalysts were successfully prepared in laboratory scale by solid-state ion exchange with CuCl salt, together with introduction of Zn to improve the dispersion degree of the active component Cu(I) on the surface. With increase of the amounts of Zn and CuCl from 0% to 9.0% and 25.0% respectively, CO adsorption the amounts of increased from 10.6 mmol/g to 183.0 mmol/g correspondingly. The in situ FT-IR spectra for CO adsorption demonstrated that there existed two dynamic equilibriums between surface carbonyl complexes: Cu(CO)3+ Cu(CO)2++ CO and Cu(CO)2+ Cu(CO)+ + CO. The equilibriums can be shifted reversibly by changing the temperature and pressure. Due to the modified MCM-41 mesoporous materials possess both of the acidic and metallic carbonyl centers, this kind of material can be developed into mesoporous bifunctional catalysts for carbonylation reactions, in which larger molecules are involved.展开更多
RECENTLY a new family of mesoporous molecular sieves,M41S,was reported by researchers atMobil R&D Corporation.As a member of the family,MCM-41,which exhibits a hexagonalarray of uniform channel mesopores,has been ...RECENTLY a new family of mesoporous molecular sieves,M41S,was reported by researchers atMobil R&D Corporation.As a member of the family,MCM-41,which exhibits a hexagonalarray of uniform channel mesopores,has been synthesized.The channel size can be variedfrom approximately 1.5 nm to greater than 10 nm by choosing different surfactants,auxiliarychemicals(1,3,5-trimethylbenzene)in the reactant,and by changing the reaction condi-tions.The wall thickness of this kind of molecular sieve is in the range of 0.3 to 1.3 nm esti-展开更多
Eu(TTA)4C5H5NC16H33(TTA:1-(2-Thenoy)-3,3,3-Trifluoracetate) is encapsulated in St- MCM-41 modified with N-(3-Trimethoxysilethyl)ethylene. The emission spectrum of the assembly shows only a 5D0-7F2 transition. As comp...Eu(TTA)4C5H5NC16H33(TTA:1-(2-Thenoy)-3,3,3-Trifluoracetate) is encapsulated in St- MCM-41 modified with N-(3-Trimethoxysilethyl)ethylene. The emission spectrum of the assembly shows only a 5D0-7F2 transition. As compared with the rare earth complex itself, the lifetime of the assembly becomes longer and its stability under the UV radiation is much better.展开更多
Three types of MCM-41 absorbents, namely, Al^（3＋）-MCM-41, La^（3＋）-MCM-41, and Zn^（2＋）-MCM-41, were prepared through amine grafting, phosphonate modification, and metal ion chelation and characterized by Fouri...Three types of MCM-41 absorbents, namely, Al^（3＋）-MCM-41, La^（3＋）-MCM-41, and Zn^（2＋）-MCM-41, were prepared through amine grafting, phosphonate modification, and metal ion chelation and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and N2adsorption-desorption analysis. Results revealed that functionalized MCM-41 maintains the original structure of the molecular sieve and that the pore diameter and surface area are reduced compared with those of pure MCM-41. The adsorption behavior of DNA molecules on the surface of the modified molecular sieves was discussed according to the hard-soft acid-base（HSAB） principle. Experimental results showed that DNA purification could be effectively carried out on functionalized MCM-41 and that DNA is easily released by3-4 molL^（-1）NaCl solution. This study could be used as a general platform for future work on DNA adsorption and enrichment.展开更多
文摘The Zn-Cu(I)/HMCM-41 catalysts were successfully prepared in laboratory scale by solid-state ion exchange with CuCl salt, together with introduction of Zn to improve the dispersion degree of the active component Cu(I) on the surface. With increase of the amounts of Zn and CuCl from 0% to 9.0% and 25.0% respectively, CO adsorption the amounts of increased from 10.6 mmol/g to 183.0 mmol/g correspondingly. The in situ FT-IR spectra for CO adsorption demonstrated that there existed two dynamic equilibriums between surface carbonyl complexes: Cu(CO)3+ Cu(CO)2++ CO and Cu(CO)2+ Cu(CO)+ + CO. The equilibriums can be shifted reversibly by changing the temperature and pressure. Due to the modified MCM-41 mesoporous materials possess both of the acidic and metallic carbonyl centers, this kind of material can be developed into mesoporous bifunctional catalysts for carbonylation reactions, in which larger molecules are involved.
文摘RECENTLY a new family of mesoporous molecular sieves,M41S,was reported by researchers atMobil R&D Corporation.As a member of the family,MCM-41,which exhibits a hexagonalarray of uniform channel mesopores,has been synthesized.The channel size can be variedfrom approximately 1.5 nm to greater than 10 nm by choosing different surfactants,auxiliarychemicals(1,3,5-trimethylbenzene)in the reactant,and by changing the reaction condi-tions.The wall thickness of this kind of molecular sieve is in the range of 0.3 to 1.3 nm esti-
文摘Eu(TTA)4C5H5NC16H33(TTA:1-(2-Thenoy)-3,3,3-Trifluoracetate) is encapsulated in St- MCM-41 modified with N-(3-Trimethoxysilethyl)ethylene. The emission spectrum of the assembly shows only a 5D0-7F2 transition. As compared with the rare earth complex itself, the lifetime of the assembly becomes longer and its stability under the UV radiation is much better.
基金supported by the National Natural Science Foundation of China (No. 21205070)the Outstanding Youth Scientist Research Foundation of Shandong Province (No. 2007BS02003)
文摘Three types of MCM-41 absorbents, namely, Al^（3＋）-MCM-41, La^（3＋）-MCM-41, and Zn^（2＋）-MCM-41, were prepared through amine grafting, phosphonate modification, and metal ion chelation and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and N2adsorption-desorption analysis. Results revealed that functionalized MCM-41 maintains the original structure of the molecular sieve and that the pore diameter and surface area are reduced compared with those of pure MCM-41. The adsorption behavior of DNA molecules on the surface of the modified molecular sieves was discussed according to the hard-soft acid-base（HSAB） principle. Experimental results showed that DNA purification could be effectively carried out on functionalized MCM-41 and that DNA is easily released by3-4 molL^（-1）NaCl solution. This study could be used as a general platform for future work on DNA adsorption and enrichment.
