Highly ordered amino-functionalized hexagonal mesoporous silica （HMS-NH2） had been synthesized successfully by co-condensation. The resultant materials were characterized by means of XRD, TEM, FT-IR, N2 ad-desorptio...Highly ordered amino-functionalized hexagonal mesoporous silica （HMS-NH2） had been synthesized successfully by co-condensation. The resultant materials were characterized by means of XRD, TEM, FT-IR, N2 ad-desorption and 29Si NMR to confirm the ordered mesoporous structure and the functionalization of the amino groups. The sample was employed as a Pb2＋ adsorbent in aqueous solutions at room temperature. Both Lagergren＇s first order kinetic model and Lagergren＇s second order kinetic model were used to describe the adsorption data. It was found that the pseudo second order model fitted the sorption kinetic data better than the pseudo first order model. According to the information analyzed from AAS, HMS-NH2 had a Pb2＋ adsorption amount of over 90.7 mg·g-1 , showing a promising application for the treatment of wastewater containing Pb2＋ ions.展开更多
An imidazole modified mesoporous material has been prepared through a co-condensation procedure and adopted to covalently anchor chiral Mn(Ⅲ) salen complex. The active centers in the as-synthesized catalyst were pres...An imidazole modified mesoporous material has been prepared through a co-condensation procedure and adopted to covalently anchor chiral Mn(Ⅲ) salen complex. The active centers in the as-synthesized catalyst were presented in the form of ionic species. The results of XRD, FTIR, DRUV-Vis, and N2 sorp-tion confirmed the successful immobilization of chiral Mn(Ⅲ) salen complex inside the channels of the modified support and the maintenance of the mesoporous structure of parent support in the immobi-lized catalyst. This heterogeneous catalyst exhibited comparable catalytic activity and enantioselectiv-ity to those of the homogeneous counterpart in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, notably high turnover frequencies have been obtained over this heterogeneous catalyst for the relatively short reaction time and low catalyst amount, due in part to the ionic property as well as the uniform distribution of the active centers.展开更多
The hydrolytic co-condensation of hydrophobic phenyltriethoxysilane （PTES） and hydrophilic γ-aminopropyltriethoxysilane （APS） was investigated in toluene and water by using hydrochloric acid （HCl） catalyst. A s...The hydrolytic co-condensation of hydrophobic phenyltriethoxysilane （PTES） and hydrophilic γ-aminopropyltriethoxysilane （APS） was investigated in toluene and water by using hydrochloric acid （HCl） catalyst. A soluble and meltable poly（aminopropyl/phenylsilsesquioxane） （PAPSQ） was formed by controlling HCl amounts, APS/PTES molar ratios, water/silane molar ratios （Rw/si）, organic co-solvents and re-equilibration steps as well. The compositions of PAPSQ bearing aminopropyl and phenyl groups with the capping of trimethylsilyl group were confirmed by element analysis, fourier-transform infrared spectroscopy （FT-IR）, nuclear magnetic resonance （NMR） and thermogravimetric analysis （TGA）. Differential scanning calorimetry （DSC） was employed to characterize the melting behavior of the product. PAPSQ can be easily employed as functional molecular building blocks for the synthesis of diverse and novel inorganic-organic materials.展开更多
基金Project supported by the National Natural Science Foundation of China （Nos. 50732003, U0834003） and High Technology Study Plan of China （Nos. 2007AA021908, 2006AA03Z356）.
文摘Highly ordered amino-functionalized hexagonal mesoporous silica （HMS-NH2） had been synthesized successfully by co-condensation. The resultant materials were characterized by means of XRD, TEM, FT-IR, N2 ad-desorption and 29Si NMR to confirm the ordered mesoporous structure and the functionalization of the amino groups. The sample was employed as a Pb2＋ adsorbent in aqueous solutions at room temperature. Both Lagergren＇s first order kinetic model and Lagergren＇s second order kinetic model were used to describe the adsorption data. It was found that the pseudo second order model fitted the sorption kinetic data better than the pseudo first order model. According to the information analyzed from AAS, HMS-NH2 had a Pb2＋ adsorption amount of over 90.7 mg·g-1 , showing a promising application for the treatment of wastewater containing Pb2＋ ions.
基金Supported by the National Natural Science Foundation of China (Grant No. 20773069)the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 200800551017)
文摘An imidazole modified mesoporous material has been prepared through a co-condensation procedure and adopted to covalently anchor chiral Mn(Ⅲ) salen complex. The active centers in the as-synthesized catalyst were presented in the form of ionic species. The results of XRD, FTIR, DRUV-Vis, and N2 sorp-tion confirmed the successful immobilization of chiral Mn(Ⅲ) salen complex inside the channels of the modified support and the maintenance of the mesoporous structure of parent support in the immobi-lized catalyst. This heterogeneous catalyst exhibited comparable catalytic activity and enantioselectiv-ity to those of the homogeneous counterpart in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, notably high turnover frequencies have been obtained over this heterogeneous catalyst for the relatively short reaction time and low catalyst amount, due in part to the ionic property as well as the uniform distribution of the active centers.
基金Funded by the National Natural Science Foundation of China (No.20574020, No.10676009)
文摘The hydrolytic co-condensation of hydrophobic phenyltriethoxysilane （PTES） and hydrophilic γ-aminopropyltriethoxysilane （APS） was investigated in toluene and water by using hydrochloric acid （HCl） catalyst. A soluble and meltable poly（aminopropyl/phenylsilsesquioxane） （PAPSQ） was formed by controlling HCl amounts, APS/PTES molar ratios, water/silane molar ratios （Rw/si）, organic co-solvents and re-equilibration steps as well. The compositions of PAPSQ bearing aminopropyl and phenyl groups with the capping of trimethylsilyl group were confirmed by element analysis, fourier-transform infrared spectroscopy （FT-IR）, nuclear magnetic resonance （NMR） and thermogravimetric analysis （TGA）. Differential scanning calorimetry （DSC） was employed to characterize the melting behavior of the product. PAPSQ can be easily employed as functional molecular building blocks for the synthesis of diverse and novel inorganic-organic materials.
