SYNTHESIS OF MESOPOROUS POLY(STYRENE-co-MALEIC ANHYDRIDE)/SILICA HYBRID MATERIALS VIA A NONSURFACTANT-TEMPLATED SOL-GEL PROCESS*

Mesoporous poly (styrene-co-maleic anhydride)/silica hybrid materials have been prepared. The synthesis wasachieved by the HCl-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS) and styrene-maleic anhydride copolymerin the presence of 3-aminopropyl triethoxysilane (APTES) as a coupling agent and citric acid as a nonsurfactant template orpore-forming agent, followed by ethanol extraction. Characterization results from nitrogen sorption isotherms and powder X-ray diffraction indicate that polymer-modified mesoporous materials with large specific surface areas (e.g. 900 m~2/g) andpore volumes (e.g. 0.6 cm~3/g) could be prepared. As the citric acid concentration is increased, the specific surface areas, porevolumes and pore diameters of the hybrid materials increase.     

非表面活性剂模板法合成甲基丙烯酰氧丙基修饰的有机/无机杂化中孔材料

1992年具六角规则孔道及窄孔径分布的ＭＣＭ 41中孔分子筛合成的报道[1,2 ] 激起了中孔材料的研究热潮 .近 3年来 ,用巯基[3 ,4 ] ,苯基[5] ,氨丙基[6] ,烯丙基[7] 和乙烯基[8] 等有机基团修饰的有机 无机杂化中孔材料的研究倍受瞩目 .这些杂化中孔材料兼有无机相的光学特性、热稳定性和有机相的韧性、反应性 ,可以进一步功能化应用于催化、金属离子提取[9] 及涂料[10 ] 等领域 .1 998年 ,Ｗｅｉ等[11] 首次采用葡萄糖、麦芽糖等非表面活性剂有机分子为模板 (或成孔剂 ) ,通过溶胶 凝胶过程合成出高比表面积、孔径可调且孔径分布窄的二氧化…     

One-step synthesis of hydrothermally stable mesoporous aluminosilicates with strong acidity

Using tetraethylorthosilicate (TEOS), polymethylhydrosiloxane (PMHS) and aluminium isopropoxide (AIP) as the reactants, through a one-step nonsurfactant route based on PMHS-TEOS-AIP co-polycondensation, hydrothermally stable mesoporous aluminosilicates with different Si/Al molar ratios were successfully prepared. All samples exclusively showed narrow pore size distribution centered at 3.6 nm. To assess the hydrothermal stability, samples were subjected to 100 °C distilled water for 300 h. The boiled mesoporous aluminosilicates have nearly the same N₂ adsorption-desorption isotherms and the same pore size distributions as those newly synthesized ones, indicating excellent hydrothermal stability. The ²⁹Si MAS NMR spectra confirmed that PMHS and TEOS have jointly condensed and CH₃ groups have been introduced into the materials. The ²⁷Al MAS NMR spectra indicated that Al atoms have been incorporated in the mesopore frameworks. The NH₃ temperature-programmed desorption showed strong acidity. Due to the existence of large amount of CH₃ groups, the mesoporous aluminosilicates obtained good hydrophobicity. Owing to the relatively large pore and the strong acidity provided by the uniform four-coordinated Al atoms, the excellent catalytic performance for 1,3,5-triisopropylbenzene cracking was acquired easily. The materials may be a profitable complement for the synthesis of solid acid catalysts.