Direct synthesis of highly ordered large-pore functionalized mesoporous SBA-15 silica with methylaminopropyl groups and its catalytic reactivity in flavanone synthesis
Direct synthesis of highly ordered large-pore functionalized mesoporous SBA-15 silica with methylaminopropyl groups and its catalytic reactivity in flavanone synthesis
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DOI：
10.1016/j.micromeso.2005.06.019
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发表时间：
2005-11
影响因子：
5.2
通讯作者：
Xueguang Wang;Y. Tseng;J. Chan;S. Cheng
中科院分区：
文献类型：
--
作者：
Xueguang Wang;Y. Tseng;J. Chan;S. Cheng
以正硅酸乙酯（TEOS）和3-（甲氨基）丙基三甲氧基硅烷（MAPTMS）为原料，在酸性条件下，通过两亲性嵌段共聚物的共缩聚反应，合成了具有p6 mm对称性的功能化SBA-15介孔氧化硅材料。通过改变MAPTMS与TEOS的摩尔比，研究了初始合成混合物中MAPTMS的量对所得材料的介观结构性质的影响。X射线粉末衍射（XRD）和N2吸附结果表明，MAPTMS的加入量对介孔结构的有序性有影响。固态核磁共振（NMR），热重分析（TGA）和元素分析表明，在二氧化硅框架中的有机基团的掺入增加与MAPTMS的合成混合物中的浓度。在加入MAPTES之前的TEOS预水解对所得功能化介孔氧化硅材料的结晶有序性、孔径、比表面积和孔体积有很大影响。此外，无机盐的加入可以大大提高介孔材料的有序性和稳定性。在NaCl盐的辅助下，改性后的SBA-15材料在甲氨丙基含量达到2.37mmol/g时仍具有有序的介孔结构，比表面积达到200 m2 g − 1，孔容达到0.29cm3/g。在无溶剂条件下，改性SBA-15对取代苯乙酮和苯甲醛衍生物的Claisen-Schmidt缩合反应和随后的分子内Michael加成反应具有较高的催化活性和选择性。
Functionalized SBA-15 mesoporous silica materials with a p6mm symmetry have been synthesized through a simple co-condensation approach of tetraethylorthosilicate (TEOS) and (3-(methylamino)propyl)trimethoxysilane (MAPTMS) using amphiphilic block co-polymers under acidic conditions. The influence of the amount of MAPTMS in the initial synthesis mixture on the mesostructural properties of the resultant materials was studied by varying the molar ratios of MAPTMS to TEOS. X-ray powder diffraction (XRD) and N2sortpion results indicated that the ordering of the mesoporous structure was dependent on the amount of MAPTMS added in the initial mixture. Solid-state nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA) and elemental analysis showed that the incorporation of the organic groups in the silica framework increased with the MAPTMS concentration in the synthesis mixture. TEOS pre-hydrolysis prior to the addition of MAPTES had great influence on the crystallographic ordering, pore size, surface area and pore volume of the resultant functionalized mesoporous silica materials. Moreover, the addition of inorganic salt in the initial mixture could greatly enhance the mesostructure ordering and stability of the mesoporous materials. With the aid of NaCl salt, the modified SBA-15 materials with the content of methylaminopropyl groups up to 2.37mmol/g still possessed well-ordered mesoporous structure and had high specific area of 200m2g−1and pore volume of 0.29cm3/g. The modified SBA-15 showed high catalytic activities and selectivities toward flavanones synthesis through the Claisen–Schmidt condensation of substituted acetophenones and benzaldehyde derivatives and subsequent intramolecular Michael addition in the absence of solvent.