Preparation of porous acidic oxides from group 13 element-containing oligosilsesquioxanes
Preparation of porous acidic oxides from group 13 element-containing oligosilsesquioxanes
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由含13族元素低聚倍半硅氧烷制备多孔酸性氧化物
DOI：
10.1627/jpi.45.15
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发表时间：
2002
影响因子：
1
通讯作者：
T. Mitsudo
中科院分区：
文献类型：
--
作者：
K. Wada;Koichi Yamada;T. Kondo;T. Mitsudo
在823K左右煅烧新合成的含13组元素的硅氧烷PhB[(Me3SiO) (c-C5H9)7Si7O11] 1和[PPN]+{Ga[(Me3SiO)(c-C5H9)7Si7O11]2}-3b，以及[HNEt3]+{Al[(Me3SiO)(c-C5H9)7Si7O11]2}-2, [HNEt3]+{Ga[(Me3SiO)(c-C5H9)7Si7O11]2}-3a和[C14H18N2H]+[(c-C5H9)7Si7O12GaCl]-4，生成的酸性氧化物具有较高的BET比330-520m2g-1和均匀控制的5.1A直径的微孔。对这些氧化物的详细研究表明，13族元素和反阳离子的存在对孔结构的影响不大。然而，硅氧烷前体的结构对其酸性有很大的影响，部分受13族元素和反阳离子的控制。特别是2、3a和3b的氧化物具有较高的BET表面积和大量的酸性位点。3a的氧化物具有较强的酸性位点，而2和3b的氧化物具有弱和中等强度的酸性位点。4的氧化物表面没有明显的酸性。与前驱体结构密切相关的13族元素氧化物在硅基中分散的差异，被认为是造成酸性特征差异的部分原因。
The controlled calcination of newly-synthesized group 13 element-containing silsesquioxanes, PhB[(Me3SiO) (c-C5H9)7Si7O11] 1 and [PPN]+{Ga[(Me3SiO)(c-C5H9)7Si7O11]2}-3b, as well as [HNEt3]+{Al[(Me3SiO)(c-C5H9)7Si7O11]2}-2, [HNEt3]+{Ga[(Me3SiO)(c-C5H9)7Si7O11]2}-3a, and [C14H18N2H]+[(c-C5H9)7Si7O12GaCl]-4 at around 823K produces acidic oxides with high BET surface areas of 330-520m2g-1 and uniformly-controlled micropores of 5.1A diameter. Detailed investigation of these oxides revealed that the pore structures are not greatly influenced by the presence of the group 13 elements and counter cations. However, the acidic properties are greatly affected by the structure of the silsesquioxane precursors, and partly controlled by the group 13 elements and counter cations. In particular, oxides from 2, 3a and 3b were found to have high BET surface areas and large numbers of acidic sites. The oxides from 3a have relatively strong acidic sites, whereas oxides from 2 and 3b have weak and moderate strength acidic sites. The oxides from 4 do not show significant surface acidity. Differences in the dispersion of the oxides of group 13 elements in the silica matrixes, which are closely related to the structure of precursors, are considered partly account for the differences in acidic character.