Hybrid organic-inorganic xerogel access to meso- and microporous silica by thermal and chemical treatment
Hybrid organic-inorganic xerogel access to meso- and microporous silica by thermal and chemical treatment
复制标题
通过热处理和化学处理获得介孔和微孔二氧化硅的杂化有机-无机干凝胶
DOI：
10.1021/cm980519i
复制
发表时间：
1999
影响因子：
8.6
通讯作者：
Michel Wong Chiman
中科院分区：
文献类型：
--
作者：
B. Boury;P. Chevalier;R. Corriu;P. Delord;A. Moreau;Michel Wong Chiman
以相应的前驱体(H3CO)3Si−C⋮C−(CH2)n−C⋮C−(CH2)3为原料，在四氢呋喃中通过Sol−凝胶缩聚反应制备了通式为(O)1，5Si−C⋮C−(CH2)n−C⋮C−Si(O)1，5的杂化干凝胶。在2.0%氟化铵存在下，用甲醇和水对杂化干凝胶进行处理。对于2<；n<；4，定量地实现了有机间隔物的消除，并且以高产率回收了有机间隔物。对于n=5、6和8，增加间隔物的长度导致该化学处理的效率降低。还对杂化干凝胶进行了600−、680℃的热氧化，并在所有情况下消除了有机间隔基。用n=2−4对干凝胶进行化学处理，得到孔径分布较窄的介孔二氧化硅；在680℃下对干凝胶进行热处理，得到微孔二氧化硅。
Hybrid xerogels of general formula (O)1,5Si−C⋮C−(CH2)n−C⋮C−Si(O)1,5 were prepared by sol−gel polycondensation in THF of the corresponding precursors (H3CO)3Si−C⋮C−(CH2)n−C⋮C−Si(OCH3)3, without catalyst. Treatment of the hybrid xerogels was with methanol and water in the presence of 2.0% of ammonium fluoride as catalyst. For 2 < n < 4, elimination of the organic spacer was quantitatively achieved and the organic spacer was recovered in high yield. For n = 5, 6, and 8, increasing the length of the spacer results in a decreasing efficiency of this chemical treatment. Thermal oxidation at 600−680 °C of the hybrid xerogels was also performed and elimination of the organic spacer was obtained in all the cases. Mesoporous silica with a narrow pore-size distribution was obtained by chemical treatment of the xerogel with n = 2−4. Microporous silica was obtained by thermal treatment of the xerogel at 680 °C. All the materials were characterized by SAXS, BET, and spectroscopy analysis.