Design of Mesoporous Solid Acid Catalysts with Controlled Acid Strength
Design of Mesoporous Solid Acid Catalysts with Controlled Acid Strength
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DOI：
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发表时间：
2007
影响因子：
6.1
通讯作者：
J. Shon;Xingdong Yuan;C. Ko;H. Lee;S. S. Thakur-S.;M. Kang;M. Kang;Donghao Li;Jong‐Nam Kim;Ji Man Kim
中科院分区：
文献类型：
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作者：
J. Shon;Xingdong Yuan;C. Ko;H. Lee;S. S. Thakur-S.;M. Kang;M. Kang;Donghao Li;Jong‐Nam Kim;Ji Man Kim
采用共缩合法和后接枝法成功地制备了具有强酸（-SO 3 H）、弱酸（-PO 3 H2）和弱酸（-COOH）功能的介孔氧化硅材料SBA-15。透射电子显微镜和粉末X射线衍射表明，所有的酸官能化的SBA-15材料具有高度有序的介观结构。并将其应用于苯酚与叔丁醇的烷基化反应。酸强度以及反应参数，如温度，空速，反应物之间的摩尔比，被发现是控制烷基化反应的反应性和选择性的主要因素。SBA-15-SO_3H和SBA-15-PO_3H_2具有比SBA-15-COOH高得多的催化活性。烷基化反应的产物选择性强烈地依赖于酸强度以及反应温度。SBA-15-SO 3 H在高温下对4-叔丁基苯酚和2，4-二叔丁基苯酚具有较高的选择性，而SBA-15-PO 3 H2在中温下对2-叔丁基苯酚具有较高的选择性。在SBA-15-COOH催化剂上，在相对低的反应温度下观察到醚。
Mesoporous silica materials, SBA-15, functionalized with strong (-SO3H), moderate (-PO3H2) and weak (-COOH) acid groups have been successfully prepared by the co-condensation or post-grafting methods. Transmission electron microscopy and powder X-ray diffraction indicate that all of the acid-functionalized SBA-15 materials possess highly ordered mesostructures. These mesoporous acid catalysts have been applied to the alkylation of phenol with tert-butanol. The acid strength as well as the reaction parameters, such as the temperature, space velocity, and molar ratio between the reactants, were found to be the main factors controlling the reactivity and selectivity of the alkylation reaction. SBA-15-SO3H and SBA-15-PO3H2 exhibited much higher catalytic activities than SBA-15-COOH. The product selectivity of alkylation reaction strongly depends on the acid strength as well as the reaction temperature. The SBA-15-SO3H revealed high selectivity for 4-tert-butyl phenol and 2,4-di-tert-butyl phenol at high temperature, whereas the SBA-15-PO3H2 did so for 2-tert-butyl phenol at moderate temperature. Ether was observed at a relatively low reaction temperature over the SBA-15-COOH catalyst.