| β分子筛中Brønsted酸分布及酸性强度的量子化学ONIOM 理论计算研究 |
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| 引用本文： | 孙秀良,黄崇品,陈标华. β分子筛中Brønsted酸分布及酸性强度的量子化学ONIOM 理论计算研究[J]. 化学学报, 2009, 67(22): 2549-2553 |
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| 作者姓名： | 孙秀良 黄崇品 陈标华 |
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| 作者单位： | (北京化工大学化工资源有效利用国家重点实验室 北京 100029) |
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| 基金项目： | 国家重点基础研究发展规划(973)(No.2004CB217804);;国家杰出青年科学基金(No.20625621)资助项目 |
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| 摘 要： | 基于量子化学ONIOM [B3LYP/6-31G(d,p):UFF]计算方法, 研究了β分子筛中Brønsted酸的落位及其酸性强度. 计算采用22T簇模型, 得到了不同酸性位的(Al, H)/Si替代能和质子亲和势. 研究结果表明, Brønsted酸最有可能落位在Al(8)-O(11)-Si(4), Al(8)-O(4)-Si(1), Al(7)-O(7)-Si(2)和Al(9)-O(6)-Si(3)位置. 根据去质化能的计算, Al(7)-O(7)-Si(2)位置的酸性最强, Al(8)-O(11)-Si(4)的酸性最弱. 酸性的强弱顺序为Al(7)-O(7)-Si(2)＞Al(9)-O(6)-Si(3)＞Al(8)-O(4)-Si(1)＞Al(8)-O(11)-Si(4).
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| 关 键 词： | β分子筛 Br?nsted酸 ONIOM |
| 收稿时间： | 2009-01-12 |
| 修稿时间： | 2009-05-10 |
Location and Acid Strength of Brønsted Acid Sites in β-Zeolite: a Quantum Chemical ONIOM Study |
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| Sun Xiuliang,Huang Chongpin,Chen Biaohua. Location and Acid Strength of Brønsted Acid Sites in β-Zeolite: a Quantum Chemical ONIOM Study[J]. Acta Chimica Sinica, 2009, 67(22): 2549-2553 |
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| Authors: | Sun Xiuliang Huang Chongpin Chen Biaohua |
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| Affiliation: | (State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029) |
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| Abstract: | A quantum chemical ONIOM [B3LYP/6-31G(d,p):UFF] method has been applied to study the distribution of Brønsted acid at nine inequivalent T sites and the acidity of Brønsted acid in β-zeolite. In the calculation, the structure of β-zeolite is represented by 22T cluster model. According to the calculated (Al, H)/Si substitution and proton affinity, it was proposed that most favorable sites for Brønsted acid are Al(8)-O(11)-Si(4), Al(8)-O(4)-Si(1), Al(7)-O(7)-Si(2), and Al(9)-O(6)-Si(3). The acidity of Al(7)-O(7)-Si(2) is the most highest in the preferable Brønsted acid sites, and Al(8)-O(11)-Si(4) site is the lowest. The order of acidity is Al(7)-O(7)-Si(2)＞Al(9)-O(6)-Si(3)＞Al(8)-O(4)-Si(1)＞Al(8)-O(11)-Si(4). |
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| Keywords: | ONIOM ONIOM |
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