| 王寒露,周建敏,周如金.H-ZSM-5催化环己酮肟制ε-己内酰胺反应机理的ONIOM研究[J].分子催化,2014,(4):376-383 |
| H-ZSM-5催化环己酮肟制ε-己内酰胺反应机理的ONIOM研究 |
| Reaction Mechanism of Cyclohexanone Oxime to ε-Caprolactam Catalyzed over H-ZSM-5 : An ONIOM Study |
| 投稿时间：2014-05-20 修订日期：2014-06-26 |
| DOI： |
| 中文关键词: 贝克曼重排 分子筛 密度泛函理论 反应速率常数 |
| 英文关键词:Beckmann Rearrangement Zeolites DFT functional Reaction Rate Constant |
| 基金项目:广东石油化工学院博士启动项目 |
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| 中文摘要: |
| 采用ONIOM和DFT方法研究了H-ZSM-5分子筛催化环己酮肟制ε-己内酰胺的贝克曼重排反应机理。所有的构型优化使用ONIOM(B3LYP/6-31+G(d) : PM3)方法进行，并在基础上对得到的最优构型应用多种密度泛度方法，如B3LYP/6-31+G(d)，PBE/6-31+G(d)，M062X/6-31+G(d)和ωB97XD/6-31+G(d)进行完整46T簇模型的单点能计算。B3LYP，PBE和M062X泛函使用dftd3程序计算了额外色散校正，以考虑分子筛内部的弱相互作用。计算结果显示，经色散校正的DFT方法的计算精度被大大提高，达到一个与MP2方法相媲美的精度。反应的决速步是由第一步1，2-H转移和重排步共同决定，内部反应能垒为44.5 kcal/mol。反应速率常数表明，在293 ~ 393 K时，在H-ZSM-5上贝克曼重排反应进行得相当缓慢；当温度达到423 K时，正逆反应速率相当，反应开始发生；当达到623 K时，反应速率常数为130 1/s。 |
| 英文摘要: |
| The Backman rearrangement reaction mechanism of cyclohexanone oxime to ε-caprolactam over the H-ZSM-5 zeolite was investigated by the ONIOM and DFT method. All geometry structures optimization were employed ONIOM (B3LYP/6-31+G(d) : PM3) method. Based on the optimal configuration, a high single point calculation of complete 46T cluster model were carried out by a variety of density functionals, such as B3LYP/6-31+G(d), PBE/6-31+G(d), M062X/6-31+G(d) and ωB97XD/6-31+G(d). Additional dispersion corrections were calculated by dftd3 program to describe the weak interaction in zeolites for B3LYP, PBE and M062X functionals. The calculation results showed, the precision of the DFT functionals for dispersion correction was greatly improved, which were comparable with the MP2 method. The rate determining step was the first step 1, 2-H shift and rearrangement step, and internal reaction energy barrier was 44.5 kcal/mol. The reaction rate constants indicated that the Beckman rearrangement reaction was very slowly on the H-ZSM-5 at 293 ~ 393 K. When the temperature reached 423 K, the forward and reverse reaction rate were about the same, and the reaction occurred. When reached 623 K, the reaction rate constant was 130 1/s. |
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