• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Ab Initio Unimolecular Reaction Kinetics of CH2C(=O)OCH3 and CH3C(=O)OCH2 Radicals
【24h】

Ab Initio Unimolecular Reaction Kinetics of CH2C(=O)OCH3 and CH3C(=O)OCH2 Radicals

机译：CH2C（= O）OCH3和CH3C（= O）OCH2自由基的从头算单分子反应动力学

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The unimolecular dissociation and isomerization kinetics of the methyl ester combustion intermediates methoxycarbonylmethyl (CH2C(=O)OCH3) and acetyloxylmethyl (CH3C(=O)OCH2) are theoretically investigated using high-level ab initio methods and the Rice-Ramsperger-Kassel-Marcus (RRKM)/master equation (ME) theory. Potential energy surfaces (PESs) are obtained using coupled cluster singles and doubles with perturbative triples correction (CCSD(T)), multireference singles and doubles configuration interaction (MRSDCI) with the Davidson-Silver (DS) correction, and multireference averaged coupled pair functional (MRACPF2) theory. The transition states exhibit high T1 diagnostics in coupled cluster calculations, suggesting the need for a multireference correlated wave function treatment. MRSDCI+DS and MRACPF2 capture their multiconfigurational character well, yielding lower barrier heights than CCSD (T) for these reactions. The rate coefficients are computed using the RRKM/ME theory over a 500-2500 K temperature range and at a pressure range of 0.01 atm to the high-pressure limit. The temperature- and pressure-dependent rate coefficients are given in modified Arrhenius expressions. The beta-scission of CH2C(=O)OCH3 is predicted to have a much higher barrier than the corresponding isomerization reaction and the beta-scission of CH3C(=O)OCH2. Consequently, the rate coefficients for beta-scission of CH2C(=O)OCH3 are the smallest among the three reactions and the isomerization followed by decomposition to CH3C(=O) and HCHO is the dominant reaction pathway for CH2C(=O)OCH3. Both radicals CH2C(=O)OCH3 and CH3C(=O)OCH2 are predicted to mainly decompose to CH3C(=O) + HCHO rather than to the bimolecular product CH2C(=O) + CH3O. A newly developed MA combustion mechanism, using our theoretical rate coefficients for the MA-related reactions, predicts combustion properties in good agreement with available experimental data.
机译：理论上使用高级从头算方法和Rice-Ramsperger-Kassel-Marcus研究了甲酯燃烧中间体甲氧基羰基甲基（CH2C（= O）OCH3）和乙酰氧基甲基（CH3C（= O）OCH2）的单分子解离和异构动力学（RRKM）/主方程式（ME）理论。使用具有扰动三重校正（CCSD（T））的耦合簇单重和双重，具有Davidson-Silver（DS）校正的多参考单重和双配置相互作用（MRSDCI）以及多参考平均偶合对功能获得势能面（PES） （MRACPF2）理论。过渡态在耦合聚类计算中显示出较高的T1诊断值，表明需要多参考相关波函数处理。 MRSDCI + DS和MRACPF2很好地捕捉了它们的多构型特征，对于这些反应，其势垒高度低于CCSD（T）。速率系数是使用RRKM / ME理论在500-2500 K的温度范围内以及在0.01 atm的压力范围至高压极限的范围内计算的。在修正的Arrhenius表达式中给出了温度和压力相关的速率系数。预计CH2C（= O）OCH3的β断裂比相应的异构化反应和CH3C（= O）OCH2的β断裂具有更高的势垒。因此，在这三个反应中，CH2C（= O）OCH3的β断裂速率系数最小，异构化随后分解为CH3C（= O）和HCHO是CH2C（= O）OCH3的主要反应途径。预测自由基CH2C（= O）OCH3和CH3C（= O）OCH2都主要分解为CH3C（= O）+ HCHO，而不是分解为双分子产物CH2C（= O）+ CH3O。一种新开发的MA燃烧机制，使用我们与MA相关的反应的理论速率系数，可以预测燃烧性能，并与可用的实验数据高度吻合。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号