烷烃与氢过氧自由基氢提取反应类反应能垒与速率常数的精确计算

发布时间：2018-04-25 08:28

本文选题：反应类等键反应方法 + 反应能垒　；参考：《物理化学学报》2017年04期

【摘要】：氢过氧自由基从烷烃分子中提取氢的反应是碳氢燃料中低温燃烧化学中非常重要的一类反应。本文用等键反应方法计算了这一类反应的动力学参数。所有反应物、过渡态、产物的几何结构均在HF/6-31+G(d)水平下优化得到。以反应中的过渡态反应中心的几何结构守恒为判据,该反应类可用等键反应处理。本文选取了乙烷和氢过氧自由基的氢提取反应为参考反应,其它反应作为目标反应,用等键反应方法对目标反应在HF/6-31+G(d)水平的近似能垒和反应速率常数进行了校正。为了验证方法的可靠性,选取C5以下的烷烃分子体系,对等键反应方法校正结果和高精度CCSD(T)/CBS直接计算结果进行了比较,最大绝对误差为5.58k J?mol~(-1),因此,采用等键反应方法只需用低水平HF从头算方法就可以再现高精度CCSD(T)/CBS计算结果,从而解决了该反应类中大分子体系的能垒的精确计算。本文的研究为碳氢化合物中低温燃烧模拟中重要的烷烃与氢过氧自由基氢提取反应提供了准确的动力学参数。
[Abstract]:The extraction of hydrogen from alkanes by hydrogen peroxy radical is a very important reaction in the low temperature combustion chemistry of hydrocarbon fuel. In this paper, the kinetic parameters of this kind of reactions are calculated by using the method of equal bond reaction. The geometric structures of all reactants, transition states and products were optimized at the HF/6-31 Gnd level. The geometric structure conservation of the transition state reaction center in the reaction is taken as the criterion, and the reaction class can be treated by the equal-bond reaction. In this paper, the hydrogen extraction reaction of ethane and hydroperoxy radical is selected as the reference reaction, and the other reactions as the target reaction. The approximate energy barrier and the reaction rate constant of the target reaction at the HF/6-31 Gnd level are corrected by the equal-bond reaction method. In order to verify the reliability of the method, the calibration results of alkane molecules under C _ 5 are compared with those of high precision CCSD(T)/CBS direct calculation. The maximum absolute error is 5.58 k / mol ~ (-1) ~ (-1). By using the equal-bond reaction method, the high-precision CCSD(T)/CBS calculation results can be reproduced by using the low-level HF ab initio method, thus solving the accurate calculation of the energy barrier of the macromolecular system in this reaction class. The study in this paper provides accurate kinetic parameters for the hydrogen extraction reaction of alkanes with hydrogen peroxy radicals in the simulation of hydrocarbon combustion at low temperature.
【作者单位】：四川大学化学学院;四川大学空天科学与工程学院;四川大学化学工程学院;
【基金】：国家自然科学基金(91441114)资助项目~~
【分类号】：O643.12

【相似文献】