物理化学学报2017，Vol.33Issue(4)：763-768,6.DOI:10.3866/PKU.WHXB201701091
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
Accurate Calculation of the Energy Barriers and Rate Constants of Hydrogen Abstraction from Alkanes by Hydroperoxyl Radical
摘要
Abstract
Hydrogen abstraction from alkanes by hydroperoxyl radical is an important reaction class in the combustion of hydrocarbon fuel,particularly at low and intermediate temperature regimes.In this study,kinetic parameters for this reaction class are calculated using the isodesmic reaction method based on conservation of geometric structures for the reaction center of the transition states.The geometries for all the reactants,transition states,and products are optimized at the HF/6-31+G(d) level.Hydrogen abstraction from ethane byhydroperoxyl radical is chosen as the reference reaction;other reactions are target reactions.The isodesmicreaction method is used to correct the approximate energy barriers and rate constants of the target reactions at the HF16-31 +G(d) level.To validate the reliability of the isodesmic reaction method,the energy barriers calculated by the isodesmic reaction method and at a high level of CCSD(T)/CBS for alkanes containing less than five carbon atoms are compared.The maximum absolute difference of energy barriers between the isodesmic reaction method and CCSD(T)/CBS method is 5.58 kJ· mol-1.Therefore,after correction,using the isodesmic reaction method,the low-level HF method can reproduce the high-level CCSD(T)/CBS calculated energy barriers.Thus,we have solved the problem of accurately calculating energy barriers for large molecular systems in this reaction class.The present work provides accurate kinetic parameters for hydrogen abstraction from alkanes by hydroperoxyl radical,which are important for combustion modeling at low and intermediate temperature regimes.关键词
反应类等键反应方法/反应能垒/速率常数/烷烃氢提取/中低温燃烧Key words
Reaction class isodesmic reaction method/Energy barrier of reaction/Rate constant/Hydrogen abstraction of alkanes/Combustion at low and intermediate temperature regimes分类
化学化工引用本文复制引用
姚倩,彭莉娟,李泽荣,李象远..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[J].物理化学学报,2017,33(4):763-768,6.基金项目
The project was supported by the National Natural Science Foundation of China (91441114).国家自然科学基金(91441114)资助项目 （91441114）
