C_7H_15自由基裂解反应机理及速率常数的理论研究  

Unimolecular decomposition of heptane radicals:a mechanism and rate constant investigation

作　　者：张田雷[1] 张鹏[1] 杨晨 

机构地区：[1]陕西理工学院化学与环境科学学院陕西理工学院理论与计算化学研究所,陕西汉中723000

出　　处：《陕西理工学院学报（自然科学版）》2015年第2期50-55,61,共7页Journal of Shananxi University of Technology:Natural Science Edition

基　　金：陕西省教育厅科学研究计划项目(14JK1154);陕西理工学院校级人才启动项目(SLGQD13(2)-3)

摘　　要：采用CBS-QB3方法构建了C7H15自由基裂解反应势能剖面。计算结果表明,4种不同构型的C7H15自由基（1-C7H15,2-C7H15,3-C7H15,4-C7H15）发生多种不同类型的β位断裂,裂解成C2—C6烯烃和新的自由基。新的自由基继续发生β位断裂,形成诸如CH3自由基以及CH2CH2、CH3CHCH2等烯烃。此外,利用VKLab程序包及Wigner校正模型在200~3 000 K温度范围内计算了4种C7H15自由基各类β位断裂反应速率常数。其中1-C3H7→C2H4＋CH3反应速率常数的结果与试验结果非常吻合。The potential energy surfaces of the β-scission of heptane radicals were performed using the CBS-QB3 method. The results show that the β-scission of 1-C7H15,2-C7H15,3-C7H15 and 4-C7H15 radicals involves many different kinds of β-scission reactions to produce olefins and other radicals. Compared to the small n-alkanes,larger n-alkanes can produce more alkyl radicals,which may generate more intermediates and have more possible pathways. Main products were C2 ~ C6 olefins,methyl raticals and hydrogen radicals.The rate constants of all reactions with Eckart correction were calculated by the VKLab program package. The rate constant of 1-C3H7→C2H4＋ CH3 reaction within the temperature range of 200 ~ 3 000 K is in good agreement with available experimental values.

关 键 词：C7H15自由基 β位断裂 CBS-QB3 反应机理 速率常数 

分 类 号：O643.322[理学—物理化学]