2-甲基噻吩与NO_3反应机理的理论研究  

Theoretical study of the reaction mechanism of 2-metyhlthiophene with NO_3 radical

作　　者：陈龙[1] 王渭娜[1] 卢天宇[1] 王文亮[1] 

机构地区：[1]陕西省大分子科学重点实验室、陕西师范大学化学化工学院,陕西西安710119

出　　处：《陕西师范大学学报（自然科学版）》2014年第4期38-44,共7页Journal of Shaanxi Normal University：Natural Science Edition

基　　金：国家自然科学基金资助项目(21173139)

摘　　要：采用B3LYP/6-311++G(3df,2pd)//B3LYP/6-31+G(d,p)双水平方法对2-甲基噻吩与NO3的反应机理进行了理论研究.研究结果表明,标题反应主要存在抽氢、SN2取代和加成-消去反应3种类型,共10条反应通道.其中SN2取代和加成-消去反应通道所需能垒均较高,反应不易进行,而在抽氢反应中R4所需能垒仅为6.77kJ/mol,为标题反应的主通道.采用经Wigner校正的经典过渡态理论计算得到抽取甲基氢通道(R4)在298K时的速率常数为1.03×10-13 cm-3/(molecule·s),与Caba珘nas测定的实验值(7.21×10-13 cm3/(molecule·s))接近.The reaction mechanism of 2-metyhlthiophene with NO3 radical have been investigated at the B3LYP/6-311＋＋G（3df,2pd）//B3LYP/6-31＋G（d,p）level of theory.The results show that the title reaction mainly includes hydrogen abstraction, SN 2 substitution and addition-elimination reactions.The barriers of SN 2 substitution and addition-elimination are higher than the hydrogen abstraction reactions,in which the barrier of R4 is equal to 6.77 kJ/mol and it is a dominant pathway in the title reactions. The rate constant for the dominant channel R4 is calculated with conventional transition state theory （TST）at 298 K,where Wigner method is adopted to correct the quantum mechanical tunneling effect.The calculated value is 1.03×10^-13 cm^3/（molecule·s）,which is consistent with Cabanas′s result （7.21×10^-13 cm^3/（molecule·s）） by using laser induced fluorescence method.

关 键 词：2-甲基噻吩 NO3 反应机理 速率常数 

分 类 号：O643.12[理学—物理化学]