Kinetics and mechanism of the gas-phase reaction of the cyclohexadienyl radical c-C6H7 with O2
Kinetics and mechanism of the gas-phase reaction of the cyclohexadienyl radical c-C6H7 with O2
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环己二烯基c-C6H7与O2气相反应的动力学和机理
DOI：
10.1039/b308107a
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发表时间：
2003
影响因子：
3.3
通讯作者：
R. Lesclaux
中科院分区：
文献类型：
--
作者：
E. Estupiñán;E. Villenave;S. Raoult;J. Rayez;M. Rayez;R. Lesclaux
采用实验和理论相结合的方法研究了环己二烯基自由基c-C_6 H_7与O_2的气相反应动力学和机理。在302-456 K的温度范围内，1个大气压的压力下，使用传统的闪光光解测量的速率常数。C-C6 H7自由基是由Cl原子与1，4-环己二烯反应产生的。速率表达式为k1=（1.4±0.26）×10−13 exp[−（300±74）K/T] cm 3 molecule−1 s−1
（2σ误差条）。该反应可以通过缔合进行，产生过氧自由基RO 2或通过H-提取进行，产生苯+HO 2，这两个反应通道涉及两个不同的过渡态。与c-C6 H6 OH自由基所观察到的相反，没有与过氧自由基的平衡可以被表征。的理论方法，涉及DFT和从头算方法，被用来确定所测得的速率常数是否应分配给协会或H-抽象通道。实验和理论结果的比较表明，H-提取必须是唯一显着的反应通道。
The kinetics and mechanism of the gas-phase reaction of the cyclohexadienyl radical c-C6H7 with O2 have been investigated using both experimental and theoretical approaches. The rate constant has been measured using conventional flash photolysis in the temperature range 302–456 K, 1 atm pressure. c-C6H7 radicals were produced by reacting Cl atoms with 1,4-cyclohexadiene. The rate expression is k1=(1.4±0.26)×10−13 exp[−(300±74) K/T] cm3 molecule−1 s−1
(2σ error bars). The reaction can proceed either by association, yielding a peroxy radical RO2 or by H-abstraction, yielding benzene+HO2, the two reaction channels involving two distinct transition states. In contrast to what is observed for the c-C6H6OH radical, no equilibrium with the peroxy radical could be characterised. The theoretical approach, involving both DFT and ab initio methods, was used to determine if the measured rate constant should be assigned to the association or to the H-abstraction channel. Comparison of experimental and theoretical results shows that H-abstraction must be the only significant reaction channel.