High‐temperature dissociation of ethyl radicals and ethyl iodide
High‐temperature dissociation of ethyl radicals and ethyl iodide
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高温解离乙基自由基和乙基碘
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
R. Tranter
中科院分区：
文献类型：
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作者：
Xueliang Yang;R. Tranter
本文用激光纹影（LS）密度计研究了入射激波后碘乙烷的分解和乙基自由基的离解。假设C2 H5 I的初始解离是由87%的C-I裂变和13%的HI消除进行的，模拟了LS密度梯度分布。极好的协议之间的模拟和实验配置文件。得到了C-I断裂反应的速率系数，并显示出强烈的衰减。Gorin模型RRKM（Rice，Ramsperger，卡塞尔，和Marcus）的计算结果与实验数据非常吻合，E0 = 55.0 kcal/mol，这与最近的热化学测量和评价结果非常吻合。然而，E0比以前的估计值高出约2.7 kcal/mol。C2 H5 I解离的一级速率系数为k55 Torr = 8.65 × 1068 T −16.65 exp（− 37，890/T）s−1，k123 Torr = 3.01 × 1069 T −16.68 exp（− 38，430/T）s−1，k∞ = 2.52 × 1019 T −1.01 exp（− 28，775/T）s−1。还获得了乙基自由基的离解速率，这些与理论预测非常一致（米勒J. A.和Klippenstein S. J. Phys Chem Chem Phys 2004，6，1192-1202）。模拟结果表明，在低温下，乙基自由基消耗通过重组反应以及解离，而在高温下，解离占主导地位。© 2012 Wiley Periodicals，Inc. Int J Chem Kinet 44：433-443，2012
The decomposition of ethyl iodide and subsequent dissociation of ethyl radicals have been investigated behind incident shock waves in a diaphragmless shock tube by laser-schlieren (LS) densitometry (1150–1870 K, 55 ± 2 Torr and 123 ± 3 Torr). The LS density-gradient profiles were simulated assuming that the initial dissociation of C2H5I proceeded by 87% C–I fission and 13% HI elimination. Excellent agreement was found between the simulations and experimental profiles. Rate coefficients for the C–I scission reaction were obtained and show strong falloff. Gorin model RRKM (Rice, Ramsperger, Kassel, and Marcus) calculations are in excellent agreement with the experimental data with E0 = 55.0 kcal/mol, which is in very good agreement with recent thermochemical measurements and evaluations. However, E0 is approximately 2.7 kcal/mol higher than previous estimates. First-order rate coefficients for dissociation of C2H5I were determined to be k55Torr = 8.65 × 1068T−16.65 exp(−37,890/T) s−1, k123Torr = 3.01 × 1069T−16.68 exp(−38,430/T) s−1, k∞ = 2.52 × 1019T−1.01 exp(−28,775/T) s−1. Rates of dissociation for ethyl radicals were also obtained, and these are in very good agreement with theoretical predictions (Miller J. A. and Klippenstein S. J. Phys Chem Chem Phys 2004, 6, 1192–1202). The simulations show that at low temperatures ethyl radicals are consumed through recombination reactions as well as dissociation, whereas at high temperatures, dissociation dominates. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 433–443, 2012