Hot β-scission of radicals formed via hydrogen abstraction
Hot β-scission of radicals formed via hydrogen abstraction
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DOI：
10.1016/j.proci.2016.06.088
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
M. Döntgen;Leif C. Kröger;K. Leonhard
中科院分区：
文献类型：
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作者：
M. Döntgen;Leif C. Kröger;K. Leonhard
通常，燃料燃烧的第一步是形成燃料自由基。这些自由基可以通过夺氢形成，并且通常由于反应释放的能量而被旋转振动激发。这些激发增加了高能时的粒子数，从而增加了燃料自由基β-断裂的概率。这种非热自由基的热β-断裂可以解释为从双分子夺氢反应物到解离产物的良好跳跃反应。为此，稳定的固定点之间的自由能释放预测使用基团贡献理论。在此基础上，选取了具有明显β-断裂的自由基进行了详细的研究，发现热β-断裂对抽氢生成的甲酸根的CO2损失反应有显著的贡献.特别是对于甲酸甲酯，发现非热自由基的β-断裂在很宽的温度和压力范围内占主导地位。这表明需要包括β-断裂反应物的起源。
Often, the first step of fuel combustion is the formation of fuel radicals. These radicals can be formed via hydrogen abstraction and are typically rovibrationally excited due to the energy release from the reaction. These excitations increase the population at high energies, thus increase the probability forβ-scission of the fuel radical. Hotβ-scission of such non-thermal radicals can be interpreted as well-skipping reaction from the bimolecular hydrogen abstraction reactants to the dissociation products.In the present study, the impact of non-Boltzmann radical distributions onβ-scission kinetics is screened for several hundred fuels. For that purpose, the free energy release between stable stationary points is predicted using group contribution theory. Based on that screening, fuel radicals with potentially pronouncedβ-scission of rovibrationally excited fuel radicals are picked for more detailed study.Hotβ-scission is found to significantly contribute to the CO2loss reactions of formate radicals formed via hydrogen abstraction. Especially for methyl formate,β-scission of non-thermal radicals is found to dominate over a wide range of temperature and pressure. This reveals the need for including the origin of reactants ofβ-scission reactions.