Combustion Chemistry Centre, School of Chemistry & Ryan Institute , National University of Ireland , Galway H91TK33 , Ireland.
School of Energy and Power Engineering , Beihang University , Beijing 100191 , P. R. China.
J Phys Chem A. 2019 Oct 10;123(40):8506-8526. doi: 10.1021/acs.jpca.9b06378. Epub 2019 Sep 26.
Alkyl radicals are prominent in combustion chemistry as they are formed by hydrocarbon decomposition or from a radical attack on hydrocarbons. Accurate determinations of the thermochemistry and kinetics of their unimolecular isomerization and decomposition reactions and related addition reactions of alkenes are therefore important in simulating the combustion chemistry of virtually all hydrocarbon fuels. In this work, a comprehensive potential energy surface (PES) for Ḣ-atom addition to and abstraction from 1- and 2-pentene, and the subsequent C-C and C-H β-scission reactions, and H-atom transfer reactions has been considered. Thermochemical values for the species on the ĊH PES were calculated as a function of temperature (298-2000 K), with enthalpies of formation determined using a network of isodesmic reactions. High-pressure limiting and pressure-dependent rate constants were calculated using the Rice-Ramsperger-Kassel-Marcus theory coupled with a one-dimensional master equation. As a validation of our theoretical results, hydrogen atomic resonance absorption spectrometry experiments were performed on the Ḣ-atom addition and abstraction reactions of 1- and 2-pentene. By incorporating our calculations into a detailed chemical kinetic model (AramcoMech 3.0), excellent agreement with these experiments is observed. The theoretical results are further validated via a comprehensive series of simulations of literature data. Our model is found to reproduce important absolute species concentrations and product ratios reported therein.
烷基自由基在燃烧化学中很重要，因为它们是由碳氢化合物分解或自由基攻击碳氢化合物形成的。因此，准确确定其单一分子异构化和分解反应以及相关烯烃加成反应的热化学和动力学对于模拟几乎所有碳氢燃料的燃烧化学非常重要。在这项工作中，考虑了 H 原子加成和抽提 1-戊烯和 2-戊烯以及随后的 C-C 和 C-H β 断裂反应和 H 原子转移反应的综合势能面（PES）。使用同系反应网络计算了ĊH PES 上物种的热化学值，作为温度（298-2000 K）的函数，并用生成焓确定。使用 Rice-Ramsperger-Kassel-Marcus 理论结合一维主方程计算了高压极限和压力相关速率常数。作为我们理论结果的验证，在 1-戊烯和 2-戊烯的 H 原子共振吸收光谱实验中进行了 H 原子加成和抽提反应。通过将我们的计算纳入详细的化学动力学模型（AramcoMech 3.0），观察到与这些实验非常吻合。通过对文献数据的一系列综合模拟进一步验证了理论结果。我们的模型被发现能够重现其中报道的重要绝对物种浓度和产物比。
