A theoretical and modeling study about the low-temperature reaction mechanism between diethoxymethane radicals and O2
A theoretical and modeling study about the low-temperature reaction mechanism between diethoxymethane radicals and O2
复制标题
二乙氧基甲烷自由基与O2低温反应机理的理论与模型研究
DOI：
10.1016/j.combustflame.2023.112616
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发表时间：
2023-01-15
影响因子：
4.4
通讯作者：
Zhang, Lidong
中科院分区：
文献类型：
--
作者：
Ruan, Shanshan;Yin, Jiuzheng;Zhang, Lidong
研究了碳中性燃料二乙氧基甲烷（DEM，C2 H5-OCH 2 O-C2 H5）的低温氧化机理。在CBS-QB 3//M062 x/6-311 ++G（d，p）水平上研究了三种不同的DEM自由基与O2反应的反应势能面.根据Rice-Ramsperger-Kassel-Marcus（RRKM）理论结合过渡态理论，采用主方程计算了相关反应的速率常数。采用修正的Arrhenius方程拟合了反应速率常数与温度和压力的关系。讨论了低温燃烧的主要反应途径，认为初始加合物的生成和分子内氢转移反应是低温燃烧的关键。其中，通过六元环过渡态的H-转移反应需要克服低能垒。随后的解离反应主要是OH-损失和β-断裂反应，在大多数情况下前者更有利。此外，计算数据被纳入DEM燃烧模型。修正后的模型在激波管点火延迟时间上与实验测量数据吻合较好，对几种重要产物的摩尔分数的预测与原模型不同。本工作为进一步研究DEM氧化反应提供了理论依据。(c)第2023章燃烧研究所爱思唯尔公司出版All rights reserved.
Diethoxymethane (DEM, C2H5-OCH2O-C2H5), a carbon-neutral fuel, was investigated in this work for the low-temperature oxidation mechanism. The reaction potential energy surfaces (PESs) of three different DEM radicals reacting with O 2 were explored at the CBS-QB3//M062x/6-311 ++G(d,p) level. The rate con-stants of the relevant reactions were calculated by the master equation according to the Rice-Ramsperger-Kassel-Marcus (RRKM) theory combined with transition state theory. The modified Arrhenius equation has been utilized to fit the temperature-and pressure-dependent reaction rate constants. The main re-action channels were discussed, the generation of initial adducts and intramolecular H-transfer reactions are essential for low-temperature combustion. Among them, the H-transfer reaction via a six-member ring transition state requires a low energy barrier to be overcome. The subsequent dissociation reactions are dominated by OH-loss and beta-scission reactions, with the former being more favorable in most cases. Additionally, the calculated data were incorporated into the DEM combustion model. The modified model shows a great agreement with experimentally measured data on ignition delay times in shock tube and has different predictions for the mole fraction of several important products compared with the original model. The present work provides support for further study of DEM oxidation reactions.(c) 2023 The Combustion Institute. Published by Elsevier Inc. All rights reserved.