A quantum chemical and kinetics modeling study on the autoignition mechanism of diethyl ether
A quantum chemical and kinetics modeling study on the autoignition mechanism of diethyl ether
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DOI：
10.1016/j.proci.2016.06.037
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Yasuyuki Sakai;J. Herzler;M. Werler;C. Schulz;M. Fikri
中科院分区：
文献类型：
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作者：
Yasuyuki Sakai;J. Herzler;M. Werler;C. Schulz;M. Fikri
建立了一个详细的化学动力学模型来解释乙醚在内燃机相关条件下的自燃行为。该模型由文献中的C0-C4base模块和DEE模块组成。对于低温氧化机理，以前Sakai等人用量子化学和过渡态理论方法研究了RoO和QOOH自由基的反应。(2015)。本文用CBSQB3合成法测定了OOQOOH异构体与1-和2-乙氧基乙基自由基单分子反应的势能面。在OH基的存在下，氢从β中心(末端碳原子)移动的反应势垒与烷烃氧化时一样减小，但对α中心(靠近乙醚氧原子)的氢移动没有影响。因此，OOQOOH异构体的反应势垒与相应的Roo自由基具有相同的趋势，并确定了OOQOOH异构体的反应速率常数。用Werler等人最近提供的点火延迟时间数据对所建立的模型进行了验证。(2015)。该协议在500-1300摄氏度和1-40摄氏度的温度范围内是好的，尽管，关于900-1150摄氏度和40摄氏度的非共识仍然存在悬而未决的问题。反应路径和灵敏度分析将α位上的反应性的重要性归因于乙醚氧原子降低了C H键的解离能。
A detailed chemical kinetics model has been developed to elucidate the auto-ignition behavior of diethyl ether (DEE) under conditions relevant for internal combustion engines. The present model is composed of a C0–C4base module from literature and a DEE module. For the low-temperature oxidation mechanism, the reactions of ROO and QOOH radicals were studied previously with a quantum-chemical and transition state theory approach by Sakai et al. (2015). In the present study, the potential energy surfaces for the unimolecular reactions of OOQOOH isomers and 1- and 2-ethoxyethyl radicals were determined with a CBSQB3 composite method. In the presence of an OOH group, the reaction barrier of the hydrogen shift from the β site (terminal carbon atom) decreases as it does in alkane oxidation but there is no effect on the hydrogen shift from the α site (next to the ether oxygen atom). Therefore, the reaction barriers of OOQOOH isomers have the same trend as the corresponding ROO radical and rate constants for the reactions of OOQOOH isomers were determined. The constructed model was validated against the recent data of ignition delay times provided in literature by Werler et al. (2015). The agreement is good over the temperature range 500–1300 K and pressure range 1–40 bar, although, open questions remain regarding the non-consensus at 900–1150 K and 40 bar. Reaction-path and sensitivity analyses attribute the importance of the reactivity at the α site to the decrease of the C H bond dissociation energy due to the ether oxygen atom.