Investigation on primary decomposition of ethylcyclohexane at atmospheric pressure
Investigation on primary decomposition of ethylcyclohexane at atmospheric pressure
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DOI：
10.1016/j.proci.2014.05.119
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
Zhandong Wang;Huiting Bian;Yu Wang;Lidong Zhang;Yuyang Li;Feng Zhang;F. Qi
中科院分区：
文献类型：
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作者：
Zhandong Wang;Huiting Bian;Yu Wang;Lidong Zhang;Yuyang Li;Feng Zhang;F. Qi
为了更好地了解长侧链环烷烃的燃烧化学，在常压流动反应器中研究了乙基环己烷（ECH）的热解反应。采用同步辐射真空紫外光电离质谱和气相色谱两种方法对热解产物进行了分析。鉴定和量化了数十种物种，包括许多异构体。本研究的重点是研究ECH的初级分解过程，包括初始分解、异构化以及由ECH抽氢生成的C8 H15环自由基的进一步反应。对C_8H_（16）烯烃的观察表明ECH存在开环异构化反应。环C8 H15自由基的开环异构化反应产生烯基自由基，其进一步分解构成ECH热解中的各种链状和支链中间体。讨论了异戊二烯和乙烯基环戊烷的形成，重点讨论了辛-6-烯-1-基和辛-5-烯-1-基等烯基双键上的自由基加成异构化反应。对辛-5-烯-1-基自由基反应途径的理论计算也表明，其内部氢迁移途径可能是通过八元环与通过五元环的竞争途径。另一方面，环状C8 H15自由基的分解会形成环状中间体，即C8 H14烯烃、亚甲基环己烷和环己烯，它们是潜在的芳香族前体。
To get a better understanding of the combustion chemistry of cycloalkanes with long side chain, the pyrolysis of ethylcyclohexane (ECH) was studied in a flow reactor at atmospheric pressure. The pyrolysis species were analyzed by two methods, synchrotron vacuum ultraviolet photoionization mass spectrometry and gas chromatography. Dozens of species were identified and quantified, including lots of isomers. The emphasis of this study is to investigate the primary decomposition of ECH, including its initial decomposition, isomerization, and further reactions of the cyclic C8H15radicals formed from the H-abstraction of ECH. The observation of C8H16alkene indicates the existence of ring-opening isomerization reaction of ECH. The ring-opening isomerization reaction of cyclic C8H15radicals produces alkenyl radicals, whose further decomposition constitutes the various chain and branched intermediates in ECH pyrolysis. The formation of isoprene and vinylcyclopentane is discussed, which highlights isomerization reactions of radical addition on the double bond of alkenyl radicals, such as oct-6-en-1-yl and oct-5-en-1-yl radicals. The theoretical calculation on the reaction pathways of oct-5-en-1-yl radical also shows that its internal H-migration pathway via eight-membered ring might be competitive to the one via five-membered ring. On the other hand, the decomposition of cyclic C8H15radicals causes the formation of cyclic intermediates, i.e. C8H14alkenes, methylenecyclohexane and cyclohexene, which are potential aromatic precursors.