Density functional study of the high-temperature oxidation of o-, m- and p-xylyl radicals.
Density functional study of the high-temperature oxidation of o-, m- and p-xylyl radicals.
复制标题
DOI：
10.1021/jp902204a
复制
发表时间：
2009-10
期刊：
影响因子：
--
通讯作者：
Y. Murakami;T. Oguchi;Kohtaro Hashimoto;Y. Nosaka
中科院分区：
文献类型：
--
作者：
Y. Murakami;T. Oguchi;Kohtaro Hashimoto;Y. Nosaka
在CBS-QB 3水平上对邻、间、对二甲苯基与分子氧反应的势能面进行了理论计算。在CBS-QB ~ 3水平上，邻、间、对二甲苯基与氧的相对势能差在8.5kJ/mol以内。虽然间二甲苯基和对二甲苯基与分子氧的反应具有与苄基自由基相同的反应途径和反应热化学，但邻二甲苯基+ O（2）反应生成的邻二甲苯基过氧自由基具有额外的分子内异构化途径，从而生成邻二甲苯基过氧化氢自由基。用RRKM法和主方程分析法计算了邻二甲苯基+ O（2）及其后续反应的速率常数和产物支化比。这些反应途径对邻二甲苯燃烧的可能作用进行了讨论。
Theoretical calculations at the CBS-QB3 level of theory have been performed to investigate the potential energy surface for the reaction of o-, m- and p-xylyl with molecular oxygen. The differences of the relative potential energies for the products and the transition states of o-, m- and p-xylyl with molecular oxygen were found to be within 8.5 kJ/mol at the CBS-QB3 level of theory. Although the reaction of m- and p-xylyl radicals with molecular oxygen have the same reaction pathways and also the same reaction thermochemistry as that of benzyl radicals, the o-xylylperoxy radicals formed by the reaction of o-xylyl + O(2) had an additional intramolecular isomerization pathway to form the o-xylyl hydroperoxy radicals. The rate constants and the product branching ratios for the o-xylyl + O(2) and its subsequent reactions were evaluated by the RRKM and master equation analysis. Possible roles for these reaction pathways on the combustion of o-xylenes are discussed.