Density Functional Study of the High-Temperature Oxidation of o-, m- and p-Xylyl Radicals

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• 作者：Yoshinori Murakami ; Tatsuo Oguchi ; Kohtaro Hashimoto ; Yoshio Nosaka
• 刊名：Journal of Physical Chemistry A
• 出版年：2009
• 出版时间：October 8, 2009
• 年：2009
• 卷：113
• 期：40
• 页码：10652-10666
• 全文大小：582K
• 年卷期：v.113,no.40(October 8, 2009)
• ISSN：1520-5215

文摘

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 + O₂ 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 + O₂ 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.