J Phys Chem A. 2009 Nov 5;113(44):12045-8. doi: 10.1021/jp907230b.
This study proposes the existence of a new, highly resonantly stabilized free radical, fulvenallenyl (C7H5). Fulvenallenyl forms from dissociation or abstraction of the weak H atoms in the C7H6 compounds fulvenallene and 1-ethynylcyclopentadiene, which were recently identified as intermediates in the combustion of aromatic fuels and in sooting flames. The fulvenallenyl radical shares properties of the propargyl and cyclopentadienyl radicals, and like these species, we propose that fulvenallenyl has a significant resonance stabilization energy. This resonance energy is lost upon further reaction, making the fulvenallenyl radical resistant to oxidation and thermal decomposition. As with the resonantly stabilized radicals propargyl and cyclopentadienyl, fulvenallenyl is expected to react with other radicals in molecular weight growth reactions. Several pathways are proposed for self-reaction and cross-reactions of fulvenallenyl that directly produce two- and three-ring PAHs like naphthalene, diphenyl, and phenanthrene. Rate constants are calculated for H atom abstraction from fulvenallene and 1-ethynylcyclopentadiene by the common radicals H, OH, and CH3, to facilitate the inclusion of fulvenallenyl in kinetic models.
本研究提出了一种新的、高度共振稳定的自由基，即富烯炔基（C7H5）。富烯炔基由富烯炔和 1-乙炔基环戊二烯中较弱的 H 原子的离解或抽提形成，这两种化合物最近被确定为芳香燃料燃烧和积碳火焰中的中间体。富烯炔基自由基具有丙炔基和环戊二烯基自由基的性质，与这些物种一样，我们提出富烯炔基具有显著的共振稳定能。这种共振能在进一步反应中丧失，使富烯炔基自由基不易氧化和热分解。与共振稳定的自由基丙炔基和环戊二烯基一样，富烯炔基预计将与其他自由基发生分子量增长反应。提出了几种自反应和交叉反应途径，可直接生成萘、联苯和菲等二环和三环 PAH。计算了富烯炔和 1-乙炔基环戊二烯中 H 原子被 H、OH 和 CH3 等常见自由基抽提的速率常数，以方便将富烯炔基纳入动力学模型。
