Air Pollution Research Center, University of California, Riverside, California 92521, USA.
J Phys Chem A. 2012 Sep 27;116(38):9507-15. doi: 10.1021/jp307217m. Epub 2012 Sep 12.
Rate constants for the reactions of OH radicals with four C(6)-C(10) cycloalkenes have been measured at 297 ± 2 K using a relative rate technique. The rate constants (in units of 10(-11) cm(3) molecule(-1) s(-1)) were cyclohexene, 6.35 ± 0.12; cis-cyclooctene, 5.16 ± 0.15; cis-cyclodecene, 4.18 ± 0.06; and 1-methyl-1-cyclohexene, 9.81 ± 0.18, where the indicated errors are two least-squares standard deviations and do not include uncertainties in the rate constant for the reference compound 1,3,5-trimethylbenzene. In addition, a rate constant of (4.8 ± 1.3) × 10(-11) cm(3) molecule(-1) s(-1) was derived for the reaction of OH radicals with 1,6-hexanedial, relative to our measured rate constant for OH + cyclohexene. Analyses of products of the OH + cyclohexene, 1-methyl-1-cyclohexene, and cis-cyclooctene reactions by direct air sampling atmospheric pressure ionization mass spectrometry and/or by combined gas chromatography-mass spectrometry showed the presence of products attributed to cyclic 1,2-hydroxynitrates and the dicarbonyls 1,6-hexanedial, 6-oxo-heptanal, and 1,8-octanedial, respectively. These dicarbonyl products, which are those formed after decomposition of the intermediate cyclic 1,2-hydroxyalkoxy radicals, were quantified as their dioximes, with molar formation yields of 76 ± 10%, 82 ± 12%, and 84 ± 18% from the cyclohexene, 1-methyl-1-cyclohexene, and cis-cyclooctene reactions, respectively. Combined with literature data concerning 1,2-hydroxynitrate formation from OH + alkenes and the estimated fractions of the overall reactions proceeding by H-atom abstraction, 90 ± 12%, 95 ± 13% and 108 ± 20% of the products or reaction pathways from the OH radical-initiated reactions of cyclohexene, 1-methyl-1-cyclohexene, and cis-cyclooctene in the presence of NO are accounted for.
用相对速率法在 297 ± 2 K 下测量了四个 C(6)-C(10)环烯烃与 OH 自由基的反应的速率常数。速率常数（单位为 10(-11)cm(3)分子(-1)s(-1))为环己烯，6.35 ± 0.12；顺式-环辛烯，5.16 ± 0.15；顺式-环癸烯，4.18 ± 0.06；和 1-甲基-1-环己烯，9.81 ± 0.18，其中指出的误差是两个最小二乘标准偏差，不包括参考化合物 1,3,5-三甲基苯的速率常数的不确定度。此外，还推导了 OH 自由基与 1,6-己二醛反应的速率常数为（4.8 ± 1.3）× 10(-11)cm(3)分子(-1)s(-1)，相对于我们测量的 OH + 环己烯反应的速率常数。通过直接空气采样大气压电离质谱和/或气相色谱-质谱联用分析 OH + 环己烯、1-甲基-1-环己烯和顺式-环辛烯反应的产物，分别发现归因于环状 1,2-羟硝酸酯和二羰基化合物 1,6-己二醛、6-氧庚醛和 1,8-辛二醛的产物。这些二羰基产物是中间环状 1,2-羟烷氧基自由基分解后形成的，作为它们的二肟进行定量，环己烯、1-甲基-1-环己烯和顺式-环辛烯反应的摩尔生成产率分别为 76 ± 10%、82 ± 12%和 84 ± 18%。结合有关 OH + 烯烃形成 1,2-羟硝酸酯的文献数据以及通过 H 原子提取进行的总反应分数的估计，NO 存在时，由 OH 自由基引发的环己烯、1-甲基-1-环己烯和顺式-环辛烯反应的产物或反应途径的 90 ± 12%、95 ± 13%和 108 ± 20%归因于该反应。
