Temperature-Dependent Kinetics Study of the Reactions of OH with C2H5I, n-C3H7I, and iso-C3H7I

详细信息    查看全文

• 作者：Shaoliang Zhang ; Rafal S. Strekowski ; Anne Monod ; Lo茂c Bosland ; Cornelius Zetzsch
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：September 27, 2012
• 年：2012
• 卷：116
• 期：38
• 页码：9497-9506
• 全文大小：452K
• 年卷期：v.116,no.38(September 27, 2012)
• ISSN：1520-5215

文摘

Flash photolysis (FP) coupled with resonance fluorescence (RF) was used to measure the absolute rate coefficients for the reactions of OH(X²螤) radicals with C₂H₅I (k₁), n-C₃H₇I (k₂), and iso-C₃H₇I (k₃) at temperatures between 297 and 372 K in 188 Torr of He; this represents the first temperature-dependent kinetics studies for the title reactions. The experiments involved time-resolved RF detection of the OH (A²危⁺ 鈫?X²螤 transition at 位 = 308 nm) radicals following FP of H₂O/C₂H₅I/He, H₂O/n-C₃H₇I/He, and H₂O/iso-C₃H₇I/He mixtures. The OH(X²螤) radicals were produced by FP of H₂O in vacuum-UV at wavelengths 位 > 120 nm. Decays of OH radicals in the presence of C₂H₅I, n-C₃H₇I, and iso-C₃H₇I were observed to be exponential, and the decay rates were found to be linearly dependent on the C₂H₅I, n-C₃H₇I, and iso-C₃H₇I concentrations. The results are described by the following Arrhenius expressions (units of cm³ molecule^鈥? s^鈥?): k₁(297鈥?72 K) = (5.55 卤 3.20) 脳 10^鈥?2 exp[鈭?830 卤 90) K/T], k₂(300鈥?70 K) = (1.65 卤 0.90) 脳 10^鈥?1 exp[鈭?780 卤 90) K/T] and k₃(299鈥?69 K) = (7.58 卤 3.70) 脳 10^鈥?2 exp[鈭?530 卤 80) K/T]. Reported errors in E/R and in the pre-exponential factors are 2蟽 random errors, returned by the weighted (by 1/蟽²) least-squares fits to the kinetic data. The implications of the reported kinetic results for understanding both atmospheric and nuclear safety interests of C₂H₅I, n-C₃H₇I, and iso-C₃H₇I are discussed.