Gas-Phase Reaction of Hydroxyl Radical with p-Cymene over an Extended Temperature Range

详细信息    查看全文

• 作者：Yuri Bedjanian ; Julien Morin ; Manolis N. Romanias
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：November 12, 2015
• 年：2015
• 卷：119
• 期：45
• 页码：11076-11083
• 全文大小：409K
• ISSN：1520-5215

文摘

The kinetics of the reaction of OH radicals with p-cymene has been studied in the temperature range of 243鈥?98 K using a flow reactor combined with a quadrupole mass spectrometer: OH + p-cymene 鈫?products. The reaction rate constant was determined as a result of absolute measurements, from OH decay kinetics in excess of p-cymene and employing the relative rate method with OH reactions with n-pentane, n-heptane,1,3-dioxane, HBr, and Br₂ as the reference ones. For the rate coefficient of the H atom abstraction channel, the expression k_1b = (3.70 卤 0.42) 脳 10^鈥?1 exp[鈭?772 卤 72)/T] was obtained over the temperature range of 381鈥?98 K. The total rate constant (addition + abstraction) determined at T = 243鈥?20 K was k₁ = (1.82 卤 0.48) 脳 10^鈥?2 exp[(607 卤 70)/T] or, in a biexponential form, k₁ = k_1a + k_1b = 3.7 脳 10^鈥?1 exp(鈭?72/T) + 6.3 脳 10^鈥?3 exp(856/T), independent of the pressure between 1 and 5 Torr of helium. In addition, our results indicate that the reaction pathway involving alkyl radical elimination upon initial addition of OH to p-cymene is most probably unimportant.