Kinetics of Several Oxygen-Containing Carbon-Centered Free Radical Reactions with Nitric Oxide

详细信息    查看全文

• 作者：Matti P. Rissanen ; Marvin Ihlenborg ; Timo T. Pekkanen ; Raimo S. Timonen
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：July 16, 2015
• 年：2015
• 卷：119
• 期：28
• 页码：7734-7741
• 全文大小：325K
• ISSN：1520-5215

文摘

Kinetics of four carbon-centered, oxygen-containing free radical reactions with nitric oxide (NO) were investigated as a function of temperature at a few Torr pressure of helium, employing flow tube reactors coupled to a laser-photolysis/resonance-gas-discharge-lamp photoionization mass spectrometer (LP-RPIMS). Rate coefficients were directly determined from radical (R) decay signals under pseudo-first-order conditions ([R]₀ 鈮?[NO]). The obtained rate coefficients showed negative temperature dependences, typical for a radical鈥搑adical association process, and can be represented by the following parametrizations (all in units of cm³ molecule^鈥? s^鈥?): k(CH₂OH + NO) = (4.76 脳 10^鈥?1) 脳 (T/300 K)^15.92 脳 exp[50700/(RT)] (T = 266鈥?63 K, p = 0.79鈥?.44 Torr); k(CH₃CHOH + NO) = (1.27 脳 10^鈥?6) 脳 (T/300 K)^6.81 脳 exp[28700/(RT)] (T = 241鈥?63 K, p = 0.52鈥?.43 Torr); k(CH₃OCH₂ + NO) = (3.58 卤 0.12) 脳 10^鈥?2 脳 (T/300 K)^{鈭?.17卤0.14} (T = 221鈥?63 K, p = 0.50鈥?.80 Torr); k(T)₃ = 9.62 脳 10^鈥?1 脳 (T/300 K)^鈭?.99 脳 exp[鈭?100/(RT)] (T = 221鈥?73 K, p = 1.41鈥?.95 Torr), with the uncertainties given as standard errors of the fits and the overall uncertainties estimated as 卤20%. The rate of CH₃OCH₂ + NO reaction was measured in two density ranges due to its observed considerable pressure dependence, which was not found in the studied hydroxyalkyl reactions. In addition, the CH₃CO + NO rate coefficient was determined at two temperatures resulting in k_298K(CH₃CO + NO) = (5.6 卤 2.8) 脳 10^鈥?3 cm³ molecule^鈥? s^鈥?. No products were found during these experiments, reasons for which are briefly discussed.