CF3CH=CH2和C4F9CH=CH2的大气化学：与氯原子和羟基自由基的气相反应产物
Atmospheric chemistry of CF3CH=CH2 and C4F9CH=CH2: products of the gas-phase reactions with Cl atoms and OH radicals.
作者信息
Nakayama T, Takahashi K, Matsumi Y, Toft A, Andersen M P Sulbaek, Nielsen O J, Waterland R L, Buck R C, Hurley M D, Wallington T J
机构信息
Solar-Terrestrial Environment Laboratory and Graduate School of Science, Nagoya University, Honohara 3-13, Toyokawa, Aichi, 442-8507 Japan.
出版信息
J Phys Chem A. 2007 Feb 8;111(5):909-15. doi: 10.1021/jp066736l.
FTIR-smog chamber techniques were used to study the products of the Cl atom and OH radical initiated oxidation of CF3CH=CH2 in 700 Torr of N2/O2, diluent at 296 K. The Cl atom initiated oxidation of CF3CH=CH2 in 700 Torr of air in the absence of NOx gives CF3C(O)CH2Cl and CF3CHO in yields of 70+/-5% and 6.2+/-0.5%, respectively. Reaction with Cl atoms proceeds via addition to the >C=C< double bond (74+/-4% to the terminal and 26+/-4% to the central carbon atom) and leads to the formation of CF3CH(O)CH2Cl and CF3CHClCH2O radicals. Reaction with O2 and decomposition via C-C bond scission are competing loss mechanisms for CF3CH(O)CH2Cl radicals, kO2/kdiss=(3.8+/-1.8)x10(-18) cm3 molecule-1. The atmospheric fate of CF3CHClCH2O radicals is reaction with O2 to give CF3CHClCHO. The OH radical initiated oxidation of CxF2x+1CH=CH2 (x=1 and 4) in 700 Torr of air in the presence of NOx gives CxF2x+1CHO in a yield of 88+/-9%. Reaction with OH radicals proceeds via addition to the >C=C< double bond leading to the formation of CxF2x+1C(O)HCH2OH and CxF2x+1CHOHCH2O radicals. Decomposition via C-C bond scission is the sole fate of CxF2x+1CH(O)CH2OH and CxF2x+1CH(OH)CH2O radicals. As part of this work a rate constant of k(Cl+CF3C(O)CH2Cl)=(5.63+/-0.66)x10(-14) cm3 molecule-1 s-1 was determined. The results are discussed with respect to previous literature data and the possibility that the atmospheric oxidation of CxF2x+1CH=CH2 contributes to the observed burden of perfluorocarboxylic acids, CxF2x+1COOH, in remote locations.
采用傅里叶变换红外光谱-烟雾箱技术，在296 K、700托的N₂/O₂稀释剂中研究了Cl原子和OH自由基引发的CF₃CH=CH₂氧化产物。在不存在氮氧化物的情况下，在700托空气中，Cl原子引发的CF₃CH=CH₂氧化分别生成CF₃C(O)CH₂Cl和CF₃CHO，产率分别为70±5%和6.2±0.5%。与Cl原子的反应通过加成到>C=C<双键上进行（加成到末端碳原子的比例为74±4%，加成到中心碳原子的比例为26±4%），并导致形成CF₃CH(O)CH₂Cl和CF₃CHClCH₂O自由基。与O₂的反应以及通过C-C键断裂的分解是CF₃CH(O)CH₂Cl自由基的竞争消耗机制，kO₂/kdiss=(3.8±1.8)×10⁻¹⁸ cm³ 分子⁻¹。CF₃CHClCH₂O自由基在大气中的归宿是与O₂反应生成CF₃CHClCHO。在存在氮氧化物的情况下，在700托空气中，OH自由基引发的CxF₂x₊₁CH=CH₂（x = 1和4）氧化生成CxF₂x₊₁CHO，产率为88±9%。与OH自由基的反应通过加成到>C=C<双键上进行，导致形成CxF₂x₊₁C(O)HCH₂OH和CxF₂x₊₁CHOHCH₂O自由基。通过C-C键断裂的分解是CxF₂x₊₁CH(O)CH₂OH和CxF₂x₊₁CH(OH)CH₂O自由基的唯一归宿。作为这项工作的一部分，测定了k(Cl + CF₃C(O)CH₂Cl)=(5.63±0.66)×10⁻¹⁴ cm³ 分子⁻¹ s⁻¹的速率常数。结合先前的文献数据以及CxF₂x₊₁CH=CH₂在大气中的氧化可能导致偏远地区观察到的全氟羧酸CxF₂x₊₁COOH负担这一可能性，对结果进行了讨论。
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