Papadimitriou Vassileios C, Burkholder James B
Earth System Research Laboratory, Chemical Sciences Division, National Oceanic and Atmospheric Administration , 325 Broadway, Boulder, Colorado 80305, United States.
Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder, Colorado 80309, United States.
J Phys Chem A. 2016 Aug 25;120(33):6618-28. doi: 10.1021/acs.jpca.6b06096. Epub 2016 Aug 15.
Rate coefficients, k(T), for the OH radical + (E)-(CF3)2CFCH═CHF ((E)-1,3,4,4,4-pentafluoro-3-(trifluoromethyl)-1-butene, HFO-1438ezy(E)) gas-phase reaction were measured using pulsed laser photolysis-laser-induced fluorescence (PLP-LIF) between 214 and 380 K and 50 and 450 Torr (He or N2 bath gas) and with a relative rate method at 296 K between 100 and 400 Torr (synthetic air). Over the range of pressures included in this study, no pressure dependence in k(T) was observed. k(296 K) obtained using the two techniques agreed to within ∼3% with (3.26 ± 0.26) × 10(-13) cm(3) molecule(-1) s(-1) (2σ absolute uncertainty) obtained using the PLP-LIF technique. k(T) displayed non-Arrhenius behavior that is reproduced by (7.34 ± 0.30) × 10(-19)T(2) exp[(481 ± 10)/T) cm(3) molecule(-1) s(-1). With respect to OH reactive loss, the atmospheric lifetime of HFO-1438ezy(E) is estimated to be ∼36 days and HFO-1438ezy(E) is considered a very short-lived substance (VSLS) (the actual lifetime will depend on the time and location of the HFO-1438ezy(E) emission). On the basis of the HFO-1438ezy(E) infrared absorption spectrum measured in this work and its estimated lifetime, a radiative efficiency of 0.306 W m(-2) ppb(-1) (well-mixed gas) was calculated and its 100-year time-horizon global warming potential, GWP100, was estimated to be 8.6. CF3CFO, HC(O)F, and CF2O were identified using infrared spectroscopy as stable end products in the oxidation of HFO-1438ezy(E) in the presence of O2. Two additional fluorinated products were observed and theoretical calculations of the infrared spectra of likely degradation products are presented. The photochemical ozone creation potential of HFO-1438ezy(E) was estimated to be ∼2.15.
采用脉冲激光光解-激光诱导荧光（PLP-LIF）技术，在214至380 K、50至450 Torr（氦气或氮气浴气）条件下，以及在296 K、100至400 Torr（合成空气）条件下采用相对速率法，测量了OH自由基与（E）-（CF3）2CFCH═CHF（（E）-1,3,4,4,4-五氟-3-（三氟甲基）-1-丁烯，HFO-1438ezy（E））气相反应的速率系数k（T）。在本研究涵盖的压力范围内，未观察到k（T）与压力有关。使用这两种技术获得的k（296 K）与使用PLP-LIF技术获得的（3.26±0.26）×10⁻¹³ cm³·分子⁻¹·s⁻¹（2σ绝对不确定度）在约3%的范围内一致。k（T）表现出非阿仑尼乌斯行为，可用（7.34±0.30）×10⁻¹⁹T² exp[(481±10)/T] cm³·分子⁻¹·s⁻¹来描述。关于OH反应性损失，估计HFO-1438ezy（E）的大气寿命约为36天，HFO-1438ezy（E）被认为是一种极短寿命物质（VSLS）（实际寿命将取决于HFO-1438ezy（E）排放的时间和地点）。基于本工作中测量的HFO-1438ezy（E）红外吸收光谱及其估计寿命，计算出辐射效率为0.306 W·m⁻²·ppb⁻¹（充分混合气体），并估计其100年时间跨度的全球升温潜能值GWP100为8.6。使用红外光谱法鉴定出CF3CFO、HC（O）F和CF2O是HFO-1438ezy（E）在O2存在下氧化的稳定最终产物。观察到另外两种含氟产物，并给出了可能降解产物红外光谱的理论计算结果。估计HFO-1438ezy（E）的光化学臭氧生成潜能约为2.15。
