Oyaro Nathan, Sellevåg Stig R, Nielsen Claus J
Department of Chemistry, University of Oslo, Blindern, N-0315 Oslo, Norway.
Environ Sci Technol. 2004 Nov 1;38(21):5567-76. doi: 10.1021/es0497330.
Infrared absorption cross-sections and OH and Cl reaction rate coefficients for four C4-hydrofluoroethers (CF3)2CHOCH3, CF3CH2OCH2CF3, CF3CF2CH2OCH3, and CHF2CF2CH2OCH3 are reported. Relative rate measurements at 298 K and 1013 hPa of OH and Cl reaction rate coefficients give k(OH+(CF3)2CHOCH3) = (1.27+/-0.13) x 10(-13), k(OH+CF3CH2OCH2CF3) = (1.51+/-0.24) x 10(-13), k(OH+CF3CF2CH2OCH3) = (6.42+/-0.33) x 10(-13), k(OH+CHF2CF2CH2OCH3) = (8.7 +/-0.5) x 10(-13), k(Cl+(CF3)2CHOCH3) = (8.4+/-1.3) x 10(-12), k(Cl+CF3CH2OCH2CF3) = (6.5+/-1.7) x 10(-13), k(Cl+CF3CF2CH2OCH3) = (4.0+/-0.8) x 10(-11), and k(Cl+CHF2CF2CH2OCH3) = (2.65+/-0.17) x 10(-11) cm3 molecule(-1) s(-1). The primary products of the OH and Cl reactions with the fluorinated ethers have been identified as esters, and OH and Cl reaction rate coefficients for one of these, CF3CH2OCHO, are reported: k(OH+CF3CH2OCHO) = (7.7+/-0.9) x 10(-14) and kCl+CF3CH2OCHO) = (6.3+/-1.9) x 10(-14) cm3 molecule(-1) s(-1) The rate coefficient for the Cl-atom reaction with CHF2CH2F is derived as k(Cl+CHF2CH2F) = (3.0+/-0.9) x 10(-14) cm3 molecule(-1) s(-1) at 298 K. The error limits include 3sigma from the statistical data analyses as well as the errors in the rate coefficients of the reference compounds employed. The tropospheric lifetimes of the hydrofluoroethers are estimated to be short tauOH((CF3)2CHOCH3) approximately 100 days, tauOH(CF3CH2OCH2CF3) approximately 80 days, tauOH(CF3CF2CH2OCH3) approximately 20 days, and tauOH(CHF2CF2CH2OCH3) approximately 14 days, and their global warming potentials are small compared to CFC-11.
报道了四种C4 - 氢氟醚（CF3）2CHOCH3、CF3CH2OCH2CF3、CF3CF2CH2OCH3和CHF2CF2CH2OCH3的红外吸收截面以及与OH和Cl的反应速率系数。在298 K和1013 hPa下进行的OH和Cl反应速率系数的相对速率测量结果如下：k(OH + (CF3)2CHOCH3) = (1.27 ± 0.13)×10(-13)，k(OH + CF3CH2OCH2CF3) = (1.51 ± 0.24)×10(-13)，k(OH + CF3CF2CH2OCH3) = (6.42 ± 0.33)×10(-13)，k(OH + CHF2CF2CH2OCH3) = (8.7 ± 0.5)×10(-13)，k(Cl + (CF3)2CHOCH3) = (8.4 ± 1.3)×10(-12)，k(Cl + CF3CH2OCH2CF3) = (6.5 ± 1.7)×10(-13)，k(Cl + CF3CF2CH2OCH3) = (4.0 ± 0.8)×10(-11)，k(Cl + CHF2CF2CH2OCH3) = (2.65 ± 0.17)×10(-11) cm3·分子(-1)·s(-1)。已确定OH和Cl与含氟醚反应的主要产物为酯，并报道了其中一种CF3CH2OCHO与OH和Cl的反应速率系数：k(OH + CF3CH2OCHO) = (7.7 ± 0.9)×10(-14)和k(Cl + CF3CH2OCHO) = (6.3 ± 1.9)×10(-14) cm3·分子(-1)·s(-1)。在298 K下推导出Cl原子与CHF2CH2F反应的速率系数为k(Cl + CHF2CH2F) = (3.0 ± 0.9)×10(-14) cm3·分子(-1)·s(-1)。误差限包括统计数据分析的3σ以及所用参考化合物反应速率系数的误差。估计氢氟醚在对流层的寿命较短，τOH((CF3)2CHOCH3)约为100天，τOH(CF3CH2OCH2CF3)约为80天，τOH(CF3CF2CH2OCH3)约为20天，τOH(CHF2CF2CH2OCH3)约为14天，与CFC - 11相比，它们的全球变暖潜能较小。
