- Study of the OH and Cl-initiated oxidation, IR absorption cross-section, radiative forcing, and global warming potential of four C4- hydrofluoroethers
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Infrared absorption cross-sections and OH and Cl reaction rate coefficients for four C4-hydrofluoroethers (CF3)2- CHOCH3, CF3CH2OCH2CF3, CF3CF2CH2OCH3, and CHF 2CF2CH2-OCH3 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) × 10-13, k(OH+CF3-CH2OCH 2CF3) = (1.51 ± 0.24) × 10-13, k(OH+CF3CF2CH2OCH3) = (6.42 ± 0.33) × 10-13, k(OH+CHF2CF2CH 2OCH3) = (8.7 ± 0.5) × 10-13, k(Cl+(CF3)2CHOCH3) = (8.4 ± 1.3) × 10-12, k(Cl+CF3CH2OCH2CF 3) = (6.5 ± 1.7) × 10-13, k(Cl+CF 3CF2-CH2OCH3) = (4.0 ± 0.8) × 10-11, and k(Cl+CHF2CF2CH 2OCH3) = (2.65 ± 0.17) × 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, CF 3CH2OCHO, are reported: k(OH+CF3CH 2OCHO) = (7.7 ± 0.9) × 10-14 and k(Cl+CF 3CH2OCHO) = (6.3 ± 1.9) × 10-14 cm3 molecule-1 s-1. The rate coefficient for the Cl-atom reaction with CHF2-CH2F is derived as k(Cl+CHF2CH2F) = (3.0 ± 0.9) × 10 -14 cm3 molecule-1 s-1 at 298 K. The error limits include 3σ 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 τOH((CF3)2CHOCH3) ～ 100 days, τOH(CF3CH2OCH2-CF 3) ～ 80 days, τOH(CF3CF 2CH2OCH3) ～ 20 days, and τOH(CHF2CF2CH2OCH3) ～ 14 days, and their global warming potentials are small compared to CFC-11.
- Oyaro, Nathan,Sellevag, Stig R.,Nielsen, Claus J.
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- Atmospheric chemistry and environmental assessment of inhalational fluroxene
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Smog chamber/gas chromatography techniques are used to investigate the atmospheric degradation of fluroxene, an anesthetic, through oxidation with OH and Cl radicals at 298 K and under atmospheric pressure of N2 or air. The measured rate consta
- Bravo, Ivan,Rodriguez, Ana,Rodriguez, Diana,Diaz-De-Mera, Yolanda,Notario, Alberto,Aranda, Alfonso
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p. 3834 - 3842
(2013/11/19)
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- Atmospheric chemistry of CF3CH2OCH3: Reaction with chlorine atoms and OH radicals, kinetics, degradation mechanism and global warming potential
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FTIR smog chamber techniques were used to measure k(Cl + CF 3CH2OCH3) = (2.28 ± 0.44) × 10-11 and k(OH + CF3CH2OCH3) = (4.9 ± 1.3) × 10-13 cm3 molecule-1 s-1 in 700 Torr total pressure of air at 296 ± 2 K. The atmospheric lifetime of CF3CH2OCH3 is estimated at 25 days. Reaction of Cl atoms with CF3CH2OCH 3 proceeds 79 ± 4% at the CH3 group and 22 ± 2% at the CH2 group. Reaction with OH radicals proceeds 55 ± 5% at the CH3 group yielding CF3CH2OCHO and 45 ± 5% at the CH2 group yielding COF2 and CH 3OCHO as primary oxidation products. The infrared spectrum of CF 3CH(O)OCH3 was measured and a global warming potential GWP100 = 8 was estimated. The atmospheric chemistry and environmental impact of CF3CH2OCH3 is discussed in context of the use of hydrofluoroethers as CFC substitutes.
- ?sterstr?m, Freja From,Nielsen, Ole John,Sulbaek Andersen, Mads P.,Wallington, Timothy J.
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scheme or table
p. 32 - 37
(2012/03/09)
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