Atmospheric gas-phase degradation and global warming potentials of 2-fluoroethanol, 2,2-difluoroethanol, and 2,2,2-trifluoroethanol

Sellevåg, Stig Rune; Nielsen, Claus J.; Søvde, O. A.; Myhre, Gunnar; Sundet, Jostein K.; Stordal, Frøde; Isaksen, I. S. A.

doi:10.1016/j.atmosenv.2004.09.023

Cited by 51 publications

(89 citation statements)

References 25 publications

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“…This increase in k OH and k Cl with the length of the hydrocarbon chain has also been observed for the OH and Cl rate coefficients for partially fluorinated aldehydes CF 3 (CH 2 ) x CHO. [18] Regarding the degradation products of reactions (1) and (2), mechanistic studies carried out both in the absence and presence of NO x on the OH and Cl reactions with CF 3 CH 2 OH [6,25,26] and CF 3 CH 2 CH 2 OH [7][8][9] confirm that the main reaction pathway proceeds via hydrogen atom abstraction from the CH 2 group adjacent to the OH group, since the main primary product was the corresponding aldehyde. Theoretical studies recently performed by our group on the Cl-initiated reaction with CF 3 CH 2 OH [26] are consistent with the experimental observa- Table 2S of the Supporting Information.…”

Section: Resultsmentioning

confidence: 70%

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Atmospheric Lifetimes and Global Warming Potentials of CF₃CH₂CH₂OH and CF₃(CH₂)₂CH₂OH

et al. 2010

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A comprehensive study of several atmospheric degradation routes for two hydrofluoroalcohols, CF(3)(CH(2))(x=1,2)CH(2)OH, is presented. The gas-phase kinetics of their reactions with hydroxyl radicals (OH) and chlorine (Cl) atoms are investigated by absolute and relative techniques, respectively. The room-temperature rate coefficients (±σ, in cm(3) molecule(-1) s(-1)) k(OH) and k(Cl), are respectively (9.7±1.1)×10(-13) and (1.60±0.45)×10(-11) for CF(3)CH(2)CH(2)OH, and (2.62±0.32)×10(-12) and (8.71±0.24)×10(-11) for CF(3)(CH(2))(2)CH(2)OH. Average lifetimes of CF(3)CH(2)CH(2)OH and CF(3)(CH(2))(2)CH(2)OH due to the OH and Cl reactions are estimated to be 12 and 4 days, and greater than 20 and 4 years, respectively. Also, the IR and UV absorption cross sections of CF(3)(CH(2))(x=1,2)CH(2)OH are determined in the spectral ranges of 500-4000 cm(-1) and 200-310 nm. Photolysis of CF(3)(CH(2))(x=1,2)CH(2)OH in the actinic region (λ≥290 nm) is negligible compared to their homogeneous removal. Additionally, computational IR spectra are consistent with the experimental ones, thus giving high confidence in the obtained results. The lifetimes of CF(3)(CH(2))(x=1,2)CH(2)OH and IR spectra reported herein allow the calculation of the direct global warming potential of these hydrofluoroalcohols. The contribution of CF(3)(CH(2))(x)CH(2)OH to radiative forcing of climate change will be negligible.

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Section: Resultsmentioning

confidence: 70%

“…[5,6] It is expected that longer HFAs, CF 3 (CH 2 ) x CH 2 OH (x = 1 and 2), have a shorter t and thus lower GWP. A complete study of the gasphase kinetics of the tropospheric photooxidation of these HFAs initiated by OH radicals and chlorine (Cl) atoms is needed to better estimate t, and therefore their GWPs.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric Lifetimes and Global Warming Potentials of CF₃CH₂CH₂OH and CF₃(CH₂)₂CH₂OH

et al. 2010

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“…[4][5][6] CF 3 CH 2 CH 2 OH is the one among the family of CF 3 (CH 2 ) x CH 2 OH, and its major atmospheric photooxidation product is CF 3 CH 2 CHO. [7][8][9][10] The major degradation process of CF 3 CH 2 CHO in atmosphere is initiated by the OH radicals. Experimental studies have been performed by some groups to determine the absolute and relative rate constants of the CF 3 CH 2 CHO + OH reaction.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Studies on Mechanism and Kinetics of the Hydrogen-Abstraction Reaction of CF₃CH₂CHO with OH Radicals

Ci¹,

Yu²,

Wan³

et al. 2011

Bulletin of the Korean Chemical Society

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The hydrogen abstraction reaction of CF 3 CH 2 CHO + OH has been studied theoretically by dual-level direct dynamics method. Two stable conformers, trans-and cis-CF 3 CH 2 CHO, have been located, and there are four distinct OH hydrogen-abstraction channels from t-CF 3 CH 2 CHO and two channels from c-CF 3 CH 2 CHO. The required potential energy surface information for the kinetic calculation was obtained at the MCG3-MPWB// M06-2X/aug-cc-pVDZ level. The rate constants, which were calculated using improved canonical transitionstate theory with small-curvature tunneling correction (ICVT/SCT) were fitted by a four-parameter Arrhenius equation. It is shown that the reaction proceeds predominantly via the H-abstraction from the -CHO group over the temperature range 200-2000 K. The calculated rate constants were in good agreement with the experimental data between 263 and 358 K.

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“…On the other hand, atmospheric photooxidation of these fluorinated alcohols, initiated by hydroxyl (OH) radicals and chlorine (Cl) atoms, is known to yield fluorinated aldehydes as major products (Kelly et al, 2005;Hurley et al, 2004 and2005;Sellevåg et al, 2004a). Therefore, a complete understanding of the atmospheric fate of CF 3 (CH 2 ) x CHO would be needed in order to better evaluate the environmental implications of these hydrofluoroalcohols as CFCs substitutes.…”

Section: Introductionmentioning

confidence: 99%

“…CF 3 CH 2 OH and CF 3 CH 2 CH 2 OH have negligible GWPs (Sellevåg et al, 2004a, Waterland et al, 2005 and a zero ODP, since the −CF 3 group does not cause significant ozone depletion (Ravishankara et al, 1994). On the other hand, atmospheric photooxidation of these fluorinated alcohols, initiated by hydroxyl (OH) radicals and chlorine (Cl) atoms, is known to yield fluorinated aldehydes as major products (Kelly et al, 2005;Hurley et al, 2004 and2005;Sellevåg et al, 2004a).…”

Section: Introductionmentioning

confidence: 99%

Tropospheric photooxidation of CF3CH2CHO and CF3(CH2)2CHO initiated by Cl atoms and OH radicals

et al. 2010

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Abstract. The absolute rate coefficients for the tropospheric reactions of chlorine (Cl) atoms and hydroxyl (OH) radicals with CF 3 CH 2 CHO and CF 3 (CH 2 ) 2 CHO were measured as a function of temperature (263-371 K) and pressure (50-215 Torr of He) by pulsed UV laser photolysis techniques. Vacuum UV resonance fluorescence was employed to detect and monitor the time evolution of Cl atoms. Laser induced fluorescence was used in this work for the detection of OH radicals as a function of reaction time. No pressure dependence of the bimolecular rate coefficients, k Cl and k OH , was found at all temperatures. At room temperature k Cl and k OH were (in 10 −11 cm 3 molecule −1 s −1 ): k Cl (CF 3 CH 2 CHO) = (1.55±0.53); k Cl (CF 3 (CH 2 ) 2 CHO) = (3.39±1.38); k OH (CF 3 CH 2 CHO) = (0.259±0.050); k OH (CF 3 (CH 2 ) 2 CHO) = (1.28±0.24).A slightly positive temperature dependence of k Cl was observed for CF 3 CH 2 CHO and CF 3 (CH 2 ) 2 CHO, and k OH (CF 3 CH 2 CHO). In contrast, k OH (CF 3 (CH 2 ) 2 CHO) did not exhibit a temperature dependence over the range investigated. Arrhenius expressions for these reactions were: The atmospheric impact of the homogeneous removal by OH radicals and Cl atoms of these fluorinated aldehydes is discussed in terms of the global atmospheric lifetimes, taking into account different degradation pathways. The calculated lifetimes show that atmospheric oxidation of CF 3 (CH 2 ) x CHO are globally dominated by OH radicals, however reactions initiated by Cl atoms can act as a source of free radicals at dawn in the troposphere.

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Atmospheric gas-phase degradation and global warming potentials of 2-fluoroethanol, 2,2-difluoroethanol, and 2,2,2-trifluoroethanol

Cited by 51 publications

References 25 publications

Atmospheric Lifetimes and Global Warming Potentials of CF₃CH₂CH₂OH and CF₃(CH₂)₂CH₂OH

Atmospheric Lifetimes and Global Warming Potentials of CF₃CH₂CH₂OH and CF₃(CH₂)₂CH₂OH

Theoretical Studies on Mechanism and Kinetics of the Hydrogen-Abstraction Reaction of CF₃CH₂CHO with OH Radicals

Tropospheric photooxidation of CF<sub>3</sub>CH<sub>2</sub>CHO and CF<sub>3</sub>(CH<sub>2</sub>)<sub>2</sub>CHO initiated by Cl atoms and OH radicals

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Atmospheric gas-phase degradation and global warming potentials of 2-fluoroethanol, 2,2-difluoroethanol, and 2,2,2-trifluoroethanol

Cited by 51 publications

References 25 publications

Atmospheric Lifetimes and Global Warming Potentials of CF3CH2CH2OH and CF3(CH2)2CH2OH

Atmospheric Lifetimes and Global Warming Potentials of CF3CH2CH2OH and CF3(CH2)2CH2OH

Theoretical Studies on Mechanism and Kinetics of the Hydrogen-Abstraction Reaction of CF3CH2CHO with OH Radicals

Tropospheric photooxidation of CF&lt;sub&gt;3&lt;/sub&gt;CH&lt;sub&gt;2&lt;/sub&gt;CHO and CF&lt;sub&gt;3&lt;/sub&gt;(CH&lt;sub&gt;2&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;CHO initiated by Cl atoms and OH radicals

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Atmospheric Lifetimes and Global Warming Potentials of CF₃CH₂CH₂OH and CF₃(CH₂)₂CH₂OH

Atmospheric Lifetimes and Global Warming Potentials of CF₃CH₂CH₂OH and CF₃(CH₂)₂CH₂OH

Theoretical Studies on Mechanism and Kinetics of the Hydrogen-Abstraction Reaction of CF₃CH₂CHO with OH Radicals

Tropospheric photooxidation of CF<sub>3</sub>CH<sub>2</sub>CHO and CF<sub>3</sub>(CH<sub>2</sub>)<sub>2</sub>CHO initiated by Cl atoms and OH radicals