Atmospheric Chemistry of Hydrofluoroethers:  Reaction of a Series of Hydrofluoroethers with OH Radicals and Cl Atoms, Atmospheric Lifetimes, and Global Warming Potentials

Oyaro, Nathan; Sellevåg, Stig Rune; Nielsen, Claus J.

doi:10.1021/jp047860c

Cited by 89 publications

(147 citation statements)

References 42 publications

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“…The interaction between atomic chlorine or OH radical with organic molecules present in the atmosphere needs a detailed understanding as it might help in controlling the ozone depletion. The interaction of oxygen bases with atomic chlorine has been investigated in several works, for example the interaction of Cl • with H 2 O [1,2], halogenated ethers [3][4][5][6][7], methylacetate [8], halogenated aldehydes [9], fluorinated alcohols [10] and halogenated alkanes [11]. For most of these systems, such as the H 2 O. .…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of the interaction between pyridine derivatives and atomic chlorine. Substituent effect and nature of the bonding

2015

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The interaction of pyridine derivatives (H, ) with atomic chlorine is investigated theoretically by the density functional theory (DFT)-based LC-BLYP/aug-cc-pVDZ method. Pyridines and Cl • are held together by a (2c-3e) bond and the intermolecular distances range from 2.313 to 2.343Å. The existence of a N. . .Cl bond is confirmed by the atom-in-molecule analysis of the systems. The binding energies of the adducts, ranging from −42.08 to −53.96 kJ mol −1 , are linearly correlated to the proton affinity of the pyridines. The charge transfer from pyridine to Cl • varies between 0.222 and 0.277 e. The spin density analysis shows that the strongest complex has the highest (2c-3e) character. The CH bonds are contracted and the ν(CH) vibrations are blueshifted owing to the decrease in σ * (CH) occupation. This decrease results not only from the classical anomeric effect but also from the σ (CC) and σ (CN) → σ * (CH) delocalisation in the heteroaromatic ring.

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Section: Introductionmentioning

confidence: 99%

Theoretical study of the interaction between pyridine derivatives and atomic chlorine. Substituent effect and nature of the bonding

2015

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“…As such the overall rate constant for the reaction of OH with CF 3 OCH 2 CH 3 was reported to be 0.5 x 10 -13 which is about three times lower than the experimentally determined value of 1.55 ± 0.25 x 10 -13 cm 3 molecule -1 sec -1 at 298K and 1 atmospheric pressure based on relative rate method using gas chromatography mass spectrometry (GC-MS) detection technique. 13 In order to assess the contribution of each channel to the overall degradation rate, the present study has been undertaken, In this study the individual contribution of different reaction pathways, to the overall rate coefficient for the degradation of the title molecule has been calculated and the branching ratio determined. The aim of this work is to have deep insight into the reaction of CF 3 OCH 2 CH 3 with OH radical using state-of-art computational procedure to get reliable data.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and mechanism of gas-phase reaction of CF₃OCH₂CH₃ (HFE-263) with the OH radical — a theoretical study

Rao

Singh

2015

Can. J. Chem.

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In the present study, density functional method with recently developed M06 functionals has been used to study the reaction of CF 3 OCH 2 CH 3 with OH radical. All possible H-abstraction and displacement reaction channels have been modeled. The minimum energy path on the respective potential energy surface and energetics were calculated at M06-2X/6-311++G(d,p) level of theory. Two different reaction mechanisms (i) involving reactant and product complexes called the complex mechanism and the (ii) the direct mechanism (Reactant TS Product) were considered. Tunneling corrections were made using Eckart unsymmetrical potential. The overall rate constant calculated by complex mechanism (k eff =1.8 x 10 -13 cm 3 molecule -1 sec -1 ) has been found to be in good agreement with the experimentally determined value (1.5 ± 0.25 x 10 -13 cm 3 molecule -1 sec -1 ) while the rate constant calculated by direct mechanism (k D =7.6 x 10 -14 cm 3 molecule -1 sec -1 ) is about two times lower than the experimental value. The theoretical studies show that H atom abstraction from -CH 2 -site is most favorable reaction pathway and the reaction involves pre-reactive and product complexes before leading to stable product formation.

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“…4 Langbein et al reported that the atmospheric effects of all the halogenated anesthetics combined produce a relative contribution to global warming of .03%.…”

Section: Nitrous Oxide: a Global Toxicological Effect To Considermentioning

confidence: 99%

Nitrous Oxide: A Global Toxicological Effect to Consider

Parker

Behringer²

2009

Anesthesiology

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Nitrous Oxide: A Global Toxicological Effect to ConsiderTo the Editor:-The recent review article by Sanders et al. 1 was informative and comprehensive, with the exception of one important toxicological detail. Nitrous oxide is known to have a significant global climatologic impact as a naturally occurring greenhouse gas. After carbon dioxide and methane, nitrous oxide is the third most climatologically significant greenhouse gas. Greenhouse gases act like a warming blanket in the troposphere and prevent radiative cooling. Nitrous oxide is a particularly potent greenhouse gas with 300 times the global warming potential of carbon dioxide over 100 yr, according to the Intergovernmental Panel on Climate Change.2 It seems prudent to include the climatologic effects of nitrous oxide as a biologic effect of the gas.The climatologic effect and global warming potential of all halogenated anesthetic agents was addressed in a 1989 article, in the journal Nature, by Brown and colleagues. They concluded that the relatively short atmospheric lifetime of these agents reduces their ozone-depleting impact and global warming potential significantly, relative to other chlorofluorocarbons.3 Desflurane has a global warming potential 1,341 times more potent than that of carbon dioxide when considered over a 100-yr period. 4 Langbein et al. reported that the atmospheric effects of all the halogenated anesthetics combined produce a relative contribution to global warming of .03%.5 Nitrous oxide, in contrast, has a long atmospheric lifetime of approximately 120 yr.* The vast majority of atmospheric nitrous oxide from human activity is released from combustion and agricultural soils, particularly after the use of nitrogenous fertilizers. Although anesthetic nitrous oxide is believed to constitute a proportionally small amount of all atmospheric nitrous oxide by volume, the exact relative global warming contribution from all medical and dental anesthetic use remains to be studied.Carbon dioxide regulation has begun, and nitrous oxide emissions are targeted by the 1997 Kyoto Protocol. Nitrous oxide is likely to be further regulated after adoption of the next climate change treaty at the 2009 United Nations Climate Change Conference in Copenhagen, Denmark. Nitrous oxide's potency as a greenhouse gas and the potential for regulation under international climate change accords argue for inclusion in any review of the biologic effects of this gas. Climate change is an important global-scale biologic crisis. International dialogue and reporting are essential to find solutions to this issue.

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Atmospheric Chemistry of Hydrofluoroethers: Reaction of a Series of Hydrofluoroethers with OH Radicals and Cl Atoms, Atmospheric Lifetimes, and Global Warming Potentials

Cited by 89 publications

References 42 publications

Theoretical study of the interaction between pyridine derivatives and atomic chlorine. Substituent effect and nature of the bonding

Theoretical study of the interaction between pyridine derivatives and atomic chlorine. Substituent effect and nature of the bonding

Kinetics and mechanism of gas-phase reaction of CF₃OCH₂CH₃ (HFE-263) with the OH radical — a theoretical study

Nitrous Oxide: A Global Toxicological Effect to Consider

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Atmospheric Chemistry of Hydrofluoroethers: Reaction of a Series of Hydrofluoroethers with OH Radicals and Cl Atoms, Atmospheric Lifetimes, and Global Warming Potentials

Cited by 89 publications

References 42 publications

Theoretical study of the interaction between pyridine derivatives and atomic chlorine. Substituent effect and nature of the bonding

Theoretical study of the interaction between pyridine derivatives and atomic chlorine. Substituent effect and nature of the bonding

Kinetics and mechanism of gas-phase reaction of CF3OCH2CH3 (HFE-263) with the OH radical — a theoretical study

Nitrous Oxide: A Global Toxicological Effect to Consider

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Product

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Kinetics and mechanism of gas-phase reaction of CF₃OCH₂CH₃ (HFE-263) with the OH radical — a theoretical study