A theoretical insight into atmospheric chemistry of HFE-7100 and perfluoro-butyl formate: reactions with OH radicals and Cl atoms and the fate of alkoxy radicals

Mishra, Bhupesh Kumar; Lily, Makroni; Deka, Ramesh Chandra; Chandra, Asit K.

doi:10.1039/c5nj02752g

Cited by 20 publications

(10 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The overall rate coefficients for the PSICl + OH radical reaction in the present studied temperatures between 200 and 320 K and with an average tropospheric concentration of [OH] = 1.0 × 10 6 molecules cm –3 were used in calculating the atmospheric lifetime of PSICl with respect to the OH radical in the same studied temperature range. The atmospheric lifetime (τ) of PSICl with the OH radical was computed using equation − τ = 1/( k overall [OH]). In this equation, k overall represents the overall rate coefficient for the PSICl + OH radical reaction and [OH] represents the average tropospheric concentration of the OH radical.…”

Section: Theoretical Kinetic Analysismentioning

confidence: 99%

Thermochemistry and Kinetics of the Atmospheric Oxidation Reactions of Propanesulfinyl Chloride Initiated by OH Radicals: A Computational Approach

Arathala

Musah

2022

J. Phys. Chem. A

View full text Add to dashboard Cite

The thermochemistry and kinetics of the atmospheric oxidation mechanism for propanesulfinyl chloride (CH3–CH2–CH2–S(O)Cl; PSICl) initiated by the hydroxyl (OH) radical were investigated with high level quantum chemistry calculations and the Master equation solver for multi-energy well reaction (Mesmer) kinetic code. The mechanism for the oxidation of PSICl in the presence of OH radical can proceed via H-abstraction and substitution pathways. The CCSD(T)/aug-cc-pV(T+d)Z//MP2/aug-cc-pV(T+d)Z level calculated energies revealed addition of the OH radical to the S-atom of the sulfinyl (−S(O)) moiety, followed by cleavage of the Cl–S(O) single bond, leading to formation of propanesulfinic acid (PSIA) and the Cl radical to be the major pathway when compared to all other possible channels. The transition state barrier height for this reaction was found to be −3.0 kcal mol–1 relative to the energy of the starting PSICl + OH radical reactants. The rate coefficients were calculated for all possible paths in the atmospherically relevant temperature range of 200–320 K and at 1 atm. The rate coefficient for the formation of the PSIA + Cl radical from the PSICl + OH radical reaction was found to be 8.2 × 10–12 cm3 molecule–1 s–1 at 298 K and a pressure of 1 atm. From branching ratio calculations, it was revealed that the reaction resulting in the formation of the PSIA + Cl radical contributed ∼52% to the total reaction. The overall rate coefficient for the PSICl + OH reaction was also calculated and found to be 1.6 × 10–11 cm3 molecule–1 s–1 at 298 K and a pressure of 1 atm. In the aggregate, the results indicate the atmospheric lifetime of PSICl to be ∼12–20 h in the temperature range between 200 and 320 K, which suggests that its contribution to global warming is negligible. However, the degradation products revealed to be formed in its interactions with the OH radical, which include that SO2, Cl radical, HO2 radical, and propylene have significant effects on the formation of acid rain, secondary organic aerosols, the ozone layer, and global warming.

show abstract

Section: Theoretical Kinetic Analysismentioning

confidence: 99%

Thermochemistry and Kinetics of the Atmospheric Oxidation Reactions of Propanesulfinyl Chloride Initiated by OH Radicals: A Computational Approach

Arathala

Musah

2022

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

“…Hydrofluoroethers (HFEs) are being considered as an alternative to chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), and hydrochlorofluorocarbons (HCFCs) for wide variety of commercial applications, such as cleaning of electronic equipment, heat transfer fluid in refrigerators, lubricant deposition, and foam blowing agents. HFEs do not contain chlorine and bromine atoms that are responsible for ozone depletion. − Fluorinated compounds may exhibit strong absorption in the Earth’s infrared atmospheric transparency window, between 8 and 13 μm, thus acting as greenhouse gases . To find the global warming potential (GWP) and lifetime of a compound in the atmosphere, information about the infrared absorption spectrum and rate of the reaction are required.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric Oxidation Mechanism and Kinetics of Hydrofluoroethers, CH₃OCF₃, CH₃OCHF₂, and CHF₂OCH₂CF₃, by OH Radical: A Theoretical Study

2018

View full text Add to dashboard Cite

In the present work, the reaction mechanism of two segregated hydrofluoroethers (HFEs), CHOCF (HFE-143a) and CHOCHF (HFE-152a), and a nonsegregated HFE, CHFOCHCF (HFE-245fa2), with OH radical is studied using electronic structure calculations. The initial reaction between HFE and OH radical is studied by considering two (three for CHFOCHCF) pathways, H-atom abstraction and C-O bond breaking, OH addition reaction and C-C bond breaking, and OH addition reaction, which leads to the formation of alkyl radical intermediate. The dominant atmospheric fate of initially formed alkyl radical intermediate is its reaction with O. The peroxy radicals thus formed exit through the reaction with HO radical and NO radical resulting in the formation of products, carbonyl fluoride (COF), trifluoromethylformate, trifluoro(hydroperoxymethoxy)methane, difluoro(hydroperoxy methoxy)methane, difluoromethylformate, 2-(difluoromethoxy)-1,1,1-trifluoro-2-hydroperoxyethane, and difluoromethyl ester. The rate constant is calculated for the initial H-atom abstraction reaction using canonical variational transition state theory with small curvature tunnelling corrections over the temperature range 272-350 K. The atmospheric lifetime and global warming potential of HFEs are obtained from the calculated reaction potential energy surface and rate constant. The results are discussed with respect to the atmospheric implications of CHOCF (HFE-143a), CHOCHF (HFE-152a), and CHFOCHCF (HFE-245fa2).

show abstract

“…The cumulative atmospheric lifetime of DPTS with respect to its reactions with OH and Cl radicals was calculated using eq . − …”

Section: Results and Discussionmentioning

confidence: 99%

“…The other terms τ OH and τ Cl represent the atmospheric lifetimes of DPTS with respect to its reactions with OH and Cl radicals, respectively. The lifetime (τ) of any atmospheric molecule can be calculated using the equation − τ = 1/ k [X], where “ k ” represents the bimolecular rate coefficients for the DPTS + • Cl or DPTS + • OH reaction, and “[X]” represents the OH or Cl radical concentration. The average atmospheric concentrations of [ • OH] = 1.0 × 10 6 molecules cm –3 and [ • Cl] = 1.3 × 10 5 atoms cm –3 , respectively, ,, were used in calculating the atmospheric lifetime of DPTS with the corresponding • OH and • Cl radicals.…”

Section: Results and Discussionmentioning

confidence: 99%

Oxidation of Dipropyl Thiosulfinate Initiated by Cl Radicals in the Gas Phase: Implications for Atmospheric Chemistry

Arathala

Musah

2021

ACS Earth Space Chem.

View full text Add to dashboard Cite

The reaction mechanism for chlorine radical (•Cl)-initiated atmospheric oxidation of dipropyl thiosulfinate (DPTS) in the gas phase was investigated using ab initio/density functional theory electronic structure calculations. The DPTS + •Cl reaction proceeds by H-abstraction and substitution pathways. The results indicate that the Cl radical adds to the S-atom of the sulfinyl [S(O)] group of DPTS, which is followed by cleavage of the S(O)–S single bond, leading to the formation of propanesulfinyl chloride and propanethiyl radical (PTR). The barrier height for this reaction was estimated to be −12.2 kcal mol–1 relative to the separated starting reactants. The rate coefficients were calculated for all possible H-abstraction and substitution paths using the master equation solver for the multi-energy well reactions (MESMER) kinetic code in the atmospherically relevant temperature range of 200–300 K and at 1 atm pressure. The rate coefficient data for all reaction paths indicate that the formation of propanesulfinyl chloride and PTR from the DPTS + •Cl reaction is the major path. The rate coefficient for this reaction was estimated to be ∼6.00 × 10–10 cm3 molecule–1 s–1 at 298 K and 1 atm pressure. The overall rate coefficient for the DPTS + •Cl reaction in the same temperature range was found to be ∼8.14 × 10–10 cm3 molecule–1 s–1 at 298 K. The atmospheric lifetime of DPTS was calculated to be ∼3 h in the temperatures between 200 and 300 K and at 1 atm. In addition, the branching ratio fractions for each reaction were determined and the atmospheric implications are discussed. Overall, the results reveal that while the primary products of the DPTS + Cl radical reaction are short-lived, the compounds formed from their subsequent oxidative degradation do contribute to global warming and have the potential to exhibit adverse environmental impacts.

show abstract

A theoretical insight into atmospheric chemistry of HFE-7100 and perfluoro-butyl formate: reactions with OH radicals and Cl atoms and the fate of alkoxy radicals

Abstract: The calculated rate constants for C4F9OCH3 + OH/Cl reactions are found to be 1.94 × 10−14 and 1.74 × 10−12 cm3 molecule−1 s−1, respectively, at 298 K. The atmospheric lifetime and global warming potential for HFE-7100 are computed to be 2.12 years and 155.3, respectively.

Cited by 20 publications

References 40 publications

Thermochemistry and Kinetics of the Atmospheric Oxidation Reactions of Propanesulfinyl Chloride Initiated by OH Radicals: A Computational Approach

Thermochemistry and Kinetics of the Atmospheric Oxidation Reactions of Propanesulfinyl Chloride Initiated by OH Radicals: A Computational Approach

Atmospheric Oxidation Mechanism and Kinetics of Hydrofluoroethers, CH₃OCF₃, CH₃OCHF₂, and CHF₂OCH₂CF₃, by OH Radical: A Theoretical Study

Oxidation of Dipropyl Thiosulfinate Initiated by Cl Radicals in the Gas Phase: Implications for Atmospheric Chemistry

Contact Info

Product

Resources

About

A theoretical insight into atmospheric chemistry of HFE-7100 and perfluoro-butyl formate: reactions with OH radicals and Cl atoms and the fate of alkoxy radicals

Abstract: The calculated rate constants for C4F9OCH3 + OH/Cl reactions are found to be 1.94 × 10−14 and 1.74 × 10−12 cm3 molecule−1 s−1, respectively, at 298 K. The atmospheric lifetime and global warming potential for HFE-7100 are computed to be 2.12 years and 155.3, respectively.

Cited by 20 publications

References 40 publications

Thermochemistry and Kinetics of the Atmospheric Oxidation Reactions of Propanesulfinyl Chloride Initiated by OH Radicals: A Computational Approach

Thermochemistry and Kinetics of the Atmospheric Oxidation Reactions of Propanesulfinyl Chloride Initiated by OH Radicals: A Computational Approach

Atmospheric Oxidation Mechanism and Kinetics of Hydrofluoroethers, CH3OCF3, CH3OCHF2, and CHF2OCH2CF3, by OH Radical: A Theoretical Study

Oxidation of Dipropyl Thiosulfinate Initiated by Cl Radicals in the Gas Phase: Implications for Atmospheric Chemistry

Contact Info

Product

Resources

About

Atmospheric Oxidation Mechanism and Kinetics of Hydrofluoroethers, CH₃OCF₃, CH₃OCHF₂, and CHF₂OCH₂CF₃, by OH Radical: A Theoretical Study