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Sulbaek Andersen MP, Volkova A, Hass SA, Lengkong JW, Hovanessian D, Sølling TI, Wallington TJ, Nielsen OJ. Atmospheric chemistry of ( Z)- and ( E)-1,2-dichloroethene: kinetics and mechanisms of the reactions with Cl atoms, OH radicals, and O 3. Phys Chem Chem Phys 2022; 24:7356-7373. [PMID: 35266471 DOI: 10.1039/d1cp04877e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Smog chambers interfaced with in situ FT-IR detection were used to investigate the kinetics and mechanisms of the Cl atom, OH radical, and O3 initiated oxidation of (Z)- and (E)-1,2-dichloroethene (CHClCHCl) under atmospheric conditions. Relative and absolute rate methods were used to measure k(Cl + (Z)-CHClCHCl) = (8.80 ± 1.75) × 10-11, k(Cl + (E)-CHClCHCl) = (8.51 ± 1.69) × 10-11, k(OH + (Z)-CHClCHCl) = (2.02 ± 0.43) × 10-12, k(OH + (E)-CHClCHCl) = (1.94 ± 0.43) × 10-12, k(O3 + (Z)-CHClCHCl) = (4.50 ± 0.45) × 10-21, and k(O3 + (E)-CHClCHCl) = (1.02 ± 0.10) × 10-19 cm3 molecule-1 s-1 in 700 Torr of N2/air diluent at 298 ± 2 K. Pressure dependencies for the Cl atom reaction kinetics were observed for both isomers, consistent with isomerization occurring via Cl atom elimination from the chemically activated CHCl-CHCl-Cl adduct. The observed products from Cl initiated oxidation were HC(O)Cl (117-133%), CHCl2CHO (29-30%), and the corresponding CHClCHCl isomer (11-20%). OH radical initiated oxidation gives HC(O)Cl as a major product. For reaction of OH with (E)-CHClCHCl, (Z)-CHClCHCl was also observed as a product. A significant chlorine atom elimination channel was observed experimentally (HCl yield) and supported by computational results. Photochemical ozone creation potentials of 12 and 11 were estimated for (Z)- and (E)-CHClCHCl, respectively. Finally, an empirical kinetic relationship is explored for the addition of OH radicals or Cl atoms to small alkenes. The results are discussed in the context of the atmospheric chemistry of (Z)- and (E)-CHClCHCl.
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Affiliation(s)
- Mads P Sulbaek Andersen
- Department of Chemistry and Biochemistry, California State University Northridge, 18111 Nordhoff St., Northridge, CA 91330-8262, USA.
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Aleksandra Volkova
- Department of Chemistry and Biochemistry, California State University Northridge, 18111 Nordhoff St., Northridge, CA 91330-8262, USA.
| | - Sofie A Hass
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Jonathan W Lengkong
- Department of Chemistry and Biochemistry, California State University Northridge, 18111 Nordhoff St., Northridge, CA 91330-8262, USA.
| | - Dvien Hovanessian
- Department of Chemistry and Biochemistry, California State University Northridge, 18111 Nordhoff St., Northridge, CA 91330-8262, USA.
| | - Theis I Sølling
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
- Center for Integrative Petroleum Research, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Kingdom of Saudi Arabia
| | - Timothy J Wallington
- Research & Advanced Engineering, Ford Motor Company, Dearborn, MI 48121-2053, USA
| | - Ole J Nielsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
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Sapkota R, Marshall P. Gas-Phase Chemistry of 1,1,2,3,3,4,4-Heptafluorobut-1-ene Initiated by Chlorine Atoms. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27030647. [PMID: 35163912 PMCID: PMC8839731 DOI: 10.3390/molecules27030647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/14/2022] [Accepted: 01/14/2022] [Indexed: 11/16/2022]
Abstract
The possibility of mitigating climate change by switching to materials with low global warming potentials motivates a study of the spectroscopic and kinetic properties of a fluorinated olefin. The relative rate method was used to determine the rate constant for the reaction of heptafluorobut-1-ene (CF2=CFCF2CF2H) with chlorine atoms in air. A mercury UV lamp was used to generate atomic chlorine, which initiated chemistry monitored by FTIR spectroscopy. Ethane was used as the reference compound for kinetic studies. Oxidation of heptafluorobut-1-ene initiated by a chlorine atom creates carbonyl difluoride (CF2=O) and 2,2,3,3 tetrafluoropropanoyl fluoride (O=CFCF2CF2H) as the major products. Anharmonic frequency calculations allowing for several low-energy conformations of 1,1,2,3,3,4,4 heptafluorobut-1-ene and 2,2,3,3 tetrafluoropropanoyl fluoride, based on density functional theory, are in good accord with measurements. The global warming potentials of these two molecules were calculated from the measured IR spectra and estimated atmospheric lifetimes and found to be small, less than 1.
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Affiliation(s)
- Ramesh Sapkota
- Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, TX 76203, USA;
| | - Paul Marshall
- Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, #305070, Denton, TX 76203, USA
- Correspondence:
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Holtomo O, Rhyman L, Nsangou M, Ramasami P, Motapon O. Reaction of •OH with CHCl=CH-CHF2 and its atmospheric implication for future environmental-friendly refrigerant. PURE APPL CHEM 2021. [DOI: 10.1515/pac-2021-0116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
In order to understand the atmospheric implication of the chlorinated hydrofluoroolefin (HFO), the geometrical structures and the IR absorption cross sections of the stereoisomers 1-chloro-3,3-difluoropropene were studied using the B3LYP/6-31G(3df) and M06-2X/6-31G(3df) methods in the gas phase. The cis-trans isomerization was assessed using the M06-2X/6-311++G(3df,p)//6-31+G(3df,p) method. The latter method was also employed for thermochemistry and the rate coefficients of the reactions of •OH with the cis- and trans-isomers in the temperature ranging from 200 to 400 K. The computational method CCSD/cc-pVTZ//M06-2X/6-31+G(3df,p) was used to benchmark the rate coefficients. It turns out that, the trans-isomer is more stable than cis-isomer and the trans- to cis-isomerization is thermodynamically unfavorable. The rate coefficient follows the Gaussian law with respect to the inverse of temperature. At the global temperature of stratosphere, the calculated rate coefficients served to estimate the atmospheric lifetime along with the photochemical ozone creation potential (POCP). This yielded lifetimes of 4.31 and 7.31 days and POCPs of 3.80 and 2.23 for the cis- and trans-isomer, respectively. The radiative forcing efficiencies gave 0.0082 and 0.0152 W m−2 ppb−1 for the cis- and trans-isomer, respectively. The global warming potential approached zero for both stereoisomers at 20, 100, and 500 years time horizons.
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Affiliation(s)
- Olivier Holtomo
- Department of Physics , Faculty of Science, University of Bamenda , Bambili P.O. Box 39 , Cameroon
- Department of Physics , Faculty of Science, University of Maroua , Maroua P.O. Box 814 , Cameroon
| | - Lydia Rhyman
- Department of Chemistry , Computational Chemistry Group, Faculty of Science, University of Mauritius , Réduit 80837 Mauritius
- Department of Chemical Sciences , Centre for Natural Product Research, University of Johannesburg , Doornfontein , Johannesburg 2028 , South Africa
| | - Mama Nsangou
- Department of Physics , Higher Teacher's Training College, University of Maroua , Maroua P.O. Box 46 , Cameroon
- Department of Physics , Faculty of Science, University of Ngaoundéré , Ngaoundéré P.O. Box 454 , Cameroon
| | - Ponnadurai Ramasami
- Department of Chemistry , Computational Chemistry Group, Faculty of Science, University of Mauritius , Réduit 80837 Mauritius
- Department of Chemical Sciences , Centre for Natural Product Research, University of Johannesburg , Doornfontein , Johannesburg 2028 , South Africa
| | - Ousmanou Motapon
- Department of Physics , Faculty of Science, University of Maroua , Maroua P.O. Box 814 , Cameroon
- Laboratory of Fundamental Physics, Faculty of Science, University of Douala , Douala P.O. Box 24157 , Cameroon
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