Atmospheric reaction of hydrazine plus hydroxyl radical

Abstract Understanding the mechanism of hydrazine oxidation reaction by OH radical along with the rate constants of all possible pathways leads to explain the fate of hydrazine in the atmosphere. In this article, the comprehensive mechanisms and kinetics of the hydrazine plus hydroxyl radical reacti...

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Autores principales: Hamed Douroudgari, Morteza Vahedpour, Fahime Khouini
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Publicado: Nature Portfolio 2021
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spelling oai:doaj.org-article:714515a5ad6149aebe8a116d7b0f12fe2021-12-02T18:02:44ZAtmospheric reaction of hydrazine plus hydroxyl radical10.1038/s41598-021-92563-82045-2322https://doaj.org/article/714515a5ad6149aebe8a116d7b0f12fe2021-06-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-92563-8https://doaj.org/toc/2045-2322Abstract Understanding the mechanism of hydrazine oxidation reaction by OH radical along with the rate constants of all possible pathways leads to explain the fate of hydrazine in the atmosphere. In this article, the comprehensive mechanisms and kinetics of the hydrazine plus hydroxyl radical reaction have been investigated theoretically at different temperatures and pressures. To achieve the main goals, a series of high levels of quantum chemical calculations have been widely implemented in reliable channels of the H-abstraction, SN2, and addition/elimination reactions. The energy profile of all pathways accompanied by the molecular properties of the involved stationary points has been characterized at the MP2, M06-2X, and CCSD(T)/CBS levels. To estimate accurate barrier energies of the H-abstraction channels, large numbers of the CCSD (T) calculations in conjunction with various augmented basis sets have been implemented. The direct dynamic calculations have been carried out using the validated M06-2X/maug-cc-pVTZ level, and also by the CCSD(T) (energies) + MP2 (partition functions) level. The pressure-dependent rate constants of the barrierless pathways have been investigated by the strong collision approach. Therefore, the main behaviors of the N2H4 + OH reaction have been explored according to the influences of temperature and pressure on the computed rate coefficients within the well-behaved theoretical frameworks of the TST, VTST, and RRKM theories. It has been found that the H-abstraction mechanism (to form N2H3) is dominant relative to the SN2 reaction and OH-addition to the N center of N2H4 moiety (to form H2NOH + NH2). The computed high pressure limit rate constant of the main reaction pathway, k(298.15) = 7.31 × 10–11 cm3 molecule−1 s−1, has an excellent agreement with the experimental value (k (298.15) = (6.50 ± 1.3) × 10–11 cm3 molecule−1 s−1) recommended by Vaghjiani. Also, the atmospheric lifetime of hydrazine degradation by OH radicals has been demonstrated to be 32.80 to 1161.11 h at the altitudes of 0–50 km. Finally, the disagreement in the calculated rate constants between the previous theoretical study and experimental results has been rectified.Hamed DouroudgariMorteza VahedpourFahime KhouiniNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-16 (2021)
institution DOAJ
collection DOAJ
language EN
topic Medicine
R
Science
Q
spellingShingle Medicine
R
Science
Q
Hamed Douroudgari
Morteza Vahedpour
Fahime Khouini
Atmospheric reaction of hydrazine plus hydroxyl radical
description Abstract Understanding the mechanism of hydrazine oxidation reaction by OH radical along with the rate constants of all possible pathways leads to explain the fate of hydrazine in the atmosphere. In this article, the comprehensive mechanisms and kinetics of the hydrazine plus hydroxyl radical reaction have been investigated theoretically at different temperatures and pressures. To achieve the main goals, a series of high levels of quantum chemical calculations have been widely implemented in reliable channels of the H-abstraction, SN2, and addition/elimination reactions. The energy profile of all pathways accompanied by the molecular properties of the involved stationary points has been characterized at the MP2, M06-2X, and CCSD(T)/CBS levels. To estimate accurate barrier energies of the H-abstraction channels, large numbers of the CCSD (T) calculations in conjunction with various augmented basis sets have been implemented. The direct dynamic calculations have been carried out using the validated M06-2X/maug-cc-pVTZ level, and also by the CCSD(T) (energies) + MP2 (partition functions) level. The pressure-dependent rate constants of the barrierless pathways have been investigated by the strong collision approach. Therefore, the main behaviors of the N2H4 + OH reaction have been explored according to the influences of temperature and pressure on the computed rate coefficients within the well-behaved theoretical frameworks of the TST, VTST, and RRKM theories. It has been found that the H-abstraction mechanism (to form N2H3) is dominant relative to the SN2 reaction and OH-addition to the N center of N2H4 moiety (to form H2NOH + NH2). The computed high pressure limit rate constant of the main reaction pathway, k(298.15) = 7.31 × 10–11 cm3 molecule−1 s−1, has an excellent agreement with the experimental value (k (298.15) = (6.50 ± 1.3) × 10–11 cm3 molecule−1 s−1) recommended by Vaghjiani. Also, the atmospheric lifetime of hydrazine degradation by OH radicals has been demonstrated to be 32.80 to 1161.11 h at the altitudes of 0–50 km. Finally, the disagreement in the calculated rate constants between the previous theoretical study and experimental results has been rectified.
format article
author Hamed Douroudgari
Morteza Vahedpour
Fahime Khouini
author_facet Hamed Douroudgari
Morteza Vahedpour
Fahime Khouini
author_sort Hamed Douroudgari
title Atmospheric reaction of hydrazine plus hydroxyl radical
title_short Atmospheric reaction of hydrazine plus hydroxyl radical
title_full Atmospheric reaction of hydrazine plus hydroxyl radical
title_fullStr Atmospheric reaction of hydrazine plus hydroxyl radical
title_full_unstemmed Atmospheric reaction of hydrazine plus hydroxyl radical
title_sort atmospheric reaction of hydrazine plus hydroxyl radical
publisher Nature Portfolio
publishDate 2021
url https://doaj.org/article/714515a5ad6149aebe8a116d7b0f12fe
work_keys_str_mv AT hameddouroudgari atmosphericreactionofhydrazineplushydroxylradical
AT mortezavahedpour atmosphericreactionofhydrazineplushydroxylradical
AT fahimekhouini atmosphericreactionofhydrazineplushydroxylradical
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