Insights into the degradation of (CF3)2CHOCH3 and its oxidative product (CF3)2CHOCHO &amp; the formation and catalytic degradation of organic nitrates

Bai, Feng‐Yang; Jia, Zi-Man; Pan, Xiumei

doi:10.1016/j.atmosenv.2018.04.002

Cited by 15 publications

(2 citation statements)

References 48 publications

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“…Values of the equilibrium constant (K eq , in molecules cm À 3 ), unimolecular rate constant (k uni , s À 1 ), and overall rate constant (k tot , in cm 3 molecule À 1 s À 1 ) for the reactions of 2NO The previous reports have predicted that the water molecule has an influence on the atmospheric reactions. [63][64][65][66] The effect of water on NO 2 hydrolysis in the presence of A/MA/ DMA/U/TU has been studied deeply, and the reports have demonstrated that water molecule can reduce the barrier of 2NO 2 + H 2 O + A/MA/DMA/U/TU, and the reducing extent is decreasing as the number of the water molecules increases. [17,19,21,22] It is predicted that the water molecules have the similar influence on the systems of 2NO 2 + H 2 O + HD/MMH, so the effect of water on the reactions 2NO 2 + H 2 O + HD/MMH was not investigated.…”

Section: Kinetics Analysis Of 2no 2 + H 2 O + Hd/mmhmentioning

confidence: 99%

Hydrazine and its Derivatives: Role on Nitrogen Dioxide Hydrolysis and Ensuing Nucleation in the Atmosphere

Ni,

An,

Peng

et al. 2024

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Hydrazine (HD) and mono‐methyl hydrazine (MMH), as the compositions of rocket fuels and corrosion inhibitor, have a significant impact on the atmospheric environment. The effects of them on the reaction between NO2 and H2O were investigated theoretically from mechanism and kinetics, and it is expected that they can promote the hydrolysis of NO2 due to their lower free energy barriers. For the subsequent reaction HNO3+HONO+HD/MMH, acid base complex and zwitterionic structure were produced through isomerization. When one or two water molecules were involved in the subsequent reaction, only zwitterionic structure can be found with the lower free energy barrier, and the products were more stable than those without water molecules. To study the atmospheric behavior of HD/MMH, the structures, thermodynamics, interaction forces and temperature dependence of the clusters, which were consisted with HNO3 and HONO with the base molecules including ammonia, amine and amide, were further calculated, and the results show that the hydrogen bond is the main interaction in the clusters. The global minima remained fixed when the temperature increases from 200 K to 325 K. The forming reactions of the clusters were spontaneous, suggesting that ammonia, amine and amide can promote the nucleation of HNO3 and HONO molecules.

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Section: Kinetics Analysis Of 2no 2 + H 2 O + Hd/mmhmentioning

confidence: 99%

Hydrazine and its Derivatives: Role on Nitrogen Dioxide Hydrolysis and Ensuing Nucleation in the Atmosphere

Ni,

An,

Peng

et al. 2024

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“…The atmospheric lifetime of CH 3 CH 2 I (at 298 K) initiated by * Cl was evaluated to be 206.68 day ([ * Cl] = 1.0 × 10 4 molecule cm À 3 ) [39] according to the rate constant (5.60 × 10 À 12 cm 3 molecule À 1 s À 1 ) obtained by Jia et al. [40] This shows that * OH is more favorable than * Cl in the degradation of CH 3 CH 2 I. Bai et al [20] have evaluated the NO [41][42][43][44] Comparing the atmospheric lifetimes of CH 3 I and CH 3 CH 2 I initiated by * OH or NO 3 * radicals, it can be found that the introduction of À CH 3 can significantly shorten the atmospheric residence time of iodoalkanes and accelerate the formation of reactive iodine-containing radicals, promoting the iodine cycling process in the atmospheric environment.…”

Section: Atmospheric Lifetimementioning

confidence: 99%

Theoretical Study of the Hydroxyl‐Radical‐Initiated Degradation Mechanism, Kinetics, and Subsequent Evolution of Methyl and Ethyl Iodides in the Atmosphere

et al. 2023

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The degradation and transformation of iodinated alkanes are crucial in the iodine chemical cycle in the marine boundary layer. In this study, MP2 and CCSD(T) methods were adopted to study the atmospheric transformation mechanism and degradation kinetic properties of CH 3 I and CH 3 CH 2 I mediated by * OH radical. The results show that there are three reaction mechanisms including H-abstraction, I-substitution and I-abstraction. The H-abstraction channel producing * CH 2 I and CH 3 C • HI radicals are the main degradation pathways of CH 3 I and CH 3 CH 2 I, respectively. By means of the variational transition state theory and small curvature tunnel correction method, the rate constants and branching ratios of each reaction are calculated in the temperature range of 200-600 K. The results show that the tunneling effect contributes more to the reaction at low temperatures. Theoretical reaction rate constants of CH 3 I and CH 3 CH 2 I with * OH are calculated to be 1.42 × 10 À 13 and 4.44 × 10 À 13 cm 3 molecule À 1 s À 1 at T = 298 K, respectively, which are in good agreement with the experimental values. The atmospheric lifetimes of CH 3 I and CH 3 CH 2 I are evaluated to be 81.51 and 26.07 day, respectively. The subsequent evolution mechanism of * CH 2 I and CH 3 C • HI in the presence of O 2 , NO and HO 2 indicates that HCHO, CH 3 CHO, and I-atom are the main transformation end-products. This study provides a theoretical basis for insight into the diurnal conversion and environmental implications of iodinated alkanes.* and *OH [14,[19][20] in the atmospheric environment. Therefore, precise rate constants and subsequent reaction mechanism studies are needed to fully assess their environmental impact. The role of NO 3 * radical in the nocturnal transformation of CH 3 I and CH 3 CH 2 I has been explored by Nakano et al. [21][22] and Bai et al. [20] in experiment and theory, respectively. The results suggested that CH 3 I and CH 3 CH 2 I can be degraded in the atmosphere within a short time to serve as a source of reactive iodine compounds at night-time. Experimentally, Cotter et al. [14] inves-[a] X.

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Mechanism, kinetics, and environmental assessment of OH‐initiated transformation of CTDE in the atmosphere

Yang

Zhang

Deng

et al. 2020

Int J of Quantum Chemistry

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The transformation mechanism and kinetics of 2‐chloro‐1,1,2‐trifluoroethyl‐difluoromethyl‐ether (CTDE, CHF2OCF2CHFCl) triggered by OH radicals are studied by density‐functional theory methods and canonical variational transition state theory. The computational rate constant including small‐curvature tunneling correction is found to be in commendable agreement with the experimental data. Two hydrogen abstraction channels to form the alkyl radicals of C·F2OCF2CHFCl and CHF2OCF2C·FCl are observed, and the formation of CHF2OCF2C·FCl is found to be more favorable than C·F2OCF2CHFCl kinetically and thermodynamically. Subsequent evolution of CHF2OCF2C·FCl in the presence of NO and O2 indicates that the organic nitrate (CHF2OCF2CONO2FCl) is the stable product. The dechlorinate of alkoxy radical (CHF2OCF2C(O·)FCl) is the most favorable degradation channel, and the estimated ozone depletion potential for CTDE relative to chlorofluorocarbon‐11 is 0.0204, which could lead to ozone depletion as a consequence. The computed atmospheric lifetime for CTDE is found to be 3.69 years by considering the combined contributions from OH radicals and Cl atoms. The total radiative forcing and global warming potential of CTDE are, respectively, 0.547 W m−2 ppbv and 628.58 (100 years) at 298 K, suggesting that the contribution of CTDE to the greenhouse effect is moderate.

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Insights into the degradation of (CF3)2CHOCH3 and its oxidative product (CF3)2CHOCHO & the formation and catalytic degradation of organic nitrates

Cited by 15 publications

References 48 publications

Hydrazine and its Derivatives: Role on Nitrogen Dioxide Hydrolysis and Ensuing Nucleation in the Atmosphere

Hydrazine and its Derivatives: Role on Nitrogen Dioxide Hydrolysis and Ensuing Nucleation in the Atmosphere

Theoretical Study of the Hydroxyl‐Radical‐Initiated Degradation Mechanism, Kinetics, and Subsequent Evolution of Methyl and Ethyl Iodides in the Atmosphere

Mechanism, kinetics, and environmental assessment of OH‐initiated transformation of CTDE in the atmosphere

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