Atmospheric Fate of Nitramines: An Experimental and Theoretical Study of the OH Reactions with CH3NHNO2and (CH3)2NNO2

2014 ◽  
Vol 118 (19) ◽  
pp. 3450-3462 ◽  
Author(s):  
Mihayo Musabila Maguta ◽  
Marius Aursnes ◽  
Arne Joakim Coldevin Bunkan ◽  
Katie Edelen ◽  
Tomáš Mikoviny ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Atmospheric Fate ◽  
Oh Reactions

scholarly journals Rate Constants and Branching Ratios in the Oxidation of Aliphatic Aldehydes by OH Radicals under Atmospheric Conditions

2017 ◽  
Vol 56 (3) ◽  
Author(s):  
Romina Castañeda ◽  
Cristina Iuga ◽  
J. Raúl Álvarez-Idaboy ◽  
Annik Vivier-Bunge
Keyword(s):  
Theoretical Study ◽  
Hydrogen Abstraction ◽  
Branching Ratio ◽  
Branching Ratios ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
Atmospheric Conditions ◽  
Total Rate ◽  
Aliphatic Aldehydes ◽  
Oh Reactions

In this work, a theoretical study is presented on the mechanism of OH reactions with C1-C5 aliphatic aldehydes. We have shown that, starting from butanal, the Cβ H-abstraction channel becomes relatively important and it contributes moderately to the total rate constant. Calculated overall rate coefficients at the CCSD(T)/6-311++G**//BHandHLYP/6-311++G** level are in excellent agreement with experimental data, supporting the proposed mechanisms. Negative activation energies are found to be in agreement with the temperature dependence observed for aldehydes. The branching ratio between the aldehydic and Cβ hydrogen abstraction is not significantly modified as temperature increases from 230 to 330 K.

Experimental and Theoretical Study of the Carbon-13 and Deuterium Kinetic Isotope Effects in the Cl and OH Reactions of CH3F

2008 ◽  
Vol 112 (48) ◽  
pp. 12416-12429 ◽  
Author(s):  
Marina Marinkovic ◽  
Margret Gruber-Stadler ◽  
J. Michael Nicovich ◽  
Raenell Soller ◽  
Max Mülhäuser ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope ◽  
Oh Reactions

scholarly journals Atmospheric fate of a series of saturated alcohols: kinetic and mechanistic study

2020 ◽  
Vol 20 (2) ◽  
pp. 699-720
Author(s):  
Inmaculada Colmenar ◽  
Pilar Martin ◽  
Beatriz Cabañas ◽  
Sagrario Salgado ◽  
Araceli Tapia ◽  
...  
Keyword(s):  
Carbon Chain ◽  
Rate Coefficients ◽  
Mechanistic Study ◽  
Oh Radicals ◽  
Reaction Products ◽  
Atmospheric Fate ◽  
No3 Radical ◽  
Oh Reactions ◽  
Polyfunctional Compounds ◽  
Cl Atoms

Abstract. The atmospheric fate of a series of saturated alcohols (SAs) was evaluated through kinetic and reaction product studies with the main atmospheric oxidants. These SAs are alcohols that could be used as fuel additives. Rate coefficients (in cm3 molecule−1 s−1) measured at ∼298 K and atmospheric pressure (720±20 Torr) were as follows: k1 ((E)-4-methylcyclohexanol + Cl) = (3.70±0.16) ×10-10, k2 ((E)-4-methylcyclohexanol + OH) = (1.87±0.14) ×10-11, k3 ((E)-4-methylcyclohexanol + NO3) = (2.69±0.37) ×10-15, k4 (3,3-dimethyl-1-butanol + Cl) = (2.69±0.16) ×10-10, k5 (3,3-dimethyl-1-butanol + OH) = (5.33±0.16) ×10-12, k6 (3,3-dimethyl-2-butanol + Cl) = (1.21±0.07) ×10-10, and k7 (3,3-dimethyl-2-butanol + OH) = (10.50±0.25) ×10-12. The main products detected in the reaction of SAs with Cl atoms (in the absence/presence of NOx), OH radicals, and NO3 radicals were (E)-4-methylcyclohexanone for the reactions of (E)-4-methylcyclohexanol, 3,3-dimethylbutanal for the reactions of 3,3-dimethyl-1-butanol, and 3,3-dimethyl-2-butanone for the reactions of 3,3-dimethyl-2-butanol. Other products such as formaldehyde, 2,2-dimethylpropanal, and acetone have also been identified in the reactions of Cl atoms and OH radicals with 3,3-dimethyl-1-butanol and 3,3-dimethyl-2-butanol. In addition, the molar yields of the reaction products were estimated. The products detected indicate a hydrogen atom abstraction mechanism at different sites on the carbon chain of alcohol in the case of Cl reactions and a predominant site in the case of OH and NO3 reactions, confirming the predictions of structure–activity relationship (SAR) methods. Tropospheric lifetimes (τ) of these SAs have been calculated using the experimental rate coefficients. Lifetimes are in the range of 0.6–2 d for OH reactions, 7–13 d for NO3 radical reactions, and 1–3 months for Cl atoms. In coastal areas, the lifetime due to the reaction with Cl decreases to hours. The calculated global tropospheric lifetimes, and the polyfunctional compounds detected as reaction products in this work, imply that SAs could contribute to the formation of ozone and nitrated compounds at local, regional, and even global scales. Therefore, the use of saturated alcohols as additives in diesel blends should be considered with caution.

The atmospheric oxidation mechanism and kinetics of 1,3,5-trimethylbenzene initiated by OH radicals – a theoretical study

2017 ◽  
Vol 41 (18) ◽  
pp. 10259-10271 ◽  
Author(s):  
S. Ponnusamy ◽  
L. Sandhiya ◽  
K. Senthilkumar
Keyword(s):  
Theoretical Study ◽  
Oxidation Mechanism ◽  
Peroxy Radical ◽  
Ring Closure ◽  
Oh Radicals ◽  
Oh Radical ◽  
Radical Ring ◽  
Atmospheric Fate ◽  
Mechanism And Kinetics ◽  
Kinetics Of

The atmospheric fate of 1,3,5-trimethylbenzene is determined by OH-radical addition, and subsequent bicyclic peroxy radical ring closure and ring breaking pathways.

scholarly journals Atmospheric fate of a series of Methyl Saturated Alcohols (MSA): Kinetic and Mechanistic study

2019 ◽  
Author(s):  
Inmaculada Colmenar ◽  
Pilar Martin ◽  
Beatriz Cabañas ◽  
Sagrario Salgado ◽  
Araceli Tapia ◽  
...  
Keyword(s):  
Hydrogen Abstraction ◽  
Global Scale ◽  
Rate Coefficients ◽  
Mechanistic Study ◽  
Oh Radical ◽  
Reaction Products ◽  
Atmospheric Fate ◽  
No3 Radical ◽  
Oh Reactions ◽  
Polyfunctional Compounds

Abstract. The atmospheric fate of a series of Methyl Saturated Alcohols (MSA) has been evaluated through the kinetic and reaction product studies with the main atmospheric oxidants. Rate coefficients (in cm3 molecule−1 s−1 unit) measured at ~ 298 K and atmospheric pressure (~ 740 Torr) were as follows: (3.71 ± 0.53) × 10−10, (1.91 ± 0.65) × 10−11 and (2.92 ± 1.38) × 10−15 for reaction of E-4-methyl-cyclohexanol with Cl, OH and NO3, respectively. (2.70 ± 0.55) × 10−10 and (5.57 ± 0.66) × 10−12 for reaction of 3,3-dimethyl-1-butanol with Cl and OH radical respectively and (1.21 ± 0.37) × 10−10 and (10.51 ± 0.81) × 10−12 for reaction of 3,3-dimethyl-2-butanol with Cl and OH radical respectively. The main detected products were 4-methylcyclohexanone, 3,3-dimethylbutanal and 3,3-dimethyl-2-butanone for the reactions of E-4-methyl-cyclohexanol, 3,3-dimethyl-1-butanol and 3,3-dimethyl-2-butanol respectively with the three oxidants. A tentative estimation of yields have been done obtaining the following ranges (25–60) % for 4-methylcyclohexanone, (40–60) % for 3,3-dimethylbutanal and (40–80) % for 3,3-dimethyl-2-butanone. Other products as HCOH, 2,2-dimethylpropanal and acetone have been identified in the reaction of 3,3-dimethyl-1-butanol and 3,3-dimethyl-2-butanol. The yields of these products indicate a hydrogen abstraction mechanism at different sites of the alkyl chain in the case of Cl reaction and a predominant site in the case of OH and NO3 reactions, supported by SAR methods prediction. Tropospheric lifetimes (τ) of these MSA have been calculated using the experimental rate coefficients. Lifetimes are in the range of 0.6–2 days for OH reactions, 8–13 days for NO3 radical reactions and 1–3 months for Cl atoms. In coastal areas the lifetime due to the reaction with Cl decreases to hours. The global tropospheric lifetimes calculated, and the polyfunctional compounds detected as reaction products in this work, imply that the Methyl Saturated Alcohols could contribute to ozone and nitrated compound formation at local, but also regional and even to global scale. Therefore, the use of large saturated alcohols as additives in biofuels must be taken with caution.

Theoretical study on the atmospheric fate of carbonyl radicals: kinetics of decomposition reactions

2001 ◽  
Vol 3 (21) ◽  
pp. 4712 ◽  
Author(s):  
Raphaël Méreau ◽  
Marie-Thérèse Rayez ◽  
Jean-Claude Rayez ◽  
Françoise Caralp ◽  
Robert Lesclaux
Keyword(s):  
Theoretical Study ◽  
Decomposition Reactions ◽  
Atmospheric Fate ◽  
Kinetics Of Decomposition ◽  
Kinetics Of
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