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.

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.

scholarly journals Atmospheric degradation of 3-methylfuran: kinetic and products study

2010 ◽  
Vol 10 (10) ◽  
pp. 22905-22952
Author(s):  
A. Tapia ◽  
F. Villanueva ◽  
M. S. Salgado ◽  
B. Cabañas ◽  
E. Martínez ◽  
...  
Keyword(s):  
Aromatic Ring ◽  
Atmospheric Pressure ◽  
Ring Opening ◽  
Room Temperature ◽  
Rate Coefficients ◽  
Main Reaction ◽  
Phase Reaction ◽  
Reaction Products ◽  
No3 Radical ◽  
Cl Atoms

Abstract. A study of the kinetics and products obtained from the reactions of 3-methylfuran with the main atmospheric oxidants has been performed. The rate coefficients for the gas-phase reaction of 3-methylfuran with OH and NO3 radicals have been determined at room temperature and atmospheric pressure (air and N2 as bath gases), using a relative method with different experimental techniques. The absolute rate coefficients obtained for these reactions were (in units cm3 molecule−1 s−1): kOH=(1.13±0.22)×10−10 and kNO3=(1.26±0.18)×10−11. These rate coefficients have been compared with those available in the literature. The products from the reaction of 3-methylfuran with OH, NO3 and Cl atoms in the absence and in the presence of NOx species have also been determined. The main reaction products obtained were chlorinated methylfuranones and hydroxy-methylfuranones for the reaction of 3-methylfuran with Cl atoms, 2-methylbutenedial, 3-methyl-2,5-furanodione and hydroxy-methylfuranones for the reaction of 3-methylfuran with OH and NO3 radicals and also nitrated compounds for the reaction with NO3 radicals. The results indicate that in all cases the main reaction path is the addition to the double bond of the aromatic ring followed by ring opening in the case of OH and NO3 radicals. The formation of 3-furaldehyde and hydroxy-methylfuranones (in the reactions of 3-methylfuran with Cl atoms and NO3 radicals) confirmed the H-atom abstraction from the methyl group and from the aromatic ring, respectively. This study represents the first product determination for both Cl atoms and the NO3 radical in reactions with 3-methylfuran. The reaction mechanisms and atmospheric implications of the reactions under consideration are also discussed.

scholarly journals Rate coefficients for the reaction of methylglyoxal (CH<sub>3</sub>COCHO) with OH and NO<sub>3</sub> and glyoxal (HCO)<sub>2</sub> with NO<sub>3</sub>

2011 ◽  
Vol 11 (21) ◽  
pp. 10837-10851 ◽  
Author(s):  
R. K. Talukdar ◽  
L. Zhu ◽  
K. J. Feierabend ◽  
J. B. Burkholder
Keyword(s):  
Relative Rate ◽  
Order Conditions ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
Phase Reaction ◽  
First Order ◽  
No3 Radical ◽  
Pseudo First Order ◽  
Arrhenius Expression ◽  
Coefficient Method

Abstract. Rate coefficients, k, for the gas-phase reaction of CH3COCHO (methylglyoxal) with the OH and NO3 radicals and (CHO)2 (glyoxal) with the NO3 radical are reported. Rate coefficients for the OH + CH3COCHO (k1) reaction were measured under pseudo-first-order conditions in OH as a function of temperature (211–373 K) and pressure (100–220 Torr, He and N2 bath gases) using pulsed laser photolysis to produce OH radicals and laser induced fluorescence to measure its temporal profile. k1 was found to be independent of the bath gas pressure with k1(295 K) = (1.29 ± 0.13) × 10−11 cm3 molecule−1 s−1 and a temperature dependence that is well represented by the Arrhenius expression k1(T) = (1.74 ± 0.20) × 10−12 exp[(590 ± 40)/T] cm3 molecule−1 s−1 where the uncertainties are 2σ and include estimated systematic errors. Rate coefficients for the NO3 + (CHO)2 (k3) and NO3 + CH3COCHO (k4) reactions were measured using a relative rate technique to be k3(296 K) = (4.0 ± 1.0) × 10−16 cm3 molecule−1 s−1 and k4(296 K) = (5.1 ± 2.1) × 10−16 cm3 molecule−1 s−1. k3(T) was also measured using an absolute rate coefficient method under pseudo-first-order conditions at 296 and 353 K to be (4.2 ± 0.8) × 10−16 and (7.9 ± 3.6) × 10−16 cm3 molecule−1 s−1, respectively, in agreement with the relative rate result obtained at room temperature. The atmospheric implications of the OH and NO3 reaction rate coefficients measured in this work are discussed.

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.

Atmospheric fate of acrylic acid and acrylonitrile: Rate constants with Cl atoms and OH radicals in the gas phase

2007 ◽  
Vol 41 (27) ◽  
pp. 5769-5777 ◽  
Author(s):  
Mariano A. Teruel ◽  
María B. Blanco ◽  
Gabriela R. Luque
Keyword(s):  
Acrylic Acid ◽  
Gas Phase ◽  
Rate Constants ◽  
Oh Radicals ◽  
Atmospheric Fate ◽  
Cl Atoms

Atmospheric Degradation and Climate and Air-Quality Impact of Furan-based Biomass Burning Emission Products: A Kinetic and Mechanistic study

2020 ◽  
Author(s):  
Maria Angelaki ◽  
Vassileios Papadimitriou ◽  
Manolis Romanias
Keyword(s):  
Mass Spectrometry ◽  
Air Quality ◽  
Biomass Burning ◽  
Low Pressure ◽  
Rate Coefficients ◽  
Mechanistic Study ◽  
Ionization Mass ◽  
Kinetic Measurements ◽  
Cl Atoms ◽  
Simulation Chamber

&lt;p&gt;Biomass burning emissions, domestic- and wild-fires, agricultural burning, and fuel use, emit a blend of gases and particles with adverse effects on humans-health, climate and air quality. Furans are heterocyclic organic compounds (OVOC) that have been recently identified as important biomass burning emission-products. It is estimated that furan (C&lt;sub&gt;4&lt;/sub&gt;H&lt;sub&gt;4&lt;/sub&gt;O), 2-methylfuran (C&lt;sub&gt;5&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;O), 2-furaldehyde (C&lt;sub&gt;5&lt;/sub&gt;H&lt;sub&gt;4&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;) and benzofuran (C&lt;sub&gt;8&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;O) emission levels are 70 to 120 times higher compared to CO. Once furans are emitted in the atmosphere, they will undergo gas phase chemistry and, to an extent, they will be photolyzed at actinic wavelengths. OH and NO&lt;sub&gt;3&lt;/sub&gt; radicals, Cl atoms and O&lt;sub&gt;3&lt;/sub&gt; chemistry might result in tropospheric O&lt;sub&gt;3&lt;/sub&gt; and in secondary organic aerosols (SOA) formation, which might be enhanced due to their potent low volatility. Therefore, it is essential to investigate the kinetics and the mechanism of all the photochemically induced degradation pathways and identify and quantify SOA precursors, so as to evaluate their impact on Air-Quality and Climate.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Within this framework, a thorough laboratory study, using two complementary techniques has been carried out. First, major atmospheric oxidants reaction rate coefficients with furans were determined. Secondly, the degradation mechanisms were investigated from both kinetic and conversion-yields perspectives. A Teflon atmospheric simulation chamber, named THALAMOS (THermALly regulated AtMOSpheric simulation chamber), was used to study the reactions at atmospheric pressure. State-of-the-art in-line instrumentation, e.g., FTIR spectroscopy and Chemical ionization mass spectrometry, were used for the real-time monitoring of reactants and products. To further our understanding, the reactions rate coefficients were also measured at 2 mTorr, between 253 and 363 K, with the continuous flow technique of the Very Low Pressure Reactor, in which an effusive molecular beam is analyzed with Quadrupole Mass Spectrometry (VLPR/QMS). Intercomparing the results from the two techniques reactions mechanistic-scheme was mapped-out and their impact was evaluated.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;OH and NO&lt;sub&gt;3&lt;/sub&gt; radicals and Cl atoms reactions with all the furans were measured to be in the order of 10&lt;sup&gt;-11&lt;/sup&gt;, 10&lt;sup&gt;-10 &lt;/sup&gt;and 10&lt;sup&gt;-12&lt;/sup&gt; cm&lt;sup&gt;3&lt;/sup&gt; molecule&lt;sup&gt;-1&lt;/sup&gt; s&lt;sup&gt;-1&lt;/sup&gt;, respectively, leading to atmospheric-lifetimes between 2 and 10 hours. Temperature and pressure dependent kinetic measurements revealed association as the dominant reaction channel. However, experiments at very-low-pressure regime showed that HCl elimination cannot be excluded, especially when the furan-ring aromaticity is not breaking.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Finally, it is evident that furans degradation will occur at low altitudes and SOA precursors, i.e., end-oxidation products will be formed nearby their emission locations. Further, kinetics studies were used to study the structure-reactivity trend of furans and to estimate their Photochemical Ozone Creation Potential (POCP). Results from this study are expected to significantly improve our insight on furans tropospheric photochemistry and via identifying and quantifying end-products and SOA formation, to assess their indirect and direct impact, on Climate, Air-Quality and humans-health.&lt;/p&gt;

Atmospheric Chemistry of 1-Methoxy 2-Propyl Acetate: UV Absorption Cross Sections, Rate Coefficients, and Products of Its Reactions with OH Radicals and Cl Atoms

2016 ◽  
Vol 120 (45) ◽  
pp. 9049-9062 ◽  
Author(s):  
Antonia G. Zogka ◽  
Abdelwahid Mellouki ◽  
Manolis N. Romanias ◽  
Yuri Bedjanian ◽  
Mahmoud Idir ◽  
...  
Keyword(s):  
Cross Sections ◽  
Atmospheric Chemistry ◽  
Uv Absorption ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
Absorption Cross ◽  
Propyl Acetate ◽  
Cl Atoms

A Kinetic and Mechanistic Study of the Reactions of OH Radicals and Cl Atoms with 3,3,3-Trifluoropropanol under Atmospheric Conditions

2005 ◽  
Vol 109 (2) ◽  
pp. 347-355 ◽  
Author(s):  
Tanya Kelly ◽  
Valérie Bossoutrot ◽  
Isabelle Magneron ◽  
Klaus Wirtz ◽  
Jack Treacy ◽  
...  
Keyword(s):  
Mechanistic Study ◽  
Oh Radicals ◽  
Atmospheric Conditions ◽  
Cl Atoms

Atmospheric chemistry of (CF3)2CCH2: OH radicals, Cl atoms and O3 rate coefficients, oxidation end-products and IR spectra

2015 ◽  
Vol 17 (38) ◽  
pp. 25607-25620 ◽  
Author(s):  
Vassileios C. Papadimitriou ◽  
Christina S. Spitieri ◽  
Panos Papagiannakopoulos ◽  
Mathieu Cazaunau ◽  
Maria Lendar ◽  
...  
Keyword(s):  
Global Warming ◽  
Ir Spectra ◽  
Atmospheric Chemistry ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
End Products ◽  
Photochemical Ozone ◽  
Global Warming Potentials ◽  
Cl Atoms

OH, Cl and O3 kinetics and IR spectra of (CF3)2CCH2 utilized to estimate tropospheric lifetimes, radiative efficiencies, global warming potentials, estimated photochemical ozone creation potentials and tropospheric oxidation end-products.

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