scholarly journals Atmospheric oxidation of <i>α</i>,<i>β</i>-unsaturated ketones: kinetics and mechanism of the OH radical reaction

2021 ◽  
Vol 21 (17) ◽  
pp. 13667-13686
Author(s):  
Niklas Illmann ◽  
Rodrigo Gastón Gibilisco ◽  
Iustinian Gabriel Bejan ◽  
Iulia Patroescu-Klotz ◽  
Peter Wiesen
Keyword(s):  
Radical Reaction ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
Oh Radical ◽  
Methyl Glyoxal ◽  
Peroxyacetyl Nitrate ◽  
Unsaturated Ketones ◽  
Product Yields ◽  
Mechanistic Investigation ◽  
Cl Atoms

Abstract. The OH-radical-initiated oxidation of 3-methyl-3-penten-2-one and 4-methyl-3-penten-2-one was investigated in two atmospheric simulation chambers at 298±3 K and 990±15 mbar using long-path FTIR spectroscopy. The rate coefficients of the reactions of 3-methyl-3-penten-2-one and 4-methyl-3-penten-2-one with OH radicals were determined to be (6.5±1.2)×10-11 and (8.1±1.3)×10-11 cm3molecule-1s-1, respectively. To enlarge the kinetics data pool the rate coefficients of the target species with Cl atoms were determined to be (2.8±0.4)×10-10 and (3.1±0.4)×10-10 cm3molecule-1s-1, respectively. The mechanistic investigation of the OH-initiated oxidation focuses on the RO2+NO reaction. The quantified products were acetoin, acetaldehyde, biacetyl, CO2 and peroxyacetyl nitrate (PAN) for the reaction of 3-methyl-3-penten-2-one with OH radicals and acetone, methyl glyoxal, 2-hydroxy-2-methylpropanal, CO2 and peroxyacetyl nitrate (PAN) for the reaction of 4-methyl-3-penten-2-one with OH, respectively. Based on the calculated product yields an upper limit of 0.15 was determined for the yield of RONO2 derived from the OH reaction of 4-methyl-3-penten-2-one. By contrast, no RONO2 formation was observed for the OH reaction of 3-methyl-3-penten-2-one. Additionally, a simple model is presented to correct product yields for secondary processes.

scholarly journals Atmospheric oxidation of α,β-unsaturated ketones: kinetics and mechanism of the OH radical reaction

2021 ◽  
Author(s):  
Niklas Illmann ◽  
Rodrigo Gastón Gibilisco ◽  
Iustinian Gabriel Bejan ◽  
Iulia Patroescu-Klotz ◽  
Peter Wiesen
Keyword(s):  
Radical Reaction ◽  
Rate Coefficients ◽  
Organic Nitrates ◽  
Oh Radicals ◽  
Oh Radical ◽  
Peroxyacetyl Nitrate ◽  
Unsaturated Ketones ◽  
Product Yields ◽  
Mechanistic Investigation ◽  
Cl Atoms

Abstract. The OH radical initiated oxidation of 3-methyl-3-penten-2-one and 4-methyl-3-penten-2-one was investigated in two atmospheric simulation chambers at 298 ± 3 K and 990 ± 15 mbar using long-path FTIR spectroscopy. The rate coefficients of the reactions of 3-methyl-3-penten-2-one and 4-methyl-3-penten-2-one with OH radicals were determined to be (6.5 ± 1.2) × 10−11 cm3 molecule−1 s−1 and (8.1 ± 1.3) × 10−11 cm3 molecule−1 s−1, respectively. To enlarge the kinetics data pool the rate coefficients of the target species with Cl atoms were determined to be (2.8 ± 0.4) × 10−10 cm3 molecule−1 s−1 and (3.1 ± 0.4) × 10−10 cm3 molecule−1 s−1, respectively. The mechanistic investigation of the OH initiated oxidation focuses on the RO2 + NO reaction. The quantified products were acetoin, acetaldehyde, biacetyl, CO2 and peroxyacetyl nitrate (PAN) for the reaction of 3-methyl-3-penten-2-one with OH radicals and acetone, methyl glyoxal, 2-hydroxy-2-methylpropanal, CO2 and peroxyacetyl nitrate (PAN) for the reaction of 4-methyl-3-penten-2-one with OH, respectively. Based on the calculated product yields an upper limit of 0.15 was determined for the overall organic nitrates (RONO2) yield derived from the OH reaction of 4-methyl-3-penten-2-one. By contrast, no RONO2 formation was observed for the OH reaction of 3-methyl-3-penten-2-one. Additionally, a simple model is presented to correct product yields for secondary processes.

scholarly journals Gas-phase degradation of 2-butanethiol initiated by OH radicals and Cl atoms: kinetics, product yields and mechanism at 298 K and atmospheric pressure

RSC Advances ◽  
2019 ◽  
Vol 9 (39) ◽  
pp. 22618-22626
Author(s):  
Alejandro L. Cardona ◽  
Rodrigo G. Gibilisco ◽  
María B. Blanco ◽  
Peter Wiesen ◽  
Mariano Teruel
Keyword(s):  
Gas Phase ◽  
Atmospheric Pressure ◽  
Relative Rate ◽  
Product Distribution ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
Product Yields ◽  
Cl Atoms ◽  
Relative Rate Coefficients

Relative rate coefficients and product distribution of the reaction of 2-butanethiol (2butSH) with OH radicals and Cl atoms were obtained at atmospheric pressure and 298 K.

scholarly journals Experimental and computational kinetics investigations for the reactions of Cl atoms with series of unsaturated ketones in gas phase

2017 ◽  
Author(s):  
Siripina Vijayakumar ◽  
Avinash Kumar ◽  
Balla Rajakuma
Keyword(s):  
Gas Phase ◽  
State Theory ◽  
Rate Coefficients ◽  
Gas Phase Reactions ◽  
Temperature Dependent ◽  
Unsaturated Ketones ◽  
Temperature Range ◽  
Computational Calculations ◽  
Temperature Rate ◽  
Cl Atoms

Abstract. Temperature dependent rate coefficients for the gas phase reactions of Cl atoms with 4-hexen-3-one and 5-hexen-2-one were measured over the temperature range of 298–363 K relative to 1-pentene, 1,3-butadiene and isoprene. Gas Chromatography (GC) was used to measure the concentrations of the organics. The derived temperature dependent Arrhenius expressions are k4-hexen-3-one+Cl (298–363 K) = (2.82 ± 1.76)×10−12exp [(1556 ± 438)/T] cm3 molecule−1 s−1 and k5-hexen-2-one+Cl (298–363 K) = (4.6 ± 2.4)×10−11exp[(646 ± 171)/T] cm3 molecule−1 s−1. The corresponding room temperature rate coefficients are (5.54 ± 0.41)×10−10 cm3 molecule−1 s−1 and (4.00 ± 0.37)×10−10 cm3 molecule−1 s−1 for the reactions of Cl atoms with 4-hexen-3-one and 5-hexen-2-one respectively. To understand the mechanism of Cl atom reactions with unsaturated ketones, computational calculations were performed for the reactions of Cl atoms with 4-hexen-3-one, 5-hexen-2-one and 3-penten-2-one over the temperature range of 275–400 K using Canonical Variational Transition state theory (CVT) with Small Curvature Tunneling (SCT) in combination with CCSD(T)/6-31+G(d, p)//MP2/6-311++G(d, p) level of theory. Atmospheric implications, reaction mechanism and feasibility of the title reactions are discussed in this manuscript.

Reaction kinetics of OH radicals with glutaric acid and adipic acid in the aqueous phase

2021 ◽  
Author(s):  
Liang Wen ◽  
Thomas Schaefer ◽  
Hartmut Herrmann
Keyword(s):  
Aqueous Phase ◽  
Adipic Acid ◽  
Rate Constants ◽  
Density Functional ◽  
Glutaric Acid ◽  
Radical Reaction ◽  
Basis Set ◽  
Oh Radicals ◽  
Oh Radical ◽  
Energy Barriers

&lt;p&gt;Dicarboxylic acids (DCAs) are widely distributed in atmospheric aerosols and cloud droplets and are mainly formed by the oxidation of volatile organic compounds (VOCs). For example, glutaric acid and adipic acid are two kinds of the DCAs that can be oxidized by hydroxyl radical (&amp;#8231;OH) reactions in the aqueous phase of aerosols and droplets. In the present study, the temperature- and pH-dependent rate constants of the aqueous OH radical reactions of the two DCAs were investigated by a laser flash photolysis-long path absorption setup using the competition kinetics method. Based on speciation calculations, the OH radical reaction rate constants of the fully protonated (H&lt;sub&gt;2&lt;/sub&gt;A), deprotonated (HA&lt;sup&gt;-&lt;/sup&gt;) and fully deprotonated (A&lt;sup&gt;2-&lt;/sup&gt;) forms of the two DCAs were determined. The following Arrhenius expressions for the T-dependency of the OH radical reaction of glutaric acid, k(T, H&lt;sub&gt;2&lt;/sub&gt;A) = (3.9 &amp;#177; 0.1) &amp;#215; 10&lt;sup&gt;10&lt;/sup&gt; &amp;#215; exp[(-1270 &amp;#177; 200 K)/T], k(T, HA&lt;sup&gt;-&lt;/sup&gt;) = (2.3 &amp;#177; 0.1) &amp;#215; 10&lt;sup&gt;11&lt;/sup&gt; &amp;#215; exp[(-1660 &amp;#177; 190 K)/T], k(T, A&lt;sup&gt;2-&lt;/sup&gt;) = (1.4 &amp;#177; 0.1) &amp;#215; 10&lt;sup&gt;11&lt;/sup&gt; &amp;#215; exp[(-1400 &amp;#177; 170 K)/T] and adipic acid, k(T, H&lt;sub&gt;2&lt;/sub&gt;A) = (7.5 &amp;#177; 0.2) &amp;#215; 10&lt;sup&gt;10&lt;/sup&gt; &amp;#215; exp[(-1210 &amp;#177; 170 K)/T], k(T, HA&lt;sup&gt;-&lt;/sup&gt;) = (9.5 &amp;#177; 0.3) &amp;#215; 10&lt;sup&gt;10&lt;/sup&gt; &amp;#215; exp[(-1200 &amp;#177; 200 K)/T], k(T, A&lt;sup&gt;2-&lt;/sup&gt;) = (8.7 &amp;#177; 0.2) &amp;#215; 10&lt;sup&gt;10&lt;/sup&gt; &amp;#215; exp[(-1100 &amp;#177; 170 K)/T] (in unit of L mol&lt;sup&gt;-1&lt;/sup&gt; s&lt;sup&gt;-1&lt;/sup&gt;) were derived.&lt;/p&gt;&lt;p&gt;The energy barriers of the H-atom abstractions were simulated by the Density Functional Theory calculations run with the GAUSSIAN package using the M06-2X method and the basis set m062x/6-311++g(3df,2p). The results showed that the energy barriers were lower at the C&lt;sub&gt;&amp;#946;&lt;/sub&gt;-atoms and are higher at the C&lt;sub&gt;&amp;#945;&lt;/sub&gt;-atoms of the two DCAs, clearly suggesting that the H-atom abstractions occurred predominately at the C&lt;sub&gt;&amp;#946;&lt;/sub&gt;-atoms. In addition, the ionizations can enhance the electrostatic effects of the carboxyl groups, significantly reducing the energy barriers, leading to the order of OH radical reactivity as &amp;#160;&lt; &amp;#160;&lt; . This study intends to better characterize the losing processes of glutaric acid and adipic acid in atmospheres.&lt;/p&gt;

scholarly journals Importance of SOA formation of α-pinene, limonene and <i>m</i>-cresol comparing day-and night-time radical chemistry

2020 ◽  
Author(s):  
Anke Mutzel ◽  
Yanli Zhang ◽  
Olaf Böge ◽  
Maria Rodigast ◽  
Agata Kolodziejczyk ◽  
...  
Keyword(s):  
Mass Fraction ◽  
Radical Reaction ◽  
Water Soluble ◽  
Oh Radicals ◽  
Oh Radical ◽  
Night Time ◽  
Formation Potential ◽  
Phase Constituent ◽  
Dry Conditions ◽  
The One

Abstract. The oxidation of biogenic and anthropogenic compounds leads to the formation of secondary organic aerosol mass (SOA). The present study aims to investigate α-pinene, limonene and m-cresol with regards to their SOA formation potential dependent on relative humidity (RH) under night- (NO3 radicals) and day-time conditions (OH radicals) and the resulting chemical composition. It was found that SOA formation potential of limonene with NO3 significantly exceeds the one of the OH radical reaction, with SOA yields of 15–30 % and 10–21 %, respectively. Additionally, the nocturnal SOA yield was found to be very sensitive towards RH, yielding more SOA under dry conditions. On the contrary, the SOA formation potential of α-pinene with NO3 slightly exceeds that of the OH radical reaction, independent from RH. In average, α-pinene yielded SOA with about 6–7 % from NO3 radicals and 3–4 % from OH radical reaction. Surprisingly, unexpected high SOA yields were found for m-cresol oxidation with OH radicals (3–9 %) with the highest yield under elevated RH (9 %) which is most likely attributed to a higher fraction of 3-methyl-6-nitro-catechol (MNC). While α-pinene and m-cresol SOA was found to be mainly composed of water-soluble compounds, 50–68 % of nocturnal SOA and 22–39 % of daytime limonene SOA is water-insoluble. The fraction of SOA-bound peroxides which originated from α-pinene varied between 2–80 % as a function of RH. Furthermore, SOA from α-pinene revealed pinonic acid as the most important particle-phase constituent under day- and night-time conditions with fraction of 1–4 %. Further compounds detected are norpinonic acid (0.05–1.1 % mass fraction), terpenylic acid (0.1–1.1 % mass fraction), pinic acid (0.1–1.8 % mass fraction) and 3-methyl-1,2,3-tricarboxylic acid (0.05–0.5 % mass fraction). All marker compounds showed higher fractions under dry conditions when formed during daytime and almost no RH effect when formed during night.

scholarly journals Rate coefficients for the gas-phase reaction of OH with <i>Z</i>-3-hexen-1-ol, 1-penten-3-ol, <i>E</i>-2-penten-1-ol, and <i>E</i>-2-hexen-1-ol between 243 and 404 K

2011 ◽  
Vol 11 (1) ◽  
pp. 2377-2405 ◽  
Author(s):  
M. E. Davis ◽  
J. B. Burkholder
Keyword(s):  
Gas Phase ◽  
Negative Temperature ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
Phase Reaction ◽  
Oh Radical ◽  
Gas Phase Reaction ◽  
First Order ◽  
Unsaturated Alcohols ◽  
Temperature Dependences

Abstract. Rate coefficients, k, for the gas-phase reaction of the OH radical with (Z)-3-hexen-1-ol ((Z)-CH3CH2CH=CHCH2CH2OH). (k1), 1-penten-3-ol (CH3CH2CH(OH)CH=CH2) (k2), (E)-2-penten-1-ol ((E)-CH3CH2CH=CHCH2OH) (k3), and (E)-2-hexen-1-ol ((E)-CH3CH2CH2CH=CHCH2OH) (k4), unsaturated alcohols that are emitted into the atmosphere following vegetation wounding, are reported. Rate coefficients were measured under pseudo-first-order conditions in OH over the temperature range 243–404 K at pressures between 20 and 100 Torr (He) using pulsed laser photolysis (PLP) to produce OH radicals and laser induced fluorescence (LIF) to monitor the OH temporal profile. The obtained rate coefficients were independent of pressure with negative temperature dependences that are well described by the Arrhenius expressions k1(T) = (1.3 ± 0.1) × 10−11 exp[(580 ± 10)/T]; k1(297K) = (1.06 ± 0.12) × 10−10 k2(T) = (6.8 ± 0.7) × 10−12 exp[(690 ± 20)/T]; k2(297K) = (7.12 ± 0.73) × 10−11 k3(T) = (6.8 ± 0.8) × 10−12 exp[(680 ± 20)/T]; k3(297K) = (6.76 ± 0.70) × 10−11 k4(T) = (5.4 ± 0.6) × 10−12 exp[(690 ± 20)/T]; k4(297K) = (6.15 ± 0.75) × 10−11 (in units of cm3 molecule−1 s−1). The quoted uncertainties are at the 2σ (95% confidence) level and include estimated systematic errors. The rate coefficients obtained in this study are compared with literature values where possible.

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

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.

scholarly journals Atmospheric reaction of hydrazine plus hydroxyl radical

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hamed Douroudgari ◽  
Morteza Vahedpour ◽  
Fahime Khouini
Keyword(s):  
Hydroxyl Radical ◽  
Rate Constants ◽  
Reaction Pathway ◽  
Radical Reaction ◽  
Basis Sets ◽  
Rate Coefficients ◽  
Stationary Points ◽  
Main Reaction ◽  
Partition Functions ◽  
Oh Radicals

AbstractUnderstanding 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.

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