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Rutto P, Ubana E, Selby TM, Goulay F. Kinetic Study of OH Radical Reactions with Cyclopentenone Derivatives. J Phys Chem A 2024; 128:8209-8219. [PMID: 39285603 DOI: 10.1021/acs.jpca.4c04060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2024]
Abstract
We investigated the reactions of the hydroxyl radical (OH) with cyclopentenone derivatives and cyclopentanone in a quasi-static reaction cell at 4 Torr across a 300-500 K temperature range. The OH radicals were generated using pulsed laser photolysis of hydrogen peroxide vapors, and the ketone reactants were introduced in excess. The relative concentrations of the radicals were monitored as a function of reaction time using laser-induced fluorescence. At room temperature, the reaction rate coefficients were measured to be 1.2(±0.1) × 10-11 cm3 s-1 for reaction with 2-cyclopenten-1-one (R1); 1.7(±0.2) × 10-11 cm3 s-1 for reaction with 2-methyl-2-cyclopenten-1-one (R2); and 4.4(±0. 7) × 10-12 cm3 s-1 for reaction with 3-methyl-2-cyclopenten-1-one (R3). Over the experimental temperature range, the rate coefficients can be fitted with the modified Arrhenius expressions k1(T) = 1.2 × 10-11 (T/300)0.26 exp (6.7 kJ mol-1/R {1/T - 1/300}) cm3 s-1, k2(T) = 1.7 × 10-11 (T/300)6.4 exp (27.6 kJ mol-1/R {1/T - 1/300}) cm3 s-1, k3(T) = 4.4 × 10-12 (T/300)17.8 exp (57.8 kJ mol-1/R {1/T - 1/300}) cm3 s-1. In the cases of 2-cyclopenten-1-one and 2-methyl-2-cyclopenten-1-one, the temperature dependence of the rate coefficients is similar to that calculated or measured for noncyclic conjugated ketones. We also found that the reaction with 3-methyl-2-cyclopenten-1-one was slower, with rate coefficients similar to those measured for the reaction with the saturated cyclic ketone cyclopentanone. To discuss the experimental data, we use potential energy surfaces (PES) calculated at the CCSD(T)/cc-pVTZ//M06-2X/6-311+G** level of theory. RRKM-based Master equation calculations were also performed to infer the most likely reaction products over a wide range of temperatures and pressures. We suggest that both abstraction and addition mechanisms contribute to the overall OH removal, forming radical products stabilized by resonance. We also discuss the relevance for combustion and atmospheric chemistry.
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Affiliation(s)
- Patrick Rutto
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Emmanuel Ubana
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Talitha M Selby
- Department of Mathematics and Natural Sciences, University of Wisconsin-Milwaukee, West Bend, Wisconsin 53095, United States
| | - Fabien Goulay
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
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2
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Cho J, Mulvihill CR, Klippenstein SJ, Sivaramakrishnan R. Bimolecular Peroxy Radical (RO 2) Reactions and Their Relevance in Radical Initiated Oxidation of Hydrocarbons. J Phys Chem A 2023; 127:300-315. [PMID: 36562763 DOI: 10.1021/acs.jpca.2c06960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The kinetics of peroxy radical (RO2) reactions have been of long-standing interest in atmospheric and combustion chemistry. Nevertheless, the lack of kinetic studies at higher temperatures for their reactions with other radicals such as OH has precluded the inclusion of this class of reactions in detailed kinetics models developed for combustion applications. In this work, guided by the limited room-temperature experimental studies on selected alkyl-peroxy radicals and literature theoretical kinetics on the prototypical CH3O2 + OH system, we have performed parametric studies on the effect of uncertainties in the rate coefficients and branching ratios to potential product channels for RO2 + OH reactions at higher temperatures. Literature kinetics models were used to simulate autoignition delays, laminar flame speeds, and speciation profiles in flow and stirred reactors for a variety of common combustion-relevant fuels. Inclusion of RO2 + OH reactions was found to retard autoignition in fuel-lean (φ = 0.5) mixtures of ethane and dimethyl ether in air. The observed effects were noticeably more pronounced in ozone-enriched combustion of ethane and dimethyl ether. The simulations also examined the influence of ozone doping levels, pressures, and equivalence ratios for both ethane and dimethyl ether oxidation. Sensitivity and flux analyses revealed that the RO2 + OH reaction is a significant sink of RO2 radicals at the early stage of autoignition, affecting fuel oxidation through RO2 ↔ QOOH, RO2 ↔ alkene + HO2, or RO2 + HO2 ↔ ROOH + O2. Additionally, the kinetic stability of the trioxide formed from RO2 + OH reactions was investigated using master equation analyses. Last, we discuss other bimolecular reactions that are missing in literature kinetics models but are relevant to hydrocarbon oxidation initiated by external radical sources (plasma-enhanced, ozone-enriched combustion, etc.). The present simulations provide a strong motivation for better characterizing the bimolecular kinetics of peroxy radicals.
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Affiliation(s)
- Jaeyoung Cho
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Clayton R Mulvihill
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Stephen J Klippenstein
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Raghu Sivaramakrishnan
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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3
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Blázquez S, González D, García-Sáez A, Antiñolo M, Bergeat A, Caralp F, Mereau R, Canosa A, Ballesteros B, Albaladejo J, Jiménez E. Experimental and theoretical investigation on the OH + CH 3C(O)CH 3 reaction at interstellar temperatures (T=11.7-64.4 K). ACS EARTH & SPACE CHEMISTRY 2019; 3:1873-1883. [PMID: 31799490 PMCID: PMC6887536 DOI: 10.1021/acsearthspacechem.9b00144] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The rate coefficient, k(T), for the gas-phase reaction between OH radicals and acetone CH3C(O)CH3, has been measured using the pulsed CRESU (French acronym for Reaction Kinetics in a Uniform Supersonic Flow) technique (T = 11.7-64.4 K). The temperature dependence of k(T = 10-300 K) has also been computed using a RRKM-Master equation analysis after partial revision of the potential energy surface. In agreement with previous studies we found that the reaction proceeds via initial formation of two pre-reactive complexes both leading to H2O + CH3C(O)CH2 by H-abstraction tunneling. The experimental k(T) was found to increase as temperature was lowered. The measured values have been found to be several orders of magnitude higher than k(300 K). This trend is reproduced by calculations, with a special good agreement with experiments below 25 K. The effect of total gas density on k(T) has been explored. Experimentally, no pressure dependence of k(20 K) and k(64 K) was observed, while k(50 K) at the largest gas density 4.47×1017 cm-3 is twice higher than the average values found at lower densities. The computed k(T) is also reported for 103 cm-3 of He (representative of the interstellar medium). The predicted rate coefficients at 10 K surround the experimental value which appears to be very close to the low pressure regime prevailing in the interstellar medium. For gas-phase model chemistry of interstellar molecular clouds, we suggest using the calculated value of 1.8×10-10 cm3 molecule-1 s-1 at 10 K and the reaction products are water and CH3C(O)CH2 radicals.
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Affiliation(s)
- Sergio Blázquez
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B. 13071 Ciudad Real, Spain
| | - Daniel González
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B. 13071 Ciudad Real, Spain
| | - Alberto García-Sáez
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B. 13071 Ciudad Real, Spain
| | - María Antiñolo
- Instituto de Investigación en Combustión y Contaminación Atmosférica (ICCA). Universidad de Castilla-La Mancha, Camino de Moledores s/n. 13071 Ciudad Real, Spain
| | - Astrid Bergeat
- Univ. Bordeaux, CNRS, Bordeaux INP, ISM, UMR 5255, F-33405 Talence, France
| | - Françoise Caralp
- Univ. Bordeaux, CNRS, Bordeaux INP, ISM, UMR 5255, F-33405 Talence, France
| | - Raphaël Mereau
- Univ. Bordeaux, CNRS, Bordeaux INP, ISM, UMR 5255, F-33405 Talence, France
| | - André Canosa
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - Bernabé Ballesteros
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B. 13071 Ciudad Real, Spain
- Instituto de Investigación en Combustión y Contaminación Atmosférica (ICCA). Universidad de Castilla-La Mancha, Camino de Moledores s/n. 13071 Ciudad Real, Spain
| | - José Albaladejo
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B. 13071 Ciudad Real, Spain
- Instituto de Investigación en Combustión y Contaminación Atmosférica (ICCA). Universidad de Castilla-La Mancha, Camino de Moledores s/n. 13071 Ciudad Real, Spain
| | - Elena Jiménez
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B. 13071 Ciudad Real, Spain
- Instituto de Investigación en Combustión y Contaminación Atmosférica (ICCA). Universidad de Castilla-La Mancha, Camino de Moledores s/n. 13071 Ciudad Real, Spain
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Yu X, Hou H, Wang B. Atmospheric Chemistry of Perfluoro-3-methyl-2-butanone [CF 3C(O)CF(CF 3) 2]: Photodissociation and Reaction with OH Radicals. J Phys Chem A 2018; 122:8840-8848. [PMID: 30371084 DOI: 10.1021/acs.jpca.8b09111] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Perfluoro-3-methyl-2-butanone (CF3C(O)CF(CF3)2, abbreviated as C5) is a potentially excellent fire suppression alternative to halons and a promising dielectric gas for SF6 replacement. As a prototypical perfluorinated asymmetrical ketone, photodissociation and reaction with hydroxyl radicals of C5 have been investigated theoretically to gain insights into its atmospheric chemistry and environmental impact. C5 has a broad UV absorption band in the range 260-360 nm with a maximum at 302 nm and the maximal photolysis rate coefficient is 8.3 × 10-5 s-1. Photoexcitation from S0 through the perpendicular n → π* transition produces the excited S1 species, which can either dissociate straightforwardly via the bifurcated α-CC bond cleavage or be trickled down to T1 via the S1/T1 intersystem crossing (ISC) pathway. In the Franck-Condon region of the S1 surface, the long-lived S1 species exists and the slow ISC pathway is dominant, followed by the α-cleavage through T1 barriers to form perfluoroalkyl and perfluoroacetyl radicals. While the excitation energy exceeds 286 nm, the direct dissociation of C5 though the S1 barriers takes over before the ISC occurs. Several pathways for regeneration of the ground-state S0 from S1 and T1 via seams of crossing or internal conversion were revealed. The C5 + OH reaction occurs via direct carbonyl addition mechanism followed by the rapid displacement of one of the alkyl groups. Although it can be accelerated considerably by the H2O-mediated catalysis or the intercepted vibrationally excited quantum states in the hot S0*, the degradation of C5 by OH radicals is too slow to compete with the photolysis pathways.
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Affiliation(s)
- Xiaojuan Yu
- College of Chemistry and Molecular Sciences , Wuhan University , Wuhan 430072 , People's Republic of China
| | - Hua Hou
- College of Chemistry and Molecular Sciences , Wuhan University , Wuhan 430072 , People's Republic of China
| | - Baoshan Wang
- College of Chemistry and Molecular Sciences , Wuhan University , Wuhan 430072 , People's Republic of China
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5
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Chemical evolution of atmospheric organic carbon over multiple generations of oxidation. Nat Chem 2018; 10:462-468. [PMID: 29483638 DOI: 10.1038/s41557-018-0002-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 01/03/2018] [Indexed: 11/08/2022]
Abstract
The evolution of atmospheric organic carbon as it undergoes oxidation has a controlling influence on concentrations of key atmospheric species, including particulate matter, ozone and oxidants. However, full characterization of organic carbon over hours to days of atmospheric processing has been stymied by its extreme chemical complexity. Here we study the multigenerational oxidation of α-pinene in the laboratory, characterizing products with several state-of-the-art analytical techniques. Although quantification of some early generation products remains elusive, full carbon closure is achieved (within measurement uncertainty) by the end of the experiments. These results provide new insights into the effects of oxidation on organic carbon properties (volatility, oxidation state and reactivity) and the atmospheric lifecycle of organic carbon. Following an initial period characterized by functionalization reactions and particle growth, fragmentation reactions dominate, forming smaller species. After approximately one day of atmospheric aging, most carbon is sequestered in two long-lived reservoirs-volatile oxidized gases and low-volatility particulate matter.
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Patros KM, Mann JE, Jarrold CC. O 2-·[Polar VOC] Complexes: H-Bonding versus Charge-Dipole Interactions, and the Noninnocence of Formaldehyde. J Phys Chem A 2017; 121:5459-5467. [PMID: 28671848 DOI: 10.1021/acs.jpca.7b05124] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Anion photoelectron imaging was used to measure the photodetachment spectra of molecular complexes formed between O2- and a range of atmospherically relevant polar molecules, including species with a carbonyl group (acetone, formaldehyde) and alcohols (ethanol, propenol, butenol). Experimental spectra are analyzed using a combination of Franck-Condon simulations and electronic structure calculations. Strong charge-dipole interactions and H-bonding stabilize the complex anions relative to the neutrals, resulting in a ca. 1 eV increase in electron binding energy relative to bare O2-, an effect more pronounced in complexes with H-bonding. In addition, broken degeneracy of the O2-local πg orbitals in the complexes results in the stabilization of the low-lying excited O2 (a 1Δg)·[polar VOC] state relative to the ground O2 (X 3Σg-)·[polar VOC] state when compared to bare O2. The spectra of the O2-·[polar VOC] complexes exhibit less pronounced laser photoelectron angular distribution (PADs). The spectrum of O2-·formaldehyde is unique in terms of both spectral profile and PAD. On the basis of these experimental results in addition to computational results, the complex anion cannot be described as a distinct O2- anion partnered with an innocent solvent molecule; the molecules are more strongly coupled through charge delocalization. Overall, the results underscore how the symmetry of the O2 πg orbitals is broken by different polar partners, which may have implications for atmospheric photochemistry and models of solar radiation absorption that include collision-induced absorption.
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Affiliation(s)
- Kellyn M Patros
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Jennifer E Mann
- Physical Electronics , 18725 Lake Drive East, Chanhassen, Minnesota, 55317, United States
| | - Caroline Chick Jarrold
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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7
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Lee L, Wilson K. The Reactive–Diffusive Length of OH and Ozone in Model Organic Aerosols. J Phys Chem A 2016; 120:6800-12. [DOI: 10.1021/acs.jpca.6b05285] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lance Lee
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Kevin Wilson
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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8
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Song X, Zügner GL, Farkas M, Illés Á, Sarzyński D, Rozgonyi T, Wang B, Dóbé S. Experimental and Theoretical Study on the OH-Reaction Kinetics and Photochemistry of Acetyl Fluoride (CH3C(O)F), an Atmospheric Degradation Intermediate of HFC-161 (C2H5F). J Phys Chem A 2015; 119:7753-65. [PMID: 25859909 DOI: 10.1021/acs.jpca.5b01069] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The direct reaction kinetic method of low pressure fast discharge flow (DF) with resonance fluorescence monitoring of OH (RF) has been applied to determine rate coefficients for the overall reactions OH + C2H5F (EtF) (1) and OH + CH3C(O)F (AcF) (2). Acetyl fluoride reacts slowly with the hydroxyl radical, the rate coefficient at laboratory temperature is k2(300 K) = (0.74 ± 0.05) × 10(-14) cm(3) molecule(-1) s(-1) (given with 2σ statistical uncertainty). The temperature dependence of the reaction does not obey the Arrhenius law and it is described well by the two-exponential rate expression of k2(300-410 K) = 3.60 × 10(-3) exp(-10500/T) + 1.56 × 10(-13) exp(-910/T) cm(3) molecule(-1) s(-1). The rate coefficient of k1 = (1.90 ± 0.19) × 10(-13) cm(3) molecule(-1) s(-1) has been determined for the EtF-reaction at room temperature (T = 298 K). Microscopic mechanisms for the OH + CH3C(O)F reaction have also been studied theoretically using the ab initio CBS-QB3 and G4 methods. Variational transition state theory was employed to obtain rate coefficients for the OH + CH3C(O)F reaction as a function of temperature on the basis of the ab initio data. The calculated rate coefficients are in good agreement with the experimental data. It is revealed that the reaction takes place predominantly via the indirect H-abstraction mechanism involving H-bonded prereactive complexes and forming the nascent products of H2O and the CH2CFO radical. The non-Arrhenius behavior of the rate coefficient at temperatures below 500 K is ascribed to the significant tunneling effect of the in-the-plane H-abstraction dynamic bottleneck. The production of FC(O)OH + CH3 via the addition/elimination mechanism is hardly competitive due to the significant barriers along the reaction routes. Photochemical experiments of AcF were performed at 248 nm by using exciplex lasers. The total photodissociation quantum yield for CH3C(O)F has been found significantly less than unity; among the primary photochemical processes, C-C bond cleavage is by far dominating compared with CO-elimination. The absorption spectrum of AcF has also been determined by displaying a strong blue shift compared with the spectra of aliphatic carbonyls. Consequences of the results on atmospheric chemistry have been discussed.
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Affiliation(s)
- Xinli Song
- †College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People's Republic of China
| | - Gábor L Zügner
- ‡Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary
| | - Mária Farkas
- ‡Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary
| | - Ádám Illés
- ‡Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary
| | - Dariusz Sarzyński
- §Department of Physical Chemistry, Wroclaw Medical University, 50-556 Wroclaw, Poland
| | - Tamás Rozgonyi
- ‡Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary
| | - Baoshan Wang
- †College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People's Republic of China
| | - Sándor Dóbé
- ‡Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary
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Safron A, Strandell M, Kierkegaard A, Macleod M. Rate Constants and Activation Energies for Gas-Phase Reactions of Three Cyclic Volatile Methyl Siloxanes with the Hydroxyl Radical. INT J CHEM KINET 2015; 47:420-428. [PMID: 27708500 PMCID: PMC5029797 DOI: 10.1002/kin.20919] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 02/20/2015] [Accepted: 03/19/2015] [Indexed: 12/18/2022]
Abstract
Reaction with hydroxyl radicals (OH) is the major pathway for removal of cyclic volatile methyl siloxanes (cVMS) from air. We present new measurements of second‐order rate constants for reactions of the cVMS octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) with OH determined at temperatures between 313 and 353 K. Our measurements were made using the method of relative rates with cyclohexane as a reference substance and were conducted in a 140‐mL gas‐phase reaction chamber with online mass spectrometry analysis. When extrapolated to 298 K, our measured reaction rate constants of D4 and D5 with the OH radical are 1.9 × 10−12 (95% confidence interval (CI): (1.7–2.2) × 10−12) and 2.6 × 10−12 (CI: (2.3–2.9) × 10−12) cm3 molecule−1 s−1, respectively, which are 1.9× and 1.7× faster than previous measurements. Our measured rate constant for D6 is 2.8 × 10−12 (CI: (2.5–3.2) × 10−12) cm3 molecule−1 s−1 and to our knowledge there are no comparable laboratory measurements in the literature. Reaction rates for D5 were 33% higher than for D4 (CI: 30–37%), whereas the rates for D6 were only 8% higher than for D5 (CI: 5–10%). The activation energies of the reactions of D4, D5, and D6 with OH were not statistically different and had a value of 4300 ± 2800 J/mol.
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Affiliation(s)
- Andreas Safron
- Department of Environmental Science and Analytical Chemistry (ACES) Stockholm University SE-10691 Stockholm Sweden
| | - Michael Strandell
- Department of Environmental Science and Analytical Chemistry (ACES) Stockholm University SE-10691 Stockholm Sweden
| | - Amelie Kierkegaard
- Department of Environmental Science and Analytical Chemistry (ACES) Stockholm University SE-10691 Stockholm Sweden
| | - Matthew Macleod
- Department of Environmental Science and Analytical Chemistry (ACES) Stockholm University SE-10691 Stockholm Sweden
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10
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Badra J, Elwardany AE, Farooq A. Reaction rate constants of H-abstraction by OH from large ketones: measurements and site-specific rate rules. Phys Chem Chem Phys 2014; 16:12183-93. [DOI: 10.1039/c4cp01253d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction rate constants of the reaction of four large ketones with hydroxyl (OH) are investigated behind reflected shock waves using OH laser absorption.
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Affiliation(s)
- Jihad Badra
- Clean Combustion Research Center
- Division of Physical Sciences and Engineering
- King Abdullah University of Science and Technology (KAUST)
- Thuwal 23955, Saudi Arabia
- Saudi Aramco Research and Development Center
| | - Ahmed E. Elwardany
- Clean Combustion Research Center
- Division of Physical Sciences and Engineering
- King Abdullah University of Science and Technology (KAUST)
- Thuwal 23955, Saudi Arabia
| | - Aamir Farooq
- Clean Combustion Research Center
- Division of Physical Sciences and Engineering
- King Abdullah University of Science and Technology (KAUST)
- Thuwal 23955, Saudi Arabia
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11
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Vu ND, Khamaganov V, Nguyen VS, Carl SA, Peeters J. Absolute Rate Coefficient of the Gas-Phase Reaction between Hydroxyl Radical (OH) and Hydroxyacetone: Investigating the Effects of Temperature and Pressure. J Phys Chem A 2013; 117:12208-15. [DOI: 10.1021/jp407701z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Ngoc Duy Vu
- The Department of Chemistry, University of Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Victor Khamaganov
- The Department of Chemistry, University of Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Vinh Son Nguyen
- The Department of Chemistry, University of Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Shaun A. Carl
- The Department of Chemistry, University of Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Jozef Peeters
- The Department of Chemistry, University of Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
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12
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Renbaum-Wolff L, Smith GD. "Virtual injector" flow tube method for measuring relative rates kinetics of gas-phase and aerosol species. J Phys Chem A 2012; 116:6664-74. [PMID: 22702447 DOI: 10.1021/jp303221w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A new method for measuring gas-phase and aerosol reaction kinetics is described in which the gas flow, itself, acts as a "virtual injector" continuously increasing the contact time in analogy to conventional movable-injector kinetics techniques. In this method a laser is directed down the length of a flow tube, instantly initiating reaction by photodissociation of a precursor species at every point throughout the flow tube. Key tropospheric reactants such as OH, Cl, NO(3), and O(3) can be generated with nearly uniform concentrations along the length of the flow tube in this manner using 355 nm radiation from the third harmonic of a Nd:YAG laser. As the flow travels down the flow tube, both the gas-phase and particle-phase species react with the photogenerated radicals or O(3) for increasingly longer time before exiting and being detected. The advantages of this method are that (1) any wall loss of gas-phase and particle species is automatically accounted for, (2) the reactions are conducted under nearly pseudo-first-order conditions, (3) the progress of the reaction is followed as a continuous function of reaction time instead of reactant concentration, (4) data collection is quick with an entire decay trace being collected in as little as 1 min, (5) relative rates of several species can be measured simultaneously, and (6) bimolecular rate constants at least as small as k = 10(-17) (cm(3)/molecule)/s, or aerosol uptake coefficients at least as small as γ = 10(-4), can be measured. Using the virtual injector technique with an aerosol chemical ionization mass spectrometer (CIMS) as a detector, examples of gas-phase relative rates and uptake by oleic acid particles are given for OH, Cl, NO(3), and O(3) reactions with most agreeing to within 20% of published values, where available.
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Navarro MA, Dusanter S, Hites RA, Stevens PS. Radical dependence of the yields of methacrolein and methyl vinyl ketone from the OH-initiated oxidation of isoprene under NO(x)-free conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:923-929. [PMID: 21175163 DOI: 10.1021/es103147w] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Formation yields of methacrolein (MAC), methyl vinyl ketone (MVK), and 3-methyl furan (3MF) from the hydroxyl radical (OH) initiated oxidation of isoprene were investigated under NO(x)-free conditions (NO(x) = NO + NO(2)) at 50 °C and 1 atm in a quartz reaction chamber coupled to a mass spectrometer. Yields of the primary products were measured at various OH and hydroperoxy (HO(2)) radical concentrations and were found to decrease as the HO(2)-to-isoprene-based peroxy radical (ISORO(2)) concentration ratio increases. This is likely the result of a competition between ISORO(2) self- and cross-reactions that lead to the formation of the primary products, with reactions between these peroxy radicals and HO(2) which can lead to the formation of peroxides. Under conditions with HO(2)/ISORO(2) ratios close to 0.1, yields of MVK (15.5% ± 1.4%) and MAC (13.0% ± 1.2%) were higher than the yields of MVK (8.9% ± 0.9%) and MAC (10.9% ± 1.1%) measured under conditions with HO(2)/ISORO(2) ratios close to 1. This radical dependence of the yields was reproduced reasonably well by an explicit model of isoprene oxidation, suggesting that the model is able to reproduce the observed products yields under a realistic range of atmospheric HO(2)/ISORO(2) ratios.
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Affiliation(s)
- Maria A Navarro
- Center for Research in Environmental Science, School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana 47405, United States
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Zhou CW, Simmie JM, Curran HJ. Ab initio and kinetic study of the reaction of ketones with ȮH for T = 500–2000 K. Part I: hydrogen-abstraction from H3CC(O)CH3–x(CH3)x, x = 0 ↦ 2. Phys Chem Chem Phys 2011; 13:11175-92. [DOI: 10.1039/c0cp02754e] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Theoretical mechanisms and kinetics of the hydrogen abstraction reaction of acetone by chlorine radical. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.07.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Caralp F, Forst W, Hénon E, Bergeat A, Bohr F. Tunneling in the reaction of acetone with OH. Phys Chem Chem Phys 2006; 8:1072-8. [PMID: 16633588 DOI: 10.1039/b515118j] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Based on recent detailed quantum mechanical computations of the mechanism of the title reaction and, this paper presents kinetics analysis of the overall rate constant and its temperature dependence, for which ample experimental data are available for comparison. The analysis confirms that the principal channel is the formation of acetonyl radical + H(2)O, while the channel leading to acetic acid is of negligible importance. It is shown that the unusual temperature dependence of the overall rate constant, as observed experimentally, is well accounted for by standard RRKM treatment that includes tunneling. This treatment is applied at the microcanonical level, with chemically activated distribution of entrance species, i.e. using a stationary rather than a thermal distribution that incorporates collisional energy transfer and competition between the redissociation and exit channel. A similar procedure is applied to the isotopic reaction acetone-d6 + OH with equally satisfying results, so that the experimental temperature dependence of the KIE (kinetic isotope effect) is perfectly reproduced. This very good agreement between calculation and experiment is obtained without any fitting to experimental values and without any adjustment of the parameters of calculation.
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Affiliation(s)
- Françoise Caralp
- Laboratoire de Physicochimie Moléculaire, UMR 5803 CNRS, Université Bordeaux I, 33405, Talence Cedex, France
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Davis M, Drake W, Vimal D, Stevens P. Experimental and theoretical studies of the kinetics of the reactions of OH and OD with acetone and acetone-d6 at low pressure. J Photochem Photobiol A Chem 2005. [DOI: 10.1016/j.jphotochem.2005.08.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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