Bejan, IG, Winiberg, FAF, Mortimer, N et al. (5 more authors) (2018) Gas-phase rate coefficients for a series of alkyl cyclohexanes with OH radicals and Cl atoms. International Journal of Chemical Kinetics, 50 (8). pp. 544-555. ISSN 0538-8066
Abstract
The rate coefficients of the reactions of OH radicals and Cl atoms with three alkylcyclohexanes compounds, methylcyclohexane (MCH), trans‐1,4‐dimethylcyclohexane (DCH), and ethylcyclohexane (ECH) have been investigated at (293 ± 1) K and 1000 mbar of air using relative rate methods. A majority of the experiments were performed in the Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC), a stainless steel chamber using in situ FTIR analysis and online gas chromatography with flame ionization detection (GC‐FID) detection to monitor the decay of the alkylcyclohexanes and the reference compounds. The studies were undertaken to provide kinetic data for calibrations of radical detection techniques in HIRAC. The following rate coefficients (in cm³ molecule−¹ s−¹) were obtained for Cl reactions: k(Cl+MCH) = (3.51 ± 0.37) × 10–¹⁰, k(Cl+DCH) = (3.63 ± 0.38) × 10−¹⁰, k(Cl+ECH) = (3.88 ± 0.41) × 10−¹⁰, and for the reactions with OH radicals: k(OH+MCH) = (9.5 ± 1.3) × 10–¹², k(OH+DCH) = (12.1 ± 2.2) × 10−¹², k(OH+ECH) = (11.8 ± 2.0) × 10−¹². Errors are a combination of statistical errors in the relative rate ratio (2σ) and the error in the reference rate coefficient. Checks for possible systematic errors were made by the use of two reference compounds, two different measurement techniques, and also three different sources of OH were employed in this study: photolysis of CH₃ONO with black lamps, photolysis of H₂O₂ at 254 nm, and nonphotolytic trans‐2‐butene ozonolysis. For DCH, some direct laser flash photolysis studies were also undertaken, producing results in good agreement with the relative rate measurements. Additionally, temperature‐dependent rate coefficient investigations were performed for the reaction of methylcyclohexane with the OH radical over the range 273‐343 K using the relative rate method; the resulting recommended Arrhenius expression is k(OH + MCH) = (1.85 ± 0.27) × 10–¹¹ exp((–1.62 ± 0.16) kJ mol−¹/RT) cm³ molecule−¹ s−¹. The kinetic data are discussed in terms of OH and Cl reactivity trends, and comparisons are made with the existing literature values and with rate coefficients from structure‐activity relationship methods. This is the first study on the rate coefficient determination of the reaction of ECH with OH radicals and chlorine atoms, respectively.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2018 Wiley Periodicals, Inc. This is the peer reviewed version of the following article: Bejan, IG, Winiberg, FAF, Mortimer, N et al. (5 more authors) (2018) Gas-phase rate coefficients for a series of alkyl cyclohexanes with OH radicals and Cl atoms. International Journal of Chemical Kinetics, 50 (8). pp. 544-555, which has been published in final form at https://doi.org/10.1002/kin.21179. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. |
Keywords: | calibration of OH detector, kinetics, OH and Cl structure activity relationships, substituent effect |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Physical Chemistry (Leeds) |
Funding Information: | Funder Grant number EU - European Union 730997 |
Depositing User: | Symplectic Publications |
Date Deposited: | 10 Jul 2018 11:29 |
Last Modified: | 06 Jun 2019 00:43 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1002/kin.21179 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:133064 |