Freja F. Østerstrøm, Lavinia Onel, Alexander Brennan, Joseph M. Parr, Lisa K. Whalley, Paul W. Seakins, Dwayne E. Heard
{"title":"在高仪器化大气化学反应器中测量的CH3O2+HO2自由基交叉反应动力学","authors":"Freja F. Østerstrøm, Lavinia Onel, Alexander Brennan, Joseph M. Parr, Lisa K. Whalley, Paul W. Seakins, Dwayne E. Heard","doi":"10.1002/kin.21651","DOIUrl":null,"url":null,"abstract":"<p>The sensitive Fluorescence Assay by Gas Expansion (FAGE) method has been used to detect methyl peroxy (CH<sub>3</sub>O<sub>2</sub>) and hydroperoxyl (HO<sub>2</sub>) radicals after their conversion by titration with excess NO to methoxy (CH<sub>3</sub>O) and hydroxyl (OH) radicals, respectively, to study the kinetics of the reaction of CH<sub>3</sub>O<sub>2</sub> + HO<sub>2</sub> radicals. The rate coefficient of the reaction was measured in the Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC) at 1000 mbar of synthetic air at <i>T</i> = 268–344 K, selectively detecting both radicals. Using a numerical model to fit both CH<sub>3</sub>O<sub>2</sub> and HO<sub>2</sub> radical temporal decays globally at each temperature investigated, rate coefficients for the reaction have been obtained. The room temperature rate coefficient was found to be <i>k</i><sub>CH3O2 +HO2</sub>(295 K) = (4.6 ± 0.7) × 10<sup>−12</sup> molecule<sup>−1</sup> cm<sup>3</sup> s<sup>−1</sup> (2σ errors) and the temperature dependence of the rate coefficient can be characterized in Arrhenius form by <i>k</i><sub>CH3O2 + HO2</sub>(268 K < <i>T</i> < 344 K) = (5.1 ± 2.1) × 10<sup>−13</sup> × exp((637 ± 121)/<i>T</i>) cm<sup>3</sup> molecule<sup>−1</sup> s<sup>−1</sup>. The rate coefficients obtained here are 14%–16% lower than the literature recommended values with an uncertainty which is reduced significantly compared to previous reports.</p>","PeriodicalId":13894,"journal":{"name":"International Journal of Chemical Kinetics","volume":null,"pages":null},"PeriodicalIF":1.5000,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/kin.21651","citationCount":"0","resultStr":"{\"title\":\"Kinetics of the cross-reaction of CH3O2 + HO2 radicals measured in the Highly Instrumented Reactor for Atmospheric Chemistry\",\"authors\":\"Freja F. Østerstrøm, Lavinia Onel, Alexander Brennan, Joseph M. Parr, Lisa K. Whalley, Paul W. Seakins, Dwayne E. Heard\",\"doi\":\"10.1002/kin.21651\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>The sensitive Fluorescence Assay by Gas Expansion (FAGE) method has been used to detect methyl peroxy (CH<sub>3</sub>O<sub>2</sub>) and hydroperoxyl (HO<sub>2</sub>) radicals after their conversion by titration with excess NO to methoxy (CH<sub>3</sub>O) and hydroxyl (OH) radicals, respectively, to study the kinetics of the reaction of CH<sub>3</sub>O<sub>2</sub> + HO<sub>2</sub> radicals. The rate coefficient of the reaction was measured in the Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC) at 1000 mbar of synthetic air at <i>T</i> = 268–344 K, selectively detecting both radicals. Using a numerical model to fit both CH<sub>3</sub>O<sub>2</sub> and HO<sub>2</sub> radical temporal decays globally at each temperature investigated, rate coefficients for the reaction have been obtained. The room temperature rate coefficient was found to be <i>k</i><sub>CH3O2 +HO2</sub>(295 K) = (4.6 ± 0.7) × 10<sup>−12</sup> molecule<sup>−1</sup> cm<sup>3</sup> s<sup>−1</sup> (2σ errors) and the temperature dependence of the rate coefficient can be characterized in Arrhenius form by <i>k</i><sub>CH3O2 + HO2</sub>(268 K < <i>T</i> < 344 K) = (5.1 ± 2.1) × 10<sup>−13</sup> × exp((637 ± 121)/<i>T</i>) cm<sup>3</sup> molecule<sup>−1</sup> s<sup>−1</sup>. The rate coefficients obtained here are 14%–16% lower than the literature recommended values with an uncertainty which is reduced significantly compared to previous reports.</p>\",\"PeriodicalId\":13894,\"journal\":{\"name\":\"International Journal of Chemical Kinetics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.5000,\"publicationDate\":\"2023-05-12\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://onlinelibrary.wiley.com/doi/epdf/10.1002/kin.21651\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"International Journal of Chemical Kinetics\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1002/kin.21651\",\"RegionNum\":4,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Chemical Kinetics","FirstCategoryId":"92","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/kin.21651","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
Kinetics of the cross-reaction of CH3O2 + HO2 radicals measured in the Highly Instrumented Reactor for Atmospheric Chemistry
The sensitive Fluorescence Assay by Gas Expansion (FAGE) method has been used to detect methyl peroxy (CH3O2) and hydroperoxyl (HO2) radicals after their conversion by titration with excess NO to methoxy (CH3O) and hydroxyl (OH) radicals, respectively, to study the kinetics of the reaction of CH3O2 + HO2 radicals. The rate coefficient of the reaction was measured in the Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC) at 1000 mbar of synthetic air at T = 268–344 K, selectively detecting both radicals. Using a numerical model to fit both CH3O2 and HO2 radical temporal decays globally at each temperature investigated, rate coefficients for the reaction have been obtained. The room temperature rate coefficient was found to be kCH3O2 +HO2(295 K) = (4.6 ± 0.7) × 10−12 molecule−1 cm3 s−1 (2σ errors) and the temperature dependence of the rate coefficient can be characterized in Arrhenius form by kCH3O2 + HO2(268 K < T < 344 K) = (5.1 ± 2.1) × 10−13 × exp((637 ± 121)/T) cm3 molecule−1 s−1. The rate coefficients obtained here are 14%–16% lower than the literature recommended values with an uncertainty which is reduced significantly compared to previous reports.
期刊介绍:
As the leading archival journal devoted exclusively to chemical kinetics, the International Journal of Chemical Kinetics publishes original research in gas phase, condensed phase, and polymer reaction kinetics, as well as biochemical and surface kinetics. The Journal seeks to be the primary archive for careful experimental measurements of reaction kinetics, in both simple and complex systems. The Journal also presents new developments in applied theoretical kinetics and publishes large kinetic models, and the algorithms and estimates used in these models. These include methods for handling the large reaction networks important in biochemistry, catalysis, and free radical chemistry. In addition, the Journal explores such topics as the quantitative relationships between molecular structure and chemical reactivity, organic/inorganic chemistry and reaction mechanisms, and the reactive chemistry at interfaces.