Kinetic Study Of Gas-phase Reaction Research Articles

Kinetic Study of Gas-Phase Reactions of Pyruvic Acid with HO2

Gas-phase reactions between pyruvic acid (PA) and HO2 radicals were examined using ab initio quantum chemistry and transition state theory. The rate coefficients were determined over a temperature range of 200-400 K including tunneling contributions. Six potential reaction pathways were identified. The two hydrogen abstraction reactions yielding the H2O2 product were found to have high barriers. The HO2 radical was also found to have a catalytic effect on the intramolecular hydrogen transfer reactions occurring by three distinct routes. These hydrogen-shift reactions are very interesting mechanistically although they are highly endothermic. The only reaction that contributes significantly to the consumption of PA is a multistep pathway involving a peroxy-radical intermediate, PA + HO2 → CH3COOH + OH + CO2. This exothermic process has potential atmospheric relevance because it produces an OH radical as a product. Atmospheric models currently have difficulty predicting accurate OH concentrations for certain atmospheric conditions, such as environments free of NOx and the nocturnal boundary layer. Reactions of this sort, although not necessary with PA, may account for a portion of this deficit. The present study helps settle the issue of the relative roles of reaction and photolysis in consumption of PA in the troposphere.

Kinetic Study of Gas-Phase Reactions of OH and NO3Radicals and O3with iso-Butyl andtert-Butyl Vinyl Ethers

Using a relative rate technique, kinetic studies on the gas-phase reactions of OH radicals, ozone, and NO(3) radicals with iso-butyl vinyl ether (iBVE) and tert-butyl vinyl ether (tBVE) have been performed in a 405 L Duran glass chamber at (298 ± 3) K and atmospheric pressure (750 ± 10 Torr) in synthetic air using in situ FTIR spectroscopy to monitor the reactants. The following rate coefficients (in units of cm(3) molecule(-1) s(-1)) have been obtained: (1.08 ± 0.23) × 10(-10) and (1.25 ± 0.32) × 10(-10) for the reactions of OH with iBVE and tBVE, respectively; (2.85 ± 0.62) × 10(-16) and (5.30 ± 1.07) × 10(-16) for the ozonolysis of iBVE and tBVE, respectively; and (1.99 ± 0.56) × 10(-12) and (4.81 ± 1.01) × 10(-12) for the reactions of NO(3) with iBVE and tBVE, respectively. The rate coefficients for the NO(3) reactions are first-time determinations. The measured rate coefficients are compared with estimates using current structure activity relationship (SAR) methods and the effects of the alkoxy group on the gas-phase reactivity of the alkyl vinyl ethers toward the oxidants are compared and discussed. In addition, estimates of the tropospheric lifetimes of iBVE and tBVE with respect to their reactions with OH, ozone, and NO(3) for typical OH radical, ozone, and NO(3) radical concentrations are made, and their relevance for the environmental fate of compounds is considered.

Kinetics study of gas-phase reactions of erythro/ threo-CF 3CHFCHFC 2F 5 with OH radicals at 253–328 K

Rate constants for reactions of erythro-CF 3CHFCHFC 2F 5 and threo-CF 3CHFCHFC 2F 5 with OH radicals were determined by means of a relative rate method in an 11.5-dm 3 reaction chamber at 253 –328 K: k 1 ( erythro-CF 3CHFCHFC 2F 5 + OH) = (9.60 ± 3.39) × 10 –13 exp[–(1680 ± 100)/ T] and k 2 ( threo-CF 3CHFCHFC 2F 5 + OH) = (6.60 ± 2.06) × 10 –13 exp[–(1580 ± 90)/ T] cm 3 molecule –1 s –1.

A kinetic study of gas-phase reaction of thiophene with NO 3 by using absolute and relative methods

The gas-phase rate coefficient for the reaction of thiophene with nitrate radical, NO 3, has been determined, using relative (gas chromatography as analytical tool) and absolute methods at 298 K. The absolute experiments were carried out using a fast-flow-discharge technique, with detection of the NO 3 radical by Laser Induced Fluorescence (LIF). The proposed rate coefficient at 298 K is, k=(3.16±0.27)×10 −14 cm 3 molecule −1 s −1 . The temperature dependence was studied by the absolute technique in the range 260–433 K, observing that in the interval of 260–277 K the rate coefficient decreases as the temperature increases and from 298 K onwards the rate coefficient increases with temperature.

Kinetic study of gas-phase reactions of pinonaldehyde and structurally related compounds

Rate constants for the reactions of OH, NO3, and O3 with pinonaldehyde and the structurally related compounds 3-methylbutanal, 3-methylbutan-2-one, cyclobutylmethylketone, and 2,2,3-trimethyl-cyclobutyl-1-ethanone have been measured at using on-line Fourier transform infrared spectroscopy. The rate constants obtained for the reactions with pinonaldehyde were: ,

ChemInform Abstract: HIGH‐TEMPERATURE ION‐MOLECULE CHEMISTRY. A KINETIC STUDY OF GAS‐PHASE REACTIONS OF MAGNESIUM ATOMS WITH D3+, METHANIUM, AMMONIUM, AND TERT‐C4H9+ IONS

Chemischer InformationsdienstVolume 8, Issue 44 Preparative Organic Chemistry ChemInform Abstract: HIGH-TEMPERATURE ION-MOLECULE CHEMISTRY. A KINETIC STUDY OF GAS-PHASE REACTIONS OF MAGNESIUM ATOMS WITH D3+, METHANIUM, AMMONIUM, AND TERT-C4H9+ IONS P. L. PO, P. L. POSearch for more papers by this authorR. F. PORTER, R. F. PORTERSearch for more papers by this author P. L. PO, P. L. POSearch for more papers by this authorR. F. PORTER, R. F. PORTERSearch for more papers by this author First published: November 1, 1977 https://doi.org/10.1002/chin.197744121AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume8, Issue44November 1, 1977 RelatedInformation

High-temperature ion-molecule chemistry. A kinetic study of gas-phase reactions of magnesium atoms with D3+, methanium, ammonium, and tert-C4H9+ ions

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh-temperature ion-molecule chemistry. A kinetic study of gas-phase reactions of magnesium atoms with D3+, methanium, ammonium, and tert-C4H9+ ionsP. L. Po and Richard F. PorterCite this: J. Am. Chem. Soc. 1977, 99, 15, 4922–4930Publication Date (Print):June 1, 1977Publication History Published online1 May 2002Published inissue 1 June 1977https://doi.org/10.1021/ja00457a007RIGHTS & PERMISSIONSArticle Views41Altmetric-Citations7LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (941 KB) Get e-Alerts Get e-Alerts