Stopped‐flow studies of the mechanisms of ozone–alkene reactions in the gas phase propene and isobutene

Herron, John T.; Huie, Robert E.

doi:10.1002/kin.550101003

Cited by 58 publications

(57 citation statements)

References 34 publications

(14 reference statements)

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“…In addition, the primary step in the ethene/ozonesystem is reported to possess a rate constant of only cm 3 molecule Ϫ1 s Ϫ1 [14], and so (7) in decreasing the stoichiometric ratio below unity. Furthermore, because of the relatively low value of k 4 , secondary OH radicals formed in (7) react predominantly, especially in later stages of the ozonolysis, with HCHO instead of with ET, thus regenerating HO 2 via reaction (5) in which HCO is formed followed by reaction (8).…”

Section: Resultsmentioning

confidence: 98%

“…Only selected relevant contributions shall be quoted here. Herron and Huie [8] and Martinez and Herron [9] measured product profiles using photoionization mass spectroscopy in a stopped-flow system. They postulated formation of OH radicals from unimolecular decomposition of Criegee radicals and obtained branching ratios for the decomposition channels by fitting measured data to simulated concentration profiles of the alkenes and selected products.…”

Section: Introductionmentioning

confidence: 99%

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On the use of CO as scavenger for OH radicals in the ozonolysis of simple alkenes and isoprene

Gutbrod

Meyer

Rahman

et al. 1997

Int. J. Chem. Kinet.

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The OH radical yields generated in the ozonolysis of ethene (ET), propene (PR), cis-2-butene (CB), trans-2-butene (TB), 2,3-dimethyl-2-butene (TME), and isoprene (ISP) in the presence of 20 Vol.% O 2 have been determined in a darkened glass reactor at 1 bar total pressure. The hydroxyl radicals formed were scavenged by an excess of CO added to the systems. The O 2 present converted H atoms formed in this reaction into HO 2 . From measurements of the increase in CO 2 generation by FTIR the OH formation yields were determined to be 0.08 (ET), 0.18 (PR), 0.17 (CB), 0.24 (TB), 0.36 (TME), and 0.19 (ISP), respectively, per molecule of reacted ozone. The combined error in the OH determinations is estimated to be Ͻ10%.

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Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

On the use of CO as scavenger for OH radicals in the ozonolysis of simple alkenes and isoprene

Gutbrod

Meyer

Rahman

et al. 1997

Int. J. Chem. Kinet.

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“…Based on the evidence presented by Herron and Huie [29], it has generally been assumed that 0-0 bonds in primary ozonides will split equally (i.e. k, -kb).…”

Section: Discussionmentioning

confidence: 99%

Reactions of Ozone with Unsaturated Organic Compounds

Treacy¹,

Hag²,

O'Farrell³

et al. 1992

Ber Bunsenges Phys Chem

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The basis 3df2df in Table 1 again contains one set of $functions on all heavy atoms. Second row atoms carry three sets of &functions but first row atoms only two. When this basis set is used instead of 6-31 lG(2dJp) the atomization energies of C10, OC10, and ClOO are all in acceptable agreement with experiment.The basis 3df2df has been applied to two further test molecules and to the C103-isomers. For all species in Table 1 but ClOCl the deviation is less than 5 kcalfmol.The G1 calculations on C103-isomers were started with geometry optimizations on the HF/6-31G*-and MP2f6-31G*-levels of theory. All three supposed isomers, C1000, OC100, and sym-C103 were found as minima [9] on the potential energy hypersurface. The GI total energy calculations using the basis set described above gave heats of formation of 41, 58, and 48 kcalfmol, respectively.From these ab initio calculations it appears that ClOOO might be considered as an intermediate in reaction (1). Since it is a real minimum on the potential energy hypersurface, there must exist a barrier for the exothermic dissociation of ground state ClOOO into C10 and 02.The work was supported in part by the BMFT, Bonn, withinThe authors acknowledge access to the facilities of the Hochstproject 0744120 0.leistungsrechenzentrum Julich. References Howard SidebottomUniversity College Dublin, Ireland Chemical Kinetics f Elementary Reactions f RadicalsRate constants for the gas-phase reactions of ozone with a series of alkenes have been determined using a conventional static system. Ozone loss was monitored in excess of the hydrocarbon and rate data measured at 1 atmosphere total pressure over the temperature range 240-324 K. The Arrhenius parameters obtained are discussed in terms of structure-reactivity relationships. Product studies have been carried out for the reaction of O3 with the conjugated dienes, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene) and 2,3-dimethyl-1,3-butadiene in air. The results provide information on the decomposition pathways for the primary ozonides and the relative importance of ozone addition to the two doublebonds in isoprene.cant reactivity towards ozone as well as towards hydroxyl and nitrate radicals. Numerous potentially important roles of the ozone-alkene reaction have been recognized since these reactions can provide mutual sinks for both ozone and alkenes and concomitantly serve as sources of partially oxidised compounds e. g. CO, aldehydes, ketones and organic

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“…cm6 molec-' s-' [lo] [2,3,4,5,11,12,13,14] on the ozone reactions of propene, 2-butene and 2,3-dimethyl2-butene, has provided conflicting conclusions as to the amounts of these radical products. OH produced by the reaction of ozone with isoprene is both important to smog formation in the atmoshere, and can complicate the standard 03/hydrocarbon/dark experiment, because much of the hydrocarbon that appears to be reacting with 0 3 is actually lost via reaction with OH.…”

Section: Experimental Systemmentioning

confidence: 99%

“…Although ozone-alkene reactions have been studied for decades, many questions remain, particularly as to the fate of the Criegee biradicals in the gas phase [l, and references therein]. A few of these studies have found evidence for substantial quantities of OH formation from the O3 reaction with alkenes, including tetramethylethylene [2], propene [3,4] isobutene [3], and a series of terpenes [5]. The studies of tetramethylethylene [2] and propene [4] provide the only quantification of this OH source, at 0.7 and roughly 0.3 per molecule of alkene reacted.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric photooxidation of isoprene part II: The ozone‐isoprene reaction

Paulson

Flagan

Seinfeld

1992

Int J of Chemical Kinetics

172

137

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A series of experiments have been performed to study the ozone-isoprene reaction in a smog chamber by adding externally produced 0 3 to the hydrocarbon in the dark. A chemical tracer, methyl cyclohexane, was added to probe the OH formation in the system. O(3P) formation was also examined using the known distribution of products that are unique to the 0(3P)-isoprene reaction (part I). The results provide clear evidence that both OH and O(3P) are produced by the 03-isoprene reaction directly in large quantities; about 0.68 2 0.15 and 0.45 2 0.20 per 03-isoprene reaction, respectively. These additional radicals severely complicate the analysis of the 0 3 reaction, hence, computer kinetic modeling was necessary to ascertain the products of the 0 3 reaction itself, corrected for OH and O(3P) reactions. The product distribution, which differs dramatically from that published previously, is: 67 2 9% methacrolein, 26 2 6% methyl vinyl ketone, and 7 2 3% propene, accounting for 100 * 10% of the reacted isoprene. Applicability of these results to the gas-phase 0 3 reaction with other unsaturated hydrocarbons is briefly discussed.

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Stopped‐flow studies of the mechanisms of ozone–alkene reactions in the gas phase propene and isobutene

Cited by 58 publications

References 34 publications

On the use of CO as scavenger for OH radicals in the ozonolysis of simple alkenes and isoprene

On the use of CO as scavenger for OH radicals in the ozonolysis of simple alkenes and isoprene

Reactions of Ozone with Unsaturated Organic Compounds

Atmospheric photooxidation of isoprene part II: The ozone‐isoprene reaction

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