Gas-phase reactions of the vinoxy radical with oxygen and nitric oxide

Gutman, David; Nelson, H. H.

doi:10.1021/j100243a023

Cited by 40 publications

(47 citation statements)

References 4 publications

(4 reference statements)

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“…The ring-opening reaction is thus unlikely to compete with O 2 addition to the vinoxy radical, unless the latter is for some reason several orders of magnitude slower than what is normally assumed for alkyl (and vinoxy) radicals. 41 Figure 10: Reactant, transition state and product of the ring-opening channel from one of the vinoxy radicals produced in α-pinene ozonolysis. The length of the C-C bond being broken in the transition state is 2.13 Å. Zero-point corrected F12 relative energies in kcal/mol are given for each step.…”

Section: Acs Paragon Plus Environmentmentioning

confidence: 99%

Computational Study of Hydrogen Shifts and Ring-Opening Mechanisms in α-Pinene Ozonolysis Products

et al. 2015

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Autoxidation by sequential peroxy radical hydrogen shifts (H-shifts) and O2 additions has recently emerged as a promising mechanism for the rapid formation of highly oxidized, low-volatility organic compounds in the atmosphere. A key prerequisite for autoxidation is that the H-shifts of the initial peroxy radicals formed by, e.g., OH or O3 oxidation are fast enough to compete with bimolecular sink reactions. In most atmospheric conditions, these restrict the lifetime of peroxy radicals to be on the order of seconds. We have systematically investigated all potentially important (nonmethyl, sterically unhindered) H-shifts of all four peroxy radicals formed in the ozonolysis of α-pinene using density functional (ωB97XD) and coupled cluster [CCSD(T)-F12] theory. In contrast to the related but chemically simpler cyclohexene ozonolysis system, none of the calculated H-shifts have rate constants above 1 s(-1) at 298 K, and most are below 0.01 s(-1). The low rate constants are connected to the presence of the strained cyclobutyl ring in the α-pinene-derived peroxy radicals, which hinders H-shifts both from and across the ring. For autoxidation to yield the experimentally observed highly oxidized products in the α-pinene ozonolysis system, additional ring-opening reaction mechanisms breaking the cyclobutyl ring are therefore needed. We further investigate possible uni- and bimolecular pathways for opening the cyclobutyl ring in the α-pinene ozonolysis system.

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Section: Acs Paragon Plus Environmentmentioning

confidence: 99%

Computational Study of Hydrogen Shifts and Ring-Opening Mechanisms in α-Pinene Ozonolysis Products

et al. 2015

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“…believed to be and/or OH ϩ (CHO) OH ϩ 2 [16] at 90 torr total pressure. As a check HCHO ϩ CO of this work we tried to measure the absorbance of OH radicals at 309.1 nm following radiolysis of 0.5 mbar CH 3 CHO, 200 mbar O 2 , and 800 mbar of SF 6 .…”

Section: ϫ13mentioning

confidence: 99%

“…The rate constant for reaction (17) 17 17 15 in the fit. The resulting values of b and k /(k ϩ 17 17 were and , respec- [16], and the high-pressure limit of k(CH ϩ NO) ϭ 3 cm 3 molecule Ϫ1 s Ϫ1 [25], giv-…”

mentioning

confidence: 95%

Absolute rate constants for F + CH3CHO and CH3CO + O2, relative rate study of CH3CO + NO, and the product distribution of the F + CH3CHO reaction

Sehested

Christensen

Nielsen

et al. 1998

Int. J. Chem. Kinet.

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Using a pulse-radiolysis transient UV-VIS absorption system, rate constants for the reactions of F atoms with CH 3 CHO (1) and CH 3 CO radicals with O 2 (2) and NO (3) at 295 K and 1000 mbar total pressure of SF 6 was determined to be Ϫ10 k ϭ (1.4 Ϯ 0.2) ϫ 10 , k ϭ 1 2 By monitoring the for-Ϫ12 Ϫ11 3 Ϫ1 Ϫ1(4.4 Ϯ 0.7) ϫ 10 , and k ϭ (2.4 Ϯ 0.7) ϫ 10 cm molecule s . 3 mation of CH 3 C(O)O 2 radicals ( Ͼ 250nm) and NO 2 ( ϭ 400.5nm) following radiolysis of SF 6 /CH 3 CHO/O 2 and SF 6 /CH 3 CHO/O 2 /NO mixtures, respectively, it was deduced that reaction of F atoms with CH 3 CHO gives (65 Ϯ 9)% CH 3 CO and (35 Ϯ 9)% HC(O)CH 2 radicals. Finally, the data obtained here suggest that decomposition of HC(O)CH 2 O radicals via C9C bond scission occurs at a rate of

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“…The vinoxy radical (CH 2 CHO) is a likely product of the OH radical-initiated oxidation of acetaldehyde at elevated temperatures [1]. Vinoxy is also an intermediate in the high-temperature oxidation of ethylene (via reaction with O atoms) [3] and acetylene (via reaction with OH) [4]. Acetaldehyde is also an air pollutant.…”

Section: Introductionmentioning

confidence: 99%

The reaction of OH with acetaldehyde and deuterated acetaldehyde: Further insight into the reaction mechanism at both low and elevated temperatures

Taylor

Yamada

Marshall

2006

Int J of Chemical Kinetics

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The pulsed laser photolysis/laser-induced fluorescence technique has been used to conduct additional measurements of the gas-phase CH 3 CHO + OH reaction. These measurements were conducted to verify the complex temperature dependence previously observed by the authors and to acquire mechanistic information about the reaction mechanism in the form of primary kinetic isotope effects. Primary kinetic isotope effect measurements at temperatures of 297, 383, 600, and 860 K indicate that H abstraction from the acetyl group dominates that of the methyl group at low to modest temperatures (≤600 K) and H abstraction from the methyl group dominates that from the acetyl group at higher temperatures (860 K). A bi-exponential

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Gas-phase reactions of the vinoxy radical with oxygen and nitric oxide

Cited by 40 publications

References 4 publications

Computational Study of Hydrogen Shifts and Ring-Opening Mechanisms in α-Pinene Ozonolysis Products

Computational Study of Hydrogen Shifts and Ring-Opening Mechanisms in α-Pinene Ozonolysis Products

Absolute rate constants for F + CH3CHO and CH3CO + O2, relative rate study of CH3CO + NO, and the product distribution of the F + CH3CHO reaction

The reaction of OH with acetaldehyde and deuterated acetaldehyde: Further insight into the reaction mechanism at both low and elevated temperatures

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