Near-IR Cavity Ringdown Spectroscopy and Kinetics of the Isomers and Conformers of the Butyl Peroxy Radical

Glover, Brent G.; Miller, Terry A.

doi:10.1021/jp054838q

Cited by 39 publications

(58 citation statements)

References 25 publications

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“…The cross-reaction between primary peroxyl radicals is known to be significantly faster than for secondary peroxyl radicals (6 10 8 versus 4 10 7 m À1 s À1 ). [23] Given the typical radical concentrations during autoxidations of about 10 À7 m, relative to hydrogen abstraction (120 m À1 s À1 ) and C=C addition (4.3 m À1 s…”

Section: The Source Of Alcohol and Ketonementioning

confidence: 99%

Peculiarities of β‐Pinene Autoxidation

2011

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The thermal oxidation of the renewable olefin β-pinene with molecular oxygen was experimentally and computationally investigated. Peroxyl radicals abstract weakly bonded allylic hydrogen atoms from the substrate, yielding allylic hydroperoxides (i.e., myrtenyl and pinocarvyl hydroperoxide). In addition, peroxyl radicals add to the C=C bond of the substrate to form an epoxide. It was found that a relatively high peroxyl radical concentration, together with the high rate of peroxyl cross-reactions, make radical-radical reactions surprisingly important for this particular substrate. Approximately 60 % of these peroxyl cross-reactions lead to termination (radical destruction), keeping a radical chain length of approximately 4 at 10 % conversion. Numerical simulation of the reaction-based on the proposed reaction mechanism and known or predicted rate constants-demonstrate the importance of peroxyl cross-reactions for the formation of alkoxyl radicals, which are the precursor of alcohol and ketone products.

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Section: The Source Of Alcohol and Ketonementioning

confidence: 99%

Peculiarities of β‐Pinene Autoxidation

2011

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“…Vibronic spectroscopy in the IR, corresponding to añ A ←X excitation, mitigates this dilemma and yields structured spectra [8,10,11]. Although this is a relatively weak transition, advances in spectroscopic techniques -including cavity ring-down [12][13][14][15], IR/vacuum-UV ionisation [16], and negative-ion photoelectron spectroscopies [17] -have fostered interest in this absorbance as a tool for monitoring peroxy radicals.…”

Section: Introductionmentioning

confidence: 99%

Examining the ground and first excited states of methyl peroxy radical with high-level coupled-cluster theory

2015

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Peroxy radicals (RO 2 ) are intermediates in fuel combustion, where they engage in efficiency-limiting autoignition reactions. They also participate in atmospheric chemistry leading to the formation of unwanted tropospheric ozone. Advances in spectroscopic techniques have allowed for the possibility of employing the lowest (Ã ←X) electronic transition of RO 2 as a tool to selectively monitor these species, enabling accurate kinetic values to be obtained. Herein, high-level ab initio methods are employed to systematically refine spectroscopic predictions for the methyl peroxy radical (CH 3 O 2 ), one of the most abundant peroxy radicals in the atmosphere. In particular, vibrationally corrected geometries and anharmonic vibrational frequencies for both the ground (X 2 A ) and first excited (Ã 2 A ) state are predicted using coupled-cluster theory with up to perturbative triples [CCSD(T)] and large atomic natural orbital basis sets. Equation-of-motion coupled-cluster theory is utilised to compute verticalÃ 2 A ←X 2 A transition properties; a radiative lifetime of 4.7 ms is suggested for the excited state. Finally, we predict the adiabatic excitation energy (T 0 ) via systematic extrapolation to the complete basis limit of coupled-cluster with up to full quadruples (CCSDTQ). After accounting for several approximations, and including an anharmonic zero-point vibrational energy correction, we match experiment for this transition to within 9 cm −1 .

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“…Comments*Reported rate coefficient not corrected for the effects of secondary chemistry, which can lead to either an overestimate or underestimate of the rate coefficient; a IUPAC Task Group recommendation (http://iupac.pole-ether.fr/); b Taken fromGlover et al (2005); c Taken fromBoyd et al (1999);…”

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confidence: 99%

Estimation of rate coefficients and branching ratios for reactions of organic peroxy radicals for use in automated mechanism construction

Jenkin¹,

Valorso²,

Aumont³

et al. 2019

Preprint

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Abstract. Organic peroxy radicals (RO2), formed from the degradation of hydrocarbons and other volatile organic compounds (VOCs), play a key role in tropospheric oxidation mechanisms. Several competing reactions may be available for a given RO2 radical, the relative rates of which depend on both the structure of RO2 and the ambient conditions. Published kinetics and branching ratio data are reviewed for the bimolecular reactions of RO2 with NO, NO2, NO3, OH and HO2; and for their self-reactions and cross-reactions with other RO2 radicals. This information is used to define generic rate coefficients and structure-activity relationship (SAR) methods that can be applied to the bimolecular reactions of a series of important classes of hydrocarbon and oxygenated RO2 radical. Information for selected unimolecular isomerization reactions (i.e. H-atom shift and ring-closure reactions) is also summarised and discussed. The methods presented here are intended to guide the representation of RO2 radical chemistry in the next generation of explicit detailed chemical mechanisms.

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Near-IR Cavity Ringdown Spectroscopy and Kinetics of the Isomers and Conformers of the Butyl Peroxy Radical

Cited by 39 publications

References 25 publications

Peculiarities of β‐Pinene Autoxidation

Peculiarities of β‐Pinene Autoxidation

Examining the ground and first excited states of methyl peroxy radical with high-level coupled-cluster theory

Estimation of rate coefficients and branching ratios for reactions of organic peroxy radicals for use in automated mechanism construction

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