CH2OO Criegee intermediate UV absorption cross-sections and kinetics of CH2OO + CH2OO and CH2OO + I as a function of pressure

Mir, Zara S.; Lewis, Thomas R.; Onel, Lavinia; Blitz, Mark A.; Seakins, Paul W.; Stone, Daniel

doi:10.1039/d0cp00988a

Cited by 27 publications

(42 citation statements)

References 55 publications

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“…Owing to the significant uncertainties related to the formation of IO following photolysis of CH2I2/O2/N2, 14,27,28,29 the model was constrained to the measured concentrations of IO. Further details of the uncertainties surrounding the temporal behaviour of IO during the kinetic experiments are given in the Supporting Information.…”

Section: Resultsmentioning

confidence: 99%

“…The kinetics of the CH2OO + O3 and CH2OO + IO reactions were studied using laser flash photolysis of CH2I2/O2/N2 (O2:N2 = 98:2) gas mixtures, coupled with broadband time-resolved UV absorption spectroscopy. The experimental apparatus has been described in detail previously 24 and has been used to determine the absorption cross-sections for CH2OO 14 and the kinetics of CH2OO reactions. 7,11,14 Precursor gases were mixed in a gas manifold and flowed into the reaction cell at known flow rates determined by calibrated mass flow controllers.…”

Section: Methodsmentioning

confidence: 99%

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Kinetics of the Gas Phase Reactions of the Criegee Intermediate CH₂OO with O₃ and IO

et al. 2020

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The kinetics of the gas phase reactions of the Criegee intermediate CH2OO with O3 and IO have been studied at 296 K and 300 Torr through simultaneous measurements of CH2OO, the CH2OO precursor (CH2I2), O3, and IO using flash photolysis of CH2I2/O2/O3/N2 mixtures at 248 nm coupled to time-resolved broadband UV absorption spectroscopy. Experiments were performed under pseudo-first-order conditions with respect to O3, with the rate coefficients for reactions of CH2OO with O3 and IO obtained by fitting to the observed decays of CH2OO using a model constrained to the measured concentrations of IO. Fits were performed globally, with the ratio between the initial concentration of O3 and the average concentration of IO varied in the range 30 to 700, and gave kCH2OO+O3 = (3.6 ± 0.8) × 10 -13 cm 3 molecule -1 s -1 and kCH2OO+IO = (7.6 ± 1.4) × 10 -11 cm 3 molecule -1 s -1 (where the errors are at the 2σ level). The magnitude of kCH2OO+O3 has a significant effect on the steady state concentration of CH2OO in chamber studies. Atmospheric implications of the results are discussed.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Kinetics of the Gas Phase Reactions of the Criegee Intermediate CH₂OO with O₃ and IO

et al. 2020

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“…[ 25–27 ] The used [CH 2 OO] 0 was on the order of 10 12 cm −3 . Under such conditions, the effect CH 2 OO self‐reaction [ 28 ] is minor in the kinetics of CH 2 OO reaction with DMSO.…”

Section: Resultsmentioning

confidence: 99%

“…[25][26][27] The used [CH 2 OO] 0 was on the order of 10 12 cm −3 . Under such conditions, the effect CH 2 OO self-reaction [28] is minor in the kinetics of CH 2 OO reaction with DMSO. The slopes of Figure 4 correspond to the bimolecular reaction rate coefficients k DMSO at various temperatures.…”

Section: Ir Absorption Spectra and Kinetic Analysismentioning

confidence: 99%

Temperature‐dependent kinetics of the simplest Criegee intermediate reaction with dimethyl sulfoxide

Lin

2020

J Chinese Chemical Soc

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Criegee intermediates are thought to play roles in atmospheric chemistry, including OH radical formation, oxidation of SO 2 , NO 2 , etc. CH 2 OO is the simplest Criegee intermediate, of which the reactivity has been a hot topic. Here we investigated the kinetics of CH 2 OO reaction with dimethyl sulfoxide (DMSO) under 278-349 K and 10-150 Torr. DMSO is an important species formed in the oxidation of dimethyl sulfide in the biogenic sulfur cycle. The concentration of CH 2 OO was monitored in real-time via its mid-infrared absorption band at about 1,286 cm −1 (Q branch of the ν 4 band) with a highresolution quantum cascade laser spectrometer. The 298 K bimolecular rate coefficient was determined to be k 298 = (2.3 ± 0.3) × 10 −12 cm 3 /s at 30 Torr with an Arrhenius activation energy of −3.9 ± 0.2 kcal/mol and a weak pressure dependence for pressures higher than 30 Torr (k 298 = (2.8 ± 0.3) × 10 −12 cm 3 /s at 100 Torr). The reaction is speculated to undergo a five-membered ring intermediate, analogous to that of CH 2 OO with SO 2. The negative activation energy indicates that the rate-determining transition state is submerged. The magnitude of the reaction rate coefficient lies in between those of CH 2 OO reactions with (CH 3) 2 CO and with SO 2 .

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“…After this pioneering work, the same method has been applied for generation of other CIs, like CH 3 CHOO (Taatjes et al, 2013), (CH 3 ) 2 COO (Liu et al, 2014a;Chang et al, 2016), methyl vinyl ketone oxide (MVKO) (Barber et al, 2018), methacrolein oxide (MACRO) (Vansco et al, 2019), etc. These CIs have been identified with various detection methods, like photoionization mass spectrometry (Taatjes et al, 2013), infrared action (Liu et al, 2014b) and absorption (Su et al, 2013;Lin et al, 2015) spectroscopy, UV-visible absorption or depletion spectroscopy (Liu et al, 2014a;Beames et al, 2013;Sheps, 2013;Smith et al, 2014;Chang et al, 2016;Ting et al, 2014), microwave spectroscopy (McCarthy et al, 2013;Nakajima et al, 2015), etc. In addition, utilizing the direct detection of CIs, a number of kinetic investigations of CI reactions, e.g.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of dimethyl sulfide (DMS) reactions with isoprene-derived Criegee intermediates studied with direct UV absorption

et al. 2020

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Abstract. Criegee intermediates (CIs) are formed in the ozonolysis of unsaturated hydrocarbons and play a role in atmospheric chemistry as a non-photolytic OH source or a strong oxidant. Using a relative rate method in an ozonolysis experiment, Newland et al. (2015) reported high reactivity of isoprene-derived Criegee intermediates towards dimethyl sulfide (DMS) relative to that towards SO2 with the ratio of the rate coefficients kDMS+CI/kSO2+CI = 3.5 ± 1.8. Here we reinvestigated the kinetics of DMS reactions with two major Criegee intermediates formed in isoprene ozonolysis, CH2OO, and methyl vinyl ketone oxide (MVKO). The individual CI was prepared following the reported photolytic method with suitable (diiodo) precursors in the presence of O2. The concentration of CH2OO or MVKO was monitored directly in real time through their intense UV–visible absorption. Our results indicate the reactions of DMS with CH2OO and MVKO are both very slow; the upper limits of the rate coefficients are 4 orders of magnitude smaller than the rate coefficient reported by Newland et al. (2015) These results suggest that the ozonolysis experiment could be complicated such that interpretation should be careful and these CIs would not oxidize atmospheric DMS at any substantial level.

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CH₂OO Criegee intermediate UV absorption cross-sections and kinetics of CH₂OO + CH₂OO and CH₂OO + I as a function of pressure

Abstract: The UV absorption cross-sections of the Criegee intermediate CH2OO, and kinetics of the CH2OO self-reaction and the reaction of CH2OO with I are reported as a function of pressure at 298 K.

Cited by 27 publications

References 55 publications

Kinetics of the Gas Phase Reactions of the Criegee Intermediate CH₂OO with O₃ and IO

Kinetics of the Gas Phase Reactions of the Criegee Intermediate CH₂OO with O₃ and IO

Temperature‐dependent kinetics of the simplest Criegee intermediate reaction with dimethyl sulfoxide

Kinetics of dimethyl sulfide (DMS) reactions with isoprene-derived Criegee intermediates studied with direct UV absorption

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CH2OO Criegee intermediate UV absorption cross-sections and kinetics of CH2OO + CH2OO and CH2OO + I as a function of pressure

Abstract: The UV absorption cross-sections of the Criegee intermediate CH2OO, and kinetics of the CH2OO self-reaction and the reaction of CH2OO with I are reported as a function of pressure at 298 K.

Cited by 27 publications

References 55 publications

Kinetics of the Gas Phase Reactions of the Criegee Intermediate CH2OO with O3 and IO

Kinetics of the Gas Phase Reactions of the Criegee Intermediate CH2OO with O3 and IO

Temperature‐dependent kinetics of the simplest Criegee intermediate reaction with dimethyl sulfoxide

Kinetics of dimethyl sulfide (DMS) reactions with isoprene-derived Criegee intermediates studied with direct UV absorption

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CH₂OO Criegee intermediate UV absorption cross-sections and kinetics of CH₂OO + CH₂OO and CH₂OO + I as a function of pressure

Kinetics of the Gas Phase Reactions of the Criegee Intermediate CH₂OO with O₃ and IO

Kinetics of the Gas Phase Reactions of the Criegee Intermediate CH₂OO with O₃ and IO