Temperature-Dependent Kinetics Study of the Reactions of OH with C2H5I, n-C3H7I, and iso-C3H7I

Zhang, Shaoliang; Strekowski, Rafal; Monod, Anne; Bosland, L.; Zetzsch, Cornelius

doi:10.1021/jp300575f

Cited by 12 publications

(16 citation statements)

References 59 publications

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“…To estimate the influence of the RI photolysis reactions listed above on the initial hydroxyl radical concentration, the OH radical and O( 3 P) atom consumption was simulated using the COPASI 4.6 simulation software. Similar to our previous work on OH radical reactions with C 2 H 5 I, 1‐C 3 H 7 I, and 2‐C 3 H 7 I, model results show that the OH radicals are consumed in majority by reactions – . We did not observe any influence of the RI photolysis products' secondary chemistry on the measured rate coefficients.…”

Section: Discussionsupporting

confidence: 65%

“…The experimental approach is similar to one we have employed in several previous flash photolysis (FP) studies of the reactions of atmospheric and nuclear industry safety interests. The experiments involved time‐resolved detection of OH radicals by resonance fluorescence (RF) (A 2 Σ + →X 2 Π) at λ = 308 nm following VUV FP of H 2 O/He/CHI 3 mixtures and the time‐resolved detection of O( 3 P) atoms by RF at 130.2, 130.5, and 130.6 nm following VUV FP of O 3 /He/C 2 H 5 I/synthetic air and O 3 /He/CHI 3 /synthetic air mixtures .…”

Section: Methodsmentioning

confidence: 99%

“…The gas phase CHI 3 and C 2 H 5 I concentrations were determined using the gas saturation method, one of the oldest and most versatile ways of studying heterogeneous equilibria involving low vapor pressure compounds, first developed by Regnault in 1845. The gas saturation method used in this work is same as the one employed in a number of other OH radical reactions of atmospheric interest. Briefly, the helium carrier gas was allowed to flow though the volume containing the CHI 3 or C 2 H 5 I sample that itself was mixed with glass beads and supported on a fritted glass surface.…”

Section: Methodsmentioning

confidence: 99%

“…The initial OH radical, [OH] 0 , and O( 3 P)atom, [O( 3 P)] 0 , concentrations were not measured directly but were determined experimentally at room temperature using the water vapor UV‐photolysis calibration technique and oxygen actinometry as described in detail by Dusanter et al and Faloona et al. The same actinometry technique to measure the [OH] 0 was used in our previous study on the temperature‐dependent kinetic study of the reactions of OH radicals with C 2 H 5 I, n ‐C 3 H 7 I, and iso ‐C 3 H 7 I.…”

Section: Methodsmentioning

confidence: 99%

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Temperature Dependence Kinetic Studies of the Reaction of O(³P) with CHI₃ and C₂H₅I and the 298 K Reaction of OH(X²Π) with CHI₃

Zhang

Strekowski

Monod

et al. 2014

Int J of Chemical Kinetics

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A flash photolysis–resonance fluorescence technique was used to investigate the kinetics of the OH(X2Π) radical and O(3P) atom‐initiated reactions with CHI3 and the kinetics of the O(3P) atom‐initiated reaction with C2H5I. The reactions of the O(3P) atom with CHI3 and C2H5I were studied over the temperature range of 296 to 373 K in 14 Torr of helium, and the reaction of the OH (X2Π) radical with CHI3 was studied at T = 298 K in 186 Torr of helium. The experiments involved time‐resolved resonance fluorescence detection of OH (A2Σ+ → X2Π transition at λ = 308 nm) and of O(3P) (λ = 130.2, 130.5, and 130.6 nm) following flash photolysis of the H2O/He, H2O/CHI3/He, O3/He, and O3/C2H5I/He mixtures. A xenon vacuum UV (VUV) flash lamp (λ > 120 nm) served as a photolysis light source. The OH radicals were produced by the VUV flash photolysis of water, and the O(3P) atoms were produced by the VUV flash photolysis of ozone. Decays of OH radicals and O(3P) atoms in the presence of CHI3 and C2H5I were observed to be exponential, and the decay rates were found to be linearly dependent on the CHI3 and C2H5I concentrations. Measured rate coefficients for the reaction of O(3P) atoms with CHI3 and C2H5I are described by the following Arrhenius expressions (units are cm3 s−1): kO+C2H5I(T) = (17.2 ± 7.4) × 10−12 exp[−(190 ± 140)K/T] and kO+CHI3(T) = (1.80 ± 2.70) × 10−12 exp[−(440 ± 500)K/T]; the 298 K rate coefficient for the reaction of the OH radical with CHI3 is kOH+CHI3(298 K) = (1.65 ± 0.06) × 10−11 cm3 s−1. The listed uncertainty values of the Arrhenius parameters are 2σ‐standard errors of the calculated slopes by linear regression.

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Section: Discussionsupporting

confidence: 65%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Temperature Dependence Kinetic Studies of the Reaction of O(³P) with CHI₃ and C₂H₅I and the 298 K Reaction of OH(X²Π) with CHI₃

Zhang

Strekowski

Monod

et al. 2014

Int J of Chemical Kinetics

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“…Rate coefficient data for reaction of OH with iodoalkanes have been experimentally determined for a series of alkyl iodides: CH 3 I [31][32][33] [34]. Literature data on halogenated species [20,36] suggest an increase in the rate coefficient with increasing size of the alkyl iodide.…”

Section: Introductionmentioning

confidence: 99%

A Theoretical Study of the X-Abstraction Reactions (X = H, Br, or I) from CH₂IBr by OH Radicals: Implications for Atmospheric Chemistry

Šulka

Šulková

Louis

et al. 2013

Zeitschrift für Physikalische Chemie

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We report the calculation of the H-, Br-, and I-abstraction channels in the reaction of OH radicals with bromoiodomethane CH 2 IBr. The resulting energy profiles at 0 K were obtained by high-level all-electron ab initio methods including valence and core-valence electron correlation, scalar relativistic effects, spin-orbit coupling, spin-adaptation, vibration contributions, and tunneling corrections. In terms of activation enthalpy at 0 K, the energy profile for the Br-abstraction showed that this reaction pathway is not energetically favorable in contrast to the two other channels (H-and I-abstractions), which are competitive. The H-abstraction was strongly exothermic (−84.4 kJ mol −1 ), while the I-abstraction was modestly endothermic (16.5 kJ mol −1 ). On the basis of our calculations, we predicted the rate constants using canonical transition state theory over the temperature range 250-500 K for each abstraction pathway. The overall rate constant at 298 K was estimated to be 3.40 × 10 −14 and 4.22 × 10 −14 cm 3 molecule −1 s −1 for complex and direct abstraction mechanisms, respectively. In addition, the overall rate constant computed at 277 K was used in the estimation of the atmospheric lifetime for CH 2 IBr. On the basis of our theoretical calculations, the atmospheric lifetime for the OH removal process is predicted to be close to 1 year. In terms of atmospheric lifetime, the OH reaction is not competitive with the Cl reaction and photolysis processes.

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Theoretical Study of the Hydroxyl‐Radical‐Initiated Degradation Mechanism, Kinetics, and Subsequent Evolution of Methyl and Ethyl Iodides in the Atmosphere

et al. 2023

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The degradation and transformation of iodinated alkanes are crucial in the iodine chemical cycle in the marine boundary layer. In this study, MP2 and CCSD(T) methods were adopted to study the atmospheric transformation mechanism and degradation kinetic properties of CH 3 I and CH 3 CH 2 I mediated by * OH radical. The results show that there are three reaction mechanisms including H-abstraction, I-substitution and I-abstraction. The H-abstraction channel producing * CH 2 I and CH 3 C • HI radicals are the main degradation pathways of CH 3 I and CH 3 CH 2 I, respectively. By means of the variational transition state theory and small curvature tunnel correction method, the rate constants and branching ratios of each reaction are calculated in the temperature range of 200-600 K. The results show that the tunneling effect contributes more to the reaction at low temperatures. Theoretical reaction rate constants of CH 3 I and CH 3 CH 2 I with * OH are calculated to be 1.42 × 10 À 13 and 4.44 × 10 À 13 cm 3 molecule À 1 s À 1 at T = 298 K, respectively, which are in good agreement with the experimental values. The atmospheric lifetimes of CH 3 I and CH 3 CH 2 I are evaluated to be 81.51 and 26.07 day, respectively. The subsequent evolution mechanism of * CH 2 I and CH 3 C • HI in the presence of O 2 , NO and HO 2 indicates that HCHO, CH 3 CHO, and I-atom are the main transformation end-products. This study provides a theoretical basis for insight into the diurnal conversion and environmental implications of iodinated alkanes.* and *OH [14,[19][20] in the atmospheric environment. Therefore, precise rate constants and subsequent reaction mechanism studies are needed to fully assess their environmental impact. The role of NO 3 * radical in the nocturnal transformation of CH 3 I and CH 3 CH 2 I has been explored by Nakano et al. [21][22] and Bai et al. [20] in experiment and theory, respectively. The results suggested that CH 3 I and CH 3 CH 2 I can be degraded in the atmosphere within a short time to serve as a source of reactive iodine compounds at night-time. Experimentally, Cotter et al. [14] inves-[a] X.

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Temperature-Dependent Kinetics Study of the Reactions of OH with C₂H₅I, n-C₃H₇I, and iso-C₃H₇I

Cited by 12 publications

References 59 publications

Temperature Dependence Kinetic Studies of the Reaction of O(³P) with CHI₃ and C₂H₅I and the 298 K Reaction of OH(X²Π) with CHI₃

Temperature Dependence Kinetic Studies of the Reaction of O(³P) with CHI₃ and C₂H₅I and the 298 K Reaction of OH(X²Π) with CHI₃

A Theoretical Study of the X-Abstraction Reactions (X = H, Br, or I) from CH₂IBr by OH Radicals: Implications for Atmospheric Chemistry

Theoretical Study of the Hydroxyl‐Radical‐Initiated Degradation Mechanism, Kinetics, and Subsequent Evolution of Methyl and Ethyl Iodides in the Atmosphere

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Temperature-Dependent Kinetics Study of the Reactions of OH with C2H5I, n-C3H7I, and iso-C3H7I

Cited by 12 publications

References 59 publications

Temperature Dependence Kinetic Studies of the Reaction of O(3P) with CHI3 and C2H5I and the 298 K Reaction of OH(X2Π) with CHI3

Temperature Dependence Kinetic Studies of the Reaction of O(3P) with CHI3 and C2H5I and the 298 K Reaction of OH(X2Π) with CHI3

A Theoretical Study of the X-Abstraction Reactions (X = H, Br, or I) from CH2IBr by OH Radicals: Implications for Atmospheric Chemistry

Theoretical Study of the Hydroxyl‐Radical‐Initiated Degradation Mechanism, Kinetics, and Subsequent Evolution of Methyl and Ethyl Iodides in the Atmosphere

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Temperature-Dependent Kinetics Study of the Reactions of OH with C₂H₅I, n-C₃H₇I, and iso-C₃H₇I

Temperature Dependence Kinetic Studies of the Reaction of O(³P) with CHI₃ and C₂H₅I and the 298 K Reaction of OH(X²Π) with CHI₃

Temperature Dependence Kinetic Studies of the Reaction of O(³P) with CHI₃ and C₂H₅I and the 298 K Reaction of OH(X²Π) with CHI₃

A Theoretical Study of the X-Abstraction Reactions (X = H, Br, or I) from CH₂IBr by OH Radicals: Implications for Atmospheric Chemistry