A DFT study on kinetics of the gas phase reactions of CH3CH2OCF3 with OH radicals and Cl atoms

Mishra, Bhupesh Kumar; Lily, Makroni; Chakrabartty, Arup Kumar; Deka, Ramesh Chandra; Chandra, Asit K.

doi:10.1016/j.jfluchem.2013.12.002

Cited by 18 publications

(11 citation statements)

References 49 publications

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“…Figure 5b demonstrates that the tunneling effect plays an important role at lower temperatures and can be neglected in the high temperature range. For example, the rations between the k CVT/SCT and the k CVT are 70.52 at 200 K, 31.81 at 250 K, 13.89 at 296 K, 1.88 at 600 K, 1.04 at 1,200 K, and 0.94 at 2,000 K. These similar phenomenon can be found in other homologous species [38][39][40][41] reacting with Cl atoms.…”

Section: Rate Constant Calculationssupporting

confidence: 73%

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Theoretical investigation of the mechanisms and dynamics of the reaction CHF2OCF2CHFCl+Cl

Bai

Sun

et al. 2014

J Mol Model

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The reaction of CHF2OCF2CHFCl with atomic chlorine was studied using B3LYP/6-311G(d,p), BHandHLYP/6-311G(d,p), and M06-2X/6-311G(d,p) methods and further using CCSD(T) and QCISD(T) methods. Two hydrogen abstraction channels were found for the title reaction. Dynamics calculations were followed by means of canonical variational transition state with the small-curvature tunneling correction between 220 and 2,000 K. Our rate constant k = 2.90 × 10(-15) cm(3) molecule(-1) s(-1) is in reasonable agreement with the available data (3.20 ± 0.32) × 10(-15) cm(3) molecule(-1) s(-1) at 296 K. The three-parameter Arrhenius expression (in the unit of cm(3) molecule(-1) s(-1)) for the title reaction is given as k (T) = 1.38 × 10 (-19) T (2.57) exp (-2622.95/T).

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Section: Rate Constant Calculationssupporting

confidence: 73%

“…So the reaction R1 and R2 both proceed via indirect mechanisms. The indirect mechanisms could also be found in other articles that some halogen ethers reaction with Cl atom and OH radicals [37][38][39][40][41]. The energy of complex 1ER is 0.9 kcal/mol and complex 2ER is 0.7 kcal/mol lower than that of reactants.…”

Section: Stationary Points and The Energeticssupporting

confidence: 56%

Theoretical investigation of the mechanisms and dynamics of the reaction CHF2OCF2CHFCl+Cl

Bai

Sun

et al. 2014

J Mol Model

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“…The MPWB1K/6-31+G(d,p) method was reported in earlier studies [35][36][37][38] to be sufficiently accurate for predicting reliable geometries and frequencies of the stationary points. The 6-31+G(d,p) basis set was used because the same basis set was used for developing the model functional.…”

Section: Methodsmentioning

confidence: 99%

Theoretical investigation on mechanism and kinetics of the Cl-initiated hydrogen abstraction reactions of ethyl trifluoroacetate at 298 K

2014

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Theoretical investigations were carried out on the gas-phase reactions of CF3C(O)OCH2CH3, ethyl trifluoroacetate (ETFA) with Cl atoms by means of modern density functional theory methods. The optimized geometries, frequencies and minimum energy path were obtained with the hybrid density functional model MPWB1K using the 6-31+G(d,p) basis set. The single point energy calculations were refined further using the G2(MP2) method. Two conformers relatively close in energy were identified for ETFA; both are likely to be important in the temperature range of our study. The existence of transition states on the corresponding potential energy surface was ascertained by performing intrinsic reaction coordinate calculations. The rate constant at 298 K calculated theoretically using canonical transition state theory was found to be in good agreement with experimentally measured values. Our calculations suggest that H abstraction from the -CH2 group is kinetically and thermodynamically more favorable than abstraction from the -CH3 group. The atmospheric lifetime of ETFA with Cl atoms was determined to be 1.98 years. To the best of our knowledge, this work represents the first determination of the rate coefficients for the gas-phase reaction of chlorine atoms in ETFA.

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“…Thus, the three plausible pathways of H-abstraction by OH radical from the titled molecule are shown as follows: A detail literature survey reveals that there is no comprehensive detail on the dynamics and mechanism of the atmospheric degradation of the title molecule with OH radical. Only one theoretical study 12 has recently been reported in which all the hydrogen atoms of the methyl group have been taken as equal and also the displacement reactions have not been taken into account in the calculation of the overall rate constant. As such the overall rate constant for the reaction of OH with CF 3 OCH 2 CH 3 was reported to be 0.5 x 10 -13 which is about three times lower than the experimentally determined value of 1.55 ± 0.25 x 10 -13 cm 3 molecule -1 sec -1 at 298K and 1 atmospheric pressure based on relative rate method using gas chromatography mass spectrometry (GC-MS) detection technique.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and mechanism of gas-phase reaction of CF₃OCH₂CH₃ (HFE-263) with the OH radical — a theoretical study

Rao

Singh

2015

Can. J. Chem.

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In the present study, density functional method with recently developed M06 functionals has been used to study the reaction of CF 3 OCH 2 CH 3 with OH radical. All possible H-abstraction and displacement reaction channels have been modeled. The minimum energy path on the respective potential energy surface and energetics were calculated at M06-2X/6-311++G(d,p) level of theory. Two different reaction mechanisms (i) involving reactant and product complexes called the complex mechanism and the (ii) the direct mechanism (Reactant TS Product) were considered. Tunneling corrections were made using Eckart unsymmetrical potential. The overall rate constant calculated by complex mechanism (k eff =1.8 x 10 -13 cm 3 molecule -1 sec -1 ) has been found to be in good agreement with the experimentally determined value (1.5 ± 0.25 x 10 -13 cm 3 molecule -1 sec -1 ) while the rate constant calculated by direct mechanism (k D =7.6 x 10 -14 cm 3 molecule -1 sec -1 ) is about two times lower than the experimental value. The theoretical studies show that H atom abstraction from -CH 2 -site is most favorable reaction pathway and the reaction involves pre-reactive and product complexes before leading to stable product formation.

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A DFT study on kinetics of the gas phase reactions of CH3CH2OCF3 with OH radicals and Cl atoms

Cited by 18 publications

References 49 publications

Theoretical investigation of the mechanisms and dynamics of the reaction CHF2OCF2CHFCl+Cl

Theoretical investigation of the mechanisms and dynamics of the reaction CHF2OCF2CHFCl+Cl

Theoretical investigation on mechanism and kinetics of the Cl-initiated hydrogen abstraction reactions of ethyl trifluoroacetate at 298 K

Kinetics and mechanism of gas-phase reaction of CF₃OCH₂CH₃ (HFE-263) with the OH radical — a theoretical study

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A DFT study on kinetics of the gas phase reactions of CH3CH2OCF3 with OH radicals and Cl atoms

Cited by 18 publications

References 49 publications

Theoretical investigation of the mechanisms and dynamics of the reaction CHF2OCF2CHFCl+Cl

Theoretical investigation of the mechanisms and dynamics of the reaction CHF2OCF2CHFCl+Cl

Theoretical investigation on mechanism and kinetics of the Cl-initiated hydrogen abstraction reactions of ethyl trifluoroacetate at 298 K

Kinetics and mechanism of gas-phase reaction of CF3OCH2CH3 (HFE-263) with the OH radical — a theoretical study

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Kinetics and mechanism of gas-phase reaction of CF₃OCH₂CH₃ (HFE-263) with the OH radical — a theoretical study