Theoretical studies of the reactions of Cl atoms with CF3CH2OCH n F(3−n) (n = 1, 2, 3)

Zhang, Hui; Liu, Chengyang; Zhang, Guiling; Hou, Wenjie; Sun, Min; Liu, Bo; Li, Ze-Sheng

doi:10.1007/s00214-010-0746-2

Cited by 9 publications

(2 citation statements)

References 26 publications

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“…It is interesting to note that the OH radical with some HFEs in rate constants are in this order: k CF 3 CH 2 OCH 3 > k (CF 3 ) 2 CHOCH 3 > k CF 3 CHFOCH 3 > k (CF 3 ) 2 CFOCH 3 . ,, From the above comparison, the results suggest that −CF 3 group substitution results in a greater decrease than F-substitution in the reactivity trend. With Cl + HFEs as criterion, k CF 3 CH 2 OCH 3 > k CF 3 CHFOCH 3 > k (CF 3 ) 2 CFOCH 3 . , When the calculated overall rate constant of reaction (CF 3 ) 2 CFOCHO + Cl (1.12 × 10 –14 cm 3 molecule –1 s –1 ) is compared with that of reaction CF 3 CH 2 OCHO + Cl (6.43 × 10 –14 cm 3 molecule –1 s –1 ) at 298 K, a similar conclusion can be reached.…”

Section: Resultsmentioning

confidence: 53%

“…Hence, the H-abstraction reaction with Cl atom is a more important degradation channel for (CF 3 ) 2 CFOCH 3 than for that with OH radical. To further understand the title reactions, it is worthwhile to compare the dynamics between the title reactions and similar systems (Cl atom or OH radical with (CF 3 ) 2 CHOCH 3 , CF 3 CHFOCH 3 , CF 3 CH 2 OCH 3 , and CF 3 CH 2 OCHO). ,,,− In fact, the fluorine and −CF 3 group substitution can decrease the reactivity trend. It is interesting to note that the OH radical with some HFEs in rate constants are in this order: k CF 3 CH 2 OCH 3 > k (CF 3 ) 2 CHOCH 3 > k CF 3 CHFOCH 3 > k (CF 3 ) 2 CFOCH 3 . ,, From the above comparison, the results suggest that −CF 3 group substitution results in a greater decrease than F-substitution in the reactivity trend.…”

Section: Resultsmentioning

confidence: 99%

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Theoretical Study on the Reactions of (CF₃)₂CFOCH₃ + OH/Cl and Reaction of (CF₃)₂CFOCHO with Cl Atom

et al. 2015

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Reactions of (CF3)2CFOCH3 and (CF3)2CFOCHO with hydroxyl radical and chlorine atom are studied at the B3LYP and BHandHLYP/6-311+G(d,p) levels along with the geometries and frequencies of all stationary points. This study is further refined by CCSD(T) and QCISD(T)/6-311+G(d,p) methods in the minimum energy paths. For the reaction (CF3)2CFOCH3 + OH, two hydrogen abstraction channels are found. The total rate constants for the reactions (CF3)2CFOCH3 + OH/Cl and (CF3)2CFOCHO + Cl are followed by means of the canonical variational transition state with the small-curvature tunneling correction. The comparison between the hydrogen abstraction rate constants by hydroxyl and chlorine atom is discussed. Calculated rate constants are in reasonable agreement with the available experiment data. The standard enthalpies of formation for the reactants, (CF3)2CFOCH3 and (CF3)2CFOCHO, and two products, (CF3)2CFOCH2 and (CF3)2CFOCO, are evaluated by a series of isodesmic reactions. The Arrhenius expressions for the title reactions are given as follows: k1= 1.08 × 10(-22) T(3.38) exp(-213.31/T), k2= 3.55 × 10(-22) T(3.61) exp(-240.26/T), and k3= 3.00 × 10 (-19) T(2.58) exp(-1294.34/T) cm(3) molecule(-1) s(-1).

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Section: Resultsmentioning

confidence: 53%

Section: Resultsmentioning

confidence: 99%

Theoretical Study on the Reactions of (CF₃)₂CFOCH₃ + OH/Cl and Reaction of (CF₃)₂CFOCHO with Cl Atom

et al. 2015

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Theoretical study and rate constants calculation for the reactions X + CF₃CH₂OCF₃ (X = F, Cl, Br)

Zhang

Liu

et al. 2011

J Comput Chem

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The multiple-channel reactions X + CF3CH2OCF3 (X = F, Cl, Br) are theoretically investigated. The minimum energy paths (MEP) are calculated at the MP2/6-31 + G(d,p) level, and energetic information is further refined by the MC-QCISD (single-point) method. The rate constants for major reaction channels are calculated by canonical variational transition state theory (CVT) with small-curvature tunneling (SCT) correction over the temperature range 200–2000 K. The theoretical three-parameter expressions for the three channels k1a(T) = 1.24 x 10(-15T1.24)exp(-304.81/T), k2a(T) = 7.27 x 10(-15T0.37)exp(-630.69/T), and k3a(T) = 2.84 x 10(-19T2.51)exp(-2725.17/T) cm3 molecule(-1) s(-1) are given. Our calculations indicate that hydrogen abstraction channel is only feasible channel due to the smaller barrier height among five channels considered.

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The reaction mechanisms and kinetics of CF3CHFOCH3 and CHF2CHFOCF3 with atomic chlorine: a computational study

et al. 2014

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Due to their lack of effect on the ozone depletion, hydrofluoroethers are considered as potential candidates for third generation refrigerants. In the present work, the mechanisms and kinetics of reaction of the Cl atom with CF(3)CHFOCH(3) and CHF(2)CHFOCF(3) were investigated theoretically using quantum chemical methods and transition state theory. Four reaction pathways for the title reaction were explored. By using conventional transition state theory with Eckart tunneling correction, the rate constants of the title reaction were obtained over the temperature range 200-300 K. Kinetic calculations demonstrate that H-abstraction from the -CH(3) group in CF(3)CHFOCH(3) and H-abstraction from the -CHF2 group in CHF(2)CHFOCF(3) are major reaction pathways, with the barrier heights of the two paths calculated to be -1.04 and 4.33 kcal mol(-1), respectively. However, the contribution of H-abstraction from the -CHFO- group for the two reactions should also be taken into account with increased temperature. At 298 K, the calculated overall rate constants of the reaction of CHF(2)CHFOCF(3) with the Cl atom are 4.27 × 10(-15) cm(3) molecule(-1) s(-1), which is consistent with the experimental value of (1.2 ± 2.0) × 10(-15) cm(3) molecule(-1) s(-1).

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Theoretical studies of the reactions of Cl atoms with CF3CH2OCH n F(3−n) (n = 1, 2, 3)

Cited by 9 publications

References 26 publications

Theoretical Study on the Reactions of (CF₃)₂CFOCH₃ + OH/Cl and Reaction of (CF₃)₂CFOCHO with Cl Atom

Theoretical Study on the Reactions of (CF₃)₂CFOCH₃ + OH/Cl and Reaction of (CF₃)₂CFOCHO with Cl Atom

Theoretical study and rate constants calculation for the reactions X + CF₃CH₂OCF₃ (X = F, Cl, Br)

The reaction mechanisms and kinetics of CF3CHFOCH3 and CHF2CHFOCF3 with atomic chlorine: a computational study

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Theoretical studies of the reactions of Cl atoms with CF3CH2OCH n F(3−n) (n = 1, 2, 3)

Cited by 9 publications

References 26 publications

Theoretical Study on the Reactions of (CF3)2CFOCH3 + OH/Cl and Reaction of (CF3)2CFOCHO with Cl Atom

Theoretical Study on the Reactions of (CF3)2CFOCH3 + OH/Cl and Reaction of (CF3)2CFOCHO with Cl Atom

Theoretical study and rate constants calculation for the reactions X + CF3CH2OCF3 (X = F, Cl, Br)

The reaction mechanisms and kinetics of CF3CHFOCH3 and CHF2CHFOCF3 with atomic chlorine: a computational study

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Theoretical Study on the Reactions of (CF₃)₂CFOCH₃ + OH/Cl and Reaction of (CF₃)₂CFOCHO with Cl Atom

Theoretical Study on the Reactions of (CF₃)₂CFOCH₃ + OH/Cl and Reaction of (CF₃)₂CFOCHO with Cl Atom

Theoretical study and rate constants calculation for the reactions X + CF₃CH₂OCF₃ (X = F, Cl, Br)