Some hydrogen atom abstraction reactions of CF2H and CFH2 radicals, and the CH bond dissociation energy in CF2H2

Pritchard, G. O.

doi:10.1002/kin.550010603

Cited by 22 publications

(5 citation statements)

References 37 publications

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“…These differences in behavior may not be readily explainable. We have recently summarized data on D(CF,H-H) and D(CFH,-H) and they are approximately equal [26]. C,H6F* has also been synthesized [ 10, 121 via reaction ( 13),…”

Section: Discussionmentioning

confidence: 99%

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The elimination of HF from vibrationally excited fluoroethanes. The decomposition of 1,1,1‐trifluoroethane‐d₀ and d₃

Pritchard

1970

Int J of Chemical Kinetics

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The vibrationally excited molecules CF,CH,* and CF,CD,* have been synthesized by radical combination (produced by ketone photolysis), and HF and DF elimination from them studied as a function of temperature and pressure. Using RRK theory many calculations have recently been made of critical energies for the decomposition of "hot" fluoroethane molecules. Taking CF,CH,* as an example, it is concluded that the empiricism involved in such calculations renders results of doubtful significance. The non-equilibrium kinetic isotope effect is k,/k, = 3.1 at 470°K. Arrhenius parameters are also presented for radical abstraction reactions from the ketone source molecules.

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Section: Discussionmentioning

confidence: 99%

“…CF, + Ac-do + CFSH + CHZCOCHS lhese results are compared and discussed more fully elsewhere [26], in terms of compensation in the Arrhenius parameters.…”

Section: ( 7)mentioning

confidence: 99%

The elimination of HF from vibrationally excited fluoroethanes. The decomposition of 1,1,1‐trifluoroethane‐d₀ and d₃

Pritchard

1970

Int J of Chemical Kinetics

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“…To date, unlike the H + CH 4 reaction, only a limited number of experimental measurements of the thermal rate constants are available for H abstraction reactions of fluoromethanes. However, for purpose of comparison in this study we use several sets of experimental data available in the literature at different temperatures for these four reactions. − Several previous groups − have looked at the equilibrium structures, but only Berry et al have studied the kinetics of the H + CH 4 - x F x ( x = 0−3) reactions using conventional transition state theory (TST). Recently, Hranisavljevic and Michael 19 have also studied the reaction CHF 3 + H ↔ CF 3 + H 2 , theoretically also employing TST with one-dimensional Eckart tunneling corrections.…”

Section: Introductionmentioning

confidence: 99%

Direct ab Initio Dynamics Studies of the Hydrogen Abstraction Reactions of Hydrogen Atom with Fluoromethanes

1999

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A direct ab initio dynamics study on the gas-phase reactions of atomic hydrogen with different fluoromethanes has been carried out. The thermal rate constants were calculated using canonical variational transition state (CVT) theory augmented by multidimensional semiclassical zero and small curvature tunneling approximations. The potential energy surfaces for the reactions were calculated using hybrid density functional theory, namely, Becke's half-and-half (BH) nonlocal exchange and the Lee-Yang-Parr (LYP) nonlocal correlation functionals using the cc-pVDZ basis set. The reaction energies and barrier heights were improved by single-point energy calculations along the minimum energy path (MEP) at the spin-projected fourth order Moller-Plesset perturbation theory (PMP4) using the cc-pVTZ basis set. The calculated forward and reverse thermal rate constants are in the good agreement with the experimental data. The electronic effects of fluorine substitution on the rate of this class of reactions are examined.

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“…The results for H abstraction via H and O atoms from each specific fluoromethane are summarized in Figure . This figure includes both the preferred experimental data − (as recommended by Burgess and Manion) as well as prior theoretical predictions − (to improve the clarity, theoretical results prior to the year 2000 are not shown ,, ). In each subplot, the solid black line is the current work, and the dotted blue line is the recent recommendation from ref along with the recommended uncertainty value (shaded region).…”

Section: Resultsmentioning

confidence: 99%

Theory-Based Mechanism for Fluoromethane Combustion I: Thermochemistry and Abstraction Reactions

2023

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A new detailed chemical kinetic mechanism is presented for small fluorinated hydrocarbons. Ab initio electronic structure theory is used to provide heats of formation with subchemical accuracy. The ANL0 method is extended to include fluorine. The resulting heats of formation at 0 K are in excellent agreement with 36 benchmark species in the Active Thermochemical Tables, with a mean error of μ = −0.02 kJ/mol and a standard deviation of σ = 0.91 kJ/mol. The thermophysical properties for 92 small-molecule H/C/O/F species are computed. The rate coefficients for 40+ H-abstraction reactions involving H, O, F, OH, OF, HO2, and various methyl radicals with CH4, CH3F, CH2F2, CHF3, CH2O, and CHFO are discussed. The computed rate constants are in excellent agreement with the available literature. Additionally, 30+ rate constants are provided for F abstraction, which are several orders of magnitude smaller than H abstraction. The thermophysical properties and rate constants are provided in a mechanism. This mechanism is the first in a series of theory-based investigations into the thermal destruction of per- and polyfluorinated species.

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Some hydrogen atom abstraction reactions of CF₂H and CFH₂ radicals, and the CH bond dissociation energy in CF₂H₂

Abstract: By photolyzing (CF,H),CO and (CFH,),CO the hydrogen atom abstraction reactions of CF,H radicals with (CF,H),

Cited by 22 publications

References 37 publications

The elimination of HF from vibrationally excited fluoroethanes. The decomposition of 1,1,1‐trifluoroethane‐d₀ and d₃

The elimination of HF from vibrationally excited fluoroethanes. The decomposition of 1,1,1‐trifluoroethane‐d₀ and d₃

Direct ab Initio Dynamics Studies of the Hydrogen Abstraction Reactions of Hydrogen Atom with Fluoromethanes

Theory-Based Mechanism for Fluoromethane Combustion I: Thermochemistry and Abstraction Reactions

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Some hydrogen atom abstraction reactions of CF2H and CFH2 radicals, and the CH bond dissociation energy in CF2H2

Abstract: By photolyzing (CF,H),CO and (CFH,),CO the hydrogen atom abstraction reactions of CF,H radicals with (CF,H),

Cited by 22 publications

References 37 publications

The elimination of HF from vibrationally excited fluoroethanes. The decomposition of 1,1,1‐trifluoroethane‐d0 and d3

The elimination of HF from vibrationally excited fluoroethanes. The decomposition of 1,1,1‐trifluoroethane‐d0 and d3

Direct ab Initio Dynamics Studies of the Hydrogen Abstraction Reactions of Hydrogen Atom with Fluoromethanes

Theory-Based Mechanism for Fluoromethane Combustion I: Thermochemistry and Abstraction Reactions

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Some hydrogen atom abstraction reactions of CF₂H and CFH₂ radicals, and the CH bond dissociation energy in CF₂H₂

The elimination of HF from vibrationally excited fluoroethanes. The decomposition of 1,1,1‐trifluoroethane‐d₀ and d₃

The elimination of HF from vibrationally excited fluoroethanes. The decomposition of 1,1,1‐trifluoroethane‐d₀ and d₃