Computational Study on OH and Cl Initiated Oxidation of 2,2,2-Trifluoroethyl Trifluoroacetate (CF3C(O)OCH2CF3)

Singh, Hari Ji; Tiwari, Laxmi; Rao, Pradeep Kumar

doi:10.5012/bkcs.2014.35.5.1385

Cited by 5 publications

(5 citation statements)

References 26 publications

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“…Singh et al recently have reported the theoretically computed rate coefficient for the reaction of Cl atom with an analogous molecule (CF 3 C(O)OCH 2 CF 3 ) at 298 K. The calculated barrier height at CCSD(t)/CC-PVDZ//M062X-6-31+G(d,p) for the reaction to go through the transition state TS3, from the −CH 2 – (cf. Figure ) position of the CH 3 CH 2 CH 2 C(O)OCH 2 CF 3 , is 0.29 kcal/mol.…”

Section: Computational Sectionmentioning

confidence: 99%

Gas Phase Kinetics of 2,2,2-Trifluoroethylbutyrate with the Cl Atom: An Experimental and Theoretical Study

Srinivasulu

Rajakumar

2015

J. Phys. Chem. A

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The gas phase temperature dependent rate coefficients of Cl atoms with 2,2,2-trifluoroethylbutyrate, CH3CH2CH2C(O)OCH2CF3, were measured in the temperature range 268-343 K, at atmospheric pressures using the relative rate method, with ethyl acetate and ethane as reference compounds. The temperature dependent rate coefficients for the reaction of 2,2,2-TFEB + Cl were measured and were used to deduce the Arrhenius expression: k268-343K = [(4.42 ± 0.01) × 10(-19)]T(2.6) exp{(1132 ± 566)/T} cm(3) molecule(-1) s(-1). At 298 K, the rate coefficient for the title reaction is (4.54 ± 2.87) × 10(-11) cm(3) molecule(-1) s(-1), which is in good agreement with a previously reported value at 298 K. To complement our experimental results over the studied temperature range, theoretical kinetic calculations were also performed for the title reaction using canonical variational transition state theory (CVT) with small curvature tunneling (SCT) corrections in combination with the CCSD(T)/cc-pVDZ//M062X/6-31+g(d,p) level of theory. The temperature dependent Arrhenius expression was obtained to be k(T) = (1.89 ± 2.64) × 10(-21)T(3.4) exp{(1321 ± 111)/T} cm(3) molecule(-1) s(-1). The branching ratios, atmospheric implications, and degradation mechanism of 2,2,2-trifluoroethylbutyrate, CH3CH2CH2C(O)OCH2CF3, were discussed in detail in this manuscript.

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Section: Computational Sectionmentioning

confidence: 99%

Gas Phase Kinetics of 2,2,2-Trifluoroethylbutyrate with the Cl Atom: An Experimental and Theoretical Study

Srinivasulu

Rajakumar

2015

J. Phys. Chem. A

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“…Therefore, it is necessary to understand the chemistry of fluorinated esters in the atmosphere in order to assess the environmental acceptability of HFEs as a plausible replacement for chlorofluorocarbons. The reaction mechanisms of FESs with atmospheric oxidants have been studied extensively both experimentally [20][21][22][23][24][25] and theoretically [26][27][28][29][30][31][32] and continue to receive considerable attention. FESs absorb strongly in the earthly infrared (IR) radiation region of 800-1,200 cm −1 .…”

Section: Introductionmentioning

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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“… a Boudali et al ., (1996) ; b Blanco et al ., (2007); c Singh et al ., (2014); d Blanco et al ., (2013); e This work (experimental), f This work (theoretical) and g Srinivasulu et al ., (2015).…”

Section: Resultsmentioning

confidence: 96%

“…Recently, Singh et al ., have reported the theoretically computed rate coefficient for the reaction of OH radical with an analogous molecule (CF 3 C(O)OCH 2 CF 3 ) at 298 K. In the case of (CF 3 C(O)OCH 2 CF 3 ), the barrier height for the abstraction of H by OH radical from ‐CH 2 ‐ was reported to be 3.8 kcal mol −1 at G2(MP2)//MPWB1 K/6‐31+G(d,p) level of theory. The calculated barrier height at CCSD(T)/CC‐PVDZ//M062X‐6‐31+G(d,p) theory for the reaction to go through the transition state TS3 involving H abstraction from –CH 2 ‐ ( c.f .…”

Section: Resultsmentioning

confidence: 99%

“…The rate coefficients for the reaction of test molecule and their analogous fluoroesters,, with Cl atoms and OH radicals are summarized in Table to understand the reaction mechanism of the Cl atoms and OH radicals with fluoroesters. The rate coefficients obtained in this work and our previous results for both reactions of OH/Cl with test molecule are found to be much higher than those for the analogous fluoroesters.…”

Section: Resultsmentioning

confidence: 99%

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Kinetic Investigations on the Gas Phase Reaction of 2,2,2‐Trifluoroethylbutyrate with OH Radicals: An Experimental and Theoretical Study

2018

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The temperature dependent rate coefficients for the reaction between 2,2,2‐trifluoroethylbutyrate (2,2,2‐TFEB) with OH radicals were measured as a function of temperature (268‐343 K) and pressure (400‐760 Torr; N2 and O2) using relative rate technique. The temperature dependent rate coefficients for the gas phase reaction of 2,2,2‐TFEB + OH were used to deduce the Arrhenius expression: k(268‐343 K) = (2.72 ± 1.3)×10−13 exp{(530± 72)/T}cm3 molecule−1 s−1. At 298 K, the rate coefficient for the title reaction was obtained to be (1.58 ± 0.42) ×10−12 cm3 molecule−1 s−1. Extensive computational calculations were also performed as a complement to the present experimental study using canonical variational transition state theory (CVT) with small curvature tunnelling (SCT) correction in combination with the CCSD(T)/CC‐PVDZ//M062X/6‐31+G(d,p) level of theory. The atmospheric lifetime of the test molecule due to its reaction with OH radical is about 3 days, which is short lived. And therefore, its contribution towards the global warming potentials can be insignificant. The ozone formation potential of the test molecule is calculated to be 0.229 ppm, which is again negligible.

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Computational Study on OH and Cl Initiated Oxidation of 2,2,2-Trifluoroethyl Trifluoroacetate (CF₃C(O)OCH₂CF₃)

Cited by 5 publications

References 26 publications

Gas Phase Kinetics of 2,2,2-Trifluoroethylbutyrate with the Cl Atom: An Experimental and Theoretical Study

Gas Phase Kinetics of 2,2,2-Trifluoroethylbutyrate with the Cl Atom: An Experimental and Theoretical Study

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

Kinetic Investigations on the Gas Phase Reaction of 2,2,2‐Trifluoroethylbutyrate with OH Radicals: An Experimental and Theoretical Study

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