Methyl and trifluoromethyl radical attack on ethers

Arthur, NL; Gray, Peter; Herod, Alan A.

doi:10.1139/v69-220

Cited by 16 publications

(8 citation statements)

References 1 publication

(1 reference statement)

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“…For example, Pacey 30 reports activation energy values for reaction (R2) with an uncertainty of almost ±1.7 kcal/mol with log ( A ) = 10 13.5±0.4 . During the course of this study, it was found necessary to increase the rate of reaction (R2) for temperatures higher than approximately 900 K. On the basis of these results, we performed least‐squares modified Arrhenius fit of available experimental data 29–31,45 placing larger weight on the upper uncertainty estimates of Pacey 30. Figure 2 shows the results of this new correlation against the experimental data as well as the rate expression used in the mechanism of Curran et al 1,2.…”

Section: Comprehensive Model For Dimethyl Ether Pyrolysis and Oxidationmentioning

confidence: 99%

Thermal decomposition reaction and a comprehensive kinetic model of dimethyl ether

Zhao

Chaos

Kazakov

et al. 2007

Int J of Chemical Kinetics

430

385

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The unimolecular decomposition reaction of dimethyl ether (DME) was studied theoretically using RRKM/master equation calculations. The calculated decomposition rate is significantly different from that utilized in prior work (Fischer et al., Int J Chem Kinet 2000, 32, 713-740; Curran et al., Int J Chem Kinet 2000, 32, 741-759). DME pyrolysis experiments were performed at 980 K in a variable-pressure flow reactor at a pressure of 10 atm, a considerably higher pressure than previous validation data. Both unimolecular decomposition and radical abstraction are significant in describing DME pyrolysis, and hierarchical methodology was applied to produce a comprehensive high-temperature model for pyrolysis and oxidation that includes the new decomposition parameters and more recent small molecule/radical kinetic and thermochemical data. The high-temperature model shows improved agreement against the new pyrolysis data and the wide range of high-temperature oxidation data modeled in prior work, as well as new low-pressure burner-stabilized species profiles (Cool et al., Proc Combust Inst 2007, 31, 285-294) and laminar flame data for DME/methane mixtures (Chen et al., Proc Combust Inst 2007, 31, 1215-1222. The high-temperature model was combined with low-temperature oxidation chemistry (adopted from Fischer et al., Int J Chem Kinet 2000, 32, 713-740), with some modifications to several important reactions. The revised construct shows good agreement against high-as well as low-temperature flow reactor and jet-stirred reactor data, shock tube ignition delays, and laminar flame species as well as flame speed measurements. C 2007 Wiley Periodicals, Inc. Int J Chem Kinet 40:

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Section: Comprehensive Model For Dimethyl Ether Pyrolysis and Oxidationmentioning

confidence: 99%

Thermal decomposition reaction and a comprehensive kinetic model of dimethyl ether

Zhao

Chaos

Kazakov

et al. 2007

Int J of Chemical Kinetics

430

385

View full text Add to dashboard Cite

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“…We used the experimental data of Batt et al [103], Pacey [101], Arthur et al [107], and Gray and Herod [108]. A comparison of our rate expression with those available in the literature is plotted in Figure 19.…”

Section: Dimethyl Ether Pyrolysismentioning

confidence: 99%

The reaction kinetics of dimethyl ether. I: High-temperature pyrolysis and oxidation in flow reactors

Fischer

Dryer

Curran

2000

Int. J. Chem. Kinet.

372

315

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“…However, the b ester group increases the alkoxy C-H bond strength (Table 7) suggesting a likely higher barrier height for abstraction. Furthermore, in the case of abstraction by methyl it appears from the scarce literature data 19,[67][68][69] that the reactivity of the methoxyl group varies over a wide range. The activation barrier and log 10 A for a series of methoxy hydrogen abstractions by methyl are: As can be seen it is influenced by substituents.…”

Section: Reaction Coordinate Geometry and Frequency At The Transition...mentioning

confidence: 99%

Oxygenate, oxyalkyl and alkoxycarbonyl thermochemistry and rates for hydrogen abstraction from oxygenates

Sumathi

Green

2003

Phys. Chem. Chem. Phys.

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Ab initio molecular orbital theory calculations are performed at the complete basis set (CBS-Q) level to determine thermochemical parameters (D f H 298 , S 298 , C T p ) of alcohols, methyl ethers, formates, acetates, hydroperoxides, methyl alkylperoxides and the corresponding methoxy, primary and secondary alkoxy radicals derived from these molecular families. A consistent set of 12 Benson groups transferable among these six molecular families is derived from CBS-Q results via regression together with 20 hydrogen bond increment (HBI) group values for estimating the thermochemistry of oxymethyl ( CH 2 OX), oxyethyl (CH 3 CH OX), oxyisopropyl ((CH 3 ) 2 C OX) with varying substituent X ( ¼ H, CH 3 , C(O)H, C(O)CH 3 , OH, OCH 3 ) and alkoxycarbonyl (ROC(O) ) radicals. These new groups are useful in estimating the thermochemistry of large oxygenated molecules and radicals involved in complex chemical reaction mechanisms. The kinetics of nearly 50 elementary bimolecular hydrogen abstraction reactions belonging to eight different reaction families viz.,are studied using transition state theory coupled with CBS-Q energetics. The calculated barrier height within a given reaction family varies with the nature of the b substituents. The reliability of the calculated variations in the barrier height with varying b substituents is determined through comparison of the calculated rate constants with the scarcely available experimental data. Thermodynamically consistent generic rate rules have been derived in terms of group additivity. New transferable supergroup values corresponding to the thermochemistry of the reactive moiety in transition structures are developed. The effect of non-next neighbor substituents on the enthalpy of the supergroup is quantified using Evans-Polanyi relations.

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Methyl and trifluoromethyl radical attack on ethers

Cited by 16 publications

References 1 publication

Thermal decomposition reaction and a comprehensive kinetic model of dimethyl ether

Thermal decomposition reaction and a comprehensive kinetic model of dimethyl ether

The reaction kinetics of dimethyl ether. I: High-temperature pyrolysis and oxidation in flow reactors

Oxygenate, oxyalkyl and alkoxycarbonyl thermochemistry and rates for hydrogen abstraction from oxygenates

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