The thermal unimolecular decompositions of C2H5Cl, i‐C3H7Cl, and t‐C4H9Cl

Heydtmann, H.; Dill, Bernd; Jonas, Reinhard

doi:10.1002/kin.550070615

Cited by 33 publications

(28 citation statements)

References 24 publications

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“…Many low-pressure studies of alkyl halide pyrolyses pertain to ethyl chloride [l, 361. The high-pressure Arrhenius parameters recommended by Benson and O'Neal (391 agree with those reported by Heydtmann, Dill, and Jonas [36] within the experimental error. The vibrational frequencies assigned by Millrr and Kiviat [24] are assumed to be rather accurate.…”

Section: Four-center Elimination Reactionssupporting

confidence: 80%

“…Therefore a comparison between experimental and calculated data suffers from the fact that, starting with similar km values, the particular reactions enter their falloff regions at lower pressures which are experimentally accessible with increasing difficulties. but only the very beginning of the falloff curve of t-C4H&1 has been covered and extended to k/k-= 0.8 a t 0.1 torr [36]. Nevertheless, Figures 3 and 4 clearly indicate that the agreement between experimental and calculated data is satisfactory only if the collision rate Z is reduced to about one fifth of its gas-kinetic value.…”

Section: Four-center Elimination Reactionsmentioning

confidence: 90%

“…In a previous study we have experimentally reinvestigated the falloff behavior of the pyrolyses of ethyl chloride, isopropyl chloride, and tertiary butyl chloride [36]. It was desirable to find out how the calculated results from the Forst model fit the experimental data for these and other haloalkanes.…”

Section: Four-center Elimination Reactionsmentioning

confidence: 94%

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Application of Forst's method to the calculation of thermal unimolecular reaction rates and isotope effects in the falloff region

Dill

Heydtmann

1977

Int J of Chemical Kinetics

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A method proposed in 1972 by W. Forst is used to calculate the experimentally accessible pressure dependence of thermal unimolecular rate constants. The specification of an activated complex always employed in RRKM calculs.tions is avoided. This allows for a more consistent comparison between the results obtained by the application to various unimolecular processes. In order to bring experimental and calculated curves into agreement, fourcenter eliminations of hydrogen halides from alkyl halides require the formal introduction of a collision efficiency factor h Y 0.2, and for the concerted ring opening of 1,l-dichlorocyclopropane h 'v 0.4 must be assumed. The isotope effects for the decomposition of CD3CDzCl and CH3CDzCl have been studied, and the pressure dependence of kH/kD is reported. Studying the biradical ring opening of oxetan, cyclobutane, and cyclopropane, the falloff curves and isotope effects are predicted within the experimental uncertainty by the use of h 'v 1.0. This different behavior of concerted and biradica.1 reactions against falloff calculations can hardly be attributed to experimental uncertainties in the Arrhenius parameters and/or the collision frequency alone.

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Section: Four-center Elimination Reactionssupporting

confidence: 80%

Section: Four-center Elimination Reactionsmentioning

confidence: 90%

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Application of Forst's method to the calculation of thermal unimolecular reaction rates and isotope effects in the falloff region

Dill

Heydtmann

1977

Int J of Chemical Kinetics

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“…Another reaction which has attracted much attention is the thermal decomposition of ethyl chloride to form ethylene and hydrogen chloride (5); the data are, however, much more scattered than the cyclopropane or cyclobutane data, and not always concordant (5,63). Figure 11 shows the experimental data of Holbrook and Marsh (64) at 521°C, compared with our calculated form of kuni; the agreement is equally satisfactory at other temperatures also, but unfortunately, because of the scatter inherent in the experimental measurements, does not provide a very stringent test of this reformulation.…”

Section: A the Shape Of The Fall-08 Curvementioning

confidence: 99%

“…At any pressurep and inverse temperature P, the formal expression for the activation energy The evaluation of [63] for a general system is clearly a formidable task, although some general properties regarding the pressure dependence of E,,, have been derived by various authors (6,71,72 Arrhenius behaviour), it may be computed from where Ap is a small change in the inverse temperature p.…”

Section: B the Positiofi Of The Fall-off Curvementioning

confidence: 99%

A reformulation of the theory of unimolecular reactions

Yau¹,

Pritchard²

1978

Can. J. Chem.

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PRITCHARD. Can. J. Chem. 56, 1389(19783 The theory of unimolecular reactions is reformulated in a way which makes no reference t o the concepts of a transition state, a reaction coordinate, or of an activated complex: the present theory is based, instead, on a simple master-equation approach using the estimated positions and lifetimes of the rotation-vibration energy levels of the molecule. The fundamental basis of this reformulation is that the unimolecular rate is derived from the perturbation of the normal modes of internal relaxation of the reactant molecule by the microscopic reaction processes. The thermal decompositions of cyclobutane, cyclopropane, ethyl isocyanide, ethyl chloride, and methyl isocyanide are examined in detail, and it is shown that not only is the present theory much easier to use than is conventional RRKM theory, but also that it gives better results.An Appendix provides a set of algorithms required for these calculations. Un appendice fournit l'ensemble d'algorithmes requis pour ces calculs.[Traduit par le journal]

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A spin-coupled investigation of the electrophilic addition of hydrochloric acid to ethylene

Thorsteinsson

Famulari

Raimondi

1999

Int. J. Quant. Chem.

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ABSTRACT:The gas-phase reaction of hydrochloric acid and ethylene to give Ž . chloroethane is investigated in the framework of spin-coupled SC theory, with emphasis on the widely accepted bimolecular mechanism. The transition-state structure and intrinsic reaction coordinate path are studied in detail. Our results indicate that the driving force in the reaction is the electrophilic attack of the hydrogen atom in HCl on one of the ethylenic carbons. There is little evidence supporting the occurrence of a four-membered transition state; rather, the spin-coupled results suggest that the breaking of the H-Cl bond occurs before the C-Cl bond formation. These findings are supported by the results from a topological analysis of the total electron density.

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The thermal unimolecular decompositions of C₂H₅Cl, i‐C₃H₇Cl, and t‐C₄H₉Cl

Abstract: The thermal decompositions of ethyl chloride, is0 propyl chloride, and tertiary butylThe folchloride were studied in a static system in the pressure range of 0.1-300 torr. lowing Arrhenius equations for the high-pressure limit were obtained:

Cited by 33 publications

References 24 publications

Application of Forst's method to the calculation of thermal unimolecular reaction rates and isotope effects in the falloff region

Application of Forst's method to the calculation of thermal unimolecular reaction rates and isotope effects in the falloff region

A reformulation of the theory of unimolecular reactions

A spin-coupled investigation of the electrophilic addition of hydrochloric acid to ethylene

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