THE ACTIVATION ENERGY FOR THE PYROLYSIS OF METHANE<sup>1</sup>

Palmer, Howard B.; Hirt, T. J.

doi:10.1021/j100797a502

Cited by 69 publications

(19 citation statements)

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“…Step Two initial dissociation reactions have been suggested in methane, and The endothermicity of [la] has long been established as about 102-104 kcal/mol (3,5,8). The endothermicity of [lb] has been much more unCan.…”

Section: The Mechanism Of the Decompositionmentioning

confidence: 99%

“…Subsequently i it became evident that the endothermicity of [lb] was probably equal to or greater than that of [la], so that all the earlier conclusions about the initial dissociation process based on activation energy had to be discounted (5). There now appears to be convincing evidence (12) for a value of AH;(CH,) of about 93 kcal/mol, which makes [lb] endothermic by about 109 kcal.…”

Section: The Mechanism Of the Decompositionmentioning

confidence: 99%

“…As [4] and [5] [4] and [5].3 These and other subsequent secondary reactions will not be discussed further in the present paper which is concerned chiefly with the rate of [I].…”

Section: Secondary Reactionsmentioning

confidence: 99%

“…Values of R0 for ethane and hydrogen can be obtained directly from yield-time plots, but because [.4] and [5] set in at very low conversion, accurate initial rates could not always be measured. Roc,,, may also be equated to R(c2H6+c2H,, or to +R(H2+c2H6,, which corrects for loss of ethane in [4] the best fit, and this was the method finally employed.…”

Section: Measurement Of Kmentioning

confidence: 99%

“…[Traduit par le journal] Introduction Although the pyrolysis of methane has been studied many times before, important details of the reaction mechanism have remained obscure (1)(2)(3)(4)(5). It is well established that the initial products are C2H6 and Hz, and in some shock-tube experiments the pyrolysis has been effectively limited to this ftage and initial rates measured.…”

mentioning

confidence: 99%

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The Thermal Decomposition of Methane. I. Kinetics of the Primary Decompositionto C₂H6 + H₂; Rate Constant for the Homogeneous Unimolecular Dissociation of Methane and its Pressure Dependence

Chen¹,

Back²,

Back³

1975

Can. J. Chem.

133

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The pyrolysis of methane has been studied in a static system at temperatures of 995, 1038, 1068, and 1103 K and pressures from 25 to 700 Torr. It was concluded that the initial stages of the reaction can be described by a simple homogeneous, nonchain radical mechanism:[Formula: see text]Initial rates of reaction were measured, based on analysis of hydrogen, ethane, and ethylene, and k1 was found to be pressure dependent and homogeneous. Quantitative agreement was obtained with values of k1 calculated by R.R.K.M. theory. Values of A∞ = 2.8 × 1016 s−1 and E∞ = 107.6 kcal/mol were obtained, the latter appreciably greater than the value of E0 = 103 kcal/mol used in the calculations. Comparison of previous shock-tube and flow-system data at temperatures up to 2200 K showed good agreement with values of k1 obtained by extrapolation of the present R.R.K.M. calculations. It was concluded that in all previous studies, the initial dissociation was in its pressure-dependent region. Estimates were also made of the rate constant for the reverse of [1] and showed fair agreement with recent experimental measurements.

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Section: The Mechanism Of the Decompositionmentioning

confidence: 99%

Section: The Mechanism Of the Decompositionmentioning

confidence: 99%

“…As [4] and [5] [4] and [5].3 These and other subsequent secondary reactions will not be discussed further in the present paper which is concerned chiefly with the rate of [I].…”

Section: Secondary Reactionsmentioning

confidence: 99%

Section: Measurement Of Kmentioning

confidence: 99%

mentioning

confidence: 99%

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The Thermal Decomposition of Methane. I. Kinetics of the Primary Decompositionto C₂H6 + H₂; Rate Constant for the Homogeneous Unimolecular Dissociation of Methane and its Pressure Dependence

Chen¹,

Back²,

Back³

1975

Can. J. Chem.

133

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Use of a shock tube in the study of high temperature gas reactions

Rao

Mackay²,

Trass

1965

Can J Chem Eng

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A modified single‐pulse shock tube has been used to study the pyrolysis of methane in the presence of nitrogen. The reactants are rapidly heated by a reflected shock wave for about a millisecond and cooled by rarefaction waves. In the temperature range 1600–2500°K., nitrogen is found to have no effect on the first order decomposition rates of methane. Above 2500°K., considerable quantities of hydrogen cyanide are observed due to the reaction of nitrogen with hydrocarbons.

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A shock tube study of the high temperature reactions of nitrogen with hydrocarbons

1967

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A single pulse shock tube has been used to study the reactions of nitrogen with methane, ethane and acetylene at 1400°‐6000°K. Reactants heated by the reflected shock for about 1–1.5 milliseconds are cooled by rarefaction waves, and samples obtained through a quick‐opening check valve are analyzed by gas chromatography. The effect of nitrogen on hydrocarbon pyrolysis appears to be negligible below about 2000°K. At higher temperatures, vibrationally excited nitrogen molecules react with free radicals and produce hydrogen cyanide. Activation energies in the range 23 to 54 Kcal/mole are calculated for the formation of hydrogen cyanide.

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THE ACTIVATION ENERGY FOR THE PYROLYSIS OF METHANE¹

Abstract: The recent work of Bell and Kistiakowsky2 allows one to compute //°2as for the reaction CH4 -> CH2 + ,(1) with fair accuracy. It is 103 keal., with an uncertainty of 3 or 4 keal. This may be compared with the AH°2as of about 102 keal.3 for the reaction CH4 -> CH3 + H(2)

Cited by 69 publications

References 0 publications

The Thermal Decomposition of Methane. I. Kinetics of the Primary Decompositionto C₂H6 + H₂; Rate Constant for the Homogeneous Unimolecular Dissociation of Methane and its Pressure Dependence

The Thermal Decomposition of Methane. I. Kinetics of the Primary Decompositionto C₂H6 + H₂; Rate Constant for the Homogeneous Unimolecular Dissociation of Methane and its Pressure Dependence

Use of a shock tube in the study of high temperature gas reactions

A shock tube study of the high temperature reactions of nitrogen with hydrocarbons

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THE ACTIVATION ENERGY FOR THE PYROLYSIS OF METHANE1

Abstract: The recent work of Bell and Kistiakowsky2 allows one to compute //°2as for the reaction CH4 -> CH2 + ,(1) with fair accuracy. It is 103 keal., with an uncertainty of 3 or 4 keal. This may be compared with the AH°2as of about 102 keal.3 for the reaction CH4 -> CH3 + H(2)

Cited by 69 publications

References 0 publications

The Thermal Decomposition of Methane. I. Kinetics of the Primary Decompositionto C2H6 + H2; Rate Constant for the Homogeneous Unimolecular Dissociation of Methane and its Pressure Dependence

The Thermal Decomposition of Methane. I. Kinetics of the Primary Decompositionto C2H6 + H2; Rate Constant for the Homogeneous Unimolecular Dissociation of Methane and its Pressure Dependence

Use of a shock tube in the study of high temperature gas reactions

A shock tube study of the high temperature reactions of nitrogen with hydrocarbons

Contact Info

Product

Resources

About

THE ACTIVATION ENERGY FOR THE PYROLYSIS OF METHANE¹

The Thermal Decomposition of Methane. I. Kinetics of the Primary Decompositionto C₂H6 + H₂; Rate Constant for the Homogeneous Unimolecular Dissociation of Methane and its Pressure Dependence

The Thermal Decomposition of Methane. I. Kinetics of the Primary Decompositionto C₂H6 + H₂; Rate Constant for the Homogeneous Unimolecular Dissociation of Methane and its Pressure Dependence