Minor processes in the photolysis of azomethane at low pressure: An upper limit for the rate of the unimolecular elimination of H<sub>2</sub> from vibrationally excited ethane

Revised values are given for the rate coefficients of ethane and methane decomposition derived from the laser absorption shock tube measurements performed by Davidson et al. (1992Davidson et al. ( ,1993. This revision results from a reassessment of the methyl absorption coefficient used in the original studies. 0 1995 JohnThe rate coefficients of ethane and methane decomposition reported by Davidson et al. [1,21 were derived from CH3 profiles obtained using narrow-linewidth laser absorption in a shock tube. The magnitude of the rate coefficients determined were directly related to the value of the 216.62 nm absorption coefficient of CH3 used in these studies. We had previously determined this absorption coefficient in a separate study [31. Recently, we have reevaluated this absorption coefficient and now find that it is approximately half the value that we had previously reported [41. Using the revised absorption coefficient, we have reanalyzed the data of these two decomposition studies and report the results of this reanalysis here.The time-varying absorption profiles of both the ethane and methane studies were reduced using the corrected absorption coefficient, yielding corrected methyl mole fraction profiles. As was done in the original studies, these mole fraction profiles were compared to CHEMKIN-generated mole fraction profiles and fit at early times by varying only the rate coefficient of the respective decomposition reactionThe same reaction mechanism as in the original studies was used with the following exception. The small room-temperature rate coefficient for reaction (-3) suggested by Smith [5] indicates that reaction (3) should be slow at high temperatures. (3)CH3 + CH3 -*-C2H4 + H2We have used 1/8th of the value of the rate coefficient suggested by Just [6] for k3. This lower value, supported by recent work in our laboratory [71, did not affect the early-time fitting of the methyl profiles in either of the decomposition studies.With the reduction of kg, the only significant methyl removal path in the temperature range of our original CH4 and CzH6 decomposition experiments is (4) CH3 + CH3 a CzH5 + H

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Minor processes in the photolysis of azomethane at low pressure: An upper limit for the rate of the unimolecular elimination of H₂ from vibrationally excited ethane

Cited by 4 publications

References 9 publications

The Photochemistry of the Hydrazo, Azo and Azoxy Groups

The Photochemistry of the Hydrazo, Azo and Azoxy Groups

ChemInform Abstract: Minor Processes in the Photolysis of Azomethane at Low Pressure: An Upper Limit for the Rate of the Unimolecular Elimination of H2 from Vibrationally Excited Ethane

Revised values for the rate coefficients of ethane and methane decomposition

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Minor processes in the photolysis of azomethane at low pressure: An upper limit for the rate of the unimolecular elimination of H2 from vibrationally excited ethane

Cited by 4 publications

References 9 publications

The Photochemistry of the Hydrazo, Azo and Azoxy Groups

The Photochemistry of the Hydrazo, Azo and Azoxy Groups

ChemInform Abstract: Minor Processes in the Photolysis of Azomethane at Low Pressure: An Upper Limit for the Rate of the Unimolecular Elimination of H2 from Vibrationally Excited Ethane

Revised values for the rate coefficients of ethane and methane decomposition

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Product

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Minor processes in the photolysis of azomethane at low pressure: An upper limit for the rate of the unimolecular elimination of H₂ from vibrationally excited ethane