THE THERMAL DECOMPOSITION OF ETHANE: PART II. THE UNIMOLECULAR DECOMPOSITION OF THE ETHANE MOLECULE AND THE ETHYL RADICAL

Abstract

The rate of the elementary dissociation of ethane into two methyl radicals has been measured in its pressure-dependent region at temperatures from 913–999 °K and at pressures from 1–200 mm. The high-pressure first-order rate constant obtained by extrapolation was in agreement with that obtained at lower temperatures,[Formula: see text]Comparison with calculated Kassel curves showed that the best fit of the data was obtained with the Kassel parameter s = 12 ± 1. The high-pressure first-order rate constant for the decomposition of the ethyl radical was obtained by extrapolation of the data reported in Part I, assuming the rate constant for combination of ethyl radicals is independent of temperature.[Formula: see text]From the measured constant for the dissociation of ethane, the rate constant for the combination of methyl radicals was calculated and compared with the values measured in a lower temperature region. Differences in the values of the rate constants and in the shapes of the unimolecular falloff curves are discussed.