NOTES
1950
enable any firm conclusions to be reached as to the magnitude of the activation energy of the reaction between the chain propagator X and the xylenes. The small differences which were found to exist between these activation energies are, however, in keeping with the suggestion that the chain carrier X is in fact the HOz radical. While further light has been shed on the character of some of the elementary reactions which occur in the gas phase oxidation of the xylenes, it is clear
1-01. 64
that further work is still required to establish with certainty the nature of the chain carrier or of the branching intermediate. The stoichiometry of the oxidation of the xylenes is at present being obtained. In this respect, gas chromatography is proving to be a most useful tool. Such analytical information together with the kinetic details presented here should provide an adequate basis for the formulation of a satisfactory mechanism of the slow combustion of the xylenes.
NOTES Gaseous mxtures of purified Hea, the appropriate isotopic ISOTOPE EFFECT I N RECOIL TRITIUM methanes, and other gases when required, were eealed in ABSTRACTION REACTIONS WITH Pyrex 1720 glass, and irradiated at 3 X IO9 n . / c m . s / s ~ . for two days. Two separate series were prepared: one mth METHANE CHeD2, and the other with mixtures of CHI and CD4. BY J. I
