Reaction of excited oxygen atoms, O(^1D_2), with cyclobutane

Abstract

Gas and liquid phase reaction of singlet oxygen atoms O(^1D_2) with cyclobutane has been studied at room temperature (25 ± 2°). The effects of pressure and of O_2 on the yields of the main products show that the reaction mechanism is basically the same as found in related reactions of O(^1D_2) with saturated hydrocarbons. The insertion product, excited cyclobutanol, is only partly stabilized in the gas phase at pressures below 15 atm. Its decomposition products are ethylene and acetaldehyde. From the pressure dependence of the yields of ethylene a lifetime of 8 x 10^(-12) sec is estimated for the excited cyclobutanol, assuming that deactivation occurs at each collision. This result is used to evaluate approximately the Arrhenius A factor for unimolecular decomposition of cyclobutanol. The calculated value is consistent with the literature value of A for pyrolysis of cyclobutanol, in agreement with the postulate that the "hot" intermediate is vibrationally excited cyclobutanol in the ground electronic state.

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