The mercury (3P1)-photosensitized decomposition of keten and some reactions of triplet methylene

Abstract

The mercury-photosensitized reaction of keten has been investigated in the presence and absence of neopentane and other gases (O₂, N₂, and CF₄). For the pure system a mechanism is suggested, based upon product analyses at low conversion. A key reaction in this mechanism is the combination of two triplet methylene species (³CH₂). In the presence of neopentane, most of the products are explained by radical combination processes, some of them involving ³CH₂. The observation of products derived from t-butyl radicals supports the specific case of neopentyl–³CH₂ cross combination. A portion of the 2,2-dimethylbutane (neohexane) product, unaccounted for by radical reactions, is attributed to an insertion reaction by single methylene.