Kinetic and Spectroscopic Studies on the Thermal Decomposition of 2,2,6-Trimethyl-4H-1,3-dioxin-4-one: Generation of Acetylketene

Article abstract of DOI:10.1021/ja00188a037

Acetylketene is shown to be a reactive intermediate in thermolytic reactions of 2,2,6-trimethyl-4H-1,3-dioxin-4-one (the diketene-acetone adduct) via a series of kinetic studies.The uncatalyzed acetoacetylations of phenol, 1-butanol, and di-n-butylamine with the title dioxinone at 82-107 deg C are first-order reactions in which the rate-limiting step is the formation of acetylketene and acetone, presumably via a retro-Diels-Alder reaction.Isopropenyl acetoacetate is not an intermediate in the aforementioned reactions but also provides acetylketene when heated.Acetylketene was observed by FT-IR spectroscopy in an argon matrix.