Combined experimental and theoretical study of the reactivity of γ-butyro-and related lactones, with the oh radical at room temperature

The total rates of reaction between four cyclic esters (β-butyro-, γ-butyro-, γ-valero-and σ-valero-lactones) and the OH radical have been measured relative to the rate of reaction of a reference compound, ethene, at room temperatures. The measurements show that the rates increase with increasing ring size. Theoretical calculations on the four lactones with the inclusion of a fifth, α-methyl-γ-butyrolactone, are broadly in agreement with this picture but provide a more insightful view of the sites at which hydrogen atom abstraction occurs in each molecule.