Decarboxylations of 2-cyano-2-phenylacetate ions in water, aqueous ethanol, and aqueous dioxan

Abstract

The decarboxylations of several 2-cyano-2-phenylacetate ions have been observed in water and an 80% ethanol–water mixture. All the reactions were of the first order and in all the cases examined the reaction was faster in aqueous ethanol than in water. The variations of the activation parameters ΔH‡ and ΔS‡ with solvent composition for the decarboxylation of 2-(2-chlorophenyl)- and 2-(4-chlorophenyl)-2-cyanoacetate ions in aqueous ethanol and aqueous dioxan have been investigated. The implications of the results for cycloamylose-catalysed decarboxylations are discussed.