The hydrolysis of ethyl vinyl ether. Part I. Reaction mechanism

The kinetics of the acid-catalysed hydrolysis of ethyl vinyl ether in aqueous solution have been measured by following the disappearance of the ether and by following the appearance of acetaldehyde; the two methods give identical rate constants. The reaction is first-order in ethyl vinyl ether and first-order in hydronium ion; in formic acid and acetic acid buffer solutions, it shows general acid catalysis. Proton magnetic resonance analysis of the reaction products shows that only one deuterium atom is incorporated in the methyl group of the acetaldehyde which is formed when the reaction is conducted in deuterium oxide solution. This evidence establishes the reaction as a rate-determining proton transfer from catalysing acid to substrate.