Ester Decomposition as a Two-Center Synchronous Reaction

Experimental data on the molecular decomposition of esters with various structures into an olefin and the corresponding acid in the gas phase are analyzed in terms of the intersecting parabolas method. Enthalpies and kinetic parameters characterizing this decomposition have been calculated for 33 reactions. Ester decomposition is a concerted two-center reaction characterized by a very high classical potential barrier of thermoneutral reaction (148-206 kJ/mol). The totality of reactions examined is divided into eight classes. Activation energies and rate constants have been calculated for 38 reactions using the kinetic parameters obtained. The activation energies and rate constants of the reverse bimolecular reaction of acid addition to olefins have been calculated by the intersecting parabolas method. Factors in the activation energy of ester decomposition and formation reactions are discussed.