Kinetics of the vinyl interchange reaction between benzoic acid and vinyl acetate

Abstract

In this paper, the kinetics of the vinyl interchange reaction between benzoic acid and vinyl acetate are reported. The mixed catalyst used was mercuric acetate dissolved in BF 3-acetic acid complex, the reaction being followed by IR spectrometry in a large excess of vinyl acetate at 30°. The reaction is first order with respect to the concentrations of BF 3-acetic acid and of mercuric salt. At constant HgO/BF 3 ratio (about unity) the overall order of reaction is two when the concentrations of mercury salt and BF 3 are varied simulataneously. With respect to the benzoic acid concentration, the reaction order tends to unity when the acid concentration is low. This effect was interpreted on the basis of the association of the carboxylic acid in the medium and demonstrated by a measure of the partition coefficients. With ethyl acetate as a solvent, a linear relation between vinyl acetate concentration and reaction rate is found; the activation energy was 9·4 Kcal/mole. The importance and the nature of side reactions, especially the formation of ethylidene diesters and their influence on the equilibrium position, were examined. The kinetic results are in good agreement with the mechanism discussed in the previous paper.