Application of linear free-energy relationships to perhydrolysis of different carboxylic acids over homogeneous and heterogeneous catalysts

This paper describes the application of LFER to understand the mechanism of the perhydrolysis of carboxylic acids over homogeneous and heterogeneous catalysts. Several experiments were carried out with different linear carboxylic acids: formic, acetic, propionic and butyric acids; using sulfuric acid and Amberlite IR-120 as catalyst and different reaction temperatures. From the experiments, the apparent rate constants decrease in the following order: kapp (PFA) > kapp (PAA) > kapp (PPA) > kapp (PBA), in both catalytic system. Furthermore, it was found that this reaction follows Taft and Charton correlations, which implies that the steric effect of the substituent governs that reaction and the mechanism is similar between the different carboxylic acids. Comparison between homogeneous and heterogeneous catalytic system was carried out based on the analysis of the kinetic expression.

Graphical abstractThe goal of this work was to study the influence of the carbon chain length of the carboxylic acid on the perhydrolysis reaction using linear free-energy relations. A comparison between homogeneous and heterogeneous catalysis system was carried out, based on the apparent rate constant and on the analysis of the kinetic expression.Figure optionsDownload full-size imageDownload as PowerPoint slide