Kinetics of esterification of propionic acid with n-amyl alcohol in the presence of cation exchange resins

Abstract

Esterifications of n-amyl alcohol with propionic acid catalyzed by macroporous (Amberlyst-15) and microporous (Dowex 50 W and Amberlite IR-120) polymeric ion-exchange resins were carried out between 333–348 K. When these catalysts were used as commercially available, Amberlyst-15 was observed to be the most effective catalyst with respect to rate constants, but after drying it became the less effective one. The reaction rate increased with increase in catalyst concentration and reaction temperature. Stirrer speed and different mesh sizes had virtually no effect on the rate under the experimental conditions. The effect of divinylbenzene content was examined for the microporous resin Dowex 50W, and the results showed that the propionic acid conversion decreased as the divinylbenzene content was increased. The rate data were correlated with a second-order homogeneous reaction model. The apparent activation energies, reaction enthalpies and entropy values were calculated for each catalyst. Reaction monitoring is simple and fast by volumetric method and the reproducibility of this method was the order of ± %2.54.