Kinetic study of catalytic esterification of butyric acid and n-butanol over Dowex 50Wx8-400

A kinetic investigation for the esterification of butyric acid with n-butanol over Dowex 50Wx8-400 was conducted. The catalytic experiments were performed in a reactive distillation mode, in which the byproduct (water) is eliminated to prevent the reverse reaction from taking place. The experimental parameters are reaction temperatures (100-110 degrees C), molar ratios of reactants (butyric acid/n-butanol = 0.25-4) and catalyst loading (10-40 g/L), and their effect on the reaction rate was found that the conversion increased with temperature and catalyst loading whereas it decreased as the molar ratio of reactants increased. The rate equations were derived on the basis of the pseudo-homogeneous (PH) model, Langmuir-Hinshelwood (LH) model and Eley-Rideal (ER) model. From the best fit models showing good correlation between experimental and simulation results, the surface reaction was determined to be the rate determining step, while competitive adsorption on a catalyst surface and weak interaction between resin and water by-product were confirmed in the esterification reaction of butyric acid with n-butanol. (C) 2011 Elsevier B.V. All rights reserved.