Analysis of Heterogeneously Catalyzed Ester Hydrolysis Performed in a Chromatographic Reactor and in a Reaction Calorimeter

Abstract

A discontinuously operated chromatographic reactor and a reaction calorimeter were used to study experimentally and theoretically the heterogeneously catalyzed hydrolysis reactions of four esters (methyl formate, methyl acetate, ethyl formate, and ethyl acetate). Two different batches of an acidic ion-exchange resin were used as catalyst and adsorbent. The relevant distribution equilibria were quantified using pulse chromatographic experiments. The reaction rates were quantified from (a) the shape of the elution profiles and (b) the course of the heat fluxes. To this end, systematic experiments were carried out using fixed beds packed with the catalysts and a reaction calorimeter containing catalyst suspensions. Advantages and disadvantages of these two types of experimental approaches in terms of their potential to extract reliable kinetic parameters were evaluated. A simplified pseudohomogeneous model and the determined parameters were found to be capable of describing the concentration profiles in the chromatographic reactor for all reactions studied under diverse operation conditions. Copyright © 2004 American Chemical Society [accessed 2013 November 27th

Intramolecular Catalysis in Carboxylic Acid Esterification: Modeling of Single- and Multi-Acid Esterification

“…Due to low reaction rate, esterification reactions are normally catalyzed by mineral acids. Esterification of low molecular weight carboxylic acids with methanol through homogeneous and heterogeneous catalysis is well represented in literature, e.g., acetic acid esterification − and propionic acid esterification. − In the context of formic acid, the autocatalytic hydrolysis of methyl formate was primarily investigated. − In any case, the high purity of the reactants is essential due to conversion limitation by the chemical equilibrium. Water as the byproduct in esterification shifts the equilibrium toward the reactant side.…”

Catalysis in Multifunctional Reactors

“…was carried out in a chromatographic reactor with Dowex 50W-X8 catalyst [158]. An HPLC column was used for carrying out the experiments.…”

“…[158]-(i) hydrolysis reaction of methyl formate and ethyl formate was faster as compared to methyl acetate and ethyl acetate; (ii) even at low flow rate, methyl acetate and ethyl acetate eluted from the column again confirming that these were the slowest reaction compared to methyl formate and ethyl formate; (iii) the peaks width was reduced considerably as the temperature was increased and in contrast, there was no major effect of temperature on the retention times in the studied range i.e. 298 -328 K, and (iv) the heterogeneous rate constant decreases in the order of methyl formate, ethyl formate, methyl acetate and ethyl acetate.Similarly, heterogeneously catalysed hydrolysis reaction of methyl formate and methyl acetate in the presence of Dowex 50W-X8 was studied by Vu et al[159].…”

Dynamics of reaction separation processes in the limit of chemical equilibrium

“…In other cases the solvent is one of the reactants, which also comes in large excess. Typical examples are the ester hydrolysis systems considered by Mai et al27 In both cases the bulk flow rates are only little affected by a nonequimolar reaction.…”