Rates and equilibria of ester hydrolysis: Combination of slow and rapid reactions

The kinetics kinetics and thermodynamics of ester hydrolysis were studied experimentally in a laboratory-scale batch reactor by using ethyl formate as the model molecule. The effects of the reaction conditions, such as temperature, excess water, complexing agent and initial acid charge upon the ester hydrolysis process were investigated and a kinetic model was developed for the system. Autocatalytic kinetics was observed experimentally, which was due to the carboxylic acid formed during the reaction. The reaction rate was further enhanced and the equilibrium was shifted to the product side by adding a complexing agent into the reaction mixture. A mathematical model comprising the mass balances and rate equations were developed for the system by assuming quasi-equilibrium hypothesis for the reaction involving the complexing agent. A robust calculation scheme was developed for the estimation of the kinetic and thermodynamic parameters from experimental data. The proposed model was able to predict the experimental results satisfactorily. (C) 2011 Elsevier B.V. All rights reserved.