Kinetics of Esterification of Acetic Acid and Ethanol with a Homogeneous Acid Catalyst

Abstract

In the present work, esterification reaction between acetic acid and ethanol was conducted in an isothermal batch reactor in the presence of a homogeneous acid catalyst sulphuric acid. The progress of the reaction was monitored by following the concentration of water measured using Karl Fischer titrator. The variables include the mole ratio of reactants, reaction temperature and catalyst concentration. The mole ratio of alcohol to acid was varied from 1 to 5, the reaction temperature between 20°C and 60°C and the catalyst concentration was varied from 1 to 10 weight per cent. The operating conditions for better yield of ester were identified. The experimental data were analysed by an integral method of analysis to obtain the order of the reaction. The reaction rate constants, frequency factor and activation energies have been determined. The kinetic model derived from the mechanism fits the experimental data satisfactorily. The activity coefficients of the system calculated using UNIFAC and modified UNIFAC models deviated from ideality. Both activity- and concentration-based model fits were plotted, which showed the importance of activity coefficient in the rate equation. The present work was also extended to exploit the scope of ionic liquid as a catalyst for the esterification reaction. But it was observed that the reaction is very slow and the amount of catalyst required is high to enhance the yield.