Kinetics of Transesterification of 2-Ethoxyethyl Acetate and 2-Butoxyethanol Catalyzed by Niobium Oxide

In this work, the transesterification reaction in the liquid phase catalyzed by niobium oxide between 2-ethoxyethyl acetate and 2-butoxyethanol to obtain the 2-butoxyethyl acetate and 2-ethoxyethanol was studied for the temperature range 383 to 403 K. The effects of temperature, catalysis, agitation, and initial composition on the conversion were preliminary evaluated by applying the Design of Experiments (DOE) technique, where the significant impacts of temperature and amount of catalyst in reaction rate were identified, while stirring speed and initial composition were found to have a negligible effect. The reaction kinetics were well represented by the second-order pseudohomogeneous kinetic model in terms of concentrations and in terms of activities, evaluated by the NRTL model. The rate constant and equilibrium constant were estimated from the molar concentrations and activities of the mixture’s components. The pseudohomogeneous kinetic models fitted well the experimentally measured concentrations of the reactants and products, and the catalyst employed (niobium oxide) showed high selectivity. The enthalpy of the reaction of +4.8 kJ/mol was obtained, a low value as expected for transesterification reactions. The activation energy of 71.7 kJ/mol was obtained for the nonideal model.