Determination of adsorption and kinetic parameters for methyl tert-butyl ether synthesis from tert-butyl alcohol and methanol

Abstract

Methyl tert-butyl ether (MTBE), a high-octane blending agent for motor gasoline, is produced by reacting directly tert-butyl alcohol (TBA) with methanol using Amberlyst 15 ion-exchange resin, which acts as both catalyst and adsorbent. Experiments were carried out in a fixed-bed reactor in the temperature range 318-328 K using rectangular pulse input and measuring the elution profiles of TBA, MTBE, and H2O. A mathematical model based on a quasi- homogeneous kinetics was developed, which assumes the reaction in the polymer phase to be homogeneous. The kinetic parameters, as well as the adsorption equilibrium constants of water, TBA, and MTBE in methanol together with their dependence on temperature, were determined by tuning the simulation results to fit the experimental data using a state-of-the-art optimization technique, the genetic algorithm. The model was further validated using the tuned adsorption and rate parameters to predict other experimental results. The kinetics reported in the present study were obtained under conditions free of both external and internal mass transfer resistance. The enthalpy and entropy of adsorption obtained from Arrhenius plots were found to be consistent with thermodynamics. © 2001 Academic Press.