A pervaporation membrane reactor for liquid phase synthesis of ethyl tert-butyl ether from tert-butyl alcohol and ethanol

A pervaporation membrane reactor for the synthesis of ethyl tert-butyl ether (ETBE) from a liquid phase reaction between ethanol (EtOH) and tert-butyl alcohol (TBA) was investigated. Supported beta-zeolite and a polyvinyl alcohol (PVA) membrane were used as a catalyst and a membrane in the reactor, respectively. The permeation studies of an H2O-EtOH binary system revealed that the membrane worked effectively for H2O removal at the mixtures containing H2O content lower than 62 mol%. The permeation studies of quaternary mixtures (H2O-EtOH-TBA-ETBE) were performed at 3 temperature levels of 323, 333 and 343 K. It was found that the membrane was preferentially permeable to H2O. The permeability coefficients were correlated with the Arrhenius equation. In the pervaporation membrane reactor studies, both experiment and simulation were carried out. An activity-based model was developed to investigate the performance of the pervaporation membrane reactor using parameters obtained from other independent experiments. The simulation results agreed well with experimental results. It was observed that the ratio of the initial mole of EtOH to TBA (lambda), the ratio of the membrane area to the initial mole of TBA (delta), the ratio of the amount of catalyst to the initial mole of TBA (phi), the operating temperature and the membrane selectivity played important roles on the reactor performance. The analysis of the operating temperature showed an optimum yield due to the competing effect of the rate of reaction and the rate of reactant losses.