Separation of methanol-n-butyl acetate mixtures by pervaporation: Potential of 10 commercial membranes

The transesterification reaction to produce methanol and butyl acetate has great interest in the chemical industry. The separation of these two compounds from the reaction media increases the productivity, thus, a hybrid configuration composed of reaction-pervaporation is of interest. In this work, 10 commercial specialty membranes (PolyAn and Sulzer Pervap membranes) have been studied in a pervaporation setup at three temperatures (30, 40 and 50 degrees C) and a feed concentration ranging between 20 and 80 mol% methanol/butyl acetate in order to determine their performance in terms of permeance, selectivity and the McCabe-Thiele separation diagram. From the results, it can be observed that most of the membranes are butyl acetate selective, with selectivities up to 307 and permeances of butyl acetate up to about 80,000 GPU. In general, an increase in temperature decreases the permeance of butyl acetate through the PolyAn membranes and it has a dramatic effect on the Pervap 1201 membrane since the selectivity to butyl acetate decays from 300 at 30 degrees C to around 0.2 at 50 degrees C. The Pervap 2255-50 membrane presents an increase of selectivity as the temperature increases. On this basis the potential of developing a pervaporation membrane reactor for production of butyl acetate by transesterification is assessed. (C) 2012 Elsevier B.V. All rights reserved.