(462g) Chemically Stable Polymeric Membrane Reactors for Selective Removal of Methanol From Transesterification Reactions

Membrane reactors operating in pervaporation conditions have the potential to significantly increase the conversion achieved in conventionally equilibrium-limited transesterification reactions. These reactions generate alcohol byproducts which if selectively removed can result in enhanced conversion over that conventionally achieved. If operating effectively, the membrane reactor configuration can eliminate the need for most of the down-stream separators. Thus, cost saving and energy saving will be realized.

Typically, transesterification reactions are operated at elevated temperatures in organic solvents. Unfortunately, most polymeric membranes have significant temperature and chemical limitations. In this study, an enhanced membrane reactor was developed with a nonporous chemically-stable polymer selective layer on a microporous polymeric support. This presentation will discuss the performance of a membrane commercially available from Compact Membrane Systems in this application. The model reaction of methyl benzoate with butanol to produce butyl benzoate and methanol was tested in the membrane reactor at temperature range of 75-120ºC in presence of organic solvents and aggressive acid catalyst. Our results indicate that the enhanced membrane reactor rapidly achieved conversion of approximate 77%, nearly 25% in excess of that achieved in the conventional system. The membrane had a high permselectivity of methanol over butanol. The membranes demonstrated superior chemical resistance and the purity of the methanol permeate remained high through all the runs.