(725e) Novel Perfluorinated Membrane for Drying Solvents

Data are presented on the dehydration of EtOH, IPA, MEK, THF and [C₂mim][OAc] by pervaporation.  The tests were done on a pilot scale using a chemically and thermally resistant membrane system.  The membrane consists of a perfluorinated polymer backed by a chemically and thermally resistant hollow-fiber porous support. The membrane is packed in cartridges that have several square feet of active area.  The “wet” solvent is fed to the pervaporation system in the liquid phase. The feed to the membrane is separated into two streams: the retentate, which is solvent rich, and the permeate, which is water rich and is in the vapor phase. The data show that high levels of drying can be achieved with high solvent recoveries and rapid rates of water removal.  The pervaporation process is especially advantageous for drying organics that are difficult to dry by conventional technologies (e.g., azeotropes or solvents that have boiling points close to water), heat sensitive chemicals,   reacting mixtures in which the chemical reaction is inhibited by the presence and/or generation of  water. This technology is been used commercially for the successful dehydration of lubricating oils and phosphate esters.  The pervaporation process can be combined with conventional distillation, e. g., for recovering the solvent that goes to the water-rich stream from the pervaporation process. Examples of this hybrid membrane-distillation drying process will be presented.