Olefin/paraffin gas separations with 6FDA-based polyimide membranes 

 -  Journal of Membrane Science, 170(2), p.205-214, 2000 .
<br/><br/> Pure gas permeation and sorption experiments were carried out for the gases ethylene, ethane, propylene and propane using polyimides based on 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA). Composite membranes and free films were used. Experiments were performed at 308 K and feed pressures up to 17 atm for ethylene and ethane and 9 atm for propylene and propane. Mixed gas permeation experiments were carried out with 50 : 50 olefin/paraffin feed mixtures. For all investigated polyimides, the ideal ethylene/ethane separation factor ranged between 3.3 and 4.4 and the ideal propylene/propane separation factor ranged between 10 and 16 at a feed pressure of 3.8 atm and 308 K. In mixed gas permeation experiments, up to 20 
<br/><br/><label>Subjects--Topical Terms: </label><br/>POLYIMIDE<br/>MEMBRANE<br/>GAS SEPARATION<br/>OLEFIN<br/>PARAFFIN<br/>PERMEATION<br/>SORPTION