SEPARATION OF GASEOUS OLEFIN ISOMERS USING FACILITATED TRANSPORT MEMBRANES

The sorption and transport of c-2-butene and t-2-butene in hydrated Nafion cation exchange membranes containing Ag+ ions and Na+ ions has been studied. The results of the flux measurements at 298.2 K and at feed pressures of up to 3 bars indicate that for c-2-butene/t-2-butene mixtures, a competitive effect in the Ag+ membranes occurs which increases the selectivity from the ideal Value of 1.4 calculated from pure gas fluxes to about 1.9-2.7 depending on the feed composition. Even at the highest feed gas concentrations the mixed gas selectivities do not drop below 1.9. The mixed gas solubility data of the Ag+ membranes show the same enhancement in selectivity compared to the ideal sorption selectivity calculated from pure gas solubilities. All experimental results can be described consistently with a reaction equilibrium model which does not require any adjustable parameters.