Olefin/paraffin separations by distillation are highly energy intensiv
e, Facilitated transport, or reactive membranes have long been investi
gated as an alternative and/or complementary separation technology to
conventional distillation, However, stability problems associated with
facilitated transport membranes have been the primary obstacle in the
development of commercial FT processes. In this paper, we report the
development of a polymer membrane containing silver(I) ion that facili
tates the transport of ethylene in the absence of solvent. Blends of i
onically conductive and electrically conductive polymers were found to
have the appropriate electronic environment to allow reaction of silv
er(I) ion and ethylene. The results for the ethylene/ethane separation
were obtained with composite membranes of silver(I)-form Nafion(R) an
d 2 wt% poly(pyrrole). Permeation measurements were performed with eth
ylene/ethane mixtures at total feed pressures ranging from 760 to 1900
mmHg and at temperatures of 40 degrees C to 70 degrees C, Pure gas pe
rmeability measurements were obtained at a total feed pressure of 1900
mmHg and temperatures of 30 degrees C and 40 degrees C. Ethylene/etha
ne separation factors with the silver(I)-form Nafion-poly(pyrrole) com
posite membranes increased from 8 to 15 as temperature decreased. Ethy
lene permeabilities increased from 0.2 to 1 Barrer over the temperatur
e range of 30 degrees C to 70 degrees C:. An ethylene/ethane mixed gas
permeability ratio of about 2 was observed with non-reactive proton-f
orm Nafion-poly(pyrrole) composite membranes, Ethylene permeation meas
urements as a function of membrane thickness suggested that the facili
tated transport of ethylene approached the reaction-limited regime at
membrane thickness of 5 mu m. The complexation between ethylene molecu
les and silver(I) ions in Nafion-poly(pyrrole) composite membrane was
observed with FTIR spectroscopy.