C-4 OLEFIN PARAFFIN SEPARATION BY Y[(1-TRIMETHYLSILYL)-1-PROPYNE]-GRAFT-POLY(ACRYLIC ACID)-AG+ COMPLEX MEMBRANES/

A complex membrane of y[(l-trimethylsilyl)-1-propyne]-graft-poly(acryl ic acid)-Ag+ (PTMSP-g-AA-Ag+) was synthesized and characterized for C- 4 olefin/paraffin gases separation. The 121.6% grafted PTMSP-g-AA-Agcomplex membrane showed a homogeneous silver distribution across the m embrane. Olefin could be transported across the complex membrane both by physical dissolution-diffusion phenomenon and by silver ion facilit ated transport for subsequently forming the reversible (Ag-olefin)(+) complex. The permeation properties of C-4 gases, as measured by gas ch romatography equipped with a gas permeability analyzer, indicated a fa cilitating effect for olefin. Typical selectivities of the 121.6% graf ted complex membrane at 55 degrees C for the isobutene/isobutane and t rans-2-butene/n-butane were 7.7 and 7.3, respectively. The effects of AA% grafting, measuring temperature and permanence stability on the pe rmeability coefficients and separation factors were studied. The solub ilities and diffusivities of C-4 gases as well as their selectivites w ere also examined.