Palladium modified porous polymeric membranes and their performance in selective hydrogenation of propyne

The accessible pore system of polymeric ultrafiltration membranes was modified by titanium dioxide and treated further with palladium acetate to yield catalytically active, porous nanofiltration membranes. This procedure is in general applicable for any polymeric ultrafiltration membrane. To overcome the drawback of low thermal stability of common polymeric membranes, new ultrafiltration membranes were developed, based on a polyamideimide containing up to 40 wt.% of an inorganic filler admixed to the membrane casting solution. A similar treatment yielded catalytically active polymer membranes stable up to 200°C. The membranes were characterised by several methods and their performance was tested in a membrane reactor at 30°C. The hydrogenation of propene and the selective hydrogenation of propyne were examined as test reactions. For most effective membranes, 100% conversion of propene at a maximum yield of 98% of propane was obtained at the permeate side. In the selective hydrogenation of 5% propyne in propene, a selectivity of 99% for propene at 100% conversion of propyne was achieved at a permeate flux of 0.08 m3/m2 h bar at 0.9 bar pressure difference.