Polyimide-based Carbon Molecular Sieve Membrane For Ethylene/ethane Separations

Abstract

Carbon molecular sieve membranes having desirable selectivity for ethylene/ethane separations are prepared from a 3,3?,4,4?-benzophenonetetracarboxylic acid dianhydride 5(6)-amino-1-(4?-aminophenyl)-1,3,3-trimethylindane 4,4-bismaleimidodiphenyl-methane (BTDA-DAPI) precursor solution that is then formed into films or hollow fibers which are pyrolyzed under vacuum or an inert atmosphere to form carbon molecular sieve membranes. Pyrolysis condition variables, including ramp rate, thermal soak time and temperature, are used to optimize the membrane's separation performance.