Polyimide-based carbon molecular sieve membrane for ethylene/ethane separations

摘要

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.

主权项

1. An ethane/ethylene separation membrane prepared by a process comprising dissolving an amount of 3,3′,4,4′-benzophenone tetracarboxylic dianhydride 5(6)-amino-1-(4′-aminopheny)-1,3,3-trimethylindane in a solvent such that a solution is formed; forming asymmetric hollow fiber precursors from the solution; at least partially drying the asymmetric hollow fiber precursors with a second solvent; solvent-exchanging the asymmetric hollow fiber precursors in hexane; and at least partially pyrolyzing the asymmetric hollow fiber precursors under vacuum or in an inert atmosphere to form an asymmetric hollow fiber carbon molecular sieve membrane therefrom, the asymmetric hollow fiber carbon molecular sieve membrane having an ethylene permeance of at least 0.25 Gas Permeation Units and an ethylene/ethane selectivity of at least 6.3.