Triptycene Induced Enhancement of Membrane Gas Selectivity for Microporous Tröger's Base Polymers

摘要: Polymer membranes are of increasing importance for a range molecular separations due to their potential enhanced energy-efficiency over competing technologies.1 For example, gas separation using polymer is an established industrial technology that applied O2 or N2 enrichment air, natural upgrading (i.e., predominantly removing CO2 from CH4), and hydrogen recovery ammonia manufacture (separating H2 N2).2 In addition, also predicted play role in production (e.g., separating CO2)3 post-combustion capture N2).4 any membrane it desirable have good selectivity one another, combined with high permeability flux throughput). Generally, polymers used commercial demonstrate but low permeability, however, compete other technologies very large-scale applications, materials greatly permeabilities desirable.5 Unfortunately, the given pair (x y), highly permeable display inadequate well-established trade-off between (Px) (αxy = Px/Py). most polymers, poly(trimethylsilylpropyne), has poor PO2 6000 Barrer; αO2/N2 1.8).6 The permeability-selectivity was quantified by Robeson 1991,7 revised 2008,8 plotting log Px versus αxy large number polymers. each pair, “upper bound” identified position data relative upper bound as universal performance indicator when assessing new material two gases. related difference kinetic diameter molecules size-sieving nature diffusivity selectivity) rigid glassy define it.9 Theory suggests greater can be obtained suppressing motion chain rigidity whereas relies on generation amount free volume through inter-chain separation.[9b] Conforming these design criteria, Polymers Intrinsic Microporosity (PIMs), such archetypal PIM-1 (Figure ​1a),1a), class membrane-forming designed possess wholly fused-ring structure restrict contorted prohibit space efficient packing.10 Hence, PIMs generally lie 1991 important pairs some approach, even exceed, 2008 bounds ​22).11