Pillar-layered metal-organic frameworks with benchmark C2H2/C2H4 and C2H6/C2H4 selectivity for one-step C2H4 production

Energy-efficient adsorptive separation shows great potential for the one-step production of high-purity ethylene (C 2 H 4 ) from ternary C 2 hydrocarbons. However, it remains a formidable challenge to fabricate high-performance adsorbents that exhibit simultaneous high selectivity (>2) towards acetylene/ethylene (C 2 H 2 /C 2 H 4 ) and ethane/ethylene (C 2 H 6 /C 2 H 4 ). Herein, we report a pillar-layered metal–organic framework, Ni(sdba)(dabco) 0.5 (H 2 sdba = 4,4′-sulfonyldibenzoic acid; dabco = 1,4-diazabicyclo [2.2.2] octane), for preferential trapping of C 2 H 6 and C 2 H 2 over C 2 H 4 . The abundant accessible binding sites endow Ni(sdba)(dabco) 0.5 with outstanding C 2 H 2 /C 2 H 4 (2.28) and C 2 H 6 /C 2 H 4 (2.47) selectivity with high C 2 H 6 (3.15 mmol g −1 ) and C 2 H 2 (4.41 mmol g −1 ) uptake among porous materials reported for one-step C 2 H 4 purification. Dynamic breakthrough experiments demonstrated the feasibility of producing high-purity C 2 H 4 (>99.9%) from C 2 H 2 /C 2 H 6 /C 2 H 4 gas-mixtures (1/1/1 and 1/9/90, v/v/v ) in a single step. Computational simulations reveal that the aromatic-rich pore spaces, which decorated with accessible interlayer uncoordinated oxygen atoms of sulfonyl groups and alkyl functionalities, can provide multiple C-H···O, C-H···π, and C-H···H interactions for selectively recognizing C 2 H 6 and C 2 H 2 over C 2 H 4 .