Synergistic C₂H₂ Binding Sites in Hydrogen-Bonded Supramolecular Framework for One-Step C₂H₄ Purification from...

Purification of C₂H₄ from the ternary C2 hydrocarbon mixture in one step is of critical significance but still extremely challenging according to its intermediate physical properties between C₂H₆ and C₂H₂. Hydrogen-bonded organic frameworks (HOFs) stabilized by supramolecular interactions are emerging as a new kind of adsorbents that facilitate green separation. However, it remains a problem to efficiently realize the one-step C₂H₄ purification from C₂H₆/C₂H₄/C₂H₂ mixture because of the low C₂H₂/C₂H₄ selectivity. We herein report a robust microporous HOF (termed as HOF-TDCPB) with dense O atoms and aromatic rings distributed on the pore surface which provide C₂H₆ and C₂H₂ preferred environment simultaneously. Dynamic breakthrough experiments indicate that HOF-TDCPB can not only obtain high-purity C₂H₄ from binary C2 mixture, but also firstly realize one-step C₂H₄ purification from ternary C₂H₆/C₂H₄/C₂H₂ mixture, with the C₂H₄ productivity of 3.2 L/kg (>99.999 %) for one breakthrough cycle. Furthermore, HOF-TDCPB displays outstanding stability in air, organic solvents and water, which endow it excellent cycle performance even under high-humidity conditions. Theoretical calculations indicate that multiple O sites on pore channels can create synergistic binding sites for C₂H₂, thus affording overall stronger multipoint interactions.