Molecular‐Rotor‐Enhanced Pore‐Space Partition in Metal–Organic Frameworks for Boosting One‐Step Ethylene Purification

Abstract

ABSTRACT One‐step ethylene purification from the ternary acetylene/ethane/ethylene (C 2 H 2 /C 2 H 6 /C 2 H 4 ) mixture is a pivotal yet unresolved challenge in industrial petrochemical processes. Herein, a molecular‐rotor‐enhanced pore‐space partition (MR‐enhanced PSP) strategy is proposed, which successfully achieves synergistic optimization of pore environments in metal–organic frameworks for boosting one‐step ethylene separation. The insertion of pore partitioners through open metal sites in typical MIL‐88 framework precisely tunes the local pore apertures, while aromatic molecular rotors step‐by‐step regulate the pore windows and progressively enriches the π–π and C–H⋯π interactions with gas molecules. Optimized SNNU‐636 adsorbent achieves a C 2 H 2 /C 2 H 4 selectivity of 4.17, outperforming its counterparts without molecular rotors (SNNU‐630: 1.78, SNNU‐631: 3.29, SNNU‐632: 1.42) and additionally exhibiting preferential adsorption of C 2 H 6 over C 2 H 4 . Fixed‐bed breakthrough experiments confirm that SNNU‐636 enables one‐step production of ultrahigh‐purity C 2 H 4 (> 99.9999%) from the ternary mixture with a record‐high yield of 7.8 mmol·g −1 , surpassing all benchmark adsorbents under similar conditions. Mechanistic studies further validate this MR‐enhanced PSP strategy, revealing that C 2 H 2 and C 2 H 6 are stabilized via multiple π⋯π and C–H⋯π interactions, underpinning the state‐of‐the‐art one‐step C 2 H 4 purification performance.