Efficient Purification of <scp> C ₂ H ₄ </scp> from Ternary <scp> C ₂ </scp> Hydrocarbons by <scp> C ₂ H ₂ </scp> / <scp> C ₂ H ₆ </scp> Selective Hydrogen‐Bonded Organic Fr

Comprehensive Summary One‐step purification of ethylene (C 2 H 4 ) from acetylene/ethane/ethylene (C 2 H 2 /C 2 H 6 /C 2 H 4 ) ternary mixtures remains a challenging task in the chemical industry. While hydrogen‐bonded organic frameworks (HOFs) have shown promise for separating C2 hydrocarbons—typically favoring adsorption in the order of C₂H₆ &gt; C₂H₄ &gt; C₂H₂—existing materials have largely been limited to binary separations, particularly C₂H₄/C₂H₆. Here, we report a robust HOF material, HOF‐PTBA, that selectively adsorbs both C₂H₂ and C₂H₆, enabling one‐step separation of high‐purity C₂H₄ from ternary C 2 mixtures. HOF‐PTBA exhibits the highest C₂H₆/C₂H₄ and C₂H₂/C₂H₄ adsorption ratios among all reported HOFs. Molecular simulations reveal that C₂H₂ and C₂H₆ form multiple strong interactions with the framework's pore walls, while C₂H₄ exhibits only weak interactions, allowing it to pass through unbound. HOF‐PTBA also demonstrates excellent stability under humid and acidic conditions, and can be synthesized via a simple solvent evaporation process, making it scalable and cost‐effective. These features highlight its strong potential for practical application in industrial gas purification.