Efficient Purification of C₂H₄ from Ternary C₂ Hydrocarbons by C₂H₂/C₂H₆ Selective Hydrogen-Bonded Organic Frameworks

Abstract

One-step purification of ethylene (C₂H₄) from acetylene/ethane/ethylene (C₂H₂/C₂H₆/C₂H₄) 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 > C₂H₄ > 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 C₂ 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.

Keywords

Hydrogen-bonded organic framework / C₂H₂/C₂H₆/C₂H₄ separation / Reverse adsorption / π-π stacking / Self-assembly / Weak intermolecular interactions

RIGHTS & PERMISSIONS

2025 SIOC, CAS, Shanghai, & WILEY-VCH GmbH