Optimizing the Adsorptive Separation of Three‐Component C2 Hydrocarbons by Pore Environment Regulation in Metal–Organic Frameworks

ABSTRACT One‐step adsorptive purification of ethylene (C ₂ H ₄ ) from C2 ternary hydrocarbon mixtures containing acetylene (C ₂ H ₂ ) and ethane (C ₂ H ₆ ) remains a fundamental challenge as it involves simultaneously selective adsorption of C ₂ H ₆ over C ₂ H ₄ and C ₂ H ₂ over C ₂ H ₄ . Here, we report the successful practice of a Nanopore Environment Engineering approach within isoreticular metal–organic frameworks (MOFs) that enables optimal separation of C2 ternary mixtures. Using a pair of pyrimidine‐bridged tetracarboxylate ligands bearing either methyl (─CH ₃ ) or amino (─NH ₂ ) groups, we synthesized two csq ‐type Zr‐MOFs, HIAM‐411 and HIAM‐412, with modulated nanopore environments. While HIAM‐411 displays selective adsorption of C ₂ H ₂ and C ₂ H ₆ over C ₂ H ₄ , its separation efficiency is largely restricted by the relatively low C ₂ H ₂ /C ₂ H ₄ selectivity. In contrast, the amino‐functionalized HIAM‐412 exhibited significantly strengthened hydrogen bonding interactions with C ₂ H ₂ , achieving an approximately 3‐fold enhancement in the productivity of the high‐purity C ₂ H ₄ . Our study highlights the critical role of nanopore environment regulation in optimizing the multicomponent separation performance of C2 hydrocarbons.