An Ultra-stable Supramolecular Framework Based on Consecutive Side-by-side Hydrogen Bonds for One-step C 2 H 4 /C 2 H 6 Separation.

The one-step efficient separation of high-purity C ₂ H ₄ from C ₂ H ₄ /C ₂ H ₆ mixtures by hydrogen-bonded organic frameworks (HOFs) faces two problems: lack of strategies for constructing stable pores in HOFs and how to obtain high C ₂ H ₆ selectivity. Herein, we have developed a microporous Mortise-Tenon-type HOF (MTHOF-1, MT is short for Mortise-Tenon structure) with a new self-assembly mode for C ₂ H ₄ /C ₂ H ₆ separation. Unlike previous HOFs which usually possess discrete head-to-head hydrogen bonds, MTHOF-1 is assembled by unique consecutive side-by-side hydrogen bonds, which result in mortise-and-tenon pores decorated with orderly arranged amide groups and benzene rings. As expected, MTHOF-1 exhibits excellent stability under various conditions and shows clear separation trends for C ₂ H ₆ /C ₂ H ₄ . The IAST selectivity is as high as 2.15 at 298 K. More importantly, dynamic breakthrough experiments have demonstrated that MTHOF-1 can effectively separate the C ₂ H ₆ /C ₂ H ₄ feed gas to obtain polymer-grade C ₂ H ₄ in one step even under high-humidity conditions.
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