From a Metal–Organic Square to a Robust and Regenerable Supramolecular Self‐assembly for Methane Purification

• Published in: Angewandte Chemie 2022-11, Vol.134 (48), p.n/a
• Main Authors: Cao, Zhong‐Min, Li, Guo‐Ling, Di, Zheng‐Yi, Chen, Cheng, Meng, Ling‐Yi, Wu, Mingyan, Wang, Wei, Zhuo, Zhu, Kong, Xiang‐Jian, Hong, Maochun, Huang, You‐Gui
• Format: Article
• Language: English
• Subjects: Adsorptivity; Affinity; Alkanes; Alkanes Separation; Carbon dioxide; Chemistry; CO2 Capture; Gas mixtures; Metal–Organic Square; Methane; Natural gas; Polyhedral Cavity; Purification; Robustness; Separation; Supramolecular Assembly
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202210012

Porous supramolecular assemblies constructed by noncovalent interactions are promising for adsorptive purification of methane because of their easy regeneration. However, the poor stability arising from the weak noncovalent interactions has obstructed their practical applications. Here, we report a robust and easily regenerated polyhedron‐based cationic framework assembled from a metal–organic square. This material exhibits a very low affinity for CH4 and N2, but captures other competing gases (e.g. C2H6, C3H8, and CO2) with a moderate affinity. These results underpin highly selective separation of a range of gas mixtures that are relevant to natural gas and industrial off‐gas. Dynamic breakthrough studies demonstrate its practical separation for C2H6/CH4, C3H8/CH4, CO2/N2, and CO2/CH4. Particularly, the separation time is ≈11 min g−1 for the C2H6/CH4 (15/85 v/v) mixture and ≈49 min g−1 for the C3H8/CH4 (15/85 v/v) mixture (under a flow of 2.0 mL min−1), respectively, enabling its capability for CH4 purification from light alkanes. From a metal–organic square, a robust and renewable polyhedron‐based framework material is assembled with potential for CH4 purification from natural gas and CO2 capture from industrial off‐gas.