Ethane Triggered Gate-Opening in a Flexible-Robust Metal-Organic Framework for Ultra-High Purity Ethylene Purification

Abstract

Priority recognition separation of inert and larger ethane molecules from high-concentration ethylene mixtures instead of the traditional thermodynamic or size sieving strategy is a fundamental challenge. Herein, we report ethane triggered gate-opening in the flexible-robust metal-organic framework Zn(ad)(min), the 3-methylisonicotinic acid ligand can spin as a flexible gate when adsorbing the cross-section well-matched ethane molecule, achieving an unprecedented ethane adsorption capacity (62.6 cm³ g⁻¹) and ethane/ethylene uptake ratio (3.34) under low-pressure region (0.1 bar and 298 K). The ethane-induced structural transition behavior has been uncovered by a collaboration of single-crystal X-ray diffraction, in situ variable pressure X-ray diffraction and theoretical calculations, elucidating the synergetic mechanism of cross-section matching and multiple supramolecular interactions within the tailor-made pore channels. Dynamic breakthrough experiments have revealed the outstanding separation performance of Zn(ad)(min) during the production of ultra-high purity ethylene (>99.995 %) with a productivity of up to 39.2 L/kg under ambient conditions.