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 traditional thermodynamic or size sieving strategy is a fundamental challenge. Herein, we report the 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, thus achieving the unprecedent 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 is 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 revealed the outstanding separation performance of Zn(ad)(min) in the production of ultra-high purity ethylene (> 99.995%) with a productivity of up to 39.2 L/kg under ambient conditions.