Propyne/propylene (C3 H4 /C3 H6 ) separation is an important but challenging industrial process to produce polymer-grade C3 H6 and recover high-purity C3 H4 . Herein, we report an ultrastable TiF6 2- anion cross-linked metal-organic framework (ZNU-2) with precisely controlled pore size, shape and functionality for benchmark C3 H4 storage (3.9/7.7 mmol g-1 at 0.01/1.0 bar and 298 K) and record high C3 H4 /C3 H6 (10/90) separation potential (31.0 mol kg-1 ). The remarkable C3 H4 /C3 H6 (1/99, 10/90, 50/50) separation performance was fully demonstrated by simulated and experimental breakthroughs under various conditions with excellent recyclability and high productivity (42 mol kg-1 ) of polymer-grade C3 H6 from a 1/99 C3 H4 /C3 H6 mixture. A modelling study revealed that the symmetrical spatial distribution of six TiF6 2- on the icosahedral cage surface provides two distinct binding sites for C3 H4 adsorption: one serves as a tailored single C3 H4 molecule trap and the other boosts C3 H4 accommodation by cooperative host-guest and guest-guest interactions.
Keywords: C3H4 Storage; C3H4/C3H6 Separation; Cooperative Interactions; Metal-Organic Frameworks; Pore Tuning.
© 2022 Wiley-VCH GmbH.