Immobilization of Amino-site into a Pore-Partitioned Metal-Organic Framework for Highly Efficient Separation of Propyne/Propylene.

Adsorptive separation of propyne/propylene (C 3 H 4 /C 3 H 6 ) is a crucial yet complex process, however, it remains a great difficulty in developing porous materials that can meet the requirements for practical applications, particularly with an exceptional ability to bind and store trace amounts of C 3 H 4 . Functionalization of pore-partitioned metal-organic frameworks (ppMOFs) is methodically suited for this challenge owing to the possibility of dramatically increasing binding sites on highly porous and confined domains. We here immobilized Lewis-basic (-NH 2 ) and Lewis-acidic (-NO 2 ) sites on this platform. Along with an integrated nature of high uptake of C 3 H 4 at 1 kPa, high uptake difference of C 3 H 4 -C 3 H 6 , moderated binding strength, promoted kinetic selectivity, trapping effect and high stability, the NH 2 -decorated ppMOF (NTU-100-NH 2 ) can efficiently produce polymer-grade C 3 H 6 (99.95 %, 8.3 mmol ⋅ g -1 ) at room temperature, which is six times more than the NO 2 -decorated crystal (NTU-100-NO 2 ). The in situ infrared spectroscopy, crystallographic analysis, and sequential blowing tests showed that the densely packed amino group in this highly porous system has a unique ability to recognize and stabilize C 3 H 4 molecules. Moving forward, the strategy of organic functionalization can be extended to other porous systems, making it a powerful tool to customize advanced materials for challenging tasks.