A robust metal-organic framework with guest molecules induced splint-like pore confinement to construct propane-trap for propylene purification

Abstract

A propane-trapping pillar-layered metal–organic framework with splint-like pore confinement for propylene purification exhibits excellent separation performances of C 3 H 8 /C 3 H 6 mixture. • C 3 H 8 /C 3 H 6 -induced splint-like pore confinement can be constructed in a robust MOF. • It shows excellent separation performance of C 3 H 8 /C 3 H 6 with the record selectivity. • Breakthrough experiments indicate the complete separation of C 3 H 8 /C 3 H 6 mixture. • C 3 H 6 productivity is the highest with good regenerability in dynamic separation. • Theoretical calculations and control experiments confirm the separation mechanism. It is an extremely challenging task to capture C 3 H 8 from the C 3 H 8 /C 3 H 6 mixture, which requires an adsorbent with a specific pore structure. Herein, an ultramicroporous pillared metal–organic framework Ni(ADC)(TED) 0.5 is reported for efficient C 3 H 8 /C 3 H 6 separation. Theoretical calculations revealed that the ADC ligand may form a splint-like pore confinement structure induced by the introduction of guest molecules to construct a propane-trap in the framework. As a result, excellent separation performance for C 3 H 8 /C 3 H 6 is obtained. A record-high IAST-predicted selectivity (6.4), C 3 H 8 /C 3 H 6 uptake ratio (111.0%), C 3 H 8 Henry constant (2159.2 mmol g −1 bar −1 ), and separation potential (1943.0 mmol L -1 ) exceed those in porous adsorbents reported so far. Breakthrough experiments indicate that Ni(ADC)(TED) 0.5 can completely separate C 3 H 8 /C 3 H 6 mixture with the highest C 3 H 6 productivity (0.085 mmol g −1 ) and good regenerability. These results show that this material has great potential application in C 3 H 8 /C 3 H 6 separation.