A Rod-Packing Hydrogen-Bonded Organic Framework with Suitable Pore Confinement for Benchmark Ethane/Ethylene Separation.

Abstract

For the separation of ethane from ethylene, it remains challenging to target both high C2 H6 adsorption and selectivity in a C2 H6 -selective material. Herein, we report a reversible solid-state transformation in a labile hydrogen-bonded organic framework to generate a new rod-packing desolvated framework (ZJU-HOF-1) with suitable cavity spaces and functional surfaces to optimally interact with C2 H6 . ZJU-HOF-1 thus exhibits simultaneously high C2 H6 uptake (88 cm3 g-1 at 0.5 bar and 298 K) and C2 H6 /C2 H4 selectivity (2.25), which are significantly higher than those of most top-performing materials. Theoretical calculations revealed that the cage-like cavities and functional sites synergistically "match" better with C2 H6 to provide stronger multipoint interactions with C2 H6 than C2 H4 . In combination with its high stability and ultralow water uptake, this material can efficiently capture C2 H6 from 50/50 C2 H6 /C2 H4 mixtures in ambient conditions under 60 % RH, providing a record polymer-grade C2 H4 productivity of 0.98 mmol g-1 .