Regulating the Dynamics of Interpenetrated Porous Frameworks for Inverse C2H6/C2H4 Separation at Elevated Temperature

Abstract

Selective adsorption of ethane (C2H6) from mixtures containing ethylene (C2H4) is of interest for the direct production of high purity C2H4. However, the extremely similar molecular properties of these gases make this process challenging, particularly at elevated temperatures, an implication of saved energy consumption. To address such challenge, we present a new approach for regulating the temperature-dependent dynamics in hydrogen-bonded interpenetrated frameworks. As a single H-bond linked interpenetrated porous framework, NTU-101-NH2 exhibits emerging structural dynamics in response to C2H6 (37 kPa) and C2H4 (53 kPa) and has shown a record ability to produce polymer-grade C2H4 (15.7 mL g-1) at 328 K, as the shifting of the interpenetrated frameworks here requires a relatively weak stimulus, allowing the optimization of adsorption at a higher temperatures range. Meanwhile, the robust and conveniently prepared NTU-101-NH2 shows good cyclic separation performance. In comparison, the framework response of the percussor NTU-101, connected by three H-bonds, occurs at 293 K and has a moderate separation ability (10.2 mL g-1). This work showcases the first adsorbent for direct C2H4 purification at elevated temperatures, and the insights into the hydrogen-bonded frameworks will pave the way for designing soft families capable of challenging separations with reduced energy requirements.