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.