Microporous Metal–Organic Framework with Dual Functionalities for Efficient Separation of Acetylene from Light Hydrocarbon Mixtures

Abstract

Separating acetylene from light hydrocarbon mixtures like ethylene is a very important process for downstream industrial applications. Herein, we report a new MOF [CuL₂(SiF₆)] (UTSA-220, L = (1<i>E</i>,2<i>E</i>)-1,2-bis(pyridin-4-ylmethylene)hydrazine) with dual functionalities featuring optimal pore size with strong binding sites for acetylene. UTSA-220 exhibits apparently higher uptake capacity for C₂H₂ than those for other light hydrocarbons. The potential of this material for trace C₂H₂ removal from C₂H₄ has also been demonstrated by a dynamic breakthrough experiment performed with C₂H₂/C₂H₄ (1/99 v/v) under simulated industrial conditions. According to the dispersion-corrected density functional theory (DFT-D) simulation, SiF₆ ^2- and azine moieties serve as preferential binding sites for C₂H₂, indicating the feasibility of the dual functionalities incorporated in UTSA-220 for adsorbent-based C₂H₂ separations.