Selective Acetylene Adsorption within an Imino-Functionalized Nanocage-Based Metal–Organic Framework

Removal of CH 4 and CO 2 from C 2 H 2 streams remains challenging in the chemical industry. Herein, a robust three-dimensional metal–organic framework, Cu–CPAH, was designed and synthesized through a hydrothermal method. Cu–CPAH exhibits highly selective C 2 H 2 adsorption capacity with respect to both CH 4 and CO 2, which is ascribed to the enrichment of active sites in the framework. Dynamic breakthrough results reveal that Cu–CPAH serves as a solid adsorbent for high-efficiency purification of C 2 H 2 from an equal proportion of C 2 H 2 /CO 2 or C 2 H 2 /CO 2 /CH 4 at room temperature. Discrete Fourier transform simulations confirm that various active sites preferentially interact with C 2 H 2 other than CO 2 and CH 4, signifying for the first time that the imino functional groups in the cage contribute greatly to the preferential affinity to C 2 H 2 over CO 2 and CH 4 .