One Porous Metal–Organic Framework Containing Multinuclear Clusters and Functional Groups for Purification of Acetylene and Ethylene

For the critical yet challenging industrial processes of the selective removal of trace acetylene (C 2 H 2 ) from ethylene (C 2 H 4 ) and the separation of C 2 H 2 from carbon dioxide (CO 2 ), we herein report the rational design and synthesis of a novel hydroxy-functionalized Zn(II)-based metal–organic framework, Zn-btb–OH, constructed from a custom-designed ligand, 1,3,5-tri(4-carboxyphenyl)benzene (H 3 btb–OH). Zn-btb–OH features a unique interwoven architecture comprising open channels with flattened cage-like cavities and accessible −OH groups and demonstrates a high C 2 H 2 adsorption capacity (60.1 cm 3 g –1 at 298 K and 100 kPa) and exhibits preferential adsorption for C 2 H 2 over C 2 H 4 and CO 2 . Ideal Adsorbed Solution Theory (IAST) selectivity calculations reveal values of 2.2 and 4.4 for equimolar C 2 H 2 /C 2 H 4 and C 2 H 2 /CO 2 mixtures at 298 K, respectively. Dynamic breakthrough experiments confirm its excellent practical separation performance, achieving the complete purification of C 2 H 4 from C 2 H 2 and efficient capture of C 2 H 2 from CO 2 . Grand Canonical Monte Carlo simulations elucidate that the superior affinity for C 2 H 2 originates from multiple specific host–guest interactions, including C–H···π and C–H···O contacts.