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 (C2H2) from ethylene (C2H4) and the separation of C2H2 from carbon dioxide (CO2), 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 (H3btb-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 C2H2 adsorption capacity (60.1 cm3 g-1 at 298 K and 100 kPa) and exhibits preferential adsorption for C2H2 over C2H4 and CO2. Ideal Adsorbed Solution Theory (IAST) selectivity calculations reveal values of 2.2 and 4.4 for equimolar C2H2/C2H4 and C2H2/CO2 mixtures at 298 K, respectively. Dynamic breakthrough experiments confirm its excellent practical separation performance, achieving the complete purification of C2H4 from C2H2 and efficient capture of C2H2 from CO2. Grand Canonical Monte Carlo simulations elucidate that the superior affinity for C2H2 originates from multiple specific host-guest interactions, including C-H···π and C-H···O contacts.