Construction of Octadentate Carboxylate‐Based Metal–Organic Framework for Effective Acetylene Purification

ABSTRACT The development of high‐performance acetylene (C 2 H 2 ) adsorbents remains challenging, primarily due to the mutual repulsion between their adsorption capacity and selectivity. To address this challenge, we propose introducing multiple host‐guest interaction sites into an octadentate carboxylate‐based metal–organic framework (MOF, Cu‐ETTB) featuring elevated specific surface area and substantial pore dimensions, achieved through the implementation of a polyaromatic octatopic carboxylic acid linker (H 8 ETTB). Due to its dense aromatic rings and carboxylate oxygen sites, the obtained Cu‐ETTB framework exhibits excellent C 2 H 2 adsorption capacity (108 cm 3 g −1 ) and equimolar C 2 H 2 /CO 2 selectivity (19.2) under ambient conditions (298 K, 1 bar). Breakthrough experiments confirm a dynamic C 2 H 2 adsorption capacity reaching 84.4 cm 3 g −1 for C 2 H 2 /CO 2 segregation. Grand Canonical Monte Carlo (GCMC) simulations reveal that aromatic rings and oxygen sites within Cu‐ETTB selectively capture C 2 H 2 via framework‐C 2 H 2 interactions and C 2 H 2 –C 2 H 2 intermolecular interactions, while effectively excluding CO 2 . Furthermore, the Cu‐ETTB adsorbent exhibits robust thermal/chemical stability and outstanding recyclability, holding great promise for practical separation processes. This study provides new insights for designing MOF‐based adsorbents with tailored functionality, enabling the selective capture of target gases for efficient purification.