Interpenetration-Constructed Amide-Functionalized MOF for Selective C2H2/CO2 Separation.

Acetylene (C2H2) purification plays a vital role in various chemical syntheses and industrial processes, yet the fabrication of ideal MOF adsorbents for C2H2 still remains challenging. Herein, a doubly interpenetrated metal-organic framework (Zn-btcb-dmtrz) was solvothermally synthesized from 4,4',4″-((benzene-1,3,5-tricarbonyl)tris(azanediyl))tribenzoic acid (H3btcb), 3,5-dimethyl-1,2,4-triazole (dmtrz), and Zn(NO3)2·6H2O. The interpenetrated framework integrates a high Brunauer-Emmett-Teller (BET) surface area (1015 m2/g) with densely packed amide groups, which endows the material with great capability to distinguish C2H2 from CO2. GCMC simulations confirmed the different spatial distributions of the two gas molecules: C2H2 interacts with -CONH- groups via C-H···O and C-H···N bonds, whereas CO2 forms C-H···O and N-H···O hydrogen bonds with benzene rings and -CONH- moieties. IAST calculations further showed that Zn-btcb-dmtrz delivers a C2H2 /CO2 (50/50) separation selectivity of 2.6 at 298 K and 100 kPa.