Boosting the C₂H₂/CO₂ Separation Performance of Metal-Organic Frameworks through Fluorine Substitution

Area of Science:

• Materials Science
• Chemistry
• Chemical Engineering

Background:

• Metal-organic frameworks (MOFs) are porous materials with tunable properties.
• Efficient separation of acetylene (C2H2) from carbon dioxide (CO2) is crucial for industrial processes.
• Fluorine incorporation into MOFs is an emerging strategy to modify their adsorption properties.

Purpose of the Study:

• To synthesize and characterize a fluorinated MOF, JXNU-15(F).
• To compare the acetylene/carbon dioxide separation performance of JXNU-15(F) with its non-fluorinated analog, JXNU-15.
• To investigate the role of fluorine substituents in enhancing gas separation capabilities.

Main Methods:

• Synthesis of JXNU-15 and JXNU-15(F) using benzene-1,3,5-tribenzoate (BTB) and fluorous 1,3,5-tri(3,5-bifluoro-4-carboxyphenyl)benzene (SFBTB) ligands, respectively.
• Single-component gas adsorption experiments.
• Dynamic gas mixture breakthrough experiments.
• Computational simulations to understand gas-framework interactions.

Main Results:

• JXNU-15(F) demonstrated higher acetylene uptake compared to JXNU-15.
• JXNU-15(F) exhibited enhanced adsorption selectivity for acetylene over carbon dioxide.
• Breakthrough experiments confirmed the superior C2H2/CO2 separation performance of JXNU-15(F).
• Computational simulations revealed that fluorine substituents critically influence C2H2-framework interactions.

Conclusions:

• Fluorine substitution is a powerful strategy for improving the acetylene/carbon dioxide separation ability of MOFs.
• JXNU-15(F) shows highly efficient performance for C2H2/CO2 separation.
• The study provides insights into the structure-property relationships governing gas separation in fluorinated MOFs.