An Ultramicroporous Hydrogen-Bonded Organic Framework Exhibiting High C₂ H₂ /CO₂ Separation

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Separating acetylene (C2H2) from carbon dioxide (CO2) is crucial for industrial acetylene purification.
• The similar molecular size and properties of C2H2 and CO2 present a significant separation challenge.

Purpose of the Study:

• To develop a novel material for efficient C2H2/CO2 separation.
• To investigate the separation mechanism based on molecular interactions and electrostatic potential.

Main Methods:

• Synthesis of an ultramicroporous hydrogen-bonded organic framework (HOF-FJU-1) from tetracyano bicarbazole.
• Characterization using single crystal X-ray diffraction.
• Gas adsorption and dynamic breakthrough experiments for separation performance evaluation.

Main Results:

• HOF-FJU-1 demonstrates a high affinity for C2H2 (46.73 kJ/mol) due to its pore environment and electrostatic potential.
• Achieved the highest reported IAST selectivity of 6675 for C2H2/CO2 separation.
• X-ray diffraction revealed multiple C-H···π and N···H-C interactions facilitating C2H2 adsorption.

Conclusions:

• HOF-FJU-1 is a highly effective adsorbent for C2H2/CO2 separation.
• The material's unique pore structure and interactions enable selective acetylene capture.
• Demonstrated outstanding performance in dynamic breakthrough experiments for gas mixture separation.