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

Abstract

The separation of C₂ H₂ /CO₂ is not only industrially important for acetylene purification but also great scientific challenge due to their very similar molecular size and physical properties. To address this difficulty, herein, we present an ultramicroporous hydrogen-bonded organic framework (HOF-FJU-1) from tetracyano bicarbazole to separate C₂ H₂ from CO₂ by taking advantage of differences in their electrostatic potential distribution. This material possesses a suitable pore environment and electrostatic potential distribution fitting well to C₂ H₂ , thus showing extra strong affinity to C₂ H₂ (46.73 kJ mol^-1 ) and the highest IAST selectivity of 6675 for C₂ H₂ /CO₂ separation among the adsorbents reported. The single crystal X-ray diffraction reveals that the suitable pore environment in HOF-FJU-1 provides multiple C-H⋅⋅⋅π and hydrogen-bonded interactions N⋅⋅⋅H-C with C₂ H₂ molecules. Dynamic breakthrough experiments demonstrate its outstanding separation performance to C₂ H₂ /CO₂ mixtures.

Keywords: C2H2/CO2 Separation; Electrostatic Potential; Hydrogen-Bonded Organic Framework.