A novel cage-based metal-organic framework for efficient separation of light hydrocarbons

The development of effective physical adsorbents for the separation of light hydrocarbon gas mixtures is a challenging and prime step in the petrochemical industry. In this work, we designed and synthesized a novel cage-based metal-organic framework, SDU-CP-8, featuring an ellipsoid-shaped cage and a 3-nodal (4,6,8)-connected network. SDU-CP-8 displays remarkable adsorption capacities for C3H8 (148.9 cm3 g-1) and C2H6 (126.3 cm3 g-1), significantly higher than that for CH4 (16.6 cm3 g-1) at 273 K and 100 kPa, while the gas uptake value for C2H2 (116.1 cm3 g-1) is higher than that for CO2 (61.8 cm3 g-1) at 273 K and 100 kPa. Moreover, breakthrough experiments demonstrate that SDU-CP-8 can effectively separate C3H8/C2H6/CH4 and C2H2/CO2 gas mixtures. Theoretical calculations show that multiple interactions (C-H & ctdot;O and C-H & ctdot;pi) within the cage of SDU-CP-8 significantly contribute to the high gas uptake by the framework. These results show that SDU-CP-8 is a promising adsorbent for both CH4 and C2H2 purification. A novel 3D MOF, SDU-CP-8, features an ellipsoid-shaped cage and a 3-nodal, (4,6,8)-connected network. It demonstrates excellent adsorption and separation capabilities for C3H8/C2H6/CH4 and C2H2/CO2 gas mixtures.