CH4/CO2 and CH4/C2H6 gas separation using a flexible one-dimensional copper(II) porous coordination polymer

Abstract

Porous coordination polymers (PCPs) that show a gate-type adsorption originating from structural flexibility represent a new concept for developing gas separation materials. Here, the gas adsorption and separation properties of a flexible one-dimensional (1D) copper(II) PCP, [Cu(BF4)2(1,3-bis(4-pyridyl)propane)2]n, were evaluated. The single-gas adsorption isotherms revealed different gate-opening pressures for CO2 and C1∼C4 linear alkanes, suggesting great possibility for the separation of mixtures of these gases. The gas separation properties were characterized by performing breakthrough experiments at ambient temperature using CH4/CO2 and CH4/C2H6 mixtures. The results demonstrated the practical utility of 1D PCPs in gas separation applications. Single-crystal X-ray diffraction analysis demonstrated high structural adjustability for the incorporation of a variety of guest molecules.