A Copper-Based Metal-Organic Framework for C2H2/CO2 Separation

A copper-based metal-organic framework, [Cu-2(PBTDA)(H2O)(2)] (UTSA-98, UTSA = the University of Texas at San Antonio; H(4)PBTDA = 5',5''''-(1,4-phenylene)bis-([1,1':3',1 ''-terphenyl]-4,4 ''-dicarboxylic acid)), has been solvothermally synthesized. The alternative connection of classical dicopper secondary building units and deprotonated four-branched PBTDA(4-) ligands led to the formation of the three-dimensional framework of UTSA-98 with one-dimensional rhombic channels. Its guest-free phase, UTSA-98a, uptakes much more C2H2 (82.6 cm(3)/g) than CO2 (40.3 cm(3)/g) at 298 K and 100 kPa, resulting in a high adsorption selectivity of 5.2. Furthermore, the efficient separation ability of UTSA-98a toward the C2H2/CO2 gas mixture was further verified by laboratory-scale fixed-bed breakthrough experiments.