A Copper-Based Metal-Organic Framework for Selective Separation of C2 Hydrocarbons from Methane at Ambient Conditions: Experiment and Simulation.

C2 hydrocarbon separation from methane represents a technological challenge for natural gas upgrading. Herein, we report a new metal-organic framework, [CuL(DEF)]·2DEF (; HL = 4,4',4″,4‴-((1,1',1″,1‴)-benzene-1,2,4,5-tetrayltetrakis(ethene-2,1-diyl))tetrabenzoic acid; DEF = ,-diethylformamide; UNT = University of North Texas). The linker design will potentially increase the surface area and adsorption energy owing to π(hydrocarbon)-π(linker)/M interactions, hence increasing C2 hydrocarbon/CH separation. Crystallographic data unravel an topology for , whereby [Cu(COO)]···[L] paddle-wheel units afford two-dimensional porous sheets. Activated exhibits moderate porosity with an experimental Brunauer-Emmett-Teller (BET) surface area of 480 m g (vs 1868 m g from the crystallographic data). exhibits considerable C2 uptake capacity under ambient conditions vs CH. GCMC simulations reveal higher isosteric heats of adsorption () and Henry's coefficients () for vs related literature MOFs. Ideal adsorbed solution theory yields favorable adsorption selectivity of for equimolar CH/CH gas mixtures, attaining 31.1, 11.9, and 14.8 for equimolar mixtures of CH/CH, CH/CH, and CH/CH, respectively, manifesting efficient C2 hydrocarbon/CH separation. The highest C2 uptake and being for ethane are also desirable technologically; it is attributed to the greatest number of "agostic" or other dispersion C-H bond interactions (6) vs 4/2/4 for ethylene/acetylene/methane.