An Ultramicroporous Metal-Organic Framework with Record High Selectivity for Inverse CO2/C2H2 Separation

Removal of CO2 to purify CO2/C2H2 mixtures through porous material is a more energy saving method compared with the traditional cryogenic distillation. Those CO2-selective adsorption porous materials are ideal for directly producing high-purity C2H2, especially allowing sieving separation with infinite selectivity but without sacrificing any uptake capacity. Here, we report an ultramicroporous metal–organic framework (MOF) [Cu(hfipbb)(H2hfipbb0.5)] (1), [H2hfipbb is 4,4′-(hexafluoroisopropylidene) bis(benzoic acid)] has been studied for inverse separation of CO2 from C2H2 under ambient conditions. This Cu-based MOF material was comprehensively demonstrated as an efficient CO2-selective adsorbent used for C2H2 purification by single-component adsorption isotherms, showing promise for industrial acetylene purification. An ultramicroporous Metal-Organic Frameworks (MOFs) composed of Cu(II) ions and 4,4′-(hexafluoroisopropylidene) bis(benzoic acid) linkers forming two-fold interpenetration gives an overall three-dimensional network featuring 1D zigzag pore channels. This MOF shows inverse adsorption of carbon dioxide over acetylene with a much higher CO2/C2H2 uptake ratio and high CO2/C2H2 selectivity.