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Extraordinary Separation of Acetylene-Containing Mixtures with Microporous Metal-Organic Frameworks with Open O Donor Sites and Tunable Robustness through Control of the Helical Chain Secondary Building Units
Acetylene separation is a very important but challenging industrial separation task. Here, through solvothermal reaction of CuI and 5-triazole isophthalic acid in various solvents, two metal-organic frameworks (MOFs, FJU-21 and FJU-22) with open O donor sites and controllable robustness have been obtained for acetylene separation. They contain the same paddle-wheel Cu2(COO2)4} nodes and metal-ligand connection mode, but with different helical chains as secondary building units (SBUs), leading to different structural robustness for the MOFs. FJU-21 and FJU-22 are the first examples in which the MOFs' robustness is controlled by adjusting the helical chains SBUs. Good robustness gives the activated FJU-22a with higher surface area and gas uptakes than the flexible FJU-21a. Importantly, FJU-22a shows extraordinary separation of acetylene mixtures under ambient conditions. The separation capacity of FJU-22a for 50:50 C2H2/CO2 mixtures is about twice that of the high-capacity HOF-3; and its actual separation selectivity for C2H2/C2H4 mixtures containing 1% acetylene is the highest among the reported porous materials. Based on the first-principles calculations, the extraordinary separation performance of C2H2 for FJU-22a was attributed to hydrogen bonding interactions between the C2H2 molecules with the open O donors on the wall, which provide better recognition ability for C2H2 than other functional sites, including the open metal sites (OMS) and amino groups.
metal organic frameworks, column breakthrough, open O donors, structural diversity, selective gas adsorption
Citation
Yao, Z.
, Zhang, Z.
, Liu, L.
, Li, Z.
, Zhou, W.
, Zhao, Y.
, Han, Y.
, Chen, B.
, Krishna, R.
and Xiang, S.
(2016),
Extraordinary Separation of Acetylene-Containing Mixtures with Microporous Metal-Organic Frameworks with Open O Donor Sites and Tunable Robustness through Control of the Helical Chain Secondary Building Units, Chemistry-A European Journal, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=920520
(Accessed October 12, 2025)