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

Published

May 1, 2016

Author(s)

Zizhu Yao, Zhangjing Zhang, Lizhen Liu, Ziyin Li, Wei Zhou, Yunfeng Zhao, Yu Han, Banglin Chen, Rajamani Krishna, Shengchang Xiang

Abstract

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.

Citation

Chemistry-A European Journal

Volume

22

Pub Type

Journals

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Keywords

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)