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Removal of trace propylene (C3H4) from propylene/propyne (C3H4/C3H6) mixtures is more complicated and challenging than that of acetylene/ethylene (C2H2/C2H4) in view of their closer molecular sizes and physical properties. Research on C3H4C3H6 separation, to certain extent, lags behind that on C2H2/C2H4 mixtures, and still remains a great challenge to target ideal porous materials for this separation. Herein, we carry out a comprehensive screening of large amount of metal-organic frameworks (MOFs) with broad types of structures, pore sizes and functionalities, and identify [Cu9azpy)2(SiF6)]n (UTSA-200, azpy = 4,4'-azopyridine) as the best separating material for deep removal of trace C3H4 from C3H4/C3H6 mixtures. Gas sorption isotherms reveal that UTSA-200 exhibits by far the highest reported C3H4 adsorption capacity (95 cm3 cm^-3^ under 0.01 bar and 298 K) and the record C3H4/C3H6 molecule while remaining the strong binding sites for ultrastrong, computational and neutron powder diffraction (NPD) studies. This material thus provides a record purification capacity for removal of trace C3H4 from a 1/99 (or 0.1/99.9) C3Hd4^/C3H6 mixture to produce 99.9999% pure C3H6 with a productivity of 62.0 (or 142.8) mmol g^-1^ per cycle, as revealed by experimental breakthrough curves.
Li, L.
, Wen, H.
, He, C.
, Lin, R.
, Krishna, R.
, Wu, H.
, Zhou, W.
, Li, J.
and Chen, B.
(2018),
A Metal?Organic Framework with Suitable Pore Size and Specific Functional Site for the Removal of Trace Propyne from Propylene, Angewandte Chemie-International Edition, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=926472
(Accessed October 20, 2025)