A Metal-Organic Framework with Suitable Pore Size and Specific Functional Sites for the Removal of Trace Propyne from Propylene

Separation of propyne/propylene (C₃H₄/C₃H₆) is more difficult and challenging than that of acetylene/ethylene (C₂H₂/C₂H₄) because of their closer molecular sizes. A comprehensive screening of a series of metal–organic frameworks with broad types of structures, pore sizes, and functionalities was carried out. UTSA‐200 was identified as the best separating material for the removal of trace C₃H₄ from C₃H₄/C₃H₆ mixtures. Gas sorption isotherms reveal that UTSA‐200 exhibits by far the highest C₃H₄ adsorption capacity (95 cm³ cm⁻³ at 0.01 bar and 298 K) and record C₃H₄/C₃H₆ selectivity, which was mainly attributed to the suitable dynamic pore size to efficiently block the larger C₃H₆ molecule whilst the strong binding sites and pore flexibility capture smaller C₃H₄. This material thus provides record purification capacity for the removal of C₃H₄ from a 1:99 (or 0.1:99.9, v/v) C₃H₄/C₃H₆ mixture to produce 99.9999 % pure C₃H₆ with a productivity of 62.0 (or 142.8) mmol g⁻¹.