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

Separation of propyne/propylene (C 3 H 4 /C 3 H 6 ) is more difficult and challenging than that of acetylene/ethylene (C 2 H 2 /C 2 H 4 ) 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 C 3 H 4 from C 3 H 4 /C 3 H 6 mixtures. Gas sorption isotherms reveal that UTSA‐200 exhibits by far the highest C 3 H 4 adsorption capacity (95 cm 3 cm −3 at 0.01 bar and 298 K) and record C 3 H 4 /C 3 H 6 selectivity, which was mainly attributed to the suitable dynamic pore size to efficiently block the larger C 3 H 6 molecule whilst the strong binding sites and pore flexibility capture smaller C 3 H 4 . This material thus provides record purification capacity for the removal of C 3 H 4 from a 1:99 (or 0.1:99.9, v/v) C 3 H 4 /C 3 H 6 mixture to produce 99.9999 % pure C 3 H 6 with a productivity of 62.0 (or 142.8) mmol g −1 .