Molecular Sieving of Acetylene from Ethylene in a Rigid Ultra‐microporous Metal Organic Framework.

Rigid molecular sieving materials are the ideal candidates for gas separation (e. g., C 2 H 2 /C 2 H 4 ) due to their ultrahigh adsorption selectivity and the absence of gas co‐adsorption. However, the absolute molecular sieving effect for C 2 H 2 /C 2 H 4 separation has rarely been realized because of their similar physicochemical properties. Herein, we demonstrate the absolute molecular sieving of C 2 H 2 from C 2 H 4 by a rigid ultra‐microporous metal‐organic framework ( F−PYMO−Cu ) with 1D regular channels (pore size of ca. 3.4 Å). F−PYMO−Cu exhibited moderate acetylene uptake (35.5 cm 3 /cm 3 ), but very low ethylene uptake (0.55 cm 3 /cm 3 ) at 298 K and 1 bar, yielding the second highest C 2 H 2 /C 2 H 4 uptake ratio of 63.6 up to now. One‐step C 2 H 4 production from a binary mixture of C 2 H 2 /C 2 H 4 and a ternary mixture of C 2 H 2 /CO 2 /C 2 H 4 at 298 K was achieved and verified by dynamic breakthrough experiments. Coupled with excellent thermal and water stability, F−PYMO−Cu could be a promising candidate for industrial C 2 separation tasks.