Adsorptive Separation of Acetylene from Ethylene in Isostructural Gallate‐Based Metal–Organic Frameworks

Abstract The separation of acetylene from ethylene is of paramount importance in the purification of chemical feedstocks for industrial manufacturing. Herein, an isostructural series of gallate‐based metal–organic frameworks (MOFs), M‐gallate (M=Ni, Mg, Co), featuring three‐dimensionally interconnected zigzag channels, the aperture size of which can be finely tuned within 0.3 Å by metal replacement. Controlling the aperture size of M‐gallate materials slightly from 3.69 down to 3.47 Å could result in a dramatic enhancement of C 2 H 2 /C 2 H 4 separation performance. As the smallest radius among the studied metal ions, Ni‐gallate exhibits the best C 2 H 2 /C 2 H 4 adsorption separation performance owing to the strongest confinement effect, ranking after the state‐of‐the‐art UTSA‐200a with a C 2 H 4 productivity of 85.6 mol L −1 from 1:99 C 2 H 2 /C 2 H 4 mixture. The isostructural gallate‐based MOFs, readily synthesized from inexpensive gallic acid, are demonstrated to be a new top‐performing porous material for highly efficient adsorption of C 2 H 2 from C 2 H 4 .