One‐Step Ethylene Purification from Ternary Mixtures in a Metal–Organic Framework with Customized Pore Chemistry and Shape

Adsorptive separation is an energy‐efficient technology for the separation of C2 hydrocarbons. However, it remains a critical problem to directly produce high‐purity C2H4 from ternary C2H2/C2H4/C2H6 mixtures by simultaneously trapping C2H2 and C2H6. Herein, we report the one‐step C2H4 purification from the ternary mixture by a metal–organic framework Zn(ad)(int) (ad=adeninate; int=isonicotinate). The material combines dense heterocyclic rings and accessible uncoordinated O atoms as strong binding sites for C2H6 and C2H2. Its spindle‐like cage exhibits an interesting shape matching with the targeted molecules, affording Zn(ad)(int) not only high separation selectivity for C2H6/C2H4 and C2H2/C2H4, but also excellent gas capacity. Breakthrough experiments show that polymer‐grade C2H4 can be separated from the ternary mixtures with a record productivity of 1.43 mmol g−1. In situ powder X‐ray diffraction and Fourier transform infrared spectrum analyses further provide deep insights into the separation mechanism. One‐step purification of C2H4 from ternary C2H2/C2H6/C2H4 mixtures is realized by a multifunctional MOF material via specific binding and shape matching. High adsorption selectivity and trapping capacity towards C2H6 and C2H2 are simultaneously realized, which permits the high‐efficient separation of C2H4 with a record productivity.