Separating ethylene (C 2 H 4 ) from the C 2 hydrocarbons is of prime industrial importance for the process of high-purity C 2 H 4 as an essential raw material in the petrochemical industry. Due to their similar physicochemical properties, the separation of C 2 H 4 from the C 2 hydrocarbons typically entails high-energy separation technologies such as cryogenic distillation and extraction. Alternatively, adsorption separation using metal-organic frameworks (MOFs) are low-energy separation technologies that manufacture high-purity gas under mild conditions. In this review, we summarized the recent advances in MOFs for the separation and purification of C 2 H 4 from the C 2 hydrocarbons. The mechanisms underlying separating C 2 H 4 from the C 2 hydrocarbons using MOFs are also highlighted. This review also discussed the major challenges and developments of MOFs to separate C 2 H 4 from the C 2 hydrocarbons.[a] W.

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The separation of acetylene (C2H2) from carbon dioxide (CO2) and the purification of ethylene (C2H4) from C2H2 are quite essential processes for the chemical industry. However, these processes are challenging due to their similar physical properties, including molecule sizes and boiling points. Herein, we report an N-rich cage-based microporous metal-organic framework (MOF), [Cd5(Tz)9](NO3) (termed as Cd-TZ, TZ stands for tetrazole), and its highly efficient separation of C2H2/CO2 and C2H2/C2H4. Single-component gas adsorption isotherms reveal that Cd-TZ exhibits high C2H2 adsorption capacity (3.10 mmol g-1 at 298 K and 1 bar). The N-rich cages in Cd-TZ can trap C2H2 with a higher isosteric heat of adsorption (40.8 kJ mol-1) than CO2 and C2H4 owing to the robust host-guest interactions between the noncoordinated N atoms and C2H2, which has been verified by molecular modeling studies. Cd-TZ shows a high IAST selectivity for C2H2/CO2 (8.3) and C2H2/C2H4 (13.3). The breakthrough simulations confirm the potential for separating C2H2/CO2 and the purification of C2H4 from C2H2.

Ethylene is a critical chemical raw material widely used in manufacturing and petrochemical fields. The adsorptive separation of ethylene from C2 hydrocarbon mixtures using metal‐organic frameworks to replace traditional high‐energy separation technologies is essential but challenging. This review highlights the C2hydrocarbon separation realized with MOF adsorbents. For more details, see the Review by W. Xie, L. Yang, J. Zhang, and Y. Zhao (DOI: 10.1002/chem.202300158).