One-step ethylene production from a four-component gas mixture by a single physisorbent.

One-step adsorptive purification of ethylene (CH) from four-component gas mixtures comprising acetylene (CH), ethylene (CH), ethane (CH) and carbon dioxide (CO) is an unmet challenge in the area of commodity purification. Herein, we report that the ultramicroporous sorbent Zn-atz-oba (Hoba = 4,4-dicarboxyl diphenyl ether; Hatz = 3-amino-1,2,4-triazole) enables selective adsorption of CH, CH and CO over CH thanks to the binding sites that lie in its undulating pores. Molecular simulations provide insight into the binding sites in Zn-atz-oba that are responsible for coadsorption of CH, CH and CO over CH. Dynamic breakthrough experiments demonstrate that the selective binding exhibited by Zn-atz-oba can produce polymer-grade purity (>99.95%) CH from binary (1:1 for CH/CH), ternary (1:1:1 for CH/CH/CH) and quaternary (1:1:1:1 for CH/CH/CH/CO) gas mixtures in a single step.