Synergistic sorbent separation for one-step ethylene purification from a four-component mixture

Abstract

Purification of ethylene (C₂H₄), the largest-volume product of the chemical industry, currently involves energy-intensive processes such as chemisorption (CO₂ removal), catalytic hydrogenation (C₂H₂ conversion), and cryogenic distillation (C₂H₆ separation). Although advanced physisorbent or membrane separation could lower the energy input, one-step removal of multiple impurities, especially trace impurities, has not been feasible. We introduce a synergistic sorbent separation method for the one-step production of polymer-grade C₂H₄ from ternary (C₂H₂/C₂H₆/C₂H₄) or quaternary (CO₂/C₂H₂/C₂H₆/C₂H₄) gas mixtures with a series of physisorbents in a packed-bed geometry. We synthesized ultraselective microporous metal-organic materials that were readily regenerated, including one that was selective for C₂H₆ over CO₂, C₂H₂, and C₂H₄.