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

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.