Efficient ethylene purification by a robust ethane-trapping porous organic cage

Abstract The removal of ethane (C2H6) from its analogous ethylene (C2H4) is of paramount importance in the petrochemical industry, but highly challenging due to their similar physicochemical properties. It is still remaining unexploited to utilize emerging porous organic cage (POC) materials for C2H4/C2H6 separation. Herein, we report the benchmark example of a truncated octahedral calix[4]resorcinarene-based POC adsorbent (CPOC-301), preferring to adsorb C2H6 than C2H4, and thus can be used as a robust absorbent to directly separate high-purity C2H4 from the C2H4/C2H6 mixture. Molecular modelling studies suggest the exceptional C2H6 selectivity is due to the suitable resorcin[4]arene cavities in CPOC-301, which form more multiple C–H···π hydrogen bonds with C2H6 than with C2H4 guests. This work provides a fresh avenue to utilize POC materials for highly selective separation of industrially important hydrocarbons.