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

The removal of ethane (C(2)H(6)) from its analogous ethylene (C(2)H(4)) is of paramount importance in the petrochemical industry, but highly challenging due to their similar physicochemical properties. The use of emerging porous organic cage (POC) materials for C(2)H(6)/C(2)H(4) separation is still in its infancy. Here, we report the benchmark example of a truncated octahedral calix[4]resorcinarene-based POC adsorbent (CPOC-301), preferring to adsorb C(2)H(6) than C(2)H(4), and thus can be used as a robust absorbent to directly separate high-purity C(2)H(4) from the C(2)H(6)/C(2)H(4) mixture. Molecular modelling studies suggest the exceptional C(2)H(6) selectivity is due to the suitable resorcin[4]arene cavities in CPOC-301, which form more multiple C–H···π hydrogen bonds with C(2)H(6) than with C(2)H(4) guests. This work provides a fresh avenue to utilize POC materials for highly selective separation of industrially important hydrocarbons.