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

Abstract

Abstract 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.