A Molecular Compound for Highly Selective Purification of Ethylene.

Purification of C2H4 from an C2H4 /C2H6 mixture is one of the most challenging separation processes, which is achieved mainly through energy‐intensive, cryogenic distillation in industry. Sustainable, non‐distillation methods are highly desired as alternatives. We discovered that the fluorinated bis(pyrazolyl)borate ligand supported copper(I) complex {[(CF3)2Bp]Cu}3 has features very desirable in an olefin–paraffin separation material. It binds ethylene exclusively over ethane generating [(CF3)2Bp]Cu(C2H4). This molecular compound exhibits extremely high and record ideal adsorbed solution theory (IAST) C2H4 /C2H6 gas separation selectivity, affording high purity (>99.5 %) ethylene that can be readily desorbed from separation columns. In‐situ PXRD provides a "live" picture of the reversible conversion between [(CF3)2Bp]Cu(C2H4) and the ethylene‐free sorbent in the solid‐state, driven by the presence or removal of C2H4. Molecular structures of trinuclear {[(CF3)2Bp]Cu}3 and mononuclear [(CF3)2Bp]Cu(C2H4) are also presented. [ABSTRACT FROM AUTHOR]