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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]

Purifying alkenes from alkanes requires cryogenic distillation. This consumes energy equivalent to countries of ca. 5 million people. Replacing distillation with adsorption processes would significantly increase energy efficiency. Trade‐offs between kinetics, selectivity, capacity, and heat of adsorption have prevented production of an optimal adsorbent. We report adsorbents that overcome these trade‐offs. [Cu‐Br]3 and [Cu‐H]3 are air‐stable trinuclear complexes that undergo reversible solid‐state inter‐molecular rearrangements to produce dinuclear [Cu‐Br⋅(alkene)]2 and [Cu‐H⋅(alkene)]2. The reversible solid‐state rearrangement, confirmed in situ using powder X‐ray diffraction, allows adsorbent design trade‐offs to be overcome, coupling low heat of adsorption (−10 to −17 kJ mol−1alkene), high alkene:alkane selectivity (47; 29), and uptake capacity (>2.5 molalkene mol−1Cu3). Most remarkably, [Cu‐H]3 displays fast uptake and regenerates capacity within 10 minutes. [ABSTRACT FROM AUTHOR]

Titelbild: Overcoming Fundamental Limitations in Adsorbent Design: Alkene Adsorption by Non-porous Copper(I) Complexes (Angew. Keywords: adsorption; alkenes; copper; olefin separation; X-ray diffraction EN adsorption alkenes copper olefin separation X-ray diffraction 20897 20897 1 11/11/20 20201116 NES 201116 B Das Eisberg-Motiv b illustriert, wie H. V. R. Dias, M. G. Cowan et al. in ihrem Forschungsartikel auf S. 21187 Lösungschemie in einer Festkörperreaktion für die Trennung von Alkenen und Alkanen nutzen. Adsorption, alkenes, copper, olefin separation, X-ray diffraction. [Extracted from the article]