Synthesis of a partially fluorinated ZIF-8 analog for ethane/ethene separation. Issue 39 (25th September 2017)

• Record Type: Journal Article
• Authors: Mondal, Suvendu Sekhar; Hovestadt, Maximilian; Dey, Subarna; Paula, Carolin; Glomb, Sebastian; Kelling, Alexandra; Schilde, Uwe; Janiak, Christoph; Hartmann, Martin; Holdt, Hans-Jürgen
• Is Part Of: CrystEngComm. Volume 19:Issue 39(2017)
• Page Start: 5882
• Page End: 5891
• Publication Date: 2017-09-25
• Subjects: Crystals -- Periodicals; Crystal growth -- Periodicals; Crystallography -- Periodicals; Cristaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Cristallographie -- Périodiques; 548
• DOI: 10.1039/c7ce01438d
• Languages: English
• ISSNs: 1466-8033

Abstract

Abstract : ZIF-318, isostructural to ZIF-8 but built from the mixed linkers of 2-methylimidazole and 2-trifluoromethylimidazole can be activated for gases sorption and the separation of ethane/ethene mixtures. Abstract : The separation of ethane/ethene mixtures (as well as other paraffin/olefin mixtures) is one of the most important but challenging processes in the petrochemical industry. In this work, we report the synthesis of ZIF-318, isostructural to ZIF-8 but built from the mixed linkers of 2-methylimidazole (L1) and 2-trifluoromethylimidazole (L2) (ZIF-318 = [(Zn(L1)(L2)] n ). The synthesis has been optimized to proceed without ZnO-formation. Using only the L2 linker under solvothermal conditions afforded ZnO-embedded in the H-bonded and non-porous coordination polymer ZnO@[Zn2 (L2)2 (HCOO)(OH)] n . The slight differences in the size of the substituents (–CH3 vs. –CF3 ) possibly in combination with different electronic inductive effects led to small but significant changes to the pore size and properties respectively, though the effective pore opening (aperture) size of ZIF-318 remained the same in comparison with ZIF-8. ZIF-318 is chemically (boiling water, methanol, benzene, and wide pH range at room temperature for 1 day), thermally (up to 310 °C) stable, and more hydrophobic than ZIF-8 which is proven by contact angle measurement. ZIF-318 can be activated for N2, CO2, CH4, H2, ethane, ethane, propane, and propene gases sorptions. Consequently, in breakthrough experiments, the ethane/ethene mixtures can be separated.