Water-Tolerant Trifloaluminate Ionic Liquids: New and Unique Lewis Acidic Catalysts for the Synthesis of Chromane
| Autor: | Natalia Barteczko, Sławomir Boncel, Małgorzata Swadźba-Kwaśny, Anna Chrobok, Lucy C. Brown, Peter Nockemann, Alice Culkin, Sebastian Jurczyk, Piotr Latos |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
carbon nanotubes
010405 organic chemistry metal triflates General Chemistry Nuclear magnetic resonance spectroscopy 010402 general chemistry 01 natural sciences Acceptor 0104 chemical sciences Catalysis lcsh:Chemistry Chemistry chemistry.chemical_compound chromane lcsh:QD1-999 chemistry trifloaluminate ionic liquids Polymer chemistry Ionic liquid Chromane Lewis acids and bases SILP Trifluoromethanesulfonate Isoprene Original Research |
| Zdroj: | Latos, P, Culkin, A, Barteczko, N, Boncel, S, Jurczyk, S, Brown, L, Nockemann, P, Chrobok, A & Swadzba-Kwasny, M 2018, ' Water-Tolerant Trifloaluminate Ionic Liquids: New and Unique Lewis Acidic Catalysts for the Synthesis of Chromane ', Frontiers in Chemistry, vol. 6, 535 . https://doi.org/10.3389/fchem.2018.00535 Frontiers in Chemistry, Vol 6 (2018) Frontiers in Chemistry |
| DOI: | 10.3389/fchem.2018.00535 |
| Popis: | The first example of triflometallate ionic liquids, named in analogy to chlorometallate ionic liquids, is reported. Trifloaluminate ionic liquids, synthesised from 1-alkyl-3-methylimidazolium triflates and aluminium triflate, were characterised by multinuclear NMR spectroscopy and FT-IR spectroscopy, revealing the existence of oligonuclear, multiply-charged trifloaluminate anions, with multiple bridging triflate modes. Acceptor numbers were determined to quantify their Lewis acidity, rendering trifloaluminate ionic liquids as medium-strength Lewis acids (AN = ca. 65). Used as acidic catalysts in the cycloaddition of 2,4-dimethylphenol and isoprene (molar ratio 2:1) to prepare chromane, trifloaluminate systems outperformed literature systems, showing high activity (conversions 94-99%, selectivities 80-89%) and at low loadings (0.2 mol%) at 35 °C. Using these new systems as supported ionic liquid phase (SILP) on multi-walled carbon nanotubes (ionic liquid loading 16 wt%) delivered a recyclable catalytic system, with activity enhanced with respect to the homogenous regime. |
| Databáze: | OpenAIRE |
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