6533b855fe1ef96bd12b0923
RESEARCH PRODUCT
Water-Tolerant Trifloaluminate Ionic Liquids: New and Unique Lewis Acidic Catalysts for the Synthesis of Chromane
Natalia BarteczkoSławomir BoncelMałgorzata Swadźba-kwaśnyAnna ChrobokLucy C. BrownPeter NockemannAlice CulkinSebastian JurczykPiotr Latossubject
carbon nanotubes010405 organic chemistrymetal triflatesGeneral ChemistryNuclear magnetic resonance spectroscopy010402 general chemistry01 natural sciencesAcceptor0104 chemical sciencesCatalysislcsh:ChemistryChemistrychemistry.chemical_compoundchromanelcsh:QD1-999chemistrytrifloaluminate ionic liquidsPolymer chemistryIonic liquidChromaneLewis acids and basesSILPTrifluoromethanesulfonateIsopreneOriginal Researchdescription
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.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2018-11-01 |