Abstract
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.
Original language | English |
---|---|
Article number | 535 |
Number of pages | 15 |
Journal | Frontiers in Chemistry |
Volume | 6 |
DOIs | |
Publication status | Published - 12 Nov 2018 |
Fingerprint Dive into the research topics of 'Water-Tolerant Trifloaluminate Ionic Liquids: New and Unique Lewis Acidic Catalysts for the Synthesis of Chromane'. Together they form a unique fingerprint.
Student Theses
-
Ionic Liquids for Main Group Catalysis
Author: Brown, L., Jul 2020Supervisor: Holbrey, J. (Supervisor) & Swadzba-Kwasny, M. (Supervisor)
Student thesis: Doctoral Thesis › Doctor of Philosophy
File