Water-Tolerant Trifloaluminate Ionic Liquids: New and Unique Lewis Acidic Catalysts for the Synthesis of Chromane

Piotr Latos; Alice Culkin; Natalia Barteczko; Slawomir Boncel; Sebastian  Jurczyk; Lucy Brown; Peter Nockemann; Anna Chrobok; Malgorzata Swadzba-Kwasny

doi:10.3389/fchem.2018.00535

Water-Tolerant Trifloaluminate Ionic Liquids: New and Unique Lewis Acidic Catalysts for the Synthesis of Chromane

Piotr Latos, Alice Culkin, Natalia Barteczko, Slawomir Boncel, Sebastian Jurczyk, Lucy Brown, Peter Nockemann, Anna Chrobok, Malgorzata Swadzba-Kwasny

Research output: Contribution to journal › Article

3 Citations (Scopus)

148 Downloads (Pure)

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	https://doi.org/10.3389/fchem.2018.00535
Publication status	Published - 12 Nov 2018

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Water-Tolerant Trifloaluminate Ionic Liquids: New and Unique Lewis Acidic Catalysts for the Synthesis of Chromane
Copyright 2018 the authors. This is an open access article published under a Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited.
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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, 6, [535]. https://doi.org/10.3389/fchem.2018.00535

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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.",

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Water-Tolerant Trifloaluminate Ionic Liquids: New and Unique Lewis Acidic Catalysts for the Synthesis of Chromane. / Latos, Piotr; Culkin, Alice; Barteczko, Natalia; Boncel, Slawomir; Jurczyk, Sebastian ; Brown, Lucy; Nockemann, Peter; Chrobok, Anna; Swadzba-Kwasny, Malgorzata.

In: Frontiers in Chemistry, Vol. 6, 535, 12.11.2018.

Research output: Contribution to journal › Article

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