Abstract
Levulinic acid esters (LAEs) were synthesized from α-angelica lactone and alcohols, in a reaction catalyzed by a new family of chloride-free Lewis acidic ionic liquids, containing trifloaluminate anions, [Al(OTf)3+n]n−. Changing the catalyst from poorly soluble Al(OTf)3 (used as suspension) to fully homogeneous trifloaluminate ionic liquids resulted in shorter reaction times required for full α-AL conversion (60 min at 60 °C for 0.1 mol % catalyst loading) and unprecedented selectivities to LAEs, reaching >99%. Supporting the trifloaluminate ionic liquid on multiwalled carbon nanotubes gave an easily recyclable system, with no leaching observed over six cycles. Mechanistic considerations suggest that the propensity of Al(OTf)3 to undergo very slow hydrolysis results in the correct balance of Brønsted and Lewis acidic sites in the system, which inhibit byproduct formation.
| Original language | English |
|---|---|
| Pages (from-to) | 5184-5191 |
| Number of pages | 8 |
| Journal | ACS Sustainable Chemistry & Engineering |
| Volume | 7 |
| Issue number | 5 |
| Early online date | 08 Feb 2019 |
| DOIs | |
| Publication status | Published - 2019 |
Keywords
- Angelica lactone
- Carbon nanotubes
- Ionic liquids
- Levulinic acid esters
- Lewis acids
- Supported ionic liquid phase
- Trifloaluminate ionic liquids
ASJC Scopus subject areas
- General Chemical Engineering
- General Chemistry
- Renewable Energy, Sustainability and the Environment
- Environmental Chemistry
Access to Document
- Highly efficient synthesis of alkyl levulinates from a-angelica lactone, catalysed with Lewis acidic trifloaluminate ionic liquids supported on carbon nanotubes
© 2019 American Chemical Society. This work is made available online in accordance with the publisher’s policies. Please refer to any applicable terms of use of the publisher.