Microwave-Assisted Partial Hydrogenation of Citral by using Ionic Liquid-Coated Porous Glass Catalysts
✍ Scribed by Thomas Gallert; Martin Hahn; Dr. Martin Sellin; Dr. Christine Schmöger; Dr. Achim Stolle; Prof. Dr. Bernd Ondruschka; Dr. Thomas F. Keller; Prof. Dr. Klaus D. Jandt
- Book ID
- 102130741
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 2011
- Tongue
- English
- Weight
- 454 KB
- Volume
- 4
- Category
- Article
- ISSN
- 1864-5631
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✦ Synopsis
Abstract
The microwave‐assisted hydrogenation of citral (3,7‐dimethylocta‐2,6‐dienal) to citronellal with molecular hydrogen as the reducing agent was investigated. Several polar and non‐polar solvents were screened and imidazolium‐based ionic liquids were applied as modifiers for the palladium‐containing porous glass catalysts (Pd/TP). The best results were obtained with N‐ethyl‐N’‐methylimidazolium dicyanamide, N‐ethyl‐N’‐methylimidazolium acetate, or N‐ethyl‐N’‐methylimidazolium trifluoroacetate, which were used to prepare supported catalysts with an ionic liquid layer (SCILL) on Pd/TP by wet‐impregnation. The influence of pressure and temperature when using these ionic liquid‐containing catalysts, as well as their long‐term stabilities, were examined. Working with microwave‐assisted heating, high yields of citronellal were achieved under mild conditions within short reaction times. Catalyst characterization was carried out by means of BET measurements, X‐ray photoelectron spectroscopy (XPS) and thermo‐gravimetric analyses. The influences of the ionic liquid layer were derived from experiments carried out before and after the reactions.