Ionic Liquids as Fragrance Precursors: Smart Delivery Systems for Volatile Compounds

The low volatility of many ionic liquids (ILs) can be used to design a specific delivery system with a triggered release mechanism for volatile fragrances. We present two different strategies for IL-supported profragrance compounds based on common fragrance alcohols. When the fragrance was attached to the cation, its release was triggered by heat, while the fragrance attached to the anion was released under basic conditions. Selection of the counterion allowed not only control of the physical properties of the resulting compound but also addition of a second functionality. Our design strategy shows that the choice of the IL components can result in safe, biocompatible ionic profragrances suitable for applications such as topical nutraceutical or cosmetic formulations.