Introduction
Due to their low vapor pressure and tunable solubility ionic liquids are interesting solvents for applications in the field of separations. The polarity of ionic liquids is typically in the range of short chain alcohols or aprotic solvents such as DMSO or DMF. In recent years good selectivities towards some chemicals have been described in literature. As a consequence several applications have been developed in the fields
- Metal extraction
- Deep desulfurization
- Extraction of organic compounds
- Natural product extraction
IOLITEC collected a large number of portioning coefficients for selected systems in its data base. If you are interested in further information, please contact us.
The importance of this subject reflects in the fact that the first conference on separation technology using ionic liquids (www.ilsept.com) was held in 2011. A good overview on this topic can be found in “Ionic Liquids in Synthesis” by Peter Wasserscheid and Tom Welton. [i]
Metal extraction
The extraction of metals from different sources will play an important role in times of depleting resource. Selected ionic liquids show a high extraction capacity for some metal ions which will make these ionic liquids interesting solvents for
- Waste water treatment
- Extraction of precious metals and
- Extraction of rare earth metals
(You can find an article about extration of rare earth materials from bauxite by an ionic liquid here.)
If you are interested in this subject, please contact us.
Deep Desulfurization
Deep desulfurization does not only focus on the extraction of molecular sulfur from crude oil downstream products but also the extraction of sulfur containing organic compounds such as thiophene, aliphatic thiols and many more. Many research focused on this subject in the past 10 years and several ionic liquids have been described to be efficient solvents for the removal of sulfur and sulfur compounds from the aliphatic phase.
If you are interested in further information on this topic, please contact us.
Extraction of organic molecules
Many solvents show only limited miscibility with ionic liquids. This allows ionic liquids not only to be alternative solvents in synthesis but also allows ionic liquids in liquid-liquid extractions of organic compounds
The low solubility of water in some hydrophobic ionic liquids allows applications in areas where volatile organic compounds (VOCs) are still in use. In contrast to these ionic liquids show a much lower vapor pressure which is an important issue with respect to emission and resource efficiency since ionic liquids can easily be recycled.
For many organic compounds partitioning coefficients have been published and IOLITEC has collected those data in the company database. We would be glad to share these information on request.
An overview of miscibilities of ionic liquids with common solvents can be found in this presentation (ILSEPT, Sitges/Spanien, 05.-07.09.2011).
The extraction of oil or tar sand by IL is demonstrated in this video (Penn State University):
http://www.youtube.com/watch?v=sGDKxlW1ZoQ&feature=related
Natural product extraction
The extraction of fragrances like orange oil from orange peel using ionic liquids was recently described by Rogers et al. [ii]. They were able to extract about 5% orange oil from the peel and could show by GC-MS that the major component of the extract was the valuable fragrance limonene.
If you are interested in the extraction of natural products using ionic liquids, please contact us.
Text: Dr. Thomas J. S. Schubert, IOLITEC GmbH, 2011. (German Version; English Translation: Dr. Tom Beyersdorff, IOLITEC Inc.)
[IV B]
[i] P. Wasserscheid, T. Welton, “Ionic Liquids in Synthesis”, Wiley-VCH, Weinheim, 2008.
[ii] K. Bica, P. Gaertner, R. D. Rogers, Green Chem. 2011, 13, 1997.