Ultra Purification of Ionic Liquids by Melt Crystallisation
Multi-scale and/or multi-disciplinary approach to process-product innovation
Novel Separation Techniques (T3-8)
Keywords: Ionic Liquid, Crystallization, Purification, EMIM-Chloride, EMIM-Bromide
M. Stepanski 2), A. Kuszlik 2), C. Weller 3), P. Keil 1), A. König 1)
1) Chair of Separation Science and Technology, University of Erlangen-Nürnberg, Germany
2) Sulzer Chemtech, Winterthur, Switzerland
3) Merck KGaA, Darmstadt, Germany
Ionic liquids (ILs) have received a great increase in attention in the fields of engineer-ing during last decade due to their unique properties. ILs are a very important class of non volatile environmentally friendly solvents (Tm< 100°C) in (bio)catalysis -applicable to many ionic, polar and non polar structure groups- and as efficient elec-trolytes (Wasserscheid 2003). The applications range from electrochemistry, sensors, analysis, separation techniques to catalysis and reaction engineering. Furthermore it is most important to realize low production cost including efficiently techniques for purification and ultra purification.
The paper will present results of purification and ultra purification of EMIM-Chloride and EMIM-Bromide (EMIM: 1-ethyl-3-methyl-imidazolium) by melt crystallization (König 2006). Different techniques for purification are discussed: zone melting, layer crystallization and dry sweating in lab scale und layer crystallization for static and dynamic crystallization conditions in pilot scale.
In the case of EMIM-Chloride segregation coefficients are in the range of 0,05<kseg<0,45 depending on crystallization rate, yield, feed impurity concentration and techniques used. The crystallization behaviour of purified Ionic Liquids will be discussed in detail in respect those of organic substances with similar melting points. Purification potential of EMIM-Chloride will be discussed in respect to different crys-tallization techniques and different scales used for crystallisation.
The excellent purification results of EMIM-Chloride offer a high purification potential of melt crystallization techniques for Ionic Liquids as a new innovative class of sol-vents and reactants.
Melt crystallization is a very efficient method to produce in different scales ultra pure Ionic liquids wIL >99,99%.
Wasserscheid, P.; Welton, T.: Ionic Liquids in Synthesis. Wiley-VCH. Weinheim, 2003.
König, A.; Wasserscheid, P.: Ultrapurification of Ionic Liquids by Melt Crystallisation
9th International Workshop on Industrial Crystallization (BIWIC), Ed. Ulrich, September 14th and 15th 2006 in Delft, Netherlands, Proceedings p. 35-41, ISBN 3-86010-652-X
See the full pdf manuscript of the abstract.
Presented Tuesday 18, 11:00 to 11:20, in session Novel Separation Techniques (T3-8).
