Influence of Ionic Liquids on the Phase Behavior of Aqueous Azeotropic Systems

The use of ionic liquids (ILs) in chemistry and electrochemistry has been studied for some decades. Only recently, researchers have focused on the suitability of ILs as selective solvents in the field of separation technology. ILs represent suitable entrainers and extraction solvents for the separation of azeotropic mixtures by means of extractive distillation and solvent extraction. In this work, ternary vapor−liquid and liquid−liquid equilibria of the azeotropic mixtures ethanol + water and THF + water containing different kinds of commercially available ILs are presented. The four ionic liquids used are derived from butyl-methylimidazolium tetrafluoroborate [BMIM]+ [BF4]- by systematic variation of the cation or the anion. The influence of the IL structure on the relative volatility of the low boiling component in extractive distillation and on the selectivity in solvent extraction processes is discussed in this work.

[1]  Bette Hileman.  NEWS OF THE WEEK: EVALUATING PESTICIDESEPA must consider human test data , 2003 .

[2]  T. Welton,et al.  Characterizing ionic liquids on the basis of multiple solvation interactions. , 2002, Journal of the American Chemical Society.

[3]  Peter Wasserscheid,et al.  Ionische Flüssigkeiten - neue 'Lösungen' für die Übergangsmetallkatalyse , 2000 .

[4]  H. Frey,et al.  Experimental data and theoretical considerations on vapor–liquid and liquid–liquid equilibria of hyperbranched polyglycerol and PVA solutions , 2002 .

[5]  A. G. Fadeev,et al.  Opportunities for ionic liquids in recovery of biofuels , 2001 .

[6]  E. Sada,et al.  Salt effects on vapor-liquid equilibrium of tetrahydrofuran-water system , 1975 .

[7]  Michael Freemantle,et al.  EYES ON IONIC LIQUIDS: NATO workshop examines the industrial potential of green chemistry using room-temperature 'designer solvents' , 2000 .

[8]  C. Mash,et al.  Thermodynamic properties of aqueous non-electrolyte mixtures II. Vapour pressures and excess Gibbs energies for water + ethanol at 303.15 to 363.15 K determined by an accurate static method , 1978 .

[9]  P. Wasserscheid,et al.  Journal of the Royal Institute of Chemistry. November 1959 , 1959 .

[10]  K. R. Seddon.  Ionic Liquids for Clean Technology , 1997 .

[11]  Leonid B. Datsevich,et al.  Deep desulfurization of diesel fuel by extraction with ionic liquids. , 2001, Chemical communications.

[12]  P. Wasserscheid,et al.  1-n-Butyl-3-methylimidazolium ([bmim]) octylsulfate—an even ‘greener’ ionic liquid , 2002 .

[13]  J. Brennecke,et al.  Recovery of Organic Products from Ionic Liquids Using Supercritical Carbon Dioxide , 2001 .

[14]  M. Grätzel,et al.  Hydrophobic, Highly Conductive Ambient-Temperature Molten Salts. , 1996, Inorganic chemistry.

[15]  W. Arlt,et al.  Finite and infinite dilution activity coefficients in polycarbonate systems , 1997 .

[16]  Frauke Stock,et al.  How hazardous are ionic liquids? Structure–activity relationships and biological testing as important elements for sustainability evaluationThis work was presented at the Green Solvents for Catalysis Meeting held in Bruchsal, Germany, 13–16th October 2002. , 2003 .

[17]  R. Rogers,et al.  Hydrophobic ionic liquids incorporating N-alkylisoquinolinium cations and their utilization in liquid-liquid separations. , 2001, Chemical communications.

[18]  R. Poźniak,et al.  New Ionic Liquids and Their Antielectrostatic Properties , 2001 .

[19]  C. Gordon.  New developments in catalysis using ionic liquids , 2001 .

[20]  Robin D. Rogers,et al.  Room temperature ionic liquids as novel media for ‘clean’ liquid–liquid extraction , 1998 .

[21]  Shuguang Zhang,et al.  Novel properties of ionic liquids in selective sulfur removal from fuels at room temperature , 2002 .

[22]  J. Fuller,et al.  Ionic liquid–polymer gel catalytic membrane , 1997 .

[23]  Michael J. Zaworotko,et al.  Air and water stable 1-ethyl-3-methylimidazolium based ionic liquids , 1992 .

[24]  J. Pernak,et al.  Anti-microbial activities of ionic liquids , 2003 .

[25]  T. Letcher,et al.  Ternary liquid–liquid equilibria for mixtures of 1-methyl-3-octyl-imidazolium chloride + benzene + an alkane at T=298.2 K and 1 atm , 2003 .