(619b) Investigation of Water Quantification in Ionic Liquids Utilizing Near Infrared Absorption of Water

Ionic Liquids (ILs) are potential candidates to replace traditional organic solvents for a variety of separation processes.  Some ILs are capable of forming aqueous biphasic systems which allow for solvent extraction of various solutes from aqueous solutions.   The ability to quantify water content in an IL phase is important to implementing an ionic liquid as a solvent in a real world process.  The water content of an IL affects physical properties such as density, viscosity and conductivity and also significantly affects energy costs for heating and cooling.

Here we investigate and demonstrate the use of near infrared absorption spectroscopy to quantify water content in an imidazolium-based IL.  Near infrared absorption offers an accurate, rapid and in situ method for water quantification in the ionic liquid phase, which provides a non-destructive alternative to Karl-Fischer titration/coulometry.  The change in water absorption at different water concentrations in the IL is investigated.