The Partitioning Behavior of Tyramine and 2‐Methoxyphenethylamine in a Room Temperature Ionic Liquid–Water System Compared to Traditional Organic–Water System

Abstract

Ionic liquids have been proposed as replacements for volatile organic solvents (VOSs) by a range of authors, due to their very low vapor pressure, ability to dissolve a range of organic, inorganic, and organometallic compounds, immiscibility with water, and ability to form biphasic systems depending on the choice of cation/anion combination making up the ionic liquid. In this study the room temperature ionic liquid, 1‐butyl‐3‐methylimidazolium hexafluorophosphate [bmim][PF₆] was synthesized and a range of physical properties including the interfacial tension, viscosity, and density determined. The distribution of tyramine and 2‐methoxyphenethylamine (MPEA) as a function of pH was determined for the [bmim][PF₆] system. This was compared to distribution data obtained for these solutes in conventional organic solvent/water systems: xylene/tributylphosphate (TBP)/water and xylene/Benzyl alcohol (BA)/water.

Keywords:

• 1‐Butyl‐3‐methylimidazolium hexafluorophosphate
• ionic liquid
• organic solvents
• physical properties
• Tyramine, 2‐methoxyphenethylamine
• Solvent extraction

Acknowledgments

This work was made possible from the financial support of the Australian Research Council (ARC), GlaxoSmithKline Australia Ltd. (GSK), and Particulate Fluids Processing Centre (PFPC). Dr. Peter Scammels and coworkers at Victorian College of Pharmacy at Monash University assisted in the synthesis of the ionic liquid, which was greatly appreciated.