Kinetics and Solvent Effects in the Synthesis of Ionic Liquids

Abstract

Ionic liquids (ILs) are being recognized as environmentally friendly ("green") solvents. However, their synthesis is often conducted in the very solvents that they will reportedly replace. This research has investigated the kinetics and solvent effects involved in synthesizing ILs in organic solvents and using compressed carbon dioxide. The kinetics for producing ILs have been found to be highly dependent on solvent polarities, and varied by over an order of magnitude. These dramatic effects were correlated to various polarity parameters to predict the kinetic rates. A detailed study of solvent toxicity and environmental impact was conducted to explore greener synthesis methods. Compressed CO2 was investigated as a potential benign alternative as the phase behavior and kinetics can be tuned for combined reaction and separation. Through understanding the kinetics, human/environmental impact, and phase equilibrium, ILs may be produced in a manner which may achieve their environmentally-benign potential.