A quick and green approach to prepare [Rmim]OH and its application in hydrophilic ionic liquid synthesis

Abstract

A quick and green process to prepare [Rmim]OH solutions is developed based on fast ion exchange between OH⁻ and halide ions (halide = Cl⁻ or Br⁻) in ethanol. Five ionic liquids were synthesized by neutralizing the obtained [Rmim]OH solution with acids to verify the feasibility of the whole process. The halogen content in the finally obtained ionic liquids and the experimental factors influencing the content are mainly discussed. Moreover, two other alcohols besides ethanol, propanol and iso-propanol, were further examined as solvents. The results show that this process, together with the alkylation and hydroxide anion route, is simple and efficient for preparing various ionic liquids, and that the process is a complementary synthetic route to existing strategies to prepare various ILs.