(713b) Ionic Liquid Production In CO2-Expanded DMSO

Novel applications for ionic liquids (ILs) are continually being reported in the fields of reactions, extractions, engineering fluids, CO₂-capture, material synthesis, etc.  As these new technologies mature, large volumes of ILs will be needed at low-cost and with a low environmental impact.  Previously, our group has shown that DMSO (a relatively environmentally-benign organic solvent) yields the highest kinetic rate for the synthesis of the IL, 1-hexyl-3-methylimidazolium bromide ([HMIm][Br]). However, due to the high boiling point (189°C) and heat of vaporization of pure DMSO, the energy of separations and energy-associated pollution beset the ultimate life-cycle analysis despite high kinetic rates and direct low human and environmental impact.  However, CO₂-expanded DMSO may help overcome these issues.  Gas-expanded or CO₂-expanded liquids (GXLs/CXLs) are a promising solvent media that reduce the use of organic solvents and operate at pressures often lower than conventional supercritical fluid technologies.  The temperature and pressured may be adjusted to provide rapid reactions and a phase split between the IL and DMSO to provide facile separations.  Here, we will demonstrate the phase equilibrium thermodynamics, kinetics, and transport properties of the production of [HMIm][Br] in CO₂-expanded DMSO.