Study on the Phase Behavior and Molecular Dynamics Simulation of a Supercritical Carbon Dioxide Microemulsion Containing Ionic Liquid

Abstract

We investigated the solubilization effect of a supercritical carbon dioxide microemulsion based on LS-mn (LS-36, LS-45, and LS-54) surfactants for 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) as well as the influencing factors by analyzing the cloud point pressure (CPP) curves, which served as a function of dissolved IL concentration. Results show that increased water content (W0) could enhance [Bmim][BF4] dissolution. Under the same conditions, microemulsion systems consisting of LS-54, LS-45, and LS-36 have the gradually decreased the dissolving capacity for [Bmim][BF4]. However, variation of the surfactant concentration has little influence on dissolving [Bmim][BF4]. In addition, introducing appropriate amounts of ethanol could decrease the CPP of the system, which did not bring significant enhancement on [Bmim][BF4] dissolution. Molecular dynamics (MD) simulation was implemented to give an insight about the microstructure and prove the formation of the microemulsion.