화학공학소재연구정보센터
Journal of Chemical and Engineering Data, Vol.66, No.1, 347-359, 2021
Effect of Cosolvent Ethanol on Solubilization of Ionic Liquids in Supercritical CO2 Microemulsions: Experiments and Simulations
In the presence of ethanol (EtOH), supercritical carbon dioxide (scCO(2)) microemulsions containing 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][Tf2N]) ionic liquid (IL) based on nonionic surfactants (Ls-45, Ls-S4, Ls-36, Dynol-604, and TMN-6) were constructed. We investigated the solubilization effect of the microemulsion for [Emim] [Tf2N] and analyzed the factors that affected the cloud point pressure (CPP), including temperature, IL concentration, and EtOH concentration. The results showed that as the temperature and IL concentration increased, the CPP gradually increased. Besides, small amounts of EtOH could decrease the CPP of the system. Furthermore, the higher the EtOH concentration, the more the CPP decrease. The results indicated that the addition of EtOH was beneficial to the stabilization of the microemulsion. Molecular dynamics (MD) simulations were performed to have an insight into the microstructure of Ls-45/[Emim] [Tf2N] /CO2 ternary and EtOH/Ls-45/ [Emim] [Tf2N]/CO2 quaternary microemulsion systems. The snapshots of the two systems were presented, and the radial distribution function (RDF), the gyration radius (R-g), density distributions, and distance information were calculated to investigate the interfacial structural properties. The dynamic process showed that the self-assembly of the reverse micelle took 87 ns for the ternary system and 84 ns for the quaternary system and remained stable until 100 ns. The formation of microemulsion was proved directly, and the microstructure was briefly analyzed. Finally, the possible structure of the scCO(2) microemulsion containing [Emim] [Tf2N] and EtOH was inferred.