Thermodynamics Properties and Internal Interactions of Ether-Group Functionalized Thiocyanate Ionic Liquid 1-(2-Methoxyethyl)-3-Methylimidazolium Thiocyanate and Its Mixtures with 1,4-Butyrolactone or Propylene Carbonate

Abstract

In this paper, thermodynamic properties such as density, conductivity, and viscosity of an ether-based-functionalized ionic liquid (IL) 1-(2methoxyethyl)-3-methylimidazole thiocyanate [MOEMIM][SCN] was measured at temperatures from (288.15 to 343.15) K and at atmospheric pressure (101 KPa). Then, the mixture systems blends of [MOEMIM][SCN] + 1,4-butyrolactone (GBL) or propylene carbonate (PC) were also prepared and measured over the whole composition range at the same temperature and pressure conditions. The Vogel−Fulcher−Tamman (VFT) equation was employed to describe the temperature dependence of transport properties (viscosity and conductivity). The Casteel− Amis four-parameter (C−A) equation was used to explain the mole fraction dependence of ILs on the electrical conductivity. From the experimental density and viscosity, the excess molar volume (V E ) and viscosity deviation (Δη) were obtained, and fitting results of the Redlich−Kister (R−K) polynomial equation showed that the changes of the excess properties were reasonable for the mixtures. Combined with the COSMO−RS model based on DFT calculation, the intermolecular interaction situations of the mixture systems were evaluated. Further, the σ-profile can provide the computational aspect of specific interactions between molecules or between solvent through H-bond donors and H-bond acceptors.