Theoretical and experimental study of 1-butyl-3-methylimidazolium nitrate with 1-pentanol, 1-hexanol and 1-heptanol: COSMO-RS and structure factor

Abstract

In this paper, some thermodynamic and structural properties of the binary mixtures containing [Bmim][NO3] and 1-alkanols (1-pentanol, 1-hexanol, and 1-heptanol) was studied using theoretical and experimental methods. Density and viscosity for the mixtures above were measured at temperatures (293.15 K to 323.15 K), and values of excess molar volumes, VmE and viscosity deviations Δη were calculated. For binary mixtures of [Bmim][NO3] with 1-octanol, 1-nonanol, and 1-decanol a miscibility gap was observed in the mole fraction regions between 0.1 and 0.9. Findings indicate that strong interactions occur in the binary solutions containing short-range 1-alkanol, and increasing the length of the alcohol causes the weakening of the intermolecular interactions. To obtain more information about the molecular structure of aforesaid mixtures, the conductor-like screening model for real solutions (COSMO-RS) method was applied, and the D parameter, the concentration-concentration structure factor, Scc(0), and the chemical short-range order parameter α′, were calculated for the binary mixtures.