How ideal are binary mixtures of room-temperature ionic liquids?

Abstract

Data for the densities, conductivities, viscosities and dielec. properties of binary mixts. of the tetrafluoroborate and the dicyanamide salts of 1-N-ethyl-3-N-methylimidazolium were measured at 25°. The mixts. exhibit practically "ideal" (linear) mixing behavior with respect to viscosity, molar volume, and the effective dipole moment of the obsd. relaxation assocd. with cation reorientation, indicating a smooth change in the structure of the mixts. On the other hand, the elec. cond. and dielec. relaxation time deviate considerably from "ideal" mixing behavior, indicating enhanced translational and rotational dynamics in the mixts.