Electrical Conductivities, Viscosities, and Densities of N-Acetoxyethyl-N,N-dimethyl-N-ethylammonium and N,N-Dimethyl-N-ethyl-N-methoxyethoxyethylammonium Bis(trifluoromethanesulfonyl)amide and Their Nonfunctionalized Analogues

Abstract

The temperature dependences of the density, viscosity, and electrical conductivity were investigated in four ammonium ionic liquids with the bis(trifluoromethanesulfonyl)amide anion ([Tf2N]−). The cations for the ionic liquids were N-acetoxyethyl-N,N-dimethyl-N-ethylammonium ([N112,2OCO1]+), N,N-dimethyl-N-ethyl-N-methoxyethoxyethylammonium ([N112,2O2O1]+), N,N-dimethyl-N-ethyl-N-pentylammonium ([N1125]+), and N,N-dimethyl-N-ethyl-N-heptylammonium ([N1127]+). Measurements were performed over the temperature range T = (273.15 to 363.15) K at atmospheric pressure. The densities were fitted to quadratic functions of temperature. The ionic liquids with the functionalized cations ([N112,2OCO1]+ and [N112,2O2O1]+) have the higher densities than the corresponding counterparts with the nonfunctionalized cations ([N1125]+ and [N1127]+). The viscosities and electrical conductivities were analyzed using the Litovitz and Vogel–Fulcher–Tamman equations. The ester functionalized ionic liquid, [N112,2OCO1][Tf2N], has poorer transport properties (that is, higher viscosity and lower electrical conductivity) than the nonfunctionalized [N1125][Tf2N], whereas the ether functionalized ionic liquid, [N112,2O2O1][Tf2N], has superior transport properties to its analogue, [N1127][Tf2N]. Empirical Walden plots (double logarithmic graph of molar conductivity vs reciprocal viscosity) give straight lines with slopes less than unity.