Polarity, Viscosity, and Ionic Conductivity of Liquid Mixtures Containing [C₄C₁im][Ntf₂] and a Molecular Component

Abstract

In this study, we have focused on binary mixtures composed of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)-imide, [C(4)C(1)im][Ntf(2)], and a selection of six molecular components (acetonitrile, dichloromethane, methanol, 1-butanol, t-butanol, and water) varying in polarity, size, and isomerism. Two Kamlet-Taft parameters, the polarizability π* and the hydrogen bond acceptor β coefficient were determined by spectroscopic measurements. In most cases, the solvent power (dipolarity/polarizability) of the ionic liquid is only slightly modified by the presence of the molecular component unless large quantities of this component are present. The viscosity and electrical conductivity of these mixtures were measured as a function of composition and the relationship between these two properties were studied through Walden plot curves. The viscosity of the ionic liquid dramatically decreases with the addition of the molecular component. This decrease is not directly related to the volumetric properties of each mixture or its interactions. The conductivity presents a maximum as a function of the composition and, except for the case of water, the conductivity maxima decrease for more viscous systems. The Walden plots indicate enhanced ionic association as the ionic liquid gets more diluted, a situation that is the inverse of that usually found for conventional electrolyte solutions.

Binary mixtures of ([C 4 mim][NTf 2 ] + molecular organic solvents): Thermophysical, acoustic and transport properties at various compositions and temperatures

“…where, * ,i P C is the isobaric molar heat capacity and listed in Table 7 As explained earlier by C. Lopez [27], the logarithm of viscosity of studied binary mixtures was given by Grunberg-Nissan equation [60]:…”

Ethaline and Glyceline binary eutectic mixtures: characteristics and intermolecular interactions

“…This includes the relative strength and extensiveness of hydrogen bond networks and the relative abundance of H + /OH − among others available in the respective solvents. Studies of this nature have been carried out using binary mixtures of ionic liquids, and mixtures of water and ionic liquids and mixtures of molecular solvent and ionic liquid . The properties of whose variations are frequently studied upon mixing include density, viscosity and conductivity among others.…”

Electrical Conductivities and Interactions in Binary Mixtures of Imidazolium-Based Ionic Liquids with Acetonitrile and Dimethyl Sulfoxide

“…Molecular dynamics studies [35][36][37] have indicated that there is significant ionic association in neat ILs which leads to high viscosity, limited conductivity and other peculiar properties of these organic salts. Mixing ionic liquids with molecular solvents will reduce coulombic interactions and release free ions from their associations, leading to decreased viscosity and increased conductivity [13,38]. A fluid with a large dielectric constant (as is DMSO or ACN) can interact more effectively with both ions of the ionic liquid, disrupting its polar network and causing a decrease in the viscosity of the mixture.…”

“…A fluid with a large dielectric constant (as is DMSO or ACN) can interact more effectively with both ions of the ionic liquid, disrupting its polar network and causing a decrease in the viscosity of the mixture. As a result, it increases the conductivity, thus facilitating mass transport [14,38].…”