Viscosity of binary mixtures of 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid with four organic solvents

• Viscosities of four binary mixtures of [Emim][BF4] with organic solvents.
• Viscosity models based on Eyring’s theory.
• Excess functions calculated.
• Data for binaries new in the literature, except for system with DMSO.

This paper reports experimental values of dynamic viscosity for four binary systems of 1-ethyl-3-methylimidazolium tetrafluoroborate, [Emim][BF4], with dimethyl sulfoxide (DMSO), acetonitrile (ACN), ethylene glycol (EG) and 1,4-dioxane over the temperature ranges from 293.15 K to 353.15 K at p = 0.1 MPa. All binary mixtures were completely miscible over the entire range of mole fraction, except the system with 1,4-dioxane. The viscosity results have been correlated by the one parameter Grunberg–Nissan and Fang and He equations and the two-parameter McAllister, Eyring-UNIQUAC, Eyring-NRTL and Eyring-Wilson models and the results were compared.Additionally, the viscosity deviations, Δη, and the excess Gibbs energy of activation for viscous flow, G∗E, were calculated and fitted to the Redlich–Kister equation. The results show that all Δη values are negative over the whole composition range and the G∗E values are positive, except for the system with EG. The results of the excess functions are discussed in terms of molecular interactions.