Pressure dependence on the viscosities of 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide and two tris(pentafluoroethyl)trifluorophosphate based ionic liquids: New measurements and modelling

Highlights: ► Viscosities of 3 ILs from 313.15 to 363.15 K at pressures up to 150 MPa are reported. ► Temperature and pressure correlations with modified VFT and Litovitz equations are provided. ► Local pressure–viscosity coefficient is studied for 9 ILs and other liquids. ► Density scaling concept is applied to the reduced and non-reduced viscosity for 6 ILs. -- Abstract: New experimental viscosity values for three ionic liquids, 1-butyl-2,3-dimethylimidazolium tris(pentafluoroethyl)trifluorophosphate, 1-(2-methoxyethyl)-1-methyl-pyrrolidinium tris(pentafluoroethyl)trifluorophosphate and 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, are reported in this work. The measurements were carried out using a falling-body viscometer within the temperature range from (313.15 to 363.15) K at pressures up to 150 MPa. These values were correlated as a function of temperature and pressure with four different equations. Moreover, we perform an analysis of the dependency of viscosity on pressure and temperature based on the density scaling concept for these fluids and other three ionic liquids recently studied with the same device