Rheological behaviour of binary mixtures containing hexyl(tetradecyl)phosphonium chloride (Cyphos IL 101) and bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) between 288.15Â K and 343.15Â K

► Solvation of Cyphos IL 101 by Cyanex 272 depends on mixture composition. ► Excess viscosity and activation energy for viscous flow gives useful information. ► Mixtures behave as Newtonian liquid.