Densities, viscosities, and refractive indices for the binary mixtures of tri-n-butyl phosphate (TBP) with toluene and ethylbenzene between (303.15 and 323.15) K

Densities, ρ, viscosities, η, and refractive indices, nD, were measured for the binary mixtures of tri-n-butyl phosphate (TBP) with toluene and ethylbenzene over the entire range of composition, and at different temperatures from T = (303.15 to 323.15) K. From experimental data of ρ, η, and nD, the excess molar volumes, VmE, partial molar volumes, V ¯ i , thermal expansivities, α, excess thermal expansivities, αE, deviations in viscosities, Δη, kinematic viscosities, ν, free energies, ∆G≠, excess free energies, ∆G≠E of viscous flow, deviations in refractive indices, ΔnD, and excess molar refractions, RmE, were calculated. To get the correlation coefficients and the relevant standard deviations, the values of ρ, η, and nD were correlated with concentration-dependent polynomial equations, whereas, those for the deviations/excess properties were fitted to the Redlich-Kister equation. Various laws of mixing for viscosities of liquid mixtures, such as, Grunberg-Nissan, Hind, Heric, Auslander, and McAllister, were investigated to check their correlating ability with these systems. Moreover, the temperature dependent Jouyban-Acree model was used to correlate the experimental values of ρ and η. For both systems, the signs of αE and ΔnD were found to be all negative and those of Δη were positive. Plots of VmE or RmE against the mole fraction of TBP were sigmoid and resembled with each other. These variation patterns were discussed in reference to the nature of molecular interactions taking place between the component liquids.