Viscosity of ternary mixtures. IV. Urea – tert-butyl alcohol – water at 25 °C

We have measured, at 25 °C, the viscosities of urea and tert-butyl alcohol ternary aqueous solutions for total concentrations reaching about 4 M and various ratios of the solutes. We have also determined B coefficients of the Jones–Dole law for urea in water–tert-butyl alcohol mixtures and for tert-butyl alcohol in water–urea mixtures. The results can be fitted in the form:[Formula: see text]where η r is the viscosity relative to water and subscripts 1 and 2 characterise the two solutes. B 1 and B 2 are determined in water and the additional D parameters appear as pair-interaction contributions of the solutes to the viscosity of the system. Some relations are established and verified between the previous parameters and the B coefficients of 1 and 2 determined, respectively, in the aqueous mixtures of 2 and 1.