Apparent molar volumes and viscosity B-coefficients of caffeine in aqueous thorium nitrate solutions at T = (298.15, 308.15, and 318.15) K

Apparent molar volumes ϕV and viscosity B-coefficients for caffeine in (0.00, 0.03, 0.05, and 0.07) mol · dm−3 aqueous thorium nitrate, Th(NO3)4, solutions were determined from solution density and viscosity measurements over the temperature range (298.15 to 318.15) K as function of concentration of caffeine and the relation: ϕV∘=a0+a1T+a2T2, have been used to describe the temperature dependence of the standard partial molar volumes ϕV∘. These results have been used to deduce the standard volumes of transfer ΔϕV∘ and viscosity B-coefficients of transfer ΔB for caffeine from water to aqueous Th(NO3)4 solutions for rationalizing various interactions in the ternary solutions. The structure-making or breaking ability of caffeine has been discussed in terms of the sign of (δ2ϕV∘/δT2)P. The Friedman–Krishnan co-sphere model was used to explain the transfer volume of caffeine with increasing Th(NO3)4 molarity. The activation parameters of viscous flow for the ternary solutions were also discussed in terms of transition state theory.