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 phi(v) and viscosity B-coefficients for caffeine in (0.00, 0.03, 0.05, and 0.07) mol . dm(-3) aqueous thorium nitrate, Th(NO(3))(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: phi degrees(v) = a(0) + a(1)T + a(2)T(2), have been used to describe the temperature dependence of the standard partial molar volumes phi degrees(v). These results have been used to deduce the standard volumes of transfer Delta phi degrees(v) and viscosity B-coefficients of transfer Delta B for caffeine from water to aqueous Th(N03)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 (delta(2)phi degrees(v)/delta T(2))(P). The Friedman-Krishnan co-sphere model was used to explain the transfer volume of caffeine with increasing Th(NO(3))(4) molarity. The activation parameters of viscous flow for the ternary solutions were also discussed in terms of transition state theory. (C) 2009 Elsevier Ltd. All rights reserved.