Thermodynamics Research Center / ThermoML | Thermochimica Acta

ABSTRACT

Apparent molar volumes, viscosity B-coefficients for nicotinamide (NA) in (0.03, 0.05, 0.07 and 0.10) mol.dm-3 aqueous Citric Acid, monohydrate (CA) solutions have been determined from solution density and viscosity measurements at (298.15, 308.15 and 318.15) K as function of concentration of NA. In the investigated temperature range, the relation have been used to describe the temperature dependence of standard partial molar volume V O . This results have, in conjunction with the results obtained in pure water, been used to calculate the standard volumes of transfer V O ' and viscosity Bcoefficients of transfer for NA from water to aqueous CA solutions for rationalizing various interactions in the ternary solutions. The structure making or breaking ability of NA has been discussed in terms of the sign of dB/dT . An increase in the transfer volume of NA with increasing CA concentration has been explained by Friedman-Krishnan co-sphere model. The activation parameters of viscous flow for the ternary solutions studied have also been calculated and explained by the application of transition state theory.