Journal of Chemical Thermodynamics, Vol.98, 193-199, 2016
Volumetric and viscometric studies of nicotinic acid in aqueous solutions of sodium malonate at T = (298.15-318.15) K
Densities and viscosities for the solutions of nicotinic acid in aqueous sodium malonate solutions with several molalities (m(sodium) (malonate) = 0.000, 0.005, 0.010, 0.015 and 0.020 mol . kg(-1)) of sodium malonate were determined at T = (298.15-318.15) K and at pressure p = 101 kPa. Apparent molar volume (phi(V) standard partial molar volume (phi(0)(V) the slope (S-V*), standard isobaric partial molar expansibility (phi(0)(E)) and its temperature dependence (partial derivative phi(0)(E)/partial derivative T)(p), the viscosity B-coefficient and solvation number (S-n), etc., were determined. Using the experimental data viscosity B-coefficients were further utilized to obtain the free energies of activation of viscous flow per mole of the solvents (Delta mu(0 not equal)(1)) and of the solute (Delta mu(0 not equal)(2)). Effects of molality, solute structure and temperature on all these parameters were analyzed in term of ion-ion and ion-solvent interactions; results revealed that the solutions are characterized predominantly by ion-solvent interactions and nicotinic acid behaves as a long-range structure maker. (C) 2016 Elsevier Ltd. All rights reserved.
Keywords:Standard partial molar volumes;Viscosity B-coefficients;Nicotinic acid;Aqueous sodium malonate solutions