Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The partial molar volumes V2deg and viscosity B-coefficient have been measured from density and flow time measurements for sulphanilamide, sulphanilic acid, and sulphosalicylic acid dihydrate in water and in aqueous solutions of (0.05, 0.1, 0.3, and 0.5) mol*kg-1 sodium chloride at temperatures from (288.15 to 318.15) K, by the use of a vibrating tube digital densimeter and Micro-Ubbelohde type capillary viscometer, respectively. The transfer volumes at infinite dilution calculated from partial molar volumes have both positive and negative values. The overall positive values at higher concentrations of sodium chloride are in the following order: sulphosalicylic acid dihydrate greater than sulphanilic acid greater than sulphanilamide, which is also the order of hydrophilicity of these drugs. The interaction coefficients, partial molar expansibilities VEdeg , and second-order derivative have also been calculated. The transfer B-coefficient values, ?trB, are calculated from viscosity B-coefficient data. Transition state theory has been used to calculate ?microo