No abstract

Electromotive force measurements on cells without a liquid junction have been used to determine the pK1 and pK2 values, at different temperatures, of DL-malic, maleic and fumaric acids in water and water+ 10, +20, +30 and +40 mass percent dioxan. From the temperature coefficients, the thermodynamic quantities AGO, AH", ASo and AC; of the dissociation processes have been calculated. The results have been discussed with respect to preferential solvation. The distances between the carboxylic groups have been calculated from the ratio of the successive dissociation constants in these media.

The present study deals with experiments so as to highlight the solute (drug nimesulide) - solvent(water) interactions and related modifications in case of the presence of hydrotropic agents at different temperatures T(=298.15 to 313.15)K. Density and viscosity values of nimesulide have been determined in water in (0.1, 0.2, 0.4, 0.6, 0.8, 1 and 2) mol dm-3aqueous solutions of hydrotropic agents (sodium benzoate, sodium salicylate, sodium bromide and nicotinamide) at temperatures 298.15, 303.15, 308.15 and 313.15 K where as the solubility was studied at 308.15 K. From the density values, the limiting partial molar volumes and expansibilities have been calculated. The experimental viscosity values have been analyzed in terms of jones-dole equation and on the basis of transition theory for relative viscosity.

No abstract

No abstract