Abstract

PAEZ, Manuel S; CANTERO, Plinio D  and  MARZOLA, Elfrin J. Densities and volumetric properties of glycine in aqueous solutions of sodium thiosulfate pentahydrate (Na₂S₂O₃.5H₂O) at different temperatures. Rev.Colomb.Quim. [online]. 2012, vol.41, n.3, pp.449-483. ISSN 0120-2804.

Densities of glycine in aqueous solutions sodium thiosulfate pentahydrate (0,01- 2,0 mol kg^-1) were determined using a vibrating-tube densimeter DMA 5000, at temperatures of (283,15; 288,15; 293,15; 298,15; 303,15; 308,15; 313,15 and 318,15) K and 101,1 Kpa. Apparent molar volumes (Vø), apparent molar volumes at infinite dilution (V_ø ^∞), experimental slope (S*_v), standard partial molar volumes of transfer (Δ trV°_2,m), partial molar expansivities at infinite dilution (V_E ^∞), second derivative apparent molar volume at infinite dilution with respect to temperature (δ² V_ø ^∞ / δT²)_p and hydration numbers (n_H ) were calculated. The values obtained for these parameters were discussed in terms of the interactions present in solution. Additionally, values of ΔtrV^°_2m,, have been interpreted in terms of solute-cosolute interactions on the basis of a cosphere overlap model and calculated from these parameters the double of V_AB and triple V_ABB, volumetric interaction,using the McMillan-Mayer theory. The values of ΔtrV^°_2m, are positive and increase with the increase of Na₂S₂O₃.5H₂O molality, while negative values of (∂²V_ø^∞/∂T²)_P are all mixed solvent concentrations, suggesting that the level of solution are favored and solutesolvent interactions that glycine acts as a disruptor of the structure of the aqueous solutions of sodium thiosulfate pentahydrate.

Keywords : density; glycine; solutesolvent interactions; the model of cosphere volumetric interaction parameters.

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