Volumetric properties of (ascorbic acid plus polyethylene glycol 3350+water) systems at T = (288.15, 298.15, and 308.15) K

Density and ultrasound speed were measured accurately for binary ascorbic acid-water and ternary ascorbic acid-water-polyethylene glycol 3350 (PEG3350) solutions at T=(288.15. 298.15, and 308.15) K. The data were used to evaluate thermodynamic properties as apparent molar volumes, V-phi, and apparent molar isentropic compressions, K-S Phi, of ascorbic acid in water and in aqueous PEG3350 solutions. Infinite dilution values of these parameters, V degrees(phi), and K degrees(S Phi) were obtained from their plots as a function of molality and have been utilized in obtaining transfer volumes and transfer compressions of ascorbic acid from water to PEG3350 solutions at various weight percentages. All transfer volumes and compressions at infinite dilution were found to be positive, to increase with weight per cent of PEG3350 and to decrease with temperature. Apparent molar isobaric expansions at infinite dilution were derived from the temperature dependence of V degrees(phi) values. The results were interpreted in terms of ascorbic acid-water-PEG3350 interactions. (C) 2010 Elsevier Ltd. All rights reserved.