The limiting partial molar volume and transfer partial molar volume of glycylglycine in aqueous sodium halide solutions at 298.15 K and 308.15 K

Apparent volumes V-Phi of glycylglycine in aqueous NaX (X = F-, Cl-, and Br-) solutions have been obtained from densities of their solutions at 298.15 K and 308.15 K measured by using a precise vibrating-tube digital densimeter. These values have been utilized in conjunction with the values in water to deduce partial molar volumes of transfer Delta(trs) V-Phi(o) from water to different aqueous NaX solutions. Delta V-trs(Phi)o values are positive. The interpretation is that these results arise from the dominant interaction of the NaX with the charged centers of glycylglycine. The results show that Delta V-trs(Phi)o depend less on the temperature. Hydration numbers and interaction coefficients have been calculated from V-Phi(o) and Delta V-trs(Phi)o values and the values have been interpreted in terms of various interactions. (C) 2005 Elsevier Ltd. All rights reserved.