Interactions in (glycylglycine + 1 M aqueous glucose/1 M aqueous sucrose) systems at 298.15–323.15 K

Density and speed of sound values of (glycylglycine + 1 M aqueous glucose/1 M aqueous sucrose) systems have been measured as a function of molal concentration of glycylglycine at temperatures: 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15 K by an oscillating-tube density and sound velocity meter. The partial molar volumes, isentropic compressibilities and partial molar isentropic compressibilities of the (glycylglycine + 1 M aqueous glucose/1 M aqueous sucrose) systems have been computed from the experimental density and speed of sound data at different temperatures. The isentropic compressibility values decrease with an increase in molal concentration of glycylglycine as well as temperature. The partial molar volumes increase whereas partial molar isentropic compressibilities decrease with an increase in temperature. The trends of variations of experimental and computed parameters have been discussed in terms of ionic–hydrophilic, hydrophilic–hydrophilic and hydrophobic–hydrophilic interactions operative in the systems.

► Interactions in (glycylglycine–1 mol L−1 sucrose) system are stronger than in (glycylglycine–1 mol L−1 glucose) system. ► Ionic–hydrophilic and hydrophilic–hydrophilic interactions dominate over hydrophobic–hydrophilic interactions. ► Partial molar volumes of glycylglycine in 1 mol L−1 aqueous glucose and 1 mol L−1 aqueous sucrose solutions increase with increase in temperature. ► Partial molar isentropic compressibilities of glycylglycine in 1 mol L−1 aqueous glucose and 1 mol L−1 aqueous sucrose solutions increase with increase in temperature.