Partial molar volumes and compressibilities of glycine betaine in aqueous NaCl solutions at temperatures T = (288.15–318.15) K

• We report solution properties of glycine betaine in aqueous NaCl solutions.
• Study indicated the dominance of electrostatic interactions in the systems.
• Experimental results have been compared with the literature.
• Size of the metal ions found to influence the volumetric properties.

The partial molar volumes, partial molar isentropic compressibilities, transfer molar volumes and transfer molar isentropic compressibilities of the system: glycine betaine in aqueous (0.1, 0.2, 0.3, 0.4 and 0.5 mol kg−1) NaCl solutions at different temperatures were determined using the experimental values of density and speed of sound. The positive transfer molar volumes of the systems indicated the presence of strong solute–solvent interactions. The electrostatic charge–charge interactions (among Na+/Cl− ions and amino/carboxylic groups of glycine betaine) were found to be predominant over the ionic–hydrophobic interactions (among Na+/Cl− ions and CH2/CH3 groups of the glycine betaine) in aqueous solutions. Size of the metal ion was found to influence the volumetric properties to an appreciable extent.

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