Volumetric properties for glycine and l-serine in aqueous solutions of 1-Ethyl-3-methylimidazolium hydrogen sulfate ([Emim][HSO4]) at T = (293.15–313.15) K and ambient pressure

Abstract

By using the volumetric properties, the solute–solvent interactions are studied in the ternary (glycine+1-Ethyl-3-methylimidazolium hydrogen sulfate [Emim][HSO4]+water) and (l-serine+1-Ethyl-3-methylimidazolium hydrogen sulfate [Emim][HSO4]+water) systems. For this purpose, the apparent molar volumes, Vφ, are calculated from the experimental density data. To obtain limiting apparent molar volumes Vφ0, the apparent molar volume values are fitted to the Redlich-Mayer type equation. Then the limiting apparent molar volumes of transfer, ΔVφ0, for studied amino acids from water to aqueous solutions of ionic liquid (IL) are calculated. The results showed that the ΔVφ0 values are negative for both ternary systems at all temperatures. The limiting apparent molar expansibility Eφ0 values have been obtained from the first derivative of limiting apparent molar volumes with respect to temperature. The values of second derivative of limiting apparent molar volumes respect to temperature show the structure making or breaking ability of glycine and l-serine in studied IL aqueous solutions. The results indicated that glycine and l-serine act as structure maker in studied solutions. McMillan–Mayer theory is used for evaluating the interaction parameters. Also the hydration number, nH, for both amino acids in ternary solutions has been reported.