Studies on Volumetric Properties of Concentrated Aqueous Amino Acid Ionic Liquid [C3mim][Glu]

摘要

A new amino acid ionic liquid, [C3mirn][Glu] (1-methyl-3-propylimidazolium glutamic acid salt), was prepared by a neutralization method and characterized by ~1H NMR and TA. Using an Anton Paar model DMA 4500 oscillating U-tube densitometer, the densities of aqueous [C3mim][Glu] were measured over mole fraction of IL from 0.039 to 0.543 in the temperature range of T = (283.15 to 338.15) K at intervals of 5 K. Values of the apparent molar volumes of aqueous [C3mim][Glu] were calculated and were treated by Pitzer—Simonson (PS) equation, Pitzer—Simonson—Clegg (PSC) equation, and the simplified PSC equation. In comparison with the values of PS and the simplified PSC parameters, the PSC parameters have a smaller standard deviation. Obviously, when the number of parameters augments, the fitting accuracy increases.