Enthalpy of Solution of Amino Acid Ionic Liquid 1-Ethyl-3-methylimidazolium Ammonioacetate

Abstract

The molar enthalpies of solution, ΔsolHm(wc), of 1-ethyl-3-methylimidazolium ammonioacetate (EMIGly) with various amounts of water and with various molalities were measured by the solution−reaction isoperibol calorimeter at (298.15 ± 0.01) K. According to Archer’s method, the standard molar enthalpis of solution of EMIGly with a known amount of water, ΔsolH0m(wc), were obtained. In order to eliminate the effect of the small amount of water in EMIGly, a linear fitting of ΔsolH0m(wc) against water content was carried out so that a good straight line was obtained, and the intercept was the standard molar enthalpy of solution, ΔsolH0m (pure IL EMIGly) = (−34.6 ± 0.5) kJ·mol−1. Using Glasser’s theory of lattice energy, the hydration enthalpy of the anion of glycine was estimated.