Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

A new amino acid ionic liquid (AAIL) [C3mim][Val] (1-propyl-3-methylimidazolium valine) was prepared by the neutralization method. Using the solution-reaction isoperibol calorimeter, molar solution enthalpies of the ionic liquid [C3mim][Val] with known amounts of water and with different concentrations in molality were measured at T = 298.15 K. In terms of standard addition method (SAM) and Archer's method, the standard molar enthalpy of solution for [C3mim][Val] without water, ( 55.7 +- 0.4) kJ mol-1, was obtained. The hydration enthalpy of the cation [C3mim]+, 226 kJ mol-1, was estimated in terms of Glasser's theory. Using the RD496-III heat conduction microcalorimeter, the molar enthalpies of dilution, of aqueous [C3mim][Val] with various values of molality were measured. The values of molar enthaplies of dilution were fitted to Pitzer's ion-interaction model and the values of apparent relative molar enthalpy calculated using Pitzer's ion-interaction model.