Journal of Chemical and Engineering Data, Vol.61, No.1, 264-271, 2016
Solubility and Solution Thermodynamics of the delta Form of L-Citrulline in Water plus Ethanol Binary Solvent Mixtures
The solubility of the delta form of L-citrulline in the water + ethanol solvent system was measured at temperatures ranging from 293.15 to 333.15 K at atmospheric pressure using the gravimetric method. The crystal form of the solute is recognized as the delta form. It could be concluded that ethanol was an effective antisolvent in the crystallization process on the basis of the solubility behavior of the delta form of L-citrulline. The experimental solubility data were fitted by using the modified Apelblat equation, the simplified Combined Nearly Ideal Binary Solvent/Redich-Kister (CNIBS/R-K) model and the 3D Jouyban-Acree model (the combination version of the Jouyban-Acree and vant Hoff models). The corresponding relative absolute deviation values were 1.91, 1.71, and 5.13. The thermodynamic properties, including Gibbs energy, enthalpy, and entropy were obtained by using the vant Hoff analysis, which indicated that the dissolution of the delta form of L-citrulline is an endothermic and nonspontaneous process.