Solubility of L-Glutamic acid in concentrated Water/Ethanol solutions

Maya Khellaf (1) , Catherine Charcosset (1) , Denis Mangin (1) , Elodie Chabanon (1)

1 LAGEPP - Laboratoire d'automatique, de génie des procédés et de génie pharmaceutique

In this work the solubility of the metastable α-form and the stable β-form of L-Glutamic acid in pure water and in different water/ethanol mixtures at high concentrations of ethanol is measured by analytical gravimetric method. The experiments are carried out over a temperature ranging from 283 to 343K. The experimental results show that the solubility of the stable βform is lower than the metastable α-form regardless of the solvent studied (water or water/ethanol mixtures). The results also highlight that the solubility of both polymorphs decreases with the increase of the antisolvent concentration and increases with the temperature rising. Based on the data obtained, the enthalpy and the entropy of dissolution are estimated thanks to the empirical Van't Hoff correlation. The solubility data of both polymorphs is then correlated by Combined Nearly Ideal Binary Solution (CNIBS/Redlich-Kister) equation and the parameters are determined for the temperature studied.

Mots clés: Crystallization; Solubility; L-Glutamic acid; Water/Ethanol mixtures

Domaines: Génie chimique; Sciences pharmaceutiques; Génie des procédés

Maya Khellaf, Catherine Charcosset, Denis Mangin, Elodie Chabanon. Solubility of L-Glutamic acid in concentrated Water/Ethanol solutions. Journal of Crystal Growth, 2021, 570, pp.126238. ⟨10.1016/j.jcrysgro.2021.126238⟩. ⟨hal-03759848⟩