Taurine in several aqueous binary solvents: Solubility prediction, measurement, modeling, solvent effect, and thermodynamics

The crystallization of taurine in pure water results in a low yield. Introducing anti-solvents during the cooling crystallization process would increase the yield. Therefore, measuring and evaluating the solubility of taurine in different binary aqueous solvents is necessary. In this work, the qualitative trend of the solubility of taurine in the binary solvent systems of 1,2-propanediol-water, acetonitrile–water, and ethylene glycol–water was first predicted using Hansen Solubility Parameters (HSPs), and then experimentally determined using isothermal gravimetric method. The experimentally obtained solubility is correlated with the modified Apelblat model as a linear model, and NRTL, UNIQUAC, Wilson, and λh model as nonlinear models. The solubility of taurine in binary solvents is further analyzed using the KAT-LSER model to investigate the solvent effect on solubility. For all researched systems, the standard molar enthalpy and the standard molar Gibbs energy changes are computed and found to be positive, indicating the dissolution of taurine is an endothermic process.