Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The equilibrium solubility of amidinothiourea (ATU) in mono-solvents including NMP, acetone, 1,4-dioxane, acetonitrile, ethyl acetate, toluene, methanol, 1-butanol, 1-propanol, ethanol, 2-propanol and cyclohexane was determined by using a isothermal saturation method at the temperature from T 283.15 K to 323.15 K. The experimental pressure is 101.3 kPa. The sequence of solubility from high to low is NMP greater than acetone greater than 1,4-dioxane greater than methanol greater than ethanol greater than acetonitrile greater than 1-propanol greater than ethyl acetate greater than 2-propanol greater than1-butanol greater than toluene greater than cyclohexane. Two thermodynamic models (modified Apelblat equation and h equation) were used to correlate the relationships between solubility of ATU and temperature, the values of relative average deviations (RAD) and root-mean-square deviations (RMSD) between the experimental and calculated solubility were no more than 2.07% and 1.9610-4, respectively. The appropriateness of the models was evaluated by statistical analysis. Based on the results of statistical analysis, the two thermodynamic models can correlate the solubility of ATU in mono-solvents very well. In order to study the effect of solvation interaction on solubility, the solute-solvent and solvent-solvent interactions were studied. The solubility of ATU in mono-solvents was calculated by the Kamlet and Taft linear solvation energy relationship model (KAT-LSER). Hydrogen bond donor (HBD) interaction of the solvent with the solute and nonspecific dipolarity/polarizability interactions are in favor of the increase of solubility of ATU. However, the cavity term, accounted by Hildebrand solubility parameter is unfavorable.