Thermodynamics of thiourea dissolution in methanol–water mixtures

The solubilities of thiourea in methanol-water mixtures with mass fraction of methanol of 0.54, 0.65, 0.76, 0.88, and 1.00 were determined. The experimental data were approximated with the modified Apelblat equation. The dissolution enthalpy and entropy were calculated from the experimental data and the nature of interactions between the solvent and solute were discussed. The obtained solubility data can be used for development of various technological processes involving thiourea, particularly for the synthesis of isopropyl mercaptan.