Solid-liquid phase equilibrium of N, N'-diphenyl thiourea (DPTU) in twelve pure solvents: Solubility determination, correlation, molecular simulation and thermodynamic analysis

Abstract

In this work, the equilibrium solubility and thermodynamic properties of N, N'-Diphenyl thiourea (DPTU) in twelve organic solvents were reported. The solubility of DPTU in twelve organic solvents was investigated by gravimetric method from 283.15 K to 323.15 K under atmospheric pressure. It was proved that the solubility of DPTU in twelve organic solvents is positively correlated with temperature. The results indicated the solubility of DPTU in pure solvents was well correlated by modified Apelblat equation, λh equation, Van't Hoff equation, and the NRTL model, which showed less than 8% average relative deviation (ARD) for all the four thermodynamic models. Furthermore, the thermodynamic properties of DPTU in selected solvents were analyzed by the NRTL model, which indicated that the mixing process of DPTU in organic solvents is spontaneous. In addition, the physicochemical properties of twelve organic solvents were investigated to determine the effect of solvent effects on solubility. The intermolecular forces were determined through molecular simulations, including Hirshfeld surface analysis (HS), Molecular Electrostatic Potential Surface (MEPs), and Radial distribution function (RDF) analysis. The results showed that hydrogen bond can be formed between DPTU and the selected solvents, which can help to further explain the dissolution behavior of DPTU in the solvents.