Solubility measurement, model correlation, solvent effects and thermodynamic analysis of twelve pure organic solutions of p-Chloroaniline

Abstract

As an important chemical raw material and organic intermediate, p-chloroaniline(p-CAN) is widely used in various industries, however, no systematic study on the solubility of p-CAN has been carried out. In the present study, the solubility data of p-CAN in twelve mono-solvents including methanol, ethanol, acetonitrile, toluene, n-propanol, n-butanol, ethyl formate, i-propanol, i-butanol, ethyl acetate cyclohexane, and 1,2-Dichloroethane were determined by the static isothermal saturation method at 0.1 MPa, 278.15–313.15 K. The measured data were linked and analysed using the van't Hoff equation, Apelblat equation, Yaws equation, λh equation, Wilson's model and NRTL, while the combination of ARD and RMSD data demonstrated that the Apelblat equation had an optimal fit. The thermodynamic properties of p-CAN solutions studied with the van't Hoff equation, indicating that this process is a non-spontaneous, heat-absorbing process motivated by enthalpy. Moreover, the solvent effect was studied by using the concept of Kamlet-Taft Linear Solvation Energy Relationship. The type and extent and direction of solvent-solvent and solute-solvent interactions were identified. It has been demonstrated that the solubility of p-CAN is highly correlated with the polarity, cohesive energy density and hydrogen bonding ability of the solvent. To explain the solvation behaviour of p-CAN in different pure solvents, intermolecular interactions have been analysed on molecular level by simulating the calculation of the molecular electrostatic potential surface and solvation free energy. This study provides a basic basis for the screening of solvent systems for the crystallisation of p-CAN.