Measurement, correlation, and analysis of the solubility of triethylamine hydrochloride in ten pure solvents

Abstract

In this work, the solubility of Triethylamine hydrochloride (TEA·HCl) in Ethylene carbonate (EC), Propylene carbonate (PC), Dimethyl carbonate (DMC), Vinylene carbonate (VC), Dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), Methyl isobutyl ketone (MIBK), Methanol, 2-Propanol, 1-Octanol were measured from 293.15 K to 348.15 K under ambient pressure via a static method. Subsequently, the solubility data were correlated with the modified Apelblat Equation, the Van't Hoff Equation, the λh Equation, and the NRTL model. The average relative deviation (ARD), and root-mean-square deviation (RMSD) were introduced to evaluate the correlated data. The findings indicated that, out of the four models, the modified Apelblat model offered the highest correlation. Moreover, using the Van't Hoff Equation, we determined the Gibbs energy, enthalpy, and entropy of TEA·HCl dissolution in each solvent examined, all of which point to a dissolving process that is endothermic and entropy-driven. In the temperature range studied, the solubility of TEA·HCl in selected solvents increased with the rising temperature, and the solubility sequence of TEA·HCl at 298.15 K was Methanol > VC > 2-Propanol > EC > 1-Octanol > DMSO > PC > DMF > MIBK > DMC. In order to understand how TEA·HCl dissolves, density functional theory (DFT) was used to calculate its molecular electrostatic potential (MEP) and solvation free energy. In the meantime, the KAT-LSER model for studying the solvent impact has been presented. This work will provide valuable data references for the purification of TEA·HCl by crystallization.