Solubility Measurement and Data Correlation of Pentaerythritol in Four Binary Solvent Systems at Temperatures from 283.15 to 323.15 K

The solubility of pentaerythritol (PE) in four binary solvents (methanol + water, ethanol + water, isopropanol + water, acetonitrile + water) is determined using the gravimetric method at temperatures ranging from 283.15 to 323.15 K under 0.1 MPa. The experimental results demonstrate that the solubility of PE increases with the increase of temperature in all four binary solvent systems. And water has a relatively positive effect on the solubility of PE in all four binary solvents. However, the solubility of PE in ethanol + water and isopropanol + water mixtures first increases with the increase of the ethanol/isopropanol fraction and then decreases when the temperature exceeds 303.15 and 288.15 K, respectively. And the solubility reaches the maximum when the initial mole fractions of ethanol/isopropanol of the binary solvent are 0.2. Besides, experimental solubility is fitted with three thermodynamic models including the modified Apelblat model, λh model, and CNIBS/R-K model, and all of the average relative deviation (ARDs) are less than 4%, indicating good accordance with the experimental results. In addition, among the three thermodynamic models, the CNIBS/R-K model has the best fitting performance, in which all of the ARDs are less than 1.7%.