Determination and Correlation of the Solubility of Potassium Fluoride in Eight Single Solvents and Four Binary Solvent Mixtures at Different Temperatures

Abstract

This study investigated the mole fraction solubility of potassium fluoride in eight single solvents (methanol, ethanol, n-propanol, n-butanol, 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, and 1-methoxy-2-propanol) and four binary solvent mixtures (methanol + isopropanol, methanol + acetone, methanol + acetonitrile, and methanol + ethyl acetate) using the gravimetric method within the temperature range of 278.15 to 323.15 K (with 5 K intervals). The results demonstrated a gradual decrease in the solubility of potassium fluoride with increasing temperatures across all investigated solvent systems. For the four binary solvent mixtures studied, the solubility of potassium fluoride exhibited an increase with a higher mass fraction of methanol at a constant temperature. The experimental solubility data were correlated using four empirical models (van’t Hoff model, modified Apelblat model, CNIBS/R-K model, and Jouyban–Acree–Apelblat model), all of which exhibited excellent fitting performance. Comparison of different model fitting results revealed that the modified Apelblat model yielded lower values for relative deviation (ARD) and root-mean-square deviation (RMSD), indicating its superior fitting accuracy and suitability for fitting the experimental data of potassium fluoride in the selected solvents.