Measurement and Correlation of the Solubility of Palmatine Chloride in Four Different Binary Solvent Systems at (283.15-328.15) K

The equilibrium solubility of palmatine chloride in various mixed solvents consisting of ethanol (ethylene glycol (EG), isopropyl alcohol, and propylene glycol (PG)) plus water was experimentally obtained by static technology with environment conditions (283.15-328.15 K, 101.1 kPa). The measured data of palmatine chloride had a proportional relationship with temperature under the condition of fixed solvent composition, the same as increasing with the increasing the cosolvents of ethanol and EG except for the isopropyl alcohol and PG in four binary systems. The maximum solubility (0.01339 in mole fraction at 328.15 K) of palmatine chloride was obtained in neat ethanol. Under the same solvent composition and regular temperature, palmatine chloride was most soluble in a mixture of ethanol + water among all binary systems. X-ray powder diffraction and differential scanning calorimetry were employed to analyze palmatine chloride, which showed no significant change in the crystals before and after recrystallization. Three cosolvency models, the Jouyban-Acree model, van't Hoff-Jouyban-Acree model, and Apelblat-Jouyban-Acree model were employed to correlate the measured data. In all calculation results, the largest RAD and RMSD were 1.80 x 10(-2) and 6.80 x 10(-5).