Efficient cooling crystallization of phytosterol assisted by solubility and thermodynamics analysis in organic solvents

The phytosterol solubility in fourteen organic solvents with different polarities was determined using laser monitoring technique at various different temperatures. The experimental results showed that the solubility of phytosterols in organic solvents increased with the increase of temperature. Especially in dichloroethane, the solubility was more sensitive to temperature changes and had a higher value. Further, the solubility curves were fitted using the Wilson model, and the thermodynamic data of phytosterols in different organic solvents were analyzed by using Van’t Hoff method. The results showed that the crystallization of phytosterols was an enthalpy-driven exothermic process, and the enthalpy of crystallization changed as the temperature decreased during the process. Finally, combining the solubility and the thermodynamic data obtained from the above experiments, the phytosterol-rich deodorization distillate from vegetable oil (DD oil) was subjected to a continuous cooling crystallization and purification operation. Dichloroethane was chosen as the solvent for purifying phytosterols in the cooling crystallization process. After pretreatment with DD oil, the initial raw material 2.89 wt% phytosterol solvent for crystallization was obtained after DD oil pretreatment, and the final phytosterol yield was 77.46 % with a purity of 94.8 %.