Separation And Purification Of Synthetic Borneol With Crystallization

The paper is mainly focused on the separation and purification process of synthetic borneol systematically by the means of the cooling crystallization and the anti-solvent crystallization, and establishing the thermodynamics and kinetics models of the crystallization process. The essential data for the separation and purification of synthetic borneol are obtained.Based on the purity and yield of the crystal product, the cooling crystallization and the anti-solvent crystallization are adopted. The two methods can both achieve the desired purity and yield, demonstrating the feasibility of crystallization purification with the screening solvents and the selected crystallization methods.The solubility of borneol is determined in the ethanol/water and acetone/water mixed solvents with the synthetic method, and the three modified Apelblat, General Single, and Hybrid models are adopted to correlate the solubility data. The ideal solubility models are set up. Furthermore, the thermodynamic functions are deduced by means of van’t Hoff equation.The crystallization process is studied aiming at the purity and yield of the crystal produdct:(1) To the cooling crystallization. In ethanol solvent the optimal conditions are: concentration 2.82g.g-1; seed loaded 5%; cooling rate 0.1℃/min; crystallization time 2h and the crystallization product purity 93.50%, yield 67.73%. In acetone solvent the optimal conditions are:concentration 1.75 g.g-1; seed loaded 2%; cooling rate 0.1℃/min; crystallization time 2h and the crystallization product purity 94.46%, yield 68.69%.(2) To the anti-solvent crystallization. In ethanol/water mixed solvent, the optimal conditions are:solvent composition 0.5; seed loaded 5%; anti-slovent injected slowly; crystallization time 60min and the crystallization product purity 94.38%, yield 67.24%. In acetone/water mixed solvent, the optimal conditions are:solvent composition 1.25; seed loaded 2%; anti-slovent injected slowly; crystallization time 90min and the crystallization product purity 93.64%, yield 66.27%.The metastable zone width of borneol in ethanol obtained at different cooling rates and the isothermal dependence of induction time on different supersaturations for borneol are determined. Therefore, the primary nucleation rate equation and the linear equation of metastable zone width dependent on the dissolving temperature and the cooling rate are established. BN=dN/dt=7.043×10 11△c1.88 ln(△Tmax/T0)=Φ+βlnR...