Separation and Purification of (−)-Shikimic Acid and (−)-Quinic Acid by the Phase Diagrams of the Ternary System of (−)-Shikimic Acid + (−)-Quinic Acid + H2O and the Quaternary System of (−)-Shikimic Acid + (−)-Quinic Acid + Ethanol (φ ∼ 50%,φ ∼ 75%) + H2O

The solid liquid phase equilibrium for the ternary system of (-)-Shikimic acid + (-)-Quinic acid + H2O and the quaternary system of (-)-Shikimic acid + (-)-Quinic acid + Ethanol (phi similar to 50%,phi similar to 75%) + H2O was measured at T = 298.15, 318.15, 333.15, 348.15 K, and mutual solubility was obtained. Three variable-temperature :phase diagrams were constructed according to the experimental solubility. In the phase diagrams, there were in all one invariant pint, two univariant curves, and two crystallization regions corresponding to (-)-Shikimic acid and (-)-Quinic acid at each temperature in the sttidied system. The crystallization regions of the pure two solids increase with a decrease in temperature. The variable-temperature diagrams for the quaternary system of (-)-Shikimic acid + (-)-Quinic acid + Ethanol (phi similar to 50%) + H2O can be used for effective separation and purification of (-)-Shikimic acid and (-)-Quinic acid. Meanwhile, the solid + liquid phase equilibrium data can be used for the separation process of (-)-Shikinic acid and (-)-Quinic acid in industrial production and further theoretical studies.