Allyl alcohol and water can form the lowest boiling point azeotrope, but it is very hard to acquire high-purity allyl alcohol by normal distillation methods. Herein, a separation and purification protocol is developed for perfectly separating an azeotropic mixture of allyl alcohol and water using the salting-out method, in which three potassium phosphate salts, K5P3O10, K3PO4, and K4P2O7, are systematically investigated as salting-out agents, and finally a product consisting of > 99% allyl alcohol is obtained. A thermodynamic study demonstrates that this process involves endothermy and increment entropy. There is a good correlation between the solubility of allyl alcohol and the molar concentration of salt (mol per 1 kg water), and the solubility of the allyl alcohol in the organic phase or the water phase can be forecast using the mass percentage of salts. This work provides a new methodology for the efficient separation of an azeotropic mixture of allyl alcohol and water.

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