Ethyl lactate is a hydrophilic green solvent which is bio-renewable and biodegradable with low toxicity towards humans and animals. For the first time, we report that aqueous solutions of ethyl lactate separate into two aqueous phases upon addition of salts. The performance of trisodium citrate, disodium tartrate and disodium succinate as salting-out media for the separation of natural organic compounds, such as caffeine and catechin, from their aqueous solutions was examined. In this respect, cloud points for the ternary solutions composed of ethyl lactate, water and salt were determined at ambient pressure (0.1 MPa) at 298.2 K. Partition coefficients of caffeine and catechin between two phases were determined by chemical analysis of phases in equilibrium for different initial compositions at 298.2 K. The obtained results clearly demonstrate the ability of the ternary mixture to phase separate, providing good salting-out media for the efficient and sustainable separation from aqueous solution. ¹H NMR spectroscopy was employed to elucidate the mechanisms of phase splitting in the ternary (ethyl lactate + water + salt) systems at molecular level. The discovery of aqueous biphasic system (ABS) containing ethyl lactate as hydrophilic solvent opens a new and green platform for extraction of various compounds from aqueous solutions.

乳酸乙酯是一种亲水性绿色溶剂，可生物再生和生物降解，对人类和动物毒性低。我们首次报道，加入盐后，乳酸乙酯水溶液分离成两个水相。考察了柠檬酸三钠，酒石酸二钠和琥珀酸二钠作为盐析介质从水溶液中分离出天然有机化合物（如咖啡因和儿茶素）的性能。在这方面，由乳酸乙酯，水和盐组成的三元溶液的浊点是在环境压力（0.1 MPa）和298.2 K下确定的。咖啡因和儿茶素在两相之间的分配系数通过平衡下各相的化学分析来确定。 298.2 K时的不同初始组成。¹ H NMR光谱用于阐明三元（乳酸乙酯+水+盐）系统在分子水平上的相分离机理。包含乳酸乙酯作为亲水性溶剂的双相水溶液体系（ABS）的发现为从水溶液中提取各种化合物开辟了一个新的绿色平台。