We have found that the ionic liquid (IL) [TMA][EPPS] could induce liquid–liquid phase splitting in the aqueous solution of 1,4-dioxane at ambient conditions. This IL is composed of tetramethylammonium (TMA) as a cation and a biological buffer, 4-(2-hydroxyethyl)-1-piperazinepropanesulfonic acid (EPPS), as an anion. The efficiency of this buffer-based IL for separating 1,4-dioxane from its aqueous solution has been evaluated on the basis of the liquid–liquid equilibrium (LLE) and solid–liquid–liquid equilibrium (SLLE) data of 1,4-dioane + water + [TMA][EPPS] at 298.15 K and under atmospheric pressure. The experimental LLE phase boundary data were correlated with an empirical equation and the effective excluded volume (EEV) model, respectively. The consistency of the LLE tie-line data was confirmed by using the Othmer–Tobias model. The binary interaction parameters of the NRTL model for each pair were obtained by correlating the experimental LLE and SLLE tie-line data. By using [TMA][EPPS] as an auxiliary agent, the maximum concentrations of 1,4-dioxane (97.8 wt %) in the organic-rich phase is greater than the azeotropic compositions (87.82 wt %) of the corresponding aqueous system. It clearly indicates that [TMA][EPPS] can be served as a high efficiency, noncorrosive, and biocompatible green agent for recovering high purity of 1,4-dioxane from its aqueous solution.

中文翻译：

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缓冲液型离子液体在共沸水溶液中分离1,4-二恶烷的应用

我们发现，在环境条件下，离子液体（IL）[TMA] [EPPS]可以在1,4-二恶烷水溶液中引起液相-液相分裂。该IL由四甲基铵（TMA）作为阳离子和生物缓冲剂，4-（2-羟乙基）-1-哌嗪丙烷磺酸（EPPS）作为阴离子。基于1,4-的液-液平衡（LLE）和固-液-液平衡（SLLE）数据，已评估了这种基于缓冲液的IL从水溶液中分离1,4-二恶烷的效率。在298.15 K且在大气压下的二烷+水+ [TMA] [EPPS]。实验的LEE相边界数据分别与经验方程和有效排除体积（EEV）模型相关。通过使用Othmer-Tobias模型确认了LLE联系线数据的一致性。通过关联实验LLE和SLLE联络线数据，获得每对NRTL模型的二元相互作用参数。通过使用[TMA] [EPPS]作为辅助剂，富含有机物的相中1,4-二恶烷的最大浓度（97.8 wt％）大于相应水性体系的共沸组合物（87.82 wt％）。清楚地表明，[TMA] [EPPS]可以用作从其水溶液中回收高纯度1,4-二恶烷的高效，无腐蚀性和生物相容性绿色试剂。