本研究主要目的在於探討有機水溶液中添加生物緩衝劑4-（2-羥乙基）-1-呱秦丙磺酸（3-[4-(2-hydroxyethyl)-1-piperazinyl]-propanesulfonic acid，EPPS）之混合物液液相行為，這些水溶液系統含有下列任一有機物質：正丙醇、異丙醇、叔丁醇、1,3-二氧五環、1,4-二氧陸圜、四氫呋喃或乙腈。當添加特定量的緩衝劑（EPPS）於上述之水溶液時，會產生另一新的液相。本研究所量測之三成分水溶液系統的液液相平衡及固液液相平衡數據，皆是在溫度為298.2 K且常壓下。緩衝劑（EPPS）之有效排斥體積模式參數可由液液相邊界數據經關聯後求得，Othmer-Tobias關聯式所得到的結果顯示實驗數據具有良好的一致性，實驗之縛線數據均能以NRTL模式獲得良好的關聯。此種緩衝劑析出效應可能有助於從水溶液中回收有機溶劑。

The objective of this study is to investigate the liquid-liquid phase equilibrium behavior of organic aqueous systems containing a biological buffer 3-[4-(2-hydroxyethyl)-1-piperazinyl]propanesulfonic acid (EPPS). The studied aqueous systems including one of following organic compounds：1-propanol, 2-propanol, tert-butanol, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, or acetonitrile. A new liquid phase was formed when we added certain amount of EPPS into the above mentioned aqueous solutions. The liquid-liquid equilibrium (LLE) and solid-liquid-liquid equilibrium (SLLE) data were measured for these ternary aqueous systems at 298.2 K under atmospheric pressure. The effective excluded volume (EEV) values of EPPS were obtained from the phase boundary data. The results of Othmer-Tobias illustrated that the LLE experimental data appear to be well-consistent. The experimental tie-lines data were correlated satisfactionly with the NRTL model. The buffering-out effect may be useful in the recovery of organic solvent from the aqueous solutions.

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