反應蒸餾法為一個有效的粗乳酸純化分離方法，可藉由加入正丁醇進行酯化反應，所生成的乳酸正丁酯再進行水解反應，可得到高純度乳酸。欲開發設計此製程，量測與迴歸該製程相關之相平衡數據乃屬必需，亦為本研究之目標。 本研究採用頂空層析方法來量測水-正丁醇及正丁醇-乳酸正丁酯於恆溫下(348.15K)二元成份系統之汽液相平衡數據，實驗結果通過了熱力學一致性檢驗，此外並量測了水-正丁醇-乳酸正丁酯三元成份系統之液液相平衡數據，再以動態再循環式裝置量測定壓下(45kPa)乳酸-正丁醇-水-乳酸正丁酯四元成份系統之汽液相平衡數據，以及定壓下(101.3 kPa)水-正丁醇系統之汽液液相平衡數據。本研究依照最大概似原理(Maximum-Likelihood Principle)，分別嘗試以NRTL與UNIQUAC模式進行相平衡數據迴歸，並提出四個迴歸方式，詳加分析與比較各模式之預測能力，尋找出最能代表所有相平衡數據的熱力學模式，最後使用六組NRTL二元交互作用參數(含非隨機參數)，可獲致不錯的結果，將可供製程模擬及設計之用。 Reactive distillation can be an effective means for purification of crude lactic acid. It can be achieved by esterification of crude lactic acid with n-butanol, followed by hydrolysis of butyl lactate. In order to develop this reactive distillation process, measurement of phase equilibrium data and their regression are necessary and are the focus of this study. In this study, headspace chromatography method was employed to measure binary vapor-liquild equilibrium data of n-butanol/n-butyl lactate and water/n-butanol systems at 348.15K, and the experimental results passed the thermodynamic consistency test. Liquid-liquild equilibrium data were also taken for the ternary water/n-butanol/n-butyl lactate system. In addition, a dynamic recirculating cell was used to measure isobaric quaternary vapor-liquild equilibrium data of lactic acid/n-butanol/water/n-butyl lactate system, together with vapor- liquild-liquid equilibrium data for the water/n-butanol system. Based on the Maximum Likelihood Principle, data reduction was done using NRTL and UNIQUAC models. Four regression schemes were presented and compared in terms of model predictive accuracy. Six sets of binary interaction parameters, including non-randomness parameters, that best represent the measured data were found and can be used for process simulation and design purposes.
