乙醇+甲苯+水+碳酸钾四元物系液液平衡数据的研究

Quaternary Liquid-Liquid Equilibrium Data for System of Ethanol + Toluene + Water + Potassium Carbonate

乙醇-甲苯物系为共沸物,普通精馏的方法不能将其有效地分离.本研究采用水+碳酸钾(K2CO3)混合溶剂液液萃取分离乙醇-甲苯混合物.用气相色谱测定乙醇+甲苯+水+碳酸钾四元体系在大气压下、298.15 K时的液液平衡数据,计算了水+碳酸钾混合萃取剂对乙醇的选择性系数和分配系数.实验结果表明,选择性系数及分配系数都远大于1,选择性系数随着萃余相中乙醇含量的增加而减小,随着萃取剂中盐含量的增加而增大.平衡数据采用Rajendran改进的Eisen-Joffe模型方程进行关联计算,计算方程的最小相关系数为0.994,最大标准差为0.05.

The mixture of ethanol-toluene is an azeotrope, which could not be separated effectively by simple distillation method. In this study, ethanol-toluene mixture is separated by liquid-liquid extraction with water ＋ potassium carbonate （K2CO3 ） mixed solvent. Liquid-liquid equilibrium data with the quaternary system of ethanol ＋ toluene ＋ water ＋ potassium carbonate are determined at atmospheric pressure and 298. 15 K by gas chromatography. The selectivity and partition coefficient of ethanol in water ＋ potassium carbonate extraction agent are calculated. The experimental results show that the selectivity and partition coefficient are far greater than 1. The selectivity coefficients decrease with the increase of ethanol content in the raffinate, but increase with the increase of potassium carbonate content in extraction agent. The experimental data are correlated by Rajendran＇ s improved Eisen-Joffe model. It is found that the least correlation coefficient is 0. 994, and the maximum standard deviation is 0. 05.