H_2O-CH_2Cl_2-[Bmim]BF_4体系的液液相平衡测定及其关联  

Measurement and Correlation of Liquid-Liquid Equilibrium Data for H_2O-CH_2Cl_2-[Bmim]BF_4 System

作　　者：林金清[1] 王国平[1] 方伟慧[1] 林晶[1] 金春英[1] 

机构地区：[1]华侨大学材料科学与工程学院,福建泉州362021

出　　处：《高校化学工程学报》2009年第5期736-741,共6页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金项目(20776057);国务院侨办重点课题(05QZR03);华侨大学科研基金(07X0144)

摘　　要：采用两步法合成了离子液体[Bmim]BF4,并利用红外光谱、核磁共振、元素分析等手段对所合成的产物进行表征和分析。利用浊点法测定了常压30℃下H2O-CH2Cl2-[Bmim]BF4体系的饱和溶解度曲线和密度曲线并进行了关联,还进一步采用浊点-密度法测定该体系的液液相平衡数据。由实验数结果可以看出:该体系上相以H2O为主,CH2Cl2、[Bmim]BF4的含量很少,下相则以[Bmim]BF4、CH2Cl2为主,H2O的含量很少;随着体系中CH2Cl2含量的增加上相中[Bmim]BF4的含量从0.1665下降到0.1032。由此可见在纯化离子液体[Bmim]BF4时适当地增加CH2Cl2的用量可以减少[Bmim]BF4的损失。采用Othmer-Tobias和Bancroft经验方程对液液相平衡数据进行关联,关联结果不理想;采用Othmer-Tobias经验方程+溶解度方程法对其关联,最大相对误差为4.43%,最大平均相对误差为3.03%,关联精度较高。The hydrophilic ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate （[Bmim]BF4） was synthesized with two-step method and characterized by IR,NMR and element analysis; the characterization and analysis indicate that the synthesized product is really the aim product. The solubility curve and density curve of the H2O（w1）-CH2Cl2（w2）-[Bmim]BF4（w3） system were measured with the turbidity titration method at 30℃ under atmospheric pressure and were correlated with empirical equations; The liquid-liquid phase equilibrium data of the system were further measured with the turbidity-density method. The experimental results show that the light phase of the system is mainly composed of water and the concentrations of CH2Cl2 and [Bmim]BF4 in it are very low; however,the heavy phase of the system is composed mainly of CH2Cl2 and [Bmim]BF4 and water concentration is very low. The experimental data show that,in the system,the [Bmim]BF4 concentration decreases from 0.1665 to 0.1032 with the increase of CH2Cl2 concentration. It indicates that adding CH2Cl2 properly can lessen the loss of the [Bmim]BF4 during purification of the ionic liquid. Empirical equations of Othmer-Tobias and Bancroft were used for the correlation of the liquid-liquid phase equilibrium data of the studied system and the result is not satisfactory; then a new method of using Othmer-Tobias and solubility equations to correlate the above data. The results show that,using the proposed method,the calculated results are in good agreement with the experimental data; the maximum relative error is about 4.43% and the maximum average relative error is about 3.03%.

关 键 词：[BMIM]BF4 浊点-密度法 液液相平衡 纯化 关联 

分 类 号：O642.42[理学—物理化学] TQ013.1[理学—化学]