乙酸乙酯-乙醇-1-辛基-3-甲基咪唑四氟硼酸盐物系汽液平衡数据的测定

在101.32 kPa下,用改进的Othmer汽液平衡釜测定了乙酸乙酯-乙醇-1-辛基-3-甲基咪唑四氟硼酸盐([omim]BF_4)三组分物系的等压汽液相平衡数据。采用NRTL方程对实验数据进行了关联,得到方程参数,活度系数的计算值与实验值的偏差为3.12%。实验结果表明,加入[omim]BF_4使汽液平衡线偏离乙酸乙酯-乙醇二组分物系的汽液平衡线,[omim]BF_4含量越大,偏离程度越大;[omim]BF_4具有明显的盐析效应,能够增大乙酸乙酯对乙醇的相对挥发度;当x([omim]BF_4)为10%时,乙酸乙酯-乙醇物系的共沸点消失,随[omim]BF_4含量的增加,乙酸乙酯对乙醇的相对挥发度增加。

Isobaric Vapor Liquid Equilibrium for Ethyl Acetate Ethanol 1 Octyl 3 Methyl imidazolium Tetrafluoroborate

Isobaric vapor liquid equilibrium data of ethyl acetate ethanol 1 octyl 3 methylimidazolium tetrafluoroborate([omim]BF_4) ternary system were measured at 101.32 kPa in a modified Othmer still. The ionic liquid [omim]BF_4 exhibited noticeable salt out effect which enhanced the relative volatility. When x([omim]BF_4) amounted to 10%, the azeotropic point disappeared and relative volatility of the system increased with the increase of [omim]BF_4 mole fraction. NRTL equations were used to correlate the experimental data. The average relative deviation between the predicted activity coefficients and the experimental data was 3.12%. The equations were proved to be appropriate for the system involving with ionic liquid. The predicted results agreed well with the experimental results. The vapor liquid equilibrium curve of ethyl acetate ethanol with the ionic liquid deviated from the curve of ethyl acetate ethanol without the liquid, which indicated that [omim]BF_4 could be taken as a satisfactory solvent for extractive distillation of ethyl acetate ethanol system.