Abstract: The effect of different ionic liquids on relative volatility of ethanol-cyclohexane system was examined at 0.101 MPa. The effects of solvent ratio on relative volatility of ethanol-cyclohexane system, and flow rate of ionic liquid and reflux ratio on purity and output of overhead fraction of the extractive distillation column with ionic liquid were studied. Repeated experiments were carried out under the optimum experimental conditions. The results show that the azeotropic point of ethanol-cyclohexane system is eliminated in extractive distillation with ionic liquid and relative volatility of cyclohexane to ethanol increases. The purity of cyclohexane is over 99.8% when [bmim]PF6 is used as extractant, solvent ratio 0.5, flow rate of ionic liquid 6 mL/min and reflux ratio 3. By flash distillation of residue, ethanol and ionic liquid can be separated. The recovery rate of ethanol is over 99.9% and the recycled usage of ionic liquid does not impair the separation performance.

Key words: ionic liquid, ethanol, cyclohexane, extractive distillation, azeotrope

摘要： 在0.101 MPa压力下，测定了不同离子液体对乙醇-环己烷共沸物相对挥发度的影响，研究了溶剂比(萃取剂与原料液体积比)对体系相对挥发度、离子液体加入速率和回流比对萃取精馏的影响，按实验确定的最佳工艺条件进行了重复实验. 结果表明，离子液体作为萃取剂可以消除乙醇-环己烷物系的共沸点，提高该物系的相对挥发度. 采用[bmim]PF6作为萃取剂，溶剂比为0.5，离子液体加入速率为6 mL/min，回流比为3，可得到纯度大于99.8%的环己烷. 釜液采用闪蒸分离回收乙醇和离子液体，乙醇的回收率达99.9%以上. 离子液体的循环使用不影响分离性能.

关键词: 离子液体, 乙醇, 环己烷, 萃取精馏, 共沸物