间歇萃取精馏分离苯-环己烷

Separating Benzene and Cyclohexane by Batch Extractive Distillation

利用间歇萃取精馏分离技术,分别以N,N-二甲酰胺(DMF)、二甲基亚砜(DMSO)和二者的混合物作为萃取剂,对苯、环己烷近沸点体系的分离进行了试验研究,考察了操作参数回流比和溶剂流率对分离效果的影响,结果表明:随着回流比和溶剂流率的增加,分离效果增强;三种萃取剂均能对苯和环己烷进行有效的分离,但分离效果不同,其中以DMF∶DMSO=3∶1(质量比)混合物作为萃取剂时效果最好,其次是DMF。试验结果得到的最佳分离条件是:萃取剂为DMF∶DMSO=3∶1混合物,溶剂流率为12.33 mL/min,回流比为4,其产品中环己烷摩尔分数可达86.98%以上,环己烷收率可达83.10%。

The batch extractive distillation experiment for separating benzene and cyclohexane was carried out with N, N-dimethylformide （ DMF）, dimethyl sulfoxide （DMSO） and their mixture as extractive solvent. The influence of solvent flow rate and reflux ratio on the experimental result were studied. The experiment showed that the separation effect was improved with the increase of solvent flow rate and the reflux ratio. All the three extractive solvent can separate this mixture and the best one was DMF ： DMSO = 3 ： 1, the better one was DMF. The optimal operation condition was obtained with mixture DMF ： DMSO = 3 ： 1 as extractive solvent, the solvent flow rate being 12.33 mL/min, the reflux ratio being 4, the purity and yield of cyclohexane were up to 86.98 % and 83.10 % respectively.