Study On Separation Of Azeotrope

The separation of the mixture is important in chemical, petrochemical, medical, biochemical industries. Liquid mixture having azeotropic phenomenon cannot be separated by conventional distillation. But extractive distillation and combination of extractive and distillation can be valid for them.This paper summarizes the impact principle, choice basis, choice method of extractive solvent, and the research progress, application of batch extractive distillation and extractive in recent years. The batch extractive distillation experiment to separate benzene and cyclohexane was carried out with N,N－dimethylformide, dimethyl sulfoxide and their mixture as extractive solvent in this paper. The effect of operation parameter of solvent flow rate and reflux ratio on the separation result was 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 benzene and cyclohexane to some extent. The best was N,N－dimethylformide, the next was the mixture, and the last was dimethyl sulfoxide. In the experiment the best operation condition was with N,N－dimethylformide as extractive solvent, the solvent flow rate being 12.33ml/min, the reflux ratio being 6. Meanwhile, experiment with the ternary mixture of methanol, butyl methyl ether and 1-chlorobytane showed that the system was not ternary azeotrope and can be separated by combination of extractive and rectification using water as extractive solvent.