Method for separating cyclohexane and cyclohexene by extraction and rectification

Abstract

The invention discloses a method for separating cyclohexane and cyclohexene by extraction and rectification, which comprises the following steps of: a) performing extraction and rectification on the mixed solution of the cyclohexane and the cyclohexene in an extraction and rectification tower, wherein the extraction agent is sulfolane, the cyclohexane is obtained at the top of the tower, and rich solvent solution of the cyclohexene and the sulfolane extraction agent is obtained at the bottom of the tower; and b) delivering the rich solvent solution obtained at the bottom of the extraction and rectification tower to a solvent recovery tower, wherein the cyclohexene is obtained at the top of the solvent recovery tower, and the reclaimed sulfolane extraction agent obtained at the bottom of the tower is returned to the step a) to recycle. By the separation method, high-purity cyclohexane and cyclohexene products can be obtained, the extraction agent can be recycled by reclaiming, the separation efficiency can be improved, and equipment investment and process energy consumption are remarkably reduced.

Description

technical field [0001] The invention relates to an extraction and rectification separation method, in particular to a method for extraction and rectification separation of cyclohexane and cyclohexene. Background technique [0002] With the development of the current synthetic fiber and polyamide industries, the partial hydrogenation of benzene to prepare cyclohexene has become an important research direction in the chemical industry in recent years. The cyclohexane and cyclohexene involved in the process are very important organic compounds. , the boiling points are 80.7°C and 83°C respectively, and the relative volatility is about 1.15, belonging to the near-boiling point system. The process requires that they be separated to products above 99.0% wt. If ordinary rectification is used for separation, the number of theoretical plates in the rectification column exceeds 150, and the operating reflux ratio is as high as 20, so that the energy consumption of the entire separatio...

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Problems solved by technology

[0003] Chinese patent CN200910075129.9 discloses a method for producing cyclohexanone using coking benzene as a raw material. The process uses N,N-dimethylacetamide as an extractant to separate cyclohexane and cyclohexene. The ratio of extractant to raw material It is 6: 1, and the operating reflux ratio is as high as 10: 1, and the cyclohexane above 99.5wt% and the cyclohexene above 99.0wt% can be obtained. This process obviously has a relatively large reflux ratio and extractant feed, and the energy of the whole process Consumption is the bottleneck of its process

In view of the difficult separation and high energy consumption of cyclohexane and cyclohexene, it is urgent to develop a separation process with high efficiency and low energy consumption to effectively separate cyclohexane and cyclohexene

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