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Method for separating mixture of normal hexane and tetrahydrofuran through extractive distillation

A technology of tetrahydrofuran and extractive rectification, applied in distillation purification/separation, organic chemistry and other directions, can solve problems such as inability to directly obtain tetrahydrofuran, complicated operation, etc., and achieve the effects of high recovery rate, simple process and high product purity

Active Publication Date: 2013-07-10
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method needs a large amount of water when separating the mixture of n-hexane and tetrahydrofuran. The tetrahydrofuran that enters the water phase after washing with water will form an azeotrope with water, so it is impossible to directly obtain qualified tetrahydrofuran. Meanwhile, anhydrous MgCl 2 Or the 13X molecular sieve also needs to be regenerated before it can be used, so this method is cumbersome to operate and is only suitable for the separation of a small amount of tetrahydrofuran in n-hexane

Method used

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  • Method for separating mixture of normal hexane and tetrahydrofuran through extractive distillation

Examples

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Effect test

Embodiment 1

[0013] In an extractive distillation column with an internal diameter of 50mm and 37 theoretical plates, the mixture of n-hexane and tetrahydrofuran (43% and 57% by mass) enters the column at the 20th theoretical plate at a rate of 5ml / min. The extraction agent N-methyl-2-pyrrolidone enters the column at the third theoretical plate at a rate of 20ml / min (that is, the solvent ratio is 4), and the control reflux ratio is 2, and n-hexane flows from the column at a rate of 2.4ml / min. The top extraction, the purity is 99.0%. N-methyl-2-pyrrolidone and tetrahydrofuran are extracted from the bottom of the tower and then enter the extraction agent recovery tower (with an inner diameter of 50 mm and equipped with 12 theoretical plates) on the fifth theoretical plate. The reflux ratio is 2, tetrahydrofuran is extracted from the top of the tower at a rate of 2.6ml / min, and the purity is 99.3%, and N-methyl-2-pyrrolidone is recycled from the bottom of the tower.

Embodiment 2

[0015] In an extractive distillation column with an internal diameter of 50 mm and 45 theoretical plates, the mixture of n-hexane and tetrahydrofuran (40% and 60% by mass content) enters the column at the 30th theoretical plate at a rate of 5 ml / min. The extraction agent N-methyl-2-piperidone enters the column at the 10th theoretical plate at a rate of 12ml / min (that is, the solvent ratio is 2.4), and the reflux ratio is controlled to be 5, and the rate of n-hexane is 2.3ml / min Extracted from the top of the tower, the purity is 99.1%. N-methyl-2-piperidone and tetrahydrofuran are extracted from the bottom of the tower and then enter the extraction agent recovery tower on the sixth theoretical plate (with an inner diameter of 50 mm and equipped with 15 theoretical plates. ), the reflux ratio is controlled to be 4, tetrahydrofuran is extracted from the top of the tower at a rate of 2.7ml / min, and the purity is 99.3%, and N-methyl-2-piperidone is recycled from the bottom of the to...

Embodiment 3

[0017] In an extractive distillation column with an internal diameter of 50mm and 30 theoretical plates, the mixture of n-hexane and tetrahydrofuran (60% and 40% by mass respectively) enters the column at the 15th theoretical plate at a rate of 5ml / min. The extractant N-methyl-2-piperidone enters the column at the fifth theoretical plate at a rate of 30ml / min (that is, the solvent ratio is 6), and the reflux ratio is controlled to be 2, and the rate of n-hexane is 3.5ml / min Extracted from the top of the tower with a purity of 99.2%, N-methyl-2-piperidone and tetrahydrofuran are extracted from the bottom of the tower and then enter the extraction agent recovery tower on the 8th theoretical plate (with an inner diameter of 50mm and equipped with 20 theoretical plates ), the reflux ratio is controlled to be 3, tetrahydrofuran is extracted from the top of the tower at a rate of 1.5ml / min, and the purity is 99.4%, and N-methyl-2-piperidone is recycled from the bottom of the tower. ...

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Abstract

The invention discloses a method for separating a mixture of normal hexane and tetrahydrofuran through extractive distillation. The method takes an N-substituted lactam compound as an extracting agent, and comprises the following steps of: allowing the mixture of normal hexane and tetrahydrofuran to be separated to enter an extractive distillation tower filled with 30-60 theoretical plates from the 15th to 40th theoretical plates, allowing the extracting agent to enter the tower from the 3rd to 20th theoretical plates, extracting the normal hexane from the top of the extractive distillation tower, extracting the extracting agent and the tetrahydrofuran from the bottom of the extractive distillation tower, allowing the extracting agent and the tetrahydrofuran to enter an extracting agent recovery tower filled with 12-30 theoretical plates from the 5th to 20th theoretical plates, extracting the tetrahydrofuran from the top of the extracting agent recovery tower, and extracting the extracting agent from the bottom of the extracting agent recovery tower for recycling. The method has the advantages of low energy consumption, high product purity, high recovery rate, simple process, high safety, environment friendliness and zero pollution, and clean production can be realized.

Description

technical field [0001] The invention relates to a method for separating the mixture of n-hexane and tetrahydrofuran, in particular to a method for separating the mixture of n-hexane and tetrahydrofuran by extractive distillation. Background technique [0002] n-Hexane is mainly used as a solvent in the industry, for the preparation of viscose to bond shoe leather and bags, and is often used for wiping and cleaning operations in the production process of the electronic information industry, crude oil leaching in the food manufacturing industry, and acrylic solvent in the plastic manufacturing industry n-hexane is also used in industries such as recovery, extraction agent in chemical experiments, and floral solvent extraction in daily chemical production. Tetrahydrofuran is not only a valuable organic solvent with excellent performance, but also an important organic synthesis intermediate, which is widely used in pharmaceutical, coating, leather and other fields. [0003] In ...

Claims

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Application Information

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IPC IPC(8): C07C9/15C07C7/08C07D307/08
Inventor 袁慎峰尹红杨文东陈志荣
Owner ZHEJIANG UNIV
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