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Purifying method of N-vinyl-Epsilon-caprolactam

A caprolactam and purification method technology, applied in the field of obtaining pure N-vinyl-ε-caprolactam, can solve the problems of high mother liquor content requirements, numerous process steps, and difficult control operations, etc.

Active Publication Date: 2010-04-21
GANSU RES INSTION OF CHEM IND GRICI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a purification method for N-vinyl-ε-caprolactam, so as to solve the problem that the existing purification method has many process steps, the control operation is not easy, and the shortcoming that the content of the mother liquor is required is high.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] 1. Take 1000g of N-vinyl-ε-caprolactam reaction solution, whose N-vinyl-ε-caprolactam content is 50% (GC), add 1000ml of dichloroethane to dissolve the reaction solution, add 250ml of water to wash, the first time Discard the water phase, add 4000ml water each time and wash with water 6 times,

[0019] 2. Carry out normal pressure distillation to recover organic solvent to organic phase, carry out vacuum distillation again, obtain high-content N-vinyl-ε-caprolactam, its purity is more than 99% (GC), total yield is more than 38%, solvent recovery The rate is above 83%.

[0020] The water phase distillation of the second water washing recovers caprolactam, and the water washing liquid collected for the third, fourth to sixth times can be used for washing the next batch of samples.

Embodiment 2

[0022] 1. Take 1000g of N-vinyl-ε-caprolactam reaction solution, whose N-vinyl-ε-caprolactam content is 75% (GC), add 2000ml of dichloroethane to dissolve the reaction solution, add 250ml of water to wash, the first time Discard the water phase, add 3000ml water each time and wash with water 4 times;

[0023] 2. Carry out normal pressure distillation to recover organic solvent to organic phase, carry out vacuum distillation again, obtain high-content N-vinyl-ε-caprolactam, its purity is more than 99% (GC), total yield is more than 60%, solvent recovery The rate is above 90%.

[0024] The water phase distillation of the second water washing recovers caprolactam, and the third and fourth water washing liquids can be used for washing the next batch of samples.

Embodiment 3

[0026] 1. Take 1000 g of N-vinyl-ε-caprolactam reaction liquid, whose N-vinyl-ε-caprolactam content is 85% (GC), and add 2000 ml of dichloroethane. Dissolve the reaction solution, add 250ml of water to wash, discard the water phase for the first time, add 2000ml of water each time and wash with water twice,

[0027] 2. Carry out normal pressure distillation to recover organic solvent to organic phase, carry out vacuum distillation again, obtain high-content N-vinyl-ε-caprolactam, its purity is more than 99% (GC), total yield is more than 69%, solvent recovery The rate is above 95%.

[0028] The water phase distillation of the second water washing recovers caprolactam.

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PUM

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Abstract

The invention discloses a purifying method of N-vinyl-Epsilon-caprolactam, aiming to overcome the defects of more process steps, difficult operation control and high requirement for the content of mother liquid in the traditional purifying method. The purifying method comprises the following steps: A. extracting and washing: dissolving N-vinyl-Epsilon-caprolactam reaction liquid to be washed by adding an organic solvent, adding water in an organic system to wash; and B. distilling: distilling the organic solution in the step A at normal pressure to recycle the organic solvent, and carrying out reduced pressure distillation to obtain the N-vinyl-Epsilon-caprolactam with high content. In the purifying method, a distilling method is adopted, most importantly, liquid-liquid extraction is used as a main purifying means in the method, and the reaction liquid is directly treated, thereby omitting the distilling step, ensuring that the method and needed equipment are simpler and suitable for industrial mass production, and saving the production cost; and it is worth mentioning that the caprolactam, the organic solvent and the water are all reused in the whole process.

Description

technical field [0001] The invention relates to a method for obtaining pure N-vinyl-ε-caprolactam from N-vinyl-ε-caprolactam reaction liquid. The method includes a single-step or multi-step extraction and washing method using an organic solvent / water system. Background technique [0002] N-vinyl-ε-caprolactam is a lactam compound and an important intermediate for the synthesis of poly N-vinyl-ε-caprolactam. Poly(N-vinyl-ε-caprolactam) is a temperature-sensitive high polymer with low critical phase transition temperature (LCST), which is a kind of high polymer with special thermal properties. When the temperature is lower than the LCST, its solubility in the solution will slowly decrease as the temperature increases; when the temperature rises to a small range near the LCST, its solubility will suddenly decrease, and heat sinking occurs. This change is reversible. The low critical phase transition temperature (LCST) of poly N-vinyl-ε-caprolactam is just in the physiologica...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D223/10
Inventor 李鸿洲张鹏云李春新韩庆荣刘汉功巨雪霞李丽丽
Owner GANSU RES INSTION OF CHEM IND GRICI