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Method for refining caprolactam

A technology of caprolactam and refining method, which is applied in the field of caprolactam refining, and can solve the problems of large process water consumption and complicated process flow

Inactive Publication Date: 2015-11-04
CHINA PETROLEUM & CHEM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Based on this, it is necessary to provide a caprolactam refining method with simple process flow and less process water consumption for the traditional caprolactam refining method, which has complex process flow and large process water consumption.

Method used

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  • Method for refining caprolactam

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Effect test

Embodiment 1

[0048] The benzene solution containing caprolactam to be refined is provided, the above-mentioned benzene solution containing caprolactam is heated to 75° C., and the benzene is evaporated under normal pressure to obtain molten crude caprolactam. Diisopropyl ether was added to the above molten crude caprolactam, the mass ratio of molten crude caprolactam to diisopropyl ether was 1:3, and after fully dissolved, hot filtration was performed at 40°C to obtain a filtrate. The above filtrate was crystallized at 15°C, and purified caprolactam was obtained after centrifugation.

Embodiment 2

[0050] The benzene solution containing caprolactam to be refined is provided, the above-mentioned benzene solution containing caprolactam is heated to 100° C., and the benzene is evaporated under normal pressure to obtain molten crude caprolactam. Add cyclohexane to the above molten crude caprolactam, the mass ratio of the molten crude caprolactam to cyclohexane is 2:1, fully dissolve and perform hot filtration at 85°C to obtain a filtrate. The above filtrate was crystallized at 60°C, and purified caprolactam was obtained after centrifugation.

Embodiment 3

[0052] The benzene solution containing caprolactam to be refined is provided, the above-mentioned benzene solution containing caprolactam is heated to 80° C., and the benzene is evaporated under normal pressure to obtain molten crude caprolactam. Add n-hexane to the above melted crude caprolactam, the mass ratio of molten crude caprolactam to n-hexane is 1:1, fully dissolve and perform hot filtration at 60°C to obtain filtrate. The above filtrate was crystallized at 40°C, and purified caprolactam was obtained after centrifugation.

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Abstract

The invention provides a method for refining caprolactam. The method comprises the following steps: providing a caprolactam-containing benzene solution to be refined; evaporating the caprolactam-containing benzene solution under normal pressure to remove benzene, thus obtaining molten crude caprolactam; adding a solvent to the molten crude caprolactam, hot filtering after the molten crude caprolactam is completely dissolved, thus obtaining a filtrate; and crystallizing the filtrate at 15-60 DEG C and separating centrifugally to obtain refined caprolactam. The method for refining caprolactam is simple in process flow and moreover the water consumption of the process is reduced greatly.

Description

technical field [0001] The invention relates to the field of fine chemicals, in particular to a method for refining caprolactam. Background technique [0002] In the industrial production of caprolactam, under the catalytic condition of oleum, cyclohexanone oxime undergoes Beckmann rearrangement reaction to generate caprolactam. After the rearrangement reaction, the mixed solution containing oleum and caprolactam is neutralized with ammonia water to produce Ammonium sulfate, then separate and purify ammonium sulfate and crude amide. Usually, the organic solvent benzene is first used for extraction to obtain a benzene solution containing about 30% caprolactam. Since caprolactam is an important raw material for the synthesis of polyamide, the above-mentioned benzene solution containing about 30% caprolactam needs to be further refined to meet the high purity requirement for polyamide raw materials. The traditional refining method of caprolactam is: benzene extraction→water s...

Claims

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Application Information

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IPC IPC(8): C07D223/10C07D201/16
CPCC07D223/10C07B2200/13C07D201/16
Inventor 徐风华旷志刚肖朝晖李先华曾红霞焦岳飞柳亚妮
Owner CHINA PETROLEUM & CHEM CORP
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