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Refining method of 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: 2016-06-01
CHINA PETROLEUM & CHEM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] 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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  • Refining method of caprolactam

Examples

Experimental program
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Effect test

Embodiment 1

[0056] Provide the benzene solution containing caprolactam to be refined, add the above-mentioned benzene solution containing caprolactam into methanol, mix thoroughly and then filter to obtain the filtrate, the molar ratio of methanol to benzene is 1:10. The above filtrate was distilled at 75°C under normal pressure to remove benzene and methanol to obtain molten crude caprolactam. Then add the molten crude caprolactam into diisopropyl ether, fully dissolve and crystallize at 15°C, and obtain refined caprolactam after centrifugation. The mass ratio of the above molten crude caprolactam to diisopropyl ether is 1:3.

Embodiment 2

[0058] Provide the benzene solution containing caprolactam to be refined, add the above-mentioned benzene solution containing caprolactam into ethanol, mix thoroughly and then filter to obtain the filtrate, the molar ratio of ethanol to benzene is 10:1. Distill the above filtrate at 100°C under atmospheric pressure to remove benzene and ethanol to obtain molten crude caprolactam. Then add the molten crude caprolactam into cyclohexane, fully dissolve and crystallize at 60°C, and obtain refined caprolactam after centrifugation. The mass ratio of the above molten crude caprolactam to cyclohexane is 2:1.

Embodiment 3

[0060] Provide the benzene solution containing caprolactam to be refined, add the above-mentioned benzene solution containing caprolactam into methanol, mix thoroughly and then filter to obtain the filtrate, the molar ratio of methanol to benzene is 2.2:1. Distill the above filtrate at 80°C under normal pressure to remove benzene and methanol to obtain molten crude caprolactam. Then add the melted crude caprolactam into n-hexane, fully dissolve and crystallize at 40°C, and obtain refined caprolactam after centrifugation. The mass ratio of the above-mentioned molten crude caprolactam to n-hexane is 1:1.

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Abstract

The invention provides a refining method of caprolactam. The refining method comprises following steps: a caprolactam-containing benzene solution to be refined is provided; the caprolactam-containing benzene solution is added into a first solvent, and filtering is carried out after full mixing so as to obtain a filtrate, wherein molar ratio of the first solvent to benzene is controlled to be 1:10-10:1; the filtrate is subjected to normal pressure distillation so as to remove benzene and the first solvent and obtain molten crude caprolactam; the molten crude caprolactam is added into a second solvent, crystallization is carried out at 15 to 60 DEG C after complete dissolving, and centrifugal separation is carried out so as to obtain refined caprolactam, wherein mass ratio of the molten crude caprolactam to the second solvent is controlled to be 1:3-2:1. Compared with conventional caprolactam refining methods, the above refining method of caprolactam possesses following advantages: steps such as water reverse extraction and ion exchange are avoided, process flow is simple, and process water consumption 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] The industrial production of caprolactam (HPO method) is to make cyclohexanone oxime undergo Beckmann rearrangement reaction under the condition of fuming sulfuric acid to generate caprolactam. After the rearrangement reaction, the mixed solution containing oleum and caprolactam is neutralized with ammonia water. And, 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. [0003] The refining method of caprolactam produced...

Claims

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Application Information

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IPC IPC(8): C07D223/10C07D201/16
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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