Method for refining caprolactam

A technology of caprolactam and refining method, which is applied in the field of chemical production, can solve the problems of short regeneration period and easy saturation of ion exchange resin, and achieve the effects of reducing waste water discharge, reducing operating load and prolonging life

Active Publication Date: 2019-04-30
CHINA PETROLEUM & CHEM CORP +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to provide a method for refining caprolactam, to solve the problems of easy saturation of ion exchange resin and short regeneration cycle, prolong the regeneration cycle of ion exchange resin, reduce water consumption, agent consumption, waste water discharge and caprolactam run-off in the regeneration process damage

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  • Method for refining caprolactam

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Effect test

Embodiment 1

[0020] Cyclohexanone oxime and niacin are subjected to Beckmann rearrangement reaction to obtain rearrangement liquid. The rearrangement liquid is subjected to hydrolysis, ammonia causticization, and phase separation, and the crude caprolactam with about 4% ammonium sulfate and about 25% water is obtained from the light phase. The crude caprolactam was extracted with benzene to obtain benzene caprolactam. Styrene liquid index: conductivity, 80μs / cm; extinction value 1.04; caprolactam concentration 19%. The washing solution used in the washing process is 27.5% mass concentration of hydrogen peroxide solution, the addition is 2g / kg benzene ethyl alcohol, the washing temperature is 35 degrees, the washing equipment is a washing tower, and the tower form is a large-pore sieve plate tower. The conductivity of the washed benzene ethyl alcohol solution was 10 μs / cm, and the extinction value was 0.16. Use desalted water to back-extract the washed benzene-hexane solution. The back-ex...

Embodiment 2

[0022] Cyclohexanone oxime and niacin are subjected to Beckmann rearrangement reaction to obtain rearrangement liquid. The rearrangement liquid is subjected to hydrolysis, ammonia causticization, and phase separation, and the crude caprolactam with about 4% ammonium sulfate and about 25% water is obtained from the light phase. The crude caprolactam was extracted with benzene to obtain benzene caprolactam. Styrene liquid index: conductivity, 80μs / cm; extinction value 1.04; caprolactam concentration 19%. The washing solution used in the washing process is 50% mass concentration of hydrogen peroxide solution, the addition amount is 10g / kg benzene ethyl alcohol, the washing temperature is 40 degrees, and the washing equipment is a static mixer and a phase separation tank. The electrical conductivity of the washed benzene ethyl alcohol solution is 8 μs / cm, and the extinction value is 0.10. Use desalted water to back-extract the washed benzene-hexane solution. The back-extraction ...

Embodiment 3

[0024] Cyclohexanone oxime and niacin are subjected to Beckmann rearrangement reaction to obtain rearrangement liquid. The rearrangement liquid is subjected to hydrolysis, ammonia causticization, and phase separation, and the crude caprolactam with about 4% ammonium sulfate and about 25% water is obtained from the light phase. The crude caprolactam was extracted with benzene to obtain benzene caprolactam. Styrene liquid index: conductivity, 80μs / cm; extinction value 1.04; caprolactam concentration 19%. The washing solution used in the washing process is 10% mass concentration of hydrogen peroxide solution, the addition is 1g / kg benzene ethyl alcohol, the washing temperature is 50 degrees, the washing equipment is a washing tower, and the tower form is a large-pore sieve plate tower. The conductivity of the washed benzene ethyl alcohol solution was 9 μs / cm, and the extinction value was 0.15. Use desalted water to back-extract the washed benzene-hexane solution. The back-extra...

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Abstract

The invention relates to a method for refining caprolactam. The refining process comprises: (1) extracting crude caprolactam with benzene, wherein the extraction temperature is 30+/-2 DEG C, and the pressure is 50+/-5 Kpa; (2) washing the extracted benzene caprolactam solution with a hydrogen peroxide aqueous solution, wherein the washing temperature is 35-50 DEG C; (3) carrying out water back extraction on the washed benzene caprolactam solution to obtain a caprolactam aqueous solution, wherein the water back extraction temperature is 30+/-2 DEG C, the pressure is 50+/-5 Kpa, and a feeding ratio of the water to the feed in the water back extraction is 0.40-0.60:1, and the obtained caprolactam aqueous solution has a caprolactam concentration of about 28-38%; and (4) carrying out ion exchange treatment on the caprolactam aqueous solution by using an ion exchange device, wherein the ion exchange temperature is 45+/-5 DEG C, and the residence time is 8-12 min. According to the present invention, with the method, the operating load of the subsequent ion exchange process is effectively reduced, the service life of the ion exchange resin is easily prolonged, the frequency of regenerationoperations is reduced, and the operating cost and the labor intensity are reduced.

Description

technical field [0001] The invention belongs to the technical field of chemical production and relates to a product refining technology, in particular to a method for refining caprolactam. Background technique [0002] Caprolactam is one of the important raw materials for synthetic fibers and resins, mainly used in the manufacture of polyamide fibers (nylon 6), resins and films. At present, industrial production of caprolactam mainly uses benzene as raw material, including hydrogenation of benzene to cyclohexene, cyclohexene hydration to cyclohexanone, cyclohexanone ammoximation to cyclohexanone oxime, and cyclohexanone oxime to fume Sulfuric acid catalyzed Beckmann rearrangement to obtain caprolactam and other steps. To remove the catalyst and many by-products similar to caprolactam from the crude caprolactam, it needs to go through a lengthy process for separation and purification, mainly including neutralization, benzene extraction, benzene hexane washing, water extracti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D223/10C07D201/16
CPCC07D201/16C07D223/10
Inventor 骆广生王仲霞吕阳成李辉崔焕茹
Owner CHINA PETROLEUM & CHEM CORP
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