Method for improving quality of caprolactam product subjected to liquid-phase Beckmann rearrangement

A technology of Beckmann rearrangement and caprolactam, which is applied to the preparation of lactam, chemical instruments and methods, organic chemistry, etc., can solve the problems of high product alkalinity, high environmental protection treatment costs, and large water consumption for ion exchange. Shortening the refining process, stable product quality, and good product quality

Inactive Publication Date: 2020-08-28
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, ion exchange consumes a lot of water. The regeneration of ion exchange resin in the existing process, based on the production capacity of 100,000 tons, requires 100,000 tons of wastewater to be discharged every year, consumes 3,780 tons of 45% nitric acid, 4,320 tons of 32% sodium hydroxide, and the nitrogen content of wastewater. Seriously exceeding the standard, the cost of environmental protection treatment is high, the investment is high, and the loss of caprolactam is inevitable
In addition, the quality of caprolactam products caused by ion exchange is easy to fluctuate and the product alkalinity is too high. It is difficult to improve by adjusting the existing process parameters.

Method used

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  • Method for improving quality of caprolactam product subjected to liquid-phase Beckmann rearrangement
  • Method for improving quality of caprolactam product subjected to liquid-phase Beckmann rearrangement
  • Method for improving quality of caprolactam product subjected to liquid-phase Beckmann rearrangement

Examples

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Comparison scheme
Effect test

Embodiment 1

[0054] This example illustrates the method of the invention.

[0055] Raw materials: cyclohexanone oxime liquid-phase Beckmann rearrangement reaction, liquid ammonia neutralization, ammonium extraction and stripping, benzene extraction to obtain a solution of crude caprolactam and benzene, wherein the crude caprolactam content is 17.5% by weight, and the crude caprolactam The main components are: 99.8460 wt% caprolactam, 454ppm cyclohexanone, 53ppm cyanocyclopentane, 21ppm cyclohexenone, 8ppm 3-methylaniline, 13ppm aniline, 218ppm cyclohexanone oxime , 15ppm of n-pentanamide, 25ppm of octahydrophenazine, 52ppm of 1,3,4,5-tetrahydro-2H-azepin-2-one and its isomers, and other unidentified impurities (Chromatogram see figure 2 ).

[0056] The solution of the crude caprolactam product and benzene was evaporated under normal pressure to remove part of the benzene to obtain a mixture of the crude caprolactam product and benzene with a caprolactam content of 80.5% by weight. Take...

Embodiment 2

[0084] This example illustrates the method of the invention.

[0085] Raw material is with embodiment 1.

[0086] The solution of the crude caprolactam product and benzene was evaporated under normal pressure to remove part of the benzene to obtain a mixture of the crude caprolactam product and benzene with a caprolactam content of 75.5% by weight. Take 300g of the above-mentioned mixture of caprolactam crude product and benzene with a caprolactam content of 75.5% by weight, add it to a 1L three-necked flask, and add 266g of n-octane to it (solvent: CPL=1.5:1, benzene:n-octane=21.6:78.4) , heated to 65-70°C, and stirred (at a rate of 150r / min) for 30 minutes to completely dissolve the crude caprolactam product in the mixed solvent. Continue cooling while stirring (at a rate of 100 r / min), the temperature drops to 30° C., and the caprolactam crystals are fully separated out. The obtained slurry was centrifuged to obtain 192.5 g of 99.9955% by weight caprolactam crystals and a...

Embodiment 3

[0091] This example illustrates the method of the invention.

[0092] Raw material is with embodiment 1.

[0093] The solution of the crude caprolactam product and benzene was evaporated under normal pressure to remove part of the benzene to obtain a mixture of the crude caprolactam product and benzene with a caprolactam content of 79.8% by weight. Take 300 g of the above-mentioned mixture of caprolactam crude product and benzene with a caprolactam content of 79.8% by weight, put it into a 1L three-necked flask, and add 300 g of isooctane (solvent: CPL=1.5:1, benzene:isooctane=16.8:83.2) , heated to 65-70°C, and stirred (at a rate of 150r / min) for 30 minutes to completely dissolve the crude caprolactam product in the mixed solvent. Continue cooling while stirring (at a rate of 100 r / min), the temperature drops to 30° C., and the caprolactam crystals are fully separated out. The obtained slurry was centrifuged to obtain 208.3 g of 99.9937% by weight caprolactam crystals and a...

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Abstract

The invention discloses a method for improving the quality of a caprolactam product subjected to liquid-phase Beckmann rearrangement. The method is characterized by comprising the following steps: evaporating benzene from a benzene-crude caprolactam solution obtained in a liquid-phase Beckmann rearrangement reaction process to obtain a benzene-crude caprolactam solution of which the caprolactam weight content is greater than or equal to 55%; adding alkane with the carbon atom number of 6-12 into the benzene-crude caprolactam solution with the caprolactam weight content of more than or equal to55% to obtain a benzene-alkane-crude caprolactam solution; crystallizing at a temperature of 10-65 DEG C; washing the crystal and carrying out solid-liquid separation to obtain a crystal product; andcarrying out hydrogenation reaction on the obtained crystallization product in the presence of a catalyst, wherein in the benzene-alkane-crude caprolactam solution, the weight ratio of the mixed solvent of benzene and alkane to crude caprolactam is (0.6-4.0): 1, and the weight ratio of benzene to alkane is 1: (1-50).

Description

technical field [0001] The present invention relates to a method for improving the quality of caprolactam products, more specifically a method for improving the quality of liquid-phase Beckmann rearranged caprolactam products. Background technique [0002] Caprolactam (also known as ε-caprolactam, hexahydro-2H-azepin-2-one / capron, 1,6-caprolactam, cyclohexanoneisoxime, caprolactam, 2-ketohexamethylene Amine; English name Cyclohexanoneisooxime, ε-Caprolactam, CPL, Hexahydro-2H-azepin-2-one, Epsilum-Caprolactam, Epsilon-CPL, Epsilon-Caprolactam) is a monomer of nylon-6 synthetic fiber and nylon-6 engineering plastic. Caprolactam has the longest technological process and the most complicated production technology in the production of synthetic fiber monomer raw materials. At present, the industrial production of caprolactam mainly includes phenol method, cyclohexane oxidation method, toluene method, photonitrosation method, etc., and the starting materials used are phenol, ben...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D223/10C07D201/06
CPCC07D201/06C07D223/10
Inventor 武晓婷程时标谢丽张树忠
Owner CHINA PETROLEUM & CHEM CORP
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