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Method for purifying and refining epsi-caprolactam

A technology of caprolactam and refining method, applied in the directions of preparation of lactam, separation/purification of lactam, chemical instrument and method, etc., can solve the problems of reducing the absorption value of potassium permanganate, decreasing the reaction efficiency and the like

Active Publication Date: 2007-11-14
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Excessive hydrogenation will reduce the reaction efficiency and reduce the absorption value of potassium permanganate

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] The gas phase Beckmann rearrangement reaction of cyclohexanone oxime was carried out in an 80ml fixed-bed reactor. The inner diameter of the reactor was 28mm. The molecular sieve catalyst with high silica to aluminum ratio MFI structure was loaded with 9.45g (Φ1.8mm strip catalyst). Pressure 0.1MPa, catalyst bed reaction temperature 365℃-385℃, carrier gas flow rate is 3.0L / gcat / hr, cyclohexanone oxime WHSV is 2h -1 , The partial pressure range of the mixture: cyclohexanone oxime 5.5kPa-11.6kPa, methanol (solvent) 36.9kPa-70.6kPa, nitrogen (carrier gas) 19.4kPa-52.6kPa. The reaction product is collected by circulating and cooling the ethylene glycol solution at -5°C to obtain a reaction product containing ε-caprolactam.

[0036] First, a simple distillation method is used to distill the reaction mixture to remove methanol, low boiling point impurities and high boiling point impurities, and finally crude ε-caprolactam is obtained. The crude ε-caprolactam was analyzed on Agile...

Embodiment 2

[0040] As described in Example 1, take 2.0Kg of crude ε-caprolactam obtained by the above simple distillation method, add it to a 10L reactor, and then add 2.0Kg of isopropyl ether, heat to 60-70°C, stir for 30 minutes to make ε- Caprolactam is completely dissolved in the solvent. Continue to cool while stirring, the temperature is cooled from 70°C to about 15°C, ε-caprolactam crystals are completely precipitated. After centrifugal separation, 1.94Kg 99.92% ε-caprolactam crystals and 2.05Kg 95.8% ether were obtained. The ether solvent is recovered. Return 1.94Kgε-caprolactam crystals to the 10L reactor, add 1.94Kg n-heptane, stir and wash for 30 minutes at room temperature, and then centrifuge to obtain 99.95% ε-caprolactam crystals and 98.8% n-heptane (in addition 1.00% ε-caprolactam). The n-heptane solvent is recovered. The PM value of the obtained ε-caprolactam is 126s, and the E value is less than 0.6.

[0041] Hydrogenation reaction: Take 2.1Kg of 99.95% ε-caprolactam crystal...

Embodiment 3

[0043] As described in Example 1, the ε-caprolactam crystals obtained by using isopropyl ether as the crystallization solvent and the washing solvent were subjected to a hydrogenation reaction, and the hydrogenation reaction was as follows.

[0044] Hydrogenation reaction: Take 2.1Kg isopropyl ether and 99.96% ε-caprolactam crystals after one wash, add it to a 5L reactor, add 210g SRNA-4 industrial grade amorphous nickel hydrogenation catalyst, and heat to about 90℃. Introduce hydrogen, control the hydrogen flow rate at 0.6L / min, and maintain the reaction pressure at 5atm, contact the molten ε-caprolactam with hydrogen, and react for 1 hour. After that, the reaction product was distilled under reduced pressure under the condition of about 1 mmHg to obtain 2.06 Kg of ε-caprolactam with a yield of 98%. The quality of the ε-caprolactam product obtained by analysis has a PM value of 32000s and an E value of <0.05.

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Abstract

This invention relates to a refine means of epsilon - caprolactam by separation and purification. The feature of the invention is that it includes the step of crystallize epsilon - caprolactam from ethereal solution containing crude epsilon - caprolactam. The product purity can reach 99.98%upwards, absorption value of potassium permanganate is greater than 10000 or more, the extinction value of epsilon - caprolactam at 290nm wavelength is 0.05 or smaller. The invention wholly meets the require of industrial product.

Description

Technical field [0001] The present invention relates to a method for producing ε-caprolactam, and more specifically, the invention relates to a method for separating, purifying and refining ε-caprolactam. Background technique [0002] ε-caprolactam is one of the important raw materials for synthetic fibers and synthetic resins. It is mainly used to make polyamide fibers (nylon 6), resins and films. At present, the industrial method for producing caprolactam is to use fuming sulfuric acid as a catalyst and solvent, and cyclohexanone oxime undergoes a liquid-phase Beckmann rearrangement reaction. This process has disadvantages such as corrosion of equipment, environmental pollution and unsatisfactory economic benefits, and a relatively large amount of ammonium sulfate is by-produced. [0003] The gas-phase Beckmann rearrangement reaction of cyclohexanone oxime on solid acid catalyst is a new process to realize the sulfur-free ammonium of ε-caprolactam. It has no equipment corrosion...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D201/16C07D201/04
Inventor 程时标孙斌王恩泉杨克勇张树忠吴巍闵恩泽
Owner CHINA PETROLEUM & CHEM CORP
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