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Novel Beckmann rearrangement method for preparing caprolactam from cyclohexanone oxime

A technology of Beckmann rearrangement and cyclohexanone oxime, which is applied to the preparation of lactam, chemical instruments and methods, chemical/physical/physicochemical processes, etc., can solve the problem of poor safety and reliability of reactors and reaction processes, Beckman Mann rearrangement reaction has a large amount of heat and the temperature is not easy to control, so as to achieve the effect of improving controllability and safety, reducing material retention and reducing production

Active Publication Date: 2012-05-16
TSINGHUA UNIV
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The Beckmann rearrangement reaction generates a lot of heat and the temperature is not easy to control. Conventional reactors use external circulation to obtain heat, and the circulation ratio can be as high as 245, which leads to low equipment production capacity, high operating costs, and safety and security of the reactor and reaction process. poor reliability

Method used

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  • Novel Beckmann rearrangement method for preparing caprolactam from cyclohexanone oxime
  • Novel Beckmann rearrangement method for preparing caprolactam from cyclohexanone oxime
  • Novel Beckmann rearrangement method for preparing caprolactam from cyclohexanone oxime

Examples

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Effect test

Embodiment 1

[0023] A novel Beckmann rearrangement method for preparing caprolactam by cyclohexanone oxime, as follows:

[0024] (1) Using a microreactor, using SO 3 The fuming sulfuric acid with a content of 20wt.% was used as the dispersed phase, the cyclohexanone oxime n-octane solution with a mass fraction of 10% was used as the continuous phase, the flow rate of the dispersed phase was 0.8mL / min, the flow rate of the continuous phase was 25mL / min, and the two In the microreactor, it is rapidly mixed and the Beckmann rearrangement reaction is initiated, the acid oxime ratio of the reaction is 1.06, and the temperature of the reaction system is 70 °C;

[0025] (2) the residence time of the mixed reaction material in the delay pipeline connected with the outlet of the microreactor is 40s, and it is matured to complete the reaction;

[0026] (3) The ripening product is passed into another microreactor as a continuous phase, mixed with the water passed in as a dispersed phase, and a hydro...

Embodiment 2

[0034] According to the same method as in Example 1, the temperature of the reaction system was increased from 70°C to 80°C, and other conditions were the same as those in Example 1. The product was analyzed, and the conversion of the reaction reached 100%, and the selectivity reached 99.9%.

Embodiment 3

[0036] According to the same method as in Example 1, in step (1), the flow rate of the dispersed phase was increased from 0.8 mL / min to 0.9 mL / min, and the acid oxime ratio was 1.19 at this time. The temperature of the reaction system was increased from 70°C to 80°C, and other conditions were the same as those in Example 1. The product was analyzed, and the conversion of the reaction reached 100%, and the selectivity reached 99.9%.

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Abstract

The invention discloses a novel Beckmann rearrangement method for preparing caprolactam from cyclohexanone oxime, and belongs to the technical field of chemical reaction engineering. The method comprises the following steps of: by using high-efficiency mixing and excellent mass transfer and heat transfer properties of a microreactor, using fuming sulphuric acid as a dispersed phase in a first microreactor, dissolving the cyclohexanone oxime in an inert solvent to serve as a continuous phase, mixing the two phases and initiating an rearrangement reaction; taking the cured reaction mixture as acontinuous phase, introducing the continuous phase into a second microreactor, mixing with the introduced water serving as the dispersed phase, performing hydrolysis reaction to obtain caprolactam-containing aqueous solution, and circulating the inert solvent back to the system. The method only needs the reaction time of 10 to 40 seconds in a large acid oxime ratio of 0.8 to 3.0, namely can achieve high conversion rate of over 99.9 percent and high selectivity of over 99.9 percent, and has the advantages of high operational flexibility, low operating cost, high safety and controllability, high production efficiency, and capacity of greatly reducing the yield of a byproduct ammonium sulfate.

Description

technical field [0001] The invention belongs to the technical field of chemical reaction engineering, in particular to a new Beckmann rearrangement method for preparing caprolactam from cyclohexanone oxime. Background technique [0002] ε-Caprolactam is an important organic chemical raw material, mainly used in the production of nylon 6 fiber (nylon 6) and nylon 6 engineering plastics. Among them: nylon 6 fiber is widely used in wool spinning, knitting, weaving, carpet and other industries, nylon 6 engineering plastics are widely used in electronics, automobiles, packaging films and other industries. By the end of 2007, my country's imported caprolactam amounted to 468,000 tons, and the import dependence reached 60.9%. [0003] The conversion of cyclohexanone oxime into caprolactam by liquid-phase Beckmann rearrangement is a technology commonly used in industry at present, and the catalyst used is usually concentrated sulfuric acid or oleum. The caprolactam produced by thi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D223/10C07D201/04B01J19/00
Inventor 骆广生张吉松王凯吕阳成
Owner TSINGHUA UNIV
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