Method for purifying epsilon-caprolactam and method for preparing epsilon-caprolactam

A technology of caprolactam and purification method, which is applied to the preparation of lactam, separation/purification of lactam, chemical instruments and methods, etc., can solve problems such as scaling, and achieve the effect of saving production costs

Active Publication Date: 2012-05-16
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to overcome the defect that the cooling crystallization process in the existing separation and purification method of ε-caprolactam is eas...

Method used

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Examples

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Effect test

preparation example Construction

[0022] The present invention also provides a method for preparing ε-caprolactam. The method comprises that in the presence of a molecular sieve catalyst with an MFI structure, the cyclohexanone oxime in the gas phase undergoes a Beckmann rearrangement reaction, and the reaction product is distilled to obtain ε-caprolactam. crude product, and then the ε-caprolactam crude product is crystallized and purified, and the ε-caprolactam crystals obtained after purification are subjected to a hydrogenation reaction in the presence of a hydrogenation catalyst, wherein the ε-caprolactam crude product is crystallized and purified The method is the purification method of the crude ε-caprolactam product provided by the present invention.

[0023] According to the preparation method of the ε-caprolactam provided by the present invention, the Beckmann rearrangement reaction includes reacting cyclohexanone oxime in the gas phase in the presence of a molecular sieve catalyst with an MFI structur...

Embodiment 1

[0048] This example is used to illustrate the purification method of ε-caprolactam and the preparation method of ε-caprolactam provided by the present invention.

[0049] Cyclohexanone oxime gas-phase Beckmann rearrangement reaction is carried out in the fixed-bed reactor of 80ml, and the internal diameter of this reactor is 28mm, and the molecular sieve catalyst of MFI structure (purchased from Hunan Jianchang Company, trade mark RBS-1) loading capacity is 9.45g, the reaction pressure is 0.1MPa, the catalyst bed reaction temperature is 375°C, the flow rate of nitrogen (carrier gas) is 3.0L / gcat / hr, and the weight hourly space velocity of cyclohexanone oxime is 2h -1 , the partial pressure of cyclohexanone oxime is 8.6 kPa, the partial pressure of methanol (solvent) is 60.2 kPa, and the partial pressure of nitrogen is 31.2 kPa.

[0050] The product obtained after the Beckmann rearrangement reaction was collected by circulating and cooling the ethylene glycol solution at -5°C t...

Embodiment 2

[0054] This example is used to illustrate the purification method of ε-caprolactam and the preparation method of ε-caprolactam provided by the present invention.

[0055] According to the method of Example 1, the crude product of ε-caprolactam is purified and the product of ε-caprolactam is prepared. The difference is that in the process of purifying the crude product of ε-caprolactam, the chlorinated normal A mixture of butane and chloro-tert-butane replaced the same weight of chloro-butane in Example 1 as the crystallization solvent. The yield of ε-caprolactam crystals obtained during the purification process was 92%, the purity was 99.96%, the PM value was 120s, the V.B value was 0.40mmol / kg, and the E value was 0.18. It was found by observation that the inner wall of the three-necked bottle did not produce Scaling phenomenon.

[0056] In addition, the purity of the finally prepared ε-caprolactam product is 99.98%, the PM value is 43000s, the V.B value is 0.16mmol / kg, and ...

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Abstract

The invention provides a method for purifying a crude epsilon-caprolactam product, which comprises the following steps of: dissolving the crude epsilon-caprolactam product in halogenated hydrocarbon to obtain a halogenated hydrocarbon solution of epsilon-caprolactam; and performing evaporative crystallization on the solution at the temperature of between -10 and 50 DEG C under reduced pressure to separate an epsilon-caprolactam crystal. The invention also provides a method for preparing the epsilon-caprolactam, which comprises the following steps of: performing Beckmann rearrangement reaction on gas-phase cyclohexanone-oxime in the presence of a molecular sieve catalyst with a melt flow index (MFI) structure, and distilling a reaction product to obtain the crude epsilon-caprolactam product; and performing crystallization purification by the method for purifying the crude epsilon-caprolactam product, and performing hydrogenation reaction on the epsilon-caprolactam crystal obtained after purification in the presence of a hydrogenation catalyst. By the method for purifying the crude epsilon-caprolactam product, the epsilon-caprolactam which meets the industrial product requirement can be obtained, and the phenomenon of scale formation in the crystallization process is avoided.

Description

technical field [0001] The invention relates to a method for purifying ε-caprolactam and a method for preparing ε-caprolactam. Background technique [0002] ε-caprolactam is one of the important raw materials for synthetic fibers and synthetic resins, mainly used in the manufacture of polyamide fibers (nylon 6), resins and films. At present, the industrial production method of ε-caprolactam is to use oleum as a catalyst and solvent, and cyclohexanone oxime undergoes a liquid-phase Beckmann rearrangement reaction. This process has the disadvantages of corroding equipment, polluting the environment, and unsatisfactory economic benefits, and will produce a large amount of ammonium sulfate. [0003] The gas-phase Beckmann rearrangement reaction of cyclohexanone oxime on solid acid catalyst is a new process to realize the sulfur-free ammonification of ε-caprolactam. It has no problems such as equipment corrosion and environmental pollution, and the separation and purification of...

Claims

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Application Information

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IPC IPC(8): C07D223/10C07D201/16C07D201/04
Inventor 谢丽杨克勇江雨生程时标张树忠慕旭宏
Owner CHINA PETROLEUM & CHEM CORP
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