Method for separating Beckmann rearrangement reaction products from ion liquid

A technology of Beckmann rearrangement and ionic liquid, which is applied in organic chemistry and other fields, can solve the problems of low efficiency and unusability of separated products

Active Publication Date: 2005-09-21
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, in the ionic liquid / organic solvent two-phase system, most of the rearrangement reaction products are concentrated in the ionic liquid phase, while the amount of substances in the organic phase is very small, which leads to the method of single-stage, multi-stage solvent extraction or vacuum distillation Very low efficiency in separating products from the system
On the other hand, although most of the literature reports on the liquid-phase Beckmann rearrangement reaction use ammonia water neutralization method to study the reaction results, in order to avoid the by-product of ammonium sulfate, ammonia water neutralization method cannot be used in the actual industrial production process. measures
In conclusion, there has not been any report on solving this problem so far

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-7

[0031] These examples illustrate the preparation of ionic liquids obtained from homogeneous or heterogeneous reactions containing the product of the Beckmann rearrangement reaction of cyclohexanone oxime for use in the process of the invention.

[0032] Among them, ionic liquids A, B, C, D, E, and F containing Beckmann rearrangement reaction products are obtained by heterogeneous reactions; ionic liquid G is obtained by homogeneous reactions.

[0033] Preparation of ionic liquid A: Add 10.0ml 1-butyl-3-methylimidazolium hexafluorophosphate successively in a 250ml round bottom flask (hereinafter referred to as [bmim][PF 6 ]), 25.0ml toluene and 2.5ml POCl 3 , the temperature of the oil bath is controlled at 80°C, and 37.5ml of cyclohexanone oxime-toluene solution with a concentration of 2.0mol / L is added dropwise under magnetic stirring. L's [bmim] [PF 6 ] Ionic Liquid A.

[0034] Preparation of ionic liquid B: Add 10.0ml 1-butyl-3-methylimidazolium tetrafluoroborate (herein...

Embodiment 8

[0041] This example shows that chloroform can be very effectively removed from the [bmim][PF 6 ] to isolate the rearrangement reaction product.

[0042] Add 4.0ml of ionic liquid A and 60ml of chloroform into a 200ml round bottom flask, at this time the two form a two-phase system at room temperature. Use an oil bath to control the temperature, raise the system temperature to 75° C. under magnetic stirring, and reflux and stir for 30 minutes. At this time, the two-phase system becomes homogeneous. Then the temperature of the system was lowered to 20° C., and the homogeneous system was divided into two phases again, and the chloroform phase and the ionic liquid phase were separated after resting.

[0043] The relative amount of each substance in the chloroform phase was analyzed by gas chromatography, and the results showed that the chloroform phase contained a very high concentration of rearrangement reaction products. Compared with the gas chromatogram of 2.0mol / L cyclohexa...

Embodiment 9-13

[0045] These examples illustrate that different organic solvents can be used for the same ionic liquid to carry out the method provided by the present invention.

[0046] Add 4.0ml of ionic liquid B to five 200ml round bottom flasks, and then add 30ml of chlorobenzene, tetrahydrofuran, n-butanol, cyclohexanol and isooctyl alcohol, at this time, the ionic liquid and the solvent form a two-phase system at room temperature . Use an oil bath to control the temperature, raise the system temperature to 80°C (the temperature of the ionic liquid B-tetrahydrofuran system is raised to 65°C) under magnetic stirring, and reflux and stir for 10 minutes. At this time, the two-phase system becomes homogeneous. Then the temperature of the system was lowered to 25° C., the homogeneous system was divided into two phases, and the organic solvent phase and the ionic liquid phase were separated after resting.

[0047] Analyze the amount of the rearrangement reaction product in the solvent phase a...

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Abstract

The invention relates to a method for separating Beckmann rearrangement reaction production from ion liquid, which comprises: selecting an organic dissolvant with the ion liquid used in cyclohexanone oxime Beckmann rearrangement reaction immiscible in the temperature of 10-60 Deg.C and miscible in the temperature of 50-150 Deg.C, mixing the organic dissolvant with the ion liquid with cyclohexanone oxime Beckmann rearrangement reaction production with the proportion in volume of 50 degree 1-1 degree 10 to form a immiscible two-phase system, stirring and lifting the temperature to 50-150 Deg.C to get the miscible mixture liquid of both organic dissolvents and ion liquid, holding 1-120 min in the temperature, then cooling the mixture liquid to 10-60 Deg.C to separate phase inactively.

Description

technical field [0001] The invention relates to a method for separating Beckmann rearrangement reaction products from ionic liquids. More specifically, it relates to a method for separating the Beckmann rearrangement reaction product from an ionic liquid containing the cyclohexanone oxime Beckmann rearrangement reaction product and transferring it to an organic solvent. Background technique [0002] Caprolactam is an important organic chemical raw material with a wide range of applications. About 90% of caprolactam in the world is prepared from cyclohexanone oxime through Beckmann rearrangement reaction. Therefore, Beckmann rearrangement reaction is one of the key steps in the production of caprolactam. The traditional Beckmann rearrangement reaction process uses oleum to catalyze the initial reaction step. First, the caprolactam salt of sulfuric acid is formed, and then the mixture is neutralized with ammonia water to produce ammonium sulfate and caprolactam. Each mole of c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D223/10
Inventor 张伟吴巍张树忠闵恩泽
Owner CHINA PETROLEUM & CHEM CORP
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