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Synthesis method of maleimide

A technology of maleimide and synthesis method, applied in directions such as organic chemistry, can solve problems such as unfavorable industrial production, high boiling point of DMF, dark color of crude product, etc., and achieve the effects of easy industrial production, high product quality, and simple operation.

Inactive Publication Date: 2018-05-08
浦拉司科技(上海)有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has obvious exothermic heat when thermally decomposed in DMF, it is difficult to control the temperature, the boiling point of DMF is too high, the separation is difficult, the crude product is dark in color, poor in quality, and the overall yield is relatively low, which is not conducive to industrial production

Method used

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  • Synthesis method of maleimide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Wash the 500L reaction kettle, add 100kg maleic anhydride and 61kg urea, cover the kettle, vacuum pump 150kg of glacial acetic acid, start stirring, start to heat up to 50-60°C to react, react for 18h, HPLC detects that the raw materials disappear.

Embodiment 2

[0021] Cool down the product from the previous step to about 25°C, vacuum pump 150kg of acetic anhydride, control the temperature at about 85°C, react for 2 hours, and detect the disappearance of raw materials by HPLC. The solvent was concentrated in vacuo to 75°C, 200 kg of ethyl acetate was sucked in by vacuum, centrifuged, and the solid was washed with ethyl acetate.

Embodiment 3

[0023] The above solid was transferred to a reaction kettle, 300 kg of ethyl acetate and 2.5 kg of triethylamine were sucked in by vacuum, heated to reflux, reacted for 2 hours, and the raw materials disappeared by HPLC detection. Cool down to 25°C, centrifuge, and wash the solid with ethyl acetate. The filtrate was washed 3 times with 50kg, 25kg, and 25kg deionized water respectively. Concentrate ethyl acetate, suck in 30kg of ethyl acetate to crystallize under vacuum, recrystallize twice with 30kg of water, and dry to obtain about 40kg of white solid, which is maleimide.

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Abstract

The invention relates to the technical field of maleimide synthesis, in particular to a synthesis method of maleimide. According to the method, maleic anhydride serves as an initial raw material, andN-carbamoylmaleimide is obtained through an aminolysis reaction of urea and a dehydration reaction of acetic anhydride; in the presence of triethylamine, N-carbamoylmaleimide is heated and decomposedinto maleimide. The whole process is simple in operation, the product quality is high, and industrial production is easy.

Description

technical field [0001] The invention relates to the technical field of maleimide synthesis, in particular to a method for synthesizing maleimide. Background technique [0002] Maleimide (Maleimide), also known as maleimide, CAS number: 541-59-3, is in the form of colorless needle crystals or flakes with light brown luster, sweet in taste. Maleimides are widely used in organic synthesis. However, there are still relatively few methods for synthesizing maleimides. The methods currently reported in the literature are as follows: [0003] (1) Preparation of maleimide by oxidation of pyrrole in sulfuric acid with potassium dichromate. By pyrrole and potassium dichromate reaction derived. Dissolve potassium dichromate in water and concentrated sulfuric acid, heat to 35°C, add pyrrole slowly under stirring, and the reaction temperature does not exceed 50°C. Insulation reaction until no pyrrole smell. Cool, wash, filter, and extract the lotion with ether. After the extract is ...

Claims

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Application Information

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IPC IPC(8): C07D207/448
CPCC07D207/448
Inventor 李静漆伟军蔡伟兵陆电云
Owner 浦拉司科技(上海)有限责任公司
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