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Method for preparing aromatics

An aromatic compound and aromatic technology, which is applied in the preparation of organic compounds, the preparation of cyanide reactions, chemical instruments and methods, etc., can solve the problems of increasing processes and the corrosion of the reactor, and achieve the effect of high yield

Inactive Publication Date: 2002-09-18
NIPPON SHOKUBAI CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Generally speaking, when sulfuric acid etc. are used in the reaction, since iron or stainless steel reactors are prone to corrosion, glass or glass-lined reactors are used. The method described in the above-mentioned JP-A-8-268979 is A method to prevent reactor corrosion, but when using low-purity 4-amino-2,3,5,6-tetrafluorobenzonitrile, the reactor will still produce corrosion
On the other hand, although the operation of removing impurities can prevent the reactor from being corroded, it increases the process, which is very unfavorable.

Method used

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Examples

Experimental program
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Embodiment

[0098] Hereinafter, the present invention will be described more specifically with reference to Examples.

reference example 1

[0099]

[0100] Into a 500-ml 4-neck flask equipped with a stirrer, a thermometer and a cooling tube, was charged 75 g (389 mmol) of pentafluorobenzonitrile, 225 ml of n-propyl acetate, 79.5 g (1.165 mol as ammonia) of 25% ammonia water, and 0.375g of tetrabutylammonium bromide was reacted at 25°C for 1 hour, and then at 50°C for 5 hours. After the reaction, the reaction liquid was analyzed by gas chromatography. The conversion rate of pentafluorobenzonitrile was 100%. The yield of 4-amino-2,3,5,6-tetrafluorobenzonitrile was 94%.

[0101] The n-propyl acetate layer containing 4-amino-2,3,5,6-tetrafluorobenzonitrile was separated and washed twice with 100 g of a 10 mass % aqueous sodium sulfate solution in order to remove ammonium fluoride contained in the layer. Then, the n-propyl acetate layer was heated and distilled to remove n-propyl acetate to obtain 73.5 g of 4-amino-2,3,5,6-tetrafluorobenzonitrile (purity 94%) (yield 93.6%). As an impurity, 4.5 g (6%) of 2-amino-3,4,...

Embodiment 1

[0103] (previous reaction)

[0104] Into a 200-ml glass 4-neck flask equipped with a stirrer, a thermometer and a cooling tube, 120 g of a 90 mass % sulfuric acid aqueous solution was charged, and the internal temperature was adjusted to 110°C while stirring. Next, 50 g of the solid (4-amino-2,3,5,6-tetrafluorobenzonitrile content: 94%) obtained in Reference Example 1 was fed to the holding 110 at a feeding rate of 4 g / hour under stirring. °C in a 90 mass% sulfuric acid aqueous solution. The concentration of sulfuric acid in the first-stage reaction in the reactor is 90 to 94% by mass. After the feeding was completed, the reaction was further performed for 2 hours. The reaction solution was sampled and analyzed by liquid chromatography. The conversion rate of 4-amino-2,3,5,6-tetrafluorobenzonitrile was 100 mol%, and the products were as follows:

[0105] 4-Amino-2,3,5,6-tetrafluorobenzamide 65mol%

[0106] 4-Amino-2,3,5,6-tetrafluorobenzoic acid 10mol%

[0107] 2,3,5,6-Te...

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PUM

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Abstract

A method for preparing an aromatic compound is characterized in that the hydrolysis and decarboxylation reactions are carried out in multiple stages when an aromatic cyano compound is hydrolyzed and decarboxylated in the presence of an acidic substance and the corresponding aromatic compound is prepared. Especially when the aromatic cyano compound contains halogen, it can effectively prevent the corrosion of the reactor caused by the hydrogen halide generated by the side reaction, and at the same time, the target compound can be prepared in high yield.

Description

technical field [0001] The invention relates to a method for preparing halogen-containing aromatic compounds, in particular to a halogen-containing aromatic cyano compound as a raw material for hydrolysis and decarboxylation, without corroding a reactor, and preparing aromatic compounds corresponding to the target with high efficiency Methods. Background technique [0002] Tetrahalogenated anilines contain important compounds that can be used as intermediate raw materials for medicines and pesticides. For example, the production method of 2,3,5,6-tetrafluoroaniline is described in Japanese Patent Laid-Open No. 6-211756, Japanese Patent Laid-Open No. 8-268979 and the like. In the method described in Japanese Patent Laid-Open No. 6-211756, pentafluorobenzoic acid is used as a raw material, and it is reacted with ammonia in an aqueous medium, and ammoniation and decarboxylation are carried out to obtain 2,3,5,6-tetrafluoroethylene aniline. The raw material pentafluorobenzoic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C209/68C07C211/52
CPCC07C209/68C07C211/52
Inventor 广田幸逸
Owner NIPPON SHOKUBAI CO LTD
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