Preparation method of N-hydroxyaniline

A technology of hydroxyaniline and nitrobenzene, applied in the field of preparation of N-hydroxyaniline, can solve the problems of inability to large-scale production, high cost of metal rhodium and ruthenium

Active Publication Date: 2014-09-24
HUAZHONG NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main disadvantage of this method is that the cost of metal rhodium and ruthenium is too high to be mass-produced

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0019] The preparation method of N-hydroxyaniline provided by the invention comprises that under redox conditions, nitrobenzene having a structure shown in formula (1) is contacted with a reducing agent and a catalyst in an organic solvent to obtain a compound having the formula (2) ), wherein the reducing agent is one or more of ammonia, amine and hydrazine, and the catalyst is one or more of iron, zinc, palladium carbon and Raney nickel kind;

[0020] Formula 1),

[0021] Formula (2),

[0022] Among them, R 1 is halogen, R 2 -R 11 for H or C 1 -C 5 of alkyl.

[0023] The C 1 -C 5 Specific examples of alkyl groups may include, but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, 1-ethyl Propyl, 2-methylbutyl, 3-methylbutyl and 2,2-dimethylpropyl.

[0024] According to the present invention, from the viewpoint of the easy availability of the nitrobenzene and the wide industrial application of N-hydroxyan...

Embodiment approach

[0030] According to a preferred embodiment of the present invention, the reducing agent is hydrazine, and the catalyst is Raney nickel. The inventors of the present invention found that the yield and purity of N-hydroxyaniline obtained can be more significantly improved by using the specific reducing agent and catalyst in combination. Wherein, the type of hydrazine can be reasonably selected according to the above description, and is particularly preferably one or more of hydrazine hydrate, methylhydrazine and phenylhydrazine.

[0031] The present invention does not specifically limit the contacting conditions, as long as the nitrobenzene having the structure represented by formula (1) can be converted into N-hydroxyaniline having the structure represented by formula (2). Generally speaking, the contacting conditions include contacting temperature and contacting time. Wherein, in order to facilitate the reaction, the contacting temperature is preferably -10°C to 50°C, more pr...

Embodiment 1

[0042] This embodiment is used to illustrate the preparation method of N-hydroxyaniline provided by the present invention.

[0043] 19 grams of Raney nickel was dried and activated at 300°C for 12 hours. Add the obtained activated Raney nickel into 250 mL of 1,2-dichloroethane solution, stir and add 50 g (0.152 mol) of 2-[(N-p-chlorophenyl)-3 -pyrazolyloxymethyl]nitrobenzene (having the structure shown in formula (1), R 1 for Cl, R 2 -R 11 H, the same below) and 9 grams of isopropylamine, after 3 hours of reaction, the system changed from yellow turbidity to brown clarification, suction filtered, and the filtrate was dried with anhydrous sodium sulfate, then suction filtered, and then the filtrate was depressurized The organic solvent was distilled off to obtain a product containing N-hydroxy-N-2-[(N-p-chlorophenyl)-3-pyrazolyloxymethyl]aniline. The product was recrystallized with a mixed solvent of petroleum ether and ethyl acetate to obtain a light yellow N-hydroxyl-N-2-...

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PUM

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Abstract

The invention provides a preparation method of N-hydroxyaniline, which comprises: contacting nitrobenzene with a structure as shown in formula (1) with a reducing agent and a catalyst in an organic solvent under a redox condition to obtain N-hydroxyaniline with a structure as shown in formula (2), wherein the reducing agent is one or more than one of ammonia, amine, and hydrazine, and the catalyst is one or more than one of iron, zinc, palladium carbon and raney nickel; R1 is a halogen, R2-R11 are H or C1-C5 alkyls. With the method of the invention, the yield and the purity of N-hydroxyaniline are improved.

Description

technical field [0001] The invention relates to a preparation method of N-hydroxyaniline. Background technique [0002] Pyraclostrobin, also known as pyraclostrobin, is a methyl methoxyacrylate fungicide with a pyrazole structure discovered by BASF in 1993. Since its promotion and listing in 2002, it has been favored by users and its sales have increased rapidly. According to the 2007 No. 6 report of China Pesticides, pyraclostrobin ranked third among the 15 most important fungicides in the world. The preparations of pyraclostrobin were registered in China under the trade names of Kairun, Kaiser and Baitai respectively and entered the domestic market for sale. At present, pyraclostrobin has patent rights in the United States, Europe and other countries, and has also applied for a patent in my country, but its synthesis technology has not yet been disclosed. However, from existing patents and literature reports, N-hydroxy-N-2-[(N-p-chlorophenyl)-3-pyrazolyloxymethyl]anilin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D231/22
CPCC07D231/22
Inventor 杨光富刘玉超徐平平陈琼
Owner HUAZHONG NORMAL UNIV
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