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Synthesis method of 2, 6-dichloro-4-aminophenol

A technology of aminophenol and synthesis method, which is applied to the preparation of amino compounds, preparation of amino hydroxyl compounds, chemical instruments and methods, etc., can solve the problems of difficult hydrolysis and low hydrolysis selectivity, so as to prevent dechlorination and reduce distillation Risk and energy consumption, the effect of simplifying the process flow

Inactive Publication Date: 2021-06-11
ZHEJIANG LINJIANG CHEM
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Problems solved by technology

However, there are three chlorines on the benzene ring, the hydrolysis selectivity is not particularly high, and it is more difficult to control the hydrolysis of chlorine on the para-position of the nitro group.

Method used

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  • Synthesis method of 2, 6-dichloro-4-aminophenol
  • Synthesis method of 2, 6-dichloro-4-aminophenol
  • Synthesis method of 2, 6-dichloro-4-aminophenol

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Embodiment 1

[0032] (1) Chlorination: Weigh 27.6g of p-nitroaniline and 138g of methanol into the flask, stir to dissolve, raise the temperature to 55°C, start slowly introducing chlorine gas, control the temperature at 55-60°C, gradually precipitate yellow solid, and monitor the raw materials by HPLC After the basic reaction, cool down to room temperature, filter with suction, wash the solid with water first, then wash with 2% soda ash solution until neutral, filter with suction, and dry to obtain 40g of 2,6-dichloro-4-nitroaniline, the appearance is Bright yellow solid, HPLC purity 98.4%, molar yield 96.62%.

[0033] (2) Diazo hydrolysis: Weigh 150g of 98% sulfuric acid and 158.7g of nitrososulfuric acid solution (42%) into the flask, stir, cool to 5°C, slowly add 2,6-dichloro-4-nitro A solution composed of 103.5g of aniline and 310.5g of toluene, the reaction temperature is controlled at 10-15°C, after the addition is completed, the reaction is kept at 10-15°C for 1 hour to obtain a cle...

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Abstract

The invention discloses a synthesis method of 2, 6-dichloro-4-aminophenol, and belongs to the field of preparation of pesticide, medicine and dye intermediates, 2, 6-dichloro-4-aminophenol is obtained by adopting paranitroaniline as a raw material through the steps of chlorination, diazonium hydrolysis, hydrogenation and the like, methanol is adopted as a solvent for chlorination, filtrate can be repeatedly used, and the use of a large amount of acid water is reduced; toluene is selected as a solvent in diazotization, diazonium liquid is directly layered after being hydrolyzed, an organic layer is separated out, water vapor distillation is not needed, and the distillation risk and energy consumption are reduced; toluene is selected as a hydrogenation solvent, and an organic layer separated after the diazonium liquid is hydrolyzed is directly hydrogenated, so that the process flow is simplified.

Description

technical field [0001] The invention relates to the field of preparation of pesticides, medicines and dye intermediates, and more specifically relates to a synthesis method of 2,6-dichloro-4-aminophenol. Background technique [0002] 2,6-dichloro-4-aminophenol (CAS:5930-28-9), also known as 3,5-dichloro-4-hydroxyaniline, is used as an intermediate for the synthesis of the pesticide hexaflumuron 3,5-di Chloro-4-(1,1,2,2-tetrafluoroethoxy)aniline, or 4-(3-chloro-5-trifluoromethylpyridin-2-oxyl), an intermediate in the synthesis of the pesticide chlorfluazuron -3,5-dichloroaniline. At the same time, 2,6-dichloro-4-aminophenol is also an important medicine and dye intermediate. At present, the synthesis of 2,6-dichloro-4-aminophenol mainly has the following routes: [0003] (1) Using 2,6-dichlorophenol as the starting material [Pesticides, 51(3), 184-185,192; 2012; CN106278911A], first nitrated by nitric acid, then reduced by hydrazine hydrate or catalytic hydrogenation to ob...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C213/02C07C215/76C07C201/12C07C205/12C07C209/74C07C211/52
CPCC07C201/12C07C209/74C07C213/02C07C215/76C07C205/12C07C211/52
Inventor 易克炎吴文良杨江宇严泽华徐新尹凯杨小云沈焕军任应能贾成国
Owner ZHEJIANG LINJIANG CHEM
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