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Preparation method of 2, 4-difluoro-3, 5-dichloroaniline

A technology of dichloroaniline and dichlorobenzamide, applied in rearrangement reaction preparation, resistance to vector-borne diseases, organic chemistry, etc., can solve the problems of little industrial significance, undisclosed nitration reaction steps, and impact on intermediates, etc. , to achieve the effects of green reaction process, easy scale-up production, and mild reaction conditions

Pending Publication Date: 2022-08-02
河南金鹏化工有限公司
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0011] 1. Using 1,2,4-trichlorobenzene as raw material, the key intermediate 3,5-dichloro-2,4-difluoroaniline was prepared through the steps of nitration, chlorination, fluorination and reduction This route has more nitration isomers during the nitration of trichlorobenzene, and it is not easy to separate, which directly affects the quality of the intermediate 3,5-dichloro-2,4-difluoroaniline, and has little industrial significance
[0012] 2. Using 1,2,3,4-tetrachlorobenzene as raw material, the key intermediate 3,5-dichloro-2,4-difluoroaniline was prepared through nitration, fluorination, and reduction production processes; There is a risk of explosion in the nitrification reaction in this route. In addition, a large amount of iron sludge and solid waste will be produced to pollute the environment.
[0013] 3. Using 2,4-difluoronitrobenzene as raw material, synthesize the important intermediate 3,5-dichloro-2,4-difluoroaniline through chlorination and reduction; This route does not disclose the nitration reaction step. In fact, the preparation of 2,4-difluoronitrobenzene is carried out through nitration reaction of 2,4-difluorobenzene, and the positioning effect of the nitration reaction is not good, and there are many nitration isomers. defect
[0014] As can be seen from the above, in the process of preparing 2,4-difluoro-3,5-dichloronitrobenzene in the prior art, nitration reactions, reduction reactions, etc. are all involved, and the selectivity in the reaction process is poor and the pollution is large, resulting in 2,4 - The synthesis cost of difluoro-3,5-dichloroaniline remains high

Method used

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  • Preparation method of 2, 4-difluoro-3, 5-dichloroaniline
  • Preparation method of 2, 4-difluoro-3, 5-dichloroaniline

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[0036] A general aspect of the present invention provides a preparation method of 2,4-difluoro-3,5-dichloroaniline, which is characterized in that comprising the following steps:

[0037] Step (1), 2,3,4,5-tetrachlorobenzoyl chloride reacts with ammonia water or ammonia gas to obtain 2,3,4,5-tetrachlorobenzamide;

[0038] step (2), dehydrating the 2,3,4,5-tetrachlorobenzamide prepared in step (1) in the presence of a dehydrating agent to generate 2,3,4,5-tetrachlorobenzonitrile;

[0039] In step (3), 2,3,4,5-tetrachlorobenzonitrile prepared in step (2) is reacted with KF to prepare 2,4-difluoro-3,5-dichlorobenzonitrile;

[0040] Step (4), hydrolyzing the 2,4-difluoro-3,5-dichlorobenzonitrile prepared in step (3) to obtain 2,4-difluoro-3,5-dichlorobenzamide;

[0041] Step (5), 2,4-difluoro-3,5-dichlorobenzamide prepared in step (4) is synthesized into 2,4-difluoro-3,5-dichloroaniline under the action of an oxidant .

[0042] The condition reaction of the route of the inventi...

Embodiment 12

[0062] Implement the synthesis of 12,3,4,5-tetrachlorobenzamide

[0063] Add 0.4L of ammonia water (28% ammonia water solution) to a 4L round-bottomed flask, and then dropwise add a dichloromethane solution of 2,3,4,5-tetrachlorobenzoyl chloride (1.6mol) at a low temperature of -10°C (1L), the temperature was slowly raised to room temperature after the addition, and the reaction was continued at room temperature for 2h. Then the reactant was filtered to obtain a solid, and the solid was washed twice with water to obtain a white solid product, 2,3,4,5-tetrachlorobenzamide, which was dried in vacuo to obtain a product with a yield of 96% and a HPLC purity of 98.5%.

[0064] Example 2-5 adopts the reaction conditions similar to Example 1 to prepare 2,3,4,5-tetrachlorobenzamide, only changing the reaction time, the results are shown in Table 1:

[0065] Table 1 Results of amidation reactions with different reaction times

[0066] serial number Reaction time Yield ...

Embodiment 62

[0067] Example 62, Synthesis of 3,4,5-tetrachlorobenzonitrile

[0068] Add amide (0.8mol, 207.2g) and POCl to a 1L round-bottom flask 3 (400 mL), the reaction was carried out at 110 °C for 3 h. Evaporate excess POCl under reduced pressure 3 , cooled to room temperature, and ice water was added to quench the residual POCl 3 , filtered, and washed the filtrate twice with water (100ml of water each time) to obtain a white solid product, which was dried in vacuo to obtain the product 2,3,4,5-tetrachlorobenzonitrile, the yield was 86.8%, and the HPLC purity was 96.3%.

[0069] In Examples 7-10, 2,3,4,5-tetrachlorobenzonitrile was prepared under substantially the same conditions as in Example 6, and the reaction was investigated by changing the type of dehydrating agent. The reaction results are shown in Table 2.

[0070] Table 2 Influence of dehydrating agent types on the reaction

[0071]

[0072]

[0073] In Examples 11-16, 2,3,4,5-tetrachlorobenzonitrile was prepared u...

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Abstract

The invention provides a preparation method of 2, 4-difluoro-3, 5-dichloroaniline, which comprises the following steps: (1) reacting 2, 3, 4, 5-tetrachlorobenzoyl chloride with ammonia gas or ammonia water to obtain 2, 3, 4, 5-tetrachlorobenzamide; step (2), dehydrating the 2, 3, 4, 5-tetrachlorobenzamide prepared in the step (1) to generate 2, 3, 4, 5-tetrachlorobenzonitrile; step (3), enabling the 2, 3, 4, 5-tetrachlorobenzonitrile prepared in the step (2) to react with KF to prepare 2, 4-difluoro-3, 5-dichlorobenzonitrile, and enabling the 2, 3, 4, 5-tetrachlorobenzonitrile to react with KF to prepare 2, 4-difluoro-3, 5-dichlorobenzonitrile; step (4), the 2, 4-difluoro-3, 5-dichlorobenzonitrile prepared in the step (3) is hydrolyzed, and 2, 4-difluoro-3, 5-dichlorobenzamide is obtained; and (5) preparing the 2, 4-difluoro-3, 5-dichloroaniline from the 2, 4-difluoro-3, 5-dichlorobenzamide prepared in the step (4) under the action of an oxidizing agent, so as to obtain the 2, 4-difluoro-3, 5-dichloroaniline. The process is mild in reaction condition, green and environment-friendly, and more beneficial to industrial production.

Description

technical field [0001] The invention relates to a synthesis method in the chemical field, in particular to a preparation method of 2,4-difluoro-3,5-dichloroaniline. Background technique [0002] Teflubenzuron is a benzoylurea insecticide developed by Celamerck GmbH & Co. in 1984. It was listed on the market in 1986. After several acquisitions, it is now owned by BASF. The chemical name of Fuzuron is 1-(3,5-dichloro-2,4-difluorophenyl)-3-(2,6-difluorobenzoyl)urea, and the English name is 1-(3,5 -dichloro-2,4-difluorophenyl)-3-(2,6-d ifluorobenzyl)urea, CAS number: 83121-18-0, molecular formula: C14H6Cl2F4N2O2, molecular weight: 381.11, chemical structural formula: [0003] [0004] Reference 1 (CN111995538A, 2020-11-27) discloses the current method for synthesizing fendiuron as follows. An important intermediate raw material, 2,4-difluoro-3,5-dichloroaniline, is used. [0005] [0006] 2,4-Difluoro-3,5-dichloroaniline (2,4-Difluoro-3,5-dichloroaniline), CAS No:83121-...

Claims

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Application Information

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IPC IPC(8): C07C209/56C07C211/52
CPCC07C209/56C07C231/06C07C253/30C07C253/20C07C231/04C07C211/52C07C233/65C07C255/50Y02A50/30
Inventor 周明杰孙高杰王振宋志臣董苗苗
Owner 河南金鹏化工有限公司
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