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Method for preparing 2, 6-dichloro-4-trifluoromethyl aniline

A technology of trifluoromethylaniline and trifluoromethyl, which is applied in the field of preparation of 2,6-dichloro-4-trifluoromethylaniline, and can solve problems such as unguaranteed safety, environmental impact, difficulty in purchasing, etc. problems, to achieve the effect of reducing the production of isomers, simplifying the process, and facilitating industrial production

Active Publication Date: 2014-10-01
台州达辰药业有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] 1. Using 3,4-dichlorotrifluorotoluene as raw material, it is obtained through high-pressure amination first, then chlorination, and then demethylation and final purification. In the first step of amination process, due to the impact of dimethylamine on the equipment The corrosiveness and amination reaction pressure requirements are high, and high-pressure equipment needs to be replaced frequently, and the safety cannot be guaranteed, and the process uses a large amount of sulfuryl chloride, which has a great impact on environmental protection;
[0005] 2. Obtained by high-pressure amination of 3,4,5-trichlorobenzotrifluoride. In this process, 3,4,5-trichlorobenzotrifluoride is difficult to purchase in the market, and the amination pressure reaches above 10Mpa. From the perspective of safety Difficult to meet both production and market demand

Method used

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Examples

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Effect test

preparation example Construction

[0026] The preparation method of 2,6-dichloro-4-trifluoromethylaniline of the present invention, it comprises the steps:

[0027] (1) Preparation of intermediate N-acetylaniline: Add aniline, o-dichlorobenzene and acid anhydride into the reaction kettle, slowly raise the temperature to 40.0°C for 0.5 hours, distill out acetic acid after the reaction, wash with water to obtain N-acetyl base aniline mixture;

[0028] (2) Preparation of intermediate 4-trifluoromethyl-N-acetylaniline: add sodium dithionite, disodium hydrogen phosphate to the N-acetylaniline mixture obtained in (1), and pass through trifluoro Methyl bromide, under the pressure of 2.5×105Pa-3.7×105Pa, reacted at 55°C for 3 hours, washed with water to remove salt after the reaction, and obtained 4-trifluoromethyl-N-acetylaniline mixed solution;

[0029] (3) Preparation of intermediate 2,6-dichloro-4-trifluoromethyl-N-acetylaniline: Add AIBN to the 4-trifluoromethyl-N-acetylaniline mixture obtained in (2) , then fee...

Embodiment 1

[0036] Preparation of N-acetylaniline:

[0037] Add 50.0 g of aniline to 350 g of o-dichlorobenzene, stir evenly, add 65.29 g of acetic anhydride, and slowly raise the temperature to 40.0°C for 0.5 hours. When the conversion rate of aniline is ≥95.0%, the temperature is raised to 105-110°C to recover acetic acid; after recovery, the mixed solution is washed with water to obtain N-acetylaniline mixed solution.

[0038] Preparation of 4-trifluoromethyl-N-acetylaniline:

[0039] Add 0.5 grams of sodium dithionite, 49.6 grams of disodium hydrogen phosphate into the N-acetylaniline mixed solution obtained above, and pass into 93.5 g of bromotrifluoromethane, at 2.5 × 10 5 Under Pa pressure, react at 55°C for 3 hours. After the reaction, add 100g of water and stir for 15 minutes, then stand for stratification. Take the organic layer, add 100g of water and stir for 15 minutes, then stand for stratification to obtain 4-trifluoromethyl-N - Acetaniline mixture.

[0040] Preparation o...

Embodiment 2

[0045] Preparation of N-acetylaniline:

[0046] Add 50.0g of aniline to 300g of o-dichlorobenzene, stir evenly, add 60.29g of acetic anhydride, slowly raise the temperature to 40.0°C and react for 0.5 hours. When the conversion rate of aniline is ≥95.0%, the temperature is raised to 105-110°C to recover acetic acid; after recovery, the mixed solution is washed with water to obtain N-acetylaniline mixed solution.

[0047] Preparation of 4-trifluoromethyl-N-acetylaniline:

[0048] Add 0.5 g of sodium dithionite, 49.6 g of disodium hydrogen phosphate, and 85.0 g of bromotrifluoromethane into the N-acetylaniline mixture obtained above, at 3.7×10 5 Under Pa pressure, react at 55°C for 3 hours. After the reaction, add 100g of water and stir for 15 minutes, then stand for stratification. Take the organic layer, add 100g of water and stir for 15 minutes, then stand for stratification to obtain 4-trifluoromethyl-N - Acetaniline mixture.

[0049] Preparation of 2,6-dichloro-4-trifluo...

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Abstract

The invention aims to disclose a method for preparing 2, 6-dichloro-4-trifluoromethyl aniline. The method comprises the following steps: firstly carrying out acetylation reaction cheap and available aniline serving as a starting material to prepare N-acetyl aniline; preparing an intermediate 4-trifluoromethyl-N-acetyl aniline through a para-position trifluoro methylation reaction; preparing 2, 6-dichloro-4-trifluoromethyl-N-acetyl aniline through a chlorination reaction; finally hydrolyzing by using liquid alkali to obtain a crude product and refining to obtain the 2, 6-dichloro-4-trifluoromethyl aniline. Compared with the prior art, the method has the advantages that N-acetyl aniline is firstly obtained through the acetylation reaction, so that the generation of isomer in the trifluoro methylation process is effectively reduced; the finished product is obtained through the steps of trifluoro methylation, chlorination reaction, refining and the like and the purpose is realized.

Description

technical field [0001] The invention relates to a preparation method, in particular to a preparation method of 2,6-dichloro-4-trifluoromethylaniline. Background technique [0002] 2,6-dichloro-4-trifluoromethylaniline is an important pharmaceutical and pesticide chemical intermediate, especially the precursor of pyrazole insecticides on the market. Because of its wide range of uses, it is widely used at home and abroad. focus on. [0003] At present, the large-scale production processes of 2,6-dichloro-4-trifluoromethylaniline at home and abroad mainly include the following types: [0004] 1. Using 3,4-dichlorotrifluorotoluene as raw material, it is obtained through high-pressure amination first, then chlorination, and then demethylation and final purification. In the first step of amination process, due to the impact of dimethylamine on the equipment The corrosiveness and amination reaction pressure requirements are high, and high-pressure equipment needs to be replaced f...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/52C07C209/62
Inventor 孔叶青缪炳林王洪伟俞高乾
Owner 台州达辰药业有限公司
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