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Method for preparing 99 percent of 2,6-dichloro-4-trifluoromethyl phenylamine

A technology of trifluoromethylaniline and nitrobenzotrifluoride, which is applied in the field of preparing 99% content 2, can solve the problems that the raw material trifluoromethylaniline is difficult to obtain, needs high temperature and high pressure, and has not yet found economical rationality, and can reach the goal of wastewater The effect of reducing the amount of exhaust gas, reducing the amount of exhaust gas, and reducing the water used for absorbing exhaust gas

Active Publication Date: 2017-11-03
连云港埃森化学有限公司
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The chemical name of fipronil is 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylsulfinylpyrazole, trade name Fipronil is a high-efficiency insecticide developed by the French Rhone-Planck Company from 1987 to 1989 and registered in China in 1992; the methods for synthesizing the compound mainly include the following categories; Trifluoromethylaniline is a raw material, and the target product is obtained after chlorination; the second type is to use p-chlorobenzotrifluoride as a starting material, which is first aminated to obtain p-trifluoromethylaniline and then chlorinated to obtain the target product; The third type is based on 3,4,5-trichlorobenzotrifluoride as the starting material, and the target product is obtained by amination; the fourth type is based on 3,4-dichlorobenzotrifluoride as the starting material, and after amination and chlorination The target product is obtained; the fifth type is to use p-methylaniline as the starting raw material, first make p-methyl isocyanate and then chlorinate and fluorinate to obtain the target product; the first type of synthetic method sees CN103408437A, and its shortcoming is that the raw material trifluoromethyl Aniline is difficult to obtain; the conversion rate of the second type of method can only reach less than 50% when preparing p-trifluoromethylaniline from raw material p-chlorobenzotrifluoride, and high temperature and pressure are also required, and an economically reasonable method has not been found yet; the third type of synthesis The method is described in CN101289400. Amination is an unavoidable problem of selectivity. There are about 25% of the by-product 3-amino-4,5-dichlorobenzotrifluoride, which requires rectification to obtain 95% of the target product The fourth type of synthetic method is described in detail in CN1468838. Like the third type, there are 5-10% by-product 3-amino-4-chlorobenzotrifluoride, which requires rectification to obtain 95% of the target product; the fifth Phosgene is used in the preparation of p-methyl isocyanate by a similar synthetic method, which is highly toxic and uneconomical; in summary, several existing methods have unavoidable defects, either economically unreasonable, or by-products are unavoidable , content less than 99%

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  • Method for preparing 99 percent of 2,6-dichloro-4-trifluoromethyl phenylamine

Examples

Experimental program
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Effect test

preparation Embodiment 1

[0028] Preparation of 3-Chloro-4-amino-5-nitrobenzotrifluoride

[0029] Add 600Kg of 3,4-dichloro-5-nitrobenzotrifluoride to the reaction kettle, seal the reaction kettle, replace with nitrogen, start stirring, gradually raise the temperature to 160°C, and gradually feed ammonia gas until the amount reaches 125Kg , take a sample through the sampling tube to detect 0.5% of 3,4-dichloro-5-nitrotrifluorotoluene, cool down to below 80°C, vent the ammonia gas to the tail gas recovery device, add 200Kg*2 water to the reaction kettle to wash, and use the organic layer again Washed with saturated brine, and then dehydrated under reduced pressure, the obtained material was 544Kg (content 99.2%, moisture 0.5%, yield 98.0%).

preparation Embodiment 2

[0031] Preparation of 2,6-dichloro-4-trifluoromethylaniline

[0032] Add 1200Kg of 3-chloro-4-amino-5-nitrobenzotrifluoride to the chlorination kettle, close the reaction kettle, replace with nitrogen, start stirring, gradually raise the temperature to 50°C, gradually introduce chlorine gas, and control the reaction temperature to 70- 80°C, when the input volume reaches 407Kg, pass the sampling test of 3-chloro-4-amino-5-nitrotrifluorotoluene 0.5% through the sampling tube, cool down to below 30°C, vent the chlorine gas to the tail gas recovery device, and react Add 200Kg of ammonia water to wash in the kettle, dehydrate under reduced pressure, and distill under reduced pressure to obtain 1090Kg of material (content 99.0%, moisture 0.5%, yield 95.0%).

preparation Embodiment 3

[0034] Preparation of 3-Chloro-4-amino-5-nitrobenzotrifluoride

[0035] Add 600Kg of 3,4-dichloro-5-nitrobenzotrifluoride to the reaction kettle, seal the reaction kettle, replace with nitrogen, start stirring, gradually raise the temperature to 100°C, and gradually feed ammonia gas until the amount reaches 125Kg 0.4% of 3,4-dichloro-5-nitrotrifluorotoluene was sampled through the sampling tube, the temperature was lowered to below 80°C, the ammonia gas was vented to the tail gas recovery device, and 200Kg*2 water was added to the reaction kettle for washing, and the organic layer was reused Washed with saturated brine, and then dehydrated under reduced pressure, the obtained material was 544Kg (the obtained 3-chloro-4-amino-5-nitrobenzotrifluoride, content 99.0%, moisture 0.5%, yield 97.9%).

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Abstract

The invention relates to a method for preparing 99 percent of 2,6-dichloro-4-trifluoromethyl phenylamine, which includes the following two steps of reaction: (1) amination reaction: 3,4-dichloro-5-nitrobenzotrifluoride reacts with ammonia to generate 3--chloro-4-amino-5-nitrobenzotrifluoride; (2) chlorination reaction: 3--chloro-4-amino-5-nitrobenzotrifluoride reacts with chlorine to generate 2,6-dichloro-4-trifluoromethyl phenylamine. The advantages of the invention are as follows: the target product 2,6-dichloro-4-trifluoromethyl phenylamine is prepared with 3,4-dichloro-5-nitrobenzotrifluoride as a material; the specific implementation route includes amination and chlorination, only simple distillation or steam distillation is needed, 99 percent of target product can be obtained without rectification, and the method has the advantages of mild reaction conditions, high safety and high product content; the process is suitable for mass industrial production, pollution is little, energy is saved, and the environment is protected.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a method for preparing 2,6-dichloro-4-trifluoromethylaniline with a content of 99%. Background technique [0002] 2,6-Dichloro-4-trifluoromethylaniline (target product) is a key intermediate of the pesticide fipronil. The chemical name of fipronil is 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylsulfinylpyrazole, trade name Fipronil is a high-efficiency insecticide developed by the French Rhone-Planck Company from 1987 to 1989 and registered in China in 1992; the methods for synthesizing the compound mainly include the following categories; Trifluoromethylaniline is a raw material, and the target product is obtained after chlorination; the second type is to use p-chlorobenzotrifluoride as a starting material, which is first aminated to obtain p-trifluoromethylaniline and then chlorinated to obtain the target product; The third type is based...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/52C07C209/10C07C209/74
CPCC07C209/10C07C209/74C07C211/52
Inventor 刘伟李惠跃张彦祥吴大银付登学
Owner 连云港埃森化学有限公司