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Continuous production method for industrially preparing 2,3-difluorobenzotrifluoride and 3,4-difluorobenzonitrile

A technology of difluorotrifluorotoluene and difluorobenzonitrile, which is applied in chemical instruments and methods, preparation of carboxylic acids by ozone oxidation, preparation of organic compounds, etc., can solve the problems of high cost, incomplete reaction, and high cost of raw materials, and achieve Low cost, high production efficiency, and the effect of improving product efficiency

Active Publication Date: 2017-12-19
ZIBO FEIYUAN CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] The above two patents are currently the main production methods for the production of 3,4-difluorobenzonitrile and 2,3-difluorobenzotrifluoride. The main problems are: the production process of 2,3-difluorobenzonitrile requires High temperature reaction at 250-300°C for 20 hours will decompose the product and solvent, and the single-pot yield is about 30%. Industrialization produces a large amount of waste gas and the raw material cost of this step is high. The reaction of 3,4-difluorobenzonitrile is not complete, and there are still 3 or The 4-position chlorine has not undergone fluorination reaction, and the proportion exceeds 40%. The phase transfer catalyst used is difficult to be used in industrialization in large quantities, and the cost is high

Method used

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  • Continuous production method for industrially preparing 2,3-difluorobenzotrifluoride and 3,4-difluorobenzonitrile
  • Continuous production method for industrially preparing 2,3-difluorobenzotrifluoride and 3,4-difluorobenzonitrile
  • Continuous production method for industrially preparing 2,3-difluorobenzotrifluoride and 3,4-difluorobenzonitrile

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0073] Example 1: Preparation of compound of formula (IV) (m-fluorotoluene) 1 by diazotization reaction:

[0074] Put 1236g (61.8mol) of hydrogen fluoride into a 5L fluorination reactor and cool down to 0°C, add 110g dropwise per hour and add 2153g (20.1mol) of m-methylaniline; stir and mix for 3 hours and cool and keep at -5°C, add every hour Add 1526g sodium nitrite to 292g, react at low temperature for 1h, slowly raise the temperature to 35°C at 4°C / h and react for 3h, the content of m-methylaniline should be less than 1wt%, let stand and separate, collect the organic phase, a total of 2025g, to obtain m-fluorotoluene, purity The yield was 98.4%, and the yield was 90.1%; hydrogen fluoride was recovered by condensation at -5°C.

Embodiment 2

[0075] Example 2: Preparation of compound of formula (IV) (m-fluorotoluene) 2 by diazotization reaction:

[0076] Put 1,497g (74.9mol) of hydrogen fluoride into a 5L fluorination reactor and cool down to 0°C, add 110g dropwise per hour, add 2,013g (18.8mol) of m-methylaniline; stir and mix for 3 hours, cool and keep at -5°C, and put in every hour Add 1548g sodium nitrite to 290g, react at low temperature for 1h, slowly raise the temperature to 35°C at 4°C / h and react for 3h. The yield was 97.7%, and the yield was 86.3%; hydrogen fluoride was recovered by condensation at -5°C.

Embodiment 3

[0077] Example 3: Preparation of compound of formula (V) (2-methyl-4-fluoro-benzenesulfonic acid) by substitution of sulfonic acid group:

[0078] Put 1258g of 95% sulfuric acid and 122g of sulfur trioxide into a reactor with stirring, temperature control and reflux, add 1120g (10.2mol) of m-fluorotoluene with a purity of 99%; heat to 30°C for 6h, and collect the sulfonic acid phase; The products are 1706g (about 88%) of 2-methyl-4-fluoro-benzenesulfonic acid and 182g (about 9.4%) of 2-fluoro-4-methylbenzenesulfonic acid; put them into 6.7L of toluene, stir and heat up to After dissolving at 65°C, maintain it for 2h, cool down naturally to 25°C for 6h to crystallize, and filter to obtain 947g of 4-fluoro-2-methylbenzenesulfonic acid with a purity of 98%. The toluene filtrate is recovered and recycled.

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Abstract

The invention discloses a continuous production method for industrially preparing 2,3-difluorobenzotrifluoride and 3,4-difluorobenzonitrile. The preparation process of the 2,3-difluorobenzotrifluoride comprises the preparation step of an intermediate raw material for benzene sulfonamide and benzenesulfonylurea herbicides, and the preparation process of the 3,4-difluorobenzonitrile comprises the preparation step of a cthalofop-butyl intermediate raw material. The method is suitable for industrial production; and compared with the prior art, the method has the advantages of low cost, high production method and less pollution.

Description

technical field [0001] The invention relates to a continuous production method for industrially preparing 2,3-difluorobenzonitrile and 3,4-difluorobenzonitrile, which belongs to the technical field of chemical industry. Background technique [0002] 2,3-Difluorotrifluorotoluene is the intermediate raw material of benzenesulfonamide and benzenesulfonylurea herbicides, and 3,4-difluorobenzonitrile is the intermediate raw material of cyhalofopin, among which sulfonamide herbicides According to US5858924, penoxsulam can react 2,3-difluorotrifluorotoluene with mercaptan and oxidize chlorine to generate benzenesulfonic acid, react with difluoroethanol and then react with 2-amino-5,8-dimethoxy -[1,2,4]triazolo-[1,5-C]pyrimidine is condensed into penoxsulam, and the process is as follows: [0003] [0004] Cyhalofop is prepared by reacting 3,4-difluorobenzonitrile with (R)-2-(4-hydroxyphenoxy)propionate according to US4532328, (R)-2-(4-hydroxyphenoxy ) propionate can be reacted...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C17/20C07C25/13C07C253/30C07C255/50
CPCC07C17/093C07C17/14C07C17/206C07C17/208C07C17/35C07C51/34C07C253/22C07C253/30C07C303/06C07C25/13C07C63/70C07C309/39C07C255/50
Inventor 赵皓邢茂源李飞
Owner ZIBO FEIYUAN CHEM CO LTD
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