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Preparation process for 2,4-difluorobenzonitrile

A technology that prepares and diofluorophenylpines can be used in the 2nd field. It can solve problems that are not suitable for industrial production, low product revenue, and high response temperature.

Active Publication Date: 2018-12-07
SHANDONG NORMAL UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] These above-mentioned synthetic processes generally have problems such as high reaction temperature, high requirements on equipment, unsuitability for industrial production, and low product yield; and the third synthetic process also involves the use of the highly toxic substance sodium cyanide

Method used

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  • Preparation process for 2,4-difluorobenzonitrile
  • Preparation process for 2,4-difluorobenzonitrile
  • Preparation process for 2,4-difluorobenzonitrile

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Embodiment 1: the preparation of 2,4-difluorobenzonitrile

[0044] Add 314g (2.00mol) of 2,4-difluorobenzoic acid and 952g (8.00mol) of thionyl chloride to a 2000ml single-necked bottle, heat up and reflux for about 4 hours (the temperature of temperature rise and reflux is 78°C), and concentrate to dryness under reduced pressure , to obtain a yellow oil, that is, 2,4-difluorobenzoyl chloride, to obtain 318g (1.80mol), and the yield is 90%.

[0045] Add 310g (1.76mol) of 2,4-difluorobenzoyl chloride, 500ml of acetone, and 690g of ammonia water (10.56mol) into a 2000ml single-necked bottle, react at 50°C for 3 hours, concentrate under reduced pressure to remove acetone, filter with suction, and filter cake After drying under reduced pressure, 2,4-difluorobenzamide was obtained, and 255 g (1.62 mol) was obtained, with a yield of 92%.

[0046] Into a 2000ml three-necked flask, add 236g (1.50mol) of 2,4-difluorobenzamide, 500g of tetrahydrofuran, dropwise add 378g (1.80mol...

Embodiment 2

[0047] Embodiment 2: Preparation of 2,4-difluorobenzonitrile

[0048] Add 360g (2.29mol) of 2,4-difluorobenzoic acid and 1091g (9.17mol) of thionyl chloride to a 2000ml single-necked bottle, heat up and reflux for about 5 hours (the temperature of temperature rise and reflux is 78°C), and concentrate to dryness under reduced pressure , to obtain a yellow oil, that is, 2,4-difluorobenzoyl chloride, to obtain 368g (2.08mol), yield 91%.

[0049] Add 353g (2.00mol) of 2,4-difluorobenzoyl chloride, 600ml ethanol, and 785g ammonia water (12.00mol) to a 2000ml single-necked bottle, react at 50°C for 4 hours, concentrate under reduced pressure to remove ethanol, filter with suction, and filter cake After drying under reduced pressure, 2,4-difluorobenzamide was obtained, and 289 g (1.84 mol) was obtained, with a yield of 92%.

[0050]Into a 3000ml three-neck flask, add 283g (1.80mol) of 2,4-difluorobenzamide, 600g of tetrahydrofuran, dropwise add 454g (2.16mol) of trifluoroacetic anhy...

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Abstract

The invention discloses a preparation process for 2,4-difluorobenzonitrile. The preparation process comprises the following steps: (1) with 2,4-difluorobenzoic acid and thionyl chloride as raw materials, reacting the 2,4-difluorobenzoic acid with the thionyl chloride so as to generate 2,4-difluorobenzoyl chloride; (2) reacting the 2,4-difluorobenzoyl chloride with ammonia water so as to generate 2,4-difluorobenzamide; and (3) reacting the 2,4-difluorobenzamide with trifluoroacetic anhydride so as to prepare the 2,4-difluorobenzonitrile. According to the invention, reaction raw materials and asynthetic route for synthesis of the 2,4-difluorobenzonitrile are optimally designed; the reaction raw materials adopted in the preparation process provided by the invention are cheap, easily-available and safe in use; and the preparation process provided by the invention has the advantages of mild reaction conditions, no need of a high-temperature reaction, low requirements for equipment, high product yield and purity, and easy implementation of industrial production.

Description

technical field [0001] The invention relates to the technical field of organic compound synthesis, in particular to a preparation process of 2,4-difluorobenzonitrile. Background technique [0002] 2,4-Difluorobenzonitrile is an important intermediate for the synthesis of new fluorine-containing pesticides and medicines, and has broad market application prospects. Therefore, how to efficiently synthesize 2,4-difluorobenzonitrile has attracted widespread attention. At present, the synthetic methods of 2,4-difluorobenzonitrile mainly contain the following types: [0003] 1. According to the Chinese patent "Preparation Method of Fluorobenzonitrile" (CN85100467), 2,4-dichlorobenzonitrile is used as raw material to react with potassium fluoride at 180-250°C. The reaction formula is as follows: [0004] [0005] 2. The document DE2239799, 1974 reported that using m-difluorobenzene as raw material, it undergoes methylation and ammoxidation reaction at 300°C. The reaction formul...

Claims

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Application Information

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IPC IPC(8): C07C253/20C07C255/50
CPCC07C51/60C07C231/02C07C253/20C07C255/50C07C233/65C07C63/70
Inventor 孙彬彭立增魏光雷王伟
Owner SHANDONG NORMAL UNIV
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