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Process for preparing 2,4-difluorocyanobenzene

A difluorobenzonitrile and production process technology, applied in two fields, can solve the problems of long reaction process cycle time, complex catalyst preparation, complex post-treatment, etc., and achieve the effects of high yield, low pollution and short reaction process

Inactive Publication Date: 2007-05-16
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The preparation of catalysts in the above-mentioned synthesis processes is complex, the reaction process cycle time is long, the conditions are harsh, or many experimental processes involve various problems such as highly toxic reagents, high temperature and high pressure conditions, low yield, and complicated post-processing.

Method used

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  • Process for preparing 2,4-difluorocyanobenzene
  • Process for preparing 2,4-difluorocyanobenzene
  • Process for preparing 2,4-difluorocyanobenzene

Examples

Experimental program
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Effect test

Embodiment 1

[0025] In a 1000 ml three-necked flask, under nitrogen protection, 500 ml of N,N-dimethylacetamide solvent, 57.6 g (300 mmol) of 2,4-difluorobromobenzene, 25 g (60 mmol, 0.2 Equivalent) potassium ferrocyanide trihydrate, 680 mg (3 mmol, 0.3 mol%) palladium acetate catalyst, 35 g of sodium carbonate (330 mmol, 1.1 equiv), under nitrogen protection at 100 ° C for 2 hours with stirring, The reaction was completed, followed by filtration, and the filtrate was fractionated under reduced pressure to obtain white crystals of 2,4-difluorobenzonitrile with a yield of 85%, a purity of 98%, a boiling point of 84-86°C (2666.4 Pa), and a melting point of 47-49°C.

Embodiment 2

[0027] In a 1000 ml three-necked flask, under nitrogen protection, 500 ml of N,N-dimethylacetamide solvent, 57.6 g (300 mmol) of 2,4-difluorobromobenzene, 28 g (66 mmol, 0.3 Equivalent) potassium ferrocyanide trihydrate, 340 mg (1.5 mmol, 0.5 mol%) of palladium acetate catalyst, 31.8 g of sodium carbonate (300 mmol, 1.0 equiv.), and the reaction was stirred at 120 ° C for 3 hours under nitrogen protection, The reaction was completed, followed by filtration, and the filtrate was fractionated under reduced pressure to obtain white crystals of 2,4-difluorobenzonitrile with a yield of 90%, a purity of 99%, and a melting point of 48-49°C.

Embodiment 3

[0029] In a 1000 ml three-necked flask, under nitrogen protection, 500 ml of N,N-dimethylacetamide solvent, 57.6 g (300 mmol) of 2,4-difluorobromobenzene, 27 g (66 mmol, 0.22 equiv) sodium ferrocyanide trihydrate, 15 mmol (5 mol %) bis(dibenzylidenepyruvate) palladium catalyst, 31.8 g sodium carbonate (300 mmol, 1.0 equiv), stirred at 120°C under nitrogen protection The reaction was completed for 1 hour, followed by filtration, and the filtrate was fractionated under reduced pressure to obtain 2,4-difluorobenzonitrile as white crystals with a yield of 87%, a purity of 98%, and a melting point of 47-49°C.

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Abstract

The invention discloses a manufacturing method of 2, 4-difluocyanobenzene, which comprises the following steps: adopting N, N-dimethylacetamide as reacting solvent and 0.1-5% palladium complex as catalyst; making 0.5-2% alkaline metal carbonate as alkaline; reacting 2, 4-difluobromobenzene and ferrocyanide with molar rate at 1: 0.15-0.3 to react under 100-150 Deg C for 1-6h; filtering; decompressing the filtrate; fractioning to obtain the product. The invention shortens reacting flow path, which is simple to feed and dispose without poison in the whole course.

Description

technical field [0001] The invention relates to a preparation method of a pharmaceutical intermediate, in particular to a production process of 2,4-difluorobenzonitrile. Background technique [0002] 2,4-Difluorobenzonitrile can be used in the synthesis of medicines, pesticides and fluoropolymers. The pesticide synthesized by it has strong selectivity, less usage, low toxicity and low residue to human beings, and is a green pesticide with a very broad development prospect. Therefore, how to efficiently synthesize 2,4-difluorobenzonitrile has received great attention. There have been some literature reports on the synthesis of 2,4-difluorobenzonitrile, such as the literature JP 60-72850, CN85100467 using 2,4-dichlorobenzonitrile as a raw material to synthesize 2,4-difluorobenzonitrile: [0003] [0004] Document JP 1990-113 037 takes m-diphenylamine as raw material through diazotization, and introduces cyano group to synthesize 2,4-difluorobenzonitrile: [0005] [0...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C255/50C07C253/14
Inventor 王晶林旭锋
Owner ZHEJIANG UNIV
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