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Preparation method of fipronil

A technology of fipronil and trifluoromethyl phenyl is applied in the field of oxidizing 5-amino-3-cyano-1--4-trifluoromethylthiopyrazole to generate fipronil, which can solve the problem of expensive trifluorocarbon Acetic acid and trifluoroacetic acid cannot be directly applied, etc., to achieve the effects of simple process, good industrial application prospects and environmental friendliness

Active Publication Date: 2008-08-27
HUNAN CHEM RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

US6881848 discloses the preparation method of using hydrogen peroxide to oxidize and synthesize fipronil in a trifluoroacetic acid medium; its disadvantage is that a large amount of expensive trifluoroacetic acid is used, and the recovery of trifluoroacetic acid cannot be directly applied

Method used

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Examples

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Embodiment 1

[0015] Under cooling, add 40 grams of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylthiopyrazole, 200ml of three-necked flask Methyl chloride, stir for 20 minutes, add 40 grams of 118% sulfuric acid, 1 gram of tetrabutylammonium chloride, slowly add 16 grams of 30% hydrogen peroxide, control the temperature -10~-5℃, and react at this temperature 5 After ~6 hours, sample and monitor. After the reaction is completed, 120ml of water is added dropwise at 0~4℃, and the layers are separated. The organic layer was washed with saturated sodium bicarbonate solution until it was neutral, separated into layers, desolvated, and dried to obtain 39.2 g of fipronil technical.

Embodiment 2

[0017] Under cooling, 24 grams of sodium perborate and 0.4 grams of tetrabutylammonium bromide were slowly added to 80 grams of 96% sulfuric acid, stirred for 20 minutes, and 40 grams of 5 dissolved in 200 ml of dichloromethane were added dropwise at 0-4°C. -Amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylthiopyrazole, and react at this temperature for 2 to 3 hours, and sample After monitoring, after the reaction is completed, 80 ml of water is added dropwise at 0-4°C, and the layers are separated. The organic layer was washed with saturated sodium bicarbonate solution to neutrality, separated into layers, desolvated, and dried to obtain 39.3 g of fipronil technical.

Embodiment 3

[0019] Under cooling, 20 grams of sodium perborate and 1 gram of 4-N,N-lutidine were slowly added to 400 grams of 60% sulfuric acid, stirred for 20 minutes, and then added dropwise to 50 ml of carbon tetrachloride at 10°C. 40 grams of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylthiopyrazole, and react at this temperature for 6-8 After the reaction is completed, 60ml of water is added dropwise at 10°C, and the layers are separated. The organic layer was washed with saturated sodium bicarbonate solution to neutrality, separated into layers, desolvated, and dried to obtain 39.4 g of fipronil technical.

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Abstract

The invention discloses a method for using 5-amino-3-cyano-1-(2, 6-dichloro-4-trifluoromethylphenyl)-4-Trifluoromethylthio pyrazole as raw material to generate fipronil via catalysis and oxidation in solvent and sulfate medium. The chemical equation is represented as above. The invention oxidizes sulfate medium to generate fipronil, and the sulfate can be diluted by adding water and be layered to recover. The invention has the advantages of simple process, environment protection, mild reaction conditions and low production cost, with wide industrial application.

Description

Technical field [0001] The present invention relates to a preparation method of fipronil, in particular to 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethyl sulfide The method of generating fipronil by oxidation of pyrazole. Background technique [0002] Fipronil, also known as fipronil, chemical name 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylsulfinyl Pyrazole. White solid, melting point 200-201°C. Vapor pressure 3.7×10 -4 MPa (25°C), solubility: water 2 mg / l, acetone>50%. Acute oral LD ​​in rats 50 It is 97 mg / kg. Fipronil is a broad-spectrum insecticide with touch, stomach toxicity and moderate systemic effects. It can control underground pests and above ground pests. The main targets include aphids, leafhoppers, lepidopteran larvae, Pests such as flies and coleoptera. The preparation method of fipronil described in EP0295117 is synthesized from 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole and trifl...

Claims

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Application Information

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IPC IPC(8): C07D231/44A01P7/00
Inventor 陶贤鉴黄超群熊莉莉罗亮明
Owner HUNAN CHEM RES INST
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