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Preparation method of fipronil

A technology of fipronil and trifluoromethyl phenyl, which is applied in the field of chemical synthesis, can solve the problems of reduced fipronil content and yield, large amount of trifluoroacetic acid, and a large amount of dilute sulfuric acid waste water, etc., to ensure purity, reduce The effect of reducing the amount of production process cost and environmental pollution

Active Publication Date: 2013-10-23
HAIZHENG CHEM NANTONG CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Literature (J.Fluorine Chem.2006, 127948-953) reported that dichloromethane was used as the main solvent to carry out this oxidation reaction, and the synthesis yield could reach 96%, but the content of peroxidized impurity sulfone was relatively high, and three The amount of fluoroacetic acid is still relatively large (the ratio of trifluoroacetic acid to methylene chloride is about 1:5), which is still not suitable for industrial applications
[0007] Chinese patent CN200610137282.5 discloses that trichloroisocyanuric acid (TCCA) is used as an oxidizing agent to conduct an oxidation reaction in room temperature ionic solution and acetonitrile. The product has a high purity, but the synthesis yield is only 70%, and the room temperature ionic solution It is relatively expensive as a reaction solvent, resulting in high cost, so it is not used in industry
The concentrated sulfuric acid in this method will hydrolyze fipronil and cause the content and yield to decrease, and will also produce a large amount of dilute sulfuric acid wastewater

Method used

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Experimental program
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Effect test

Embodiment 1

[0029] The preparation of embodiment 1 fipronil

[0030] 105.2 kg (237 mol) of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylthiopyrazole (95% pure, Zhejiang Hisun Chemical Co., Ltd.) mixed with 450kg (4545.45mol) dichloroethane, then added 6kg (52mol) trifluoroacetic acid and 12kg (122mol) concentrated sulfuric acid at one time, and the reaction temperature was controlled at 5-35°C , directly add 20.2kg of 50% (297mol) hydrogen peroxide. Continue stirring, when the reaction conversion rate is 67% (HPLC detection, control the mass fraction of peroxidized impurities to be less than 1%), add an aqueous solution with a mass fraction of 10% sodium sulfite to quench the reaction until the starch potassium iodide test paper does not turn blue, and then use mass fraction The pH value was adjusted to 6-7 with a 12% sodium hydroxide solution, and the solid obtained after suction filtration was crystallized 4 times with dichloroethane to obtain 61.2 kg of pu...

Embodiment 2

[0032] The preparation of embodiment 2 fipronil

[0033] 105.2 kg (237 mol) of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylthiopyrazole (95% pure, Zhejiang Hisun Chemical Co., Ltd.) and 450kg (4545.45mol) of dichloroethane were mixed and stirred, and then 1.2kg (10mol) of trifluoroacetic acid and 4.8kg (48mol) of concentrated sulfuric acid were added at one time. Control the temperature at 5-35°C, and then add 20.2kg of 50% (297mol) hydrogen peroxide. Continue to stir until the reaction conversion rate reaches 62% (HPLC detection, control the mass fraction of peroxidized impurities to be less than 1%), add an aqueous solution with a mass fraction of 10% sodium sulfite to quench the reaction until the starch potassium iodide test paper does not turn blue, and then use a mass fraction of 12% sodium hydroxide solution was used to adjust the pH value to 6-7. After suction filtration, the solid was crystallized with dichloroethane for 6 times to obtai...

Embodiment 3

[0035] The preparation of embodiment 3 fipronil

[0036]105.2 kg (237 mol) of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylthiopyrazole (95% pure, Zhejiang Hisun Chemical Co., Ltd.) and 600kg (5330mol) of chlorobenzene were mixed and stirred, and then 6kg (52mol) of trifluoroacetic acid and 12kg (122mol) of concentrated sulfuric acid were added at one time. Control the temperature at 5-35°C, and then add 20.2kg of 50% (297mol) hydrogen peroxide. Continue to stir until the reaction conversion rate reaches 70% (HPLC detection, control the mass fraction of peroxidized impurities to be less than 1%), add an aqueous solution with a mass fraction of 10% sodium sulfite to quench the reaction until the starch potassium iodide test paper does not turn blue, and then use a mass fraction of 12% sodium hydroxide solution was used to adjust the pH value to 6-7. After suction filtration, the solid was crystallized with dichloroethane for 5 times to obtain 59.1 ...

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Abstract

The invention discloses a preparation method of fipronil. The preparation method comprises the following step of: obtaining fipronil (II) by control and oxidization of 5-amino-3-cyan-1-(2, 6-dichloro-4-trifluoromethyl phenyl)-4-trifluoromethylmercaptoparazole (I) in the presence of an organic solvent, hydrogen peroxide, a catalyst A and a catalyst B at 5-35 DEG C, wherein the catalyst A is selected from a haloacetic acid; the catalyst B is selected from one of sulfonic acids or mixture of different sulfonic acids, one of inorganic acids or mixture of different inorganic acids, or mixture of sulfonic acid and inorganic acid by any ratio; and the control on the oxidization condition refers to cancellation treatment when the reaction transformation rate is 60%-80%. According to the preparation method disclosed by the invention, the preparation process of the fipronil can be stably performed within 5-35 DEG C, the usage of haloacetic acid is greatly reduced, high-purity products and few byproducts are obtained, the production cost is reduced, and the yield of the fipronil in preparation is increased.

Description

technical field [0001] The invention relates to a preparation method of fipronil, in particular to the oxidation process in the preparation method of fipronil, and belongs to the field of chemical synthesis. Background technique [0002] Fipronil is a high-efficiency broad-spectrum phenylpyrazole insecticide, and its preparation process mainly includes 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylbenzene base)-pyrazole with trifluorosulfinyl chloride acylation synthetic route and 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-tri Synthetic route of the oxidation reaction of fluoromethylthiopyrazole (I). Due to the serious environmental pollution problem of the acylation route process, although the cost is lower and the product purity is better, it is still gradually replaced by the oxidation route process in industry. [0003] Several oxidation methods for the preparation of fipronil are known in the prior art: [0004] The initial report of the oxidation ...

Claims

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Application Information

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IPC IPC(8): C07D231/44
Inventor 蒋富国沈亮戴咸本李劲林龙蔡华具
Owner HAIZHENG CHEM NANTONG CO LTD
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