Azoxystrobin intermediate refining device

Abstract

According to the azoxystrobin intermediate refining device, the lower part of an intermediate synthesis kettle is connected with the upper part of a crystallization kettle for feeding through a synthesis discharge pipe with a synthesis discharge valve, the lower part of the crystallization kettle is connected with a centrifugal machine through a crystallization discharge pipe with a crystallization discharge valve, the lower part of the centrifugal machine is connected with a methanol collecting tank, and the bottom of the centrifugal machine is connected with a dissolving kettle through a pipeline with a valve; the bottom of the dissolving kettle is connected with the refining synthesis kettle through a pipeline with a valve, one path of the methanol storage tank is connected with the upper part of the intermediate synthesis kettle for feeding through the pipeline with the valve, and the other path of the methanol storage tank is connected with the upper part of the centrifugal machine for feeding through a washing pipe with a washing valve; and the other path is connected with the upper feeding part of the dissolving kettle through a dissolving pipe with a dissolving valve. The structure is simple, efficient sealing operation is beneficial for improving the operation safety of industrial production, and synthesis after refining is beneficial for improving the yield and purity of a final product and reducing the production cost.

Description

Technical Field

[0001] This utility model relates to chemical refining equipment, specifically a refining device for the azoxystrobin intermediate 3-(α-methoxy)methenylbenzofuran-2(3H)-one. Background Technology

[0002] Azoxystrobin is a methoxyacrylate fungicide developed by Syngenta (formerly known as Syngenta). It is a novel, highly effective, and broad-spectrum methoxyacrylate fungicide synthesized by mimicking the chemical structure of the natural product Strobilurin A. It is a mitochondrial respiration inhibitor, meaning it inhibits mitochondrial respiration by suppressing electron transfer between cytochrome b and c1, thereby disrupting the energy synthesis of pathogens. It possesses protective, eradicative, penetrating, systemic, and highly effective broad-spectrum properties.

[0003] It is well known in the industry that 3-(α-methoxy)methylenebenzofuran-2(3H)-one, the main intermediate of azoxystrobin, has strong sensitizing properties. Therefore, the purification process is often skipped in the production of azoxystrobin. The next step is to undergo alcoholysis and transesterification with sodium methoxide and 4,6-dichloropyrimidine to produce methyl 3,3-dimethyl-2-(2-hydroxyphenyl)propionate. This process has stringent reaction conditions and high requirements for the raw material 3-(α-methoxy)methylenebenzofuran-2(3H)-one. The existing industrial production process mainly uses o-hydroxyphenylacetic acid or benzofuran-2(3H)-one to react with trimethyl orthoformate, with acetic anhydride added as a solvent and methanol removal agent. Under these conditions, the synthesized 3-(α-methoxy)methylenebenzofuran-2(3H)-one contains a large amount of byproducts, and the product yield can only be maintained at 92-95%. This has a certain impact on the subsequent alcoholysis and transesterification reactions. Therefore, it is necessary to carry out purification after synthesis. However, it is difficult to carry out this process due to its high sensitivity and unpleasant odor. The industry basically meets the production needs by increasing the amount of sodium methoxide and 4,6-dichloropyrimidine. This method increases the production cost and generates a lot of waste in the subsequent post-processing.

[0004] The main refining method in industrial production is recrystallization. After recrystallization, the refined product is separated from the mother liquor and manually reintroduced into the reactor for the next reaction. This method carries a very high risk of exposure for workers, making contact with the materials difficult to avoid. Furthermore, 3-(α-methoxy)methylenebenzofuran-2(3H)-one is a needle-like crystal, long and light, easily dispersed in the air, often leading to unintentional contact and allergic reactions in workers. Additionally, the acetic anhydride used in the synthesis process is volatile, forming an unpleasant acidic odor. Given this production situation, the industry often chooses to treat impurities after the synthesis of methyl 3,3-dimethyl-2-(2-hydroxyphenyl)propionate. This not only affects product quality and yield but also causes unnecessary losses of other materials. Therefore, there is an urgent need for a refining system that can perform the process without direct human intervention and with good sealing properties. Summary of the Invention

[0005] This invention provides a simple, sealed, and safe purification apparatus for the intermediate 3-(α-methoxy)methenylbenzofuran-2(3H)-one of azoxystrobin.

[0006] The technical solution adopted in this utility model is: a purification device for azoxystrobin intermediates, including an intermediate synthesis kettle, a crystallization kettle, and a centrifuge, characterized in that: it further includes a purification synthesis kettle, a methanol storage tank, and an ethyl acetate storage tank; the intermediate synthesis kettle is equipped with a solvent removal jacket; a solvent removal device is connected to the upper part of the intermediate synthesis kettle; the lower part of the intermediate synthesis kettle is connected to the upper feed of the crystallization kettle via a synthesis discharge pipe with a synthesis discharge valve; the crystallization kettle is equipped with a crystallization jacket; the lower part of the crystallization kettle is connected to the centrifuge via a crystallization discharge pipe with a crystallization discharge valve; and the lower part of the centrifuge is connected to the methanol storage tank. The alcohol collection tank is connected to the centrifuge bottom via a valved pipe to the dissolving vessel. The dissolving vessel bottom is connected to the refining synthesis vessel via a valved pipe. Both the intermediate synthesis vessel and the refining synthesis vessel are equipped with a stirrer. The methanol storage tank is connected in two branches: one branch is connected to the upper feed of the intermediate synthesis vessel via a valved pipe, and the other branch is connected to the upper feed of the centrifuge via a washing pipe with a washing valve. The ethyl acetate storage tank is connected in two branches: one branch is connected to the upper feed of the centrifuge via a flushing pipe with a flushing valve, and the other branch is connected to the upper feed of the dissolving vessel via a dissolving pipe with a dissolving valve.

[0007] The centrifuge is a belt-type scraper centrifuge.

[0008] The solvent removal device consists of a condenser and a solvent recovery tank connected in series at one or more stages.

[0009] The desolventizing jacket is connected to steam.

[0010] The crystallization jacket is connected to tap water or condensate.

[0011] The solid phase outlet at the bottom of the centrifuge is directly discharged through the discharge flange into the discharge pipeline, which is directly connected to the upper part of the dissolving vessel.

[0012] The flushing tube and the dissolving tube are connected to flow meters.

[0013] The lower part of the centrifuge is connected to a methanol collection tank via a methanol collection pipe equipped with a methanol collection valve.

[0014] The crystallization vessel is equipped with a stirrer.

[0015] After synthesizing 3-(α-methoxy)methylenebenzofuran-2(3H)-one in the intermediate synthesis reactor, the solvent is removed, and methanol is quantitatively fed into the 7-methanol storage tank. After heating and stirring to fully dissolve, the product is sent to the crystallization reactor through the synthesis discharge valve and synthesis discharge pipe. At this time, the temperature of the crystallization reactor is reduced and the mixture is stirred slowly until the crystallization process is completed. Once the crystallization process is complete, the belt-driven scraper centrifuge is started according to the established procedure. The crystallization discharge valve is opened, and the material is slowly fed into the belt-driven scraper centrifuge through the crystallization discharge pipe for normal centrifugal separation. During this process, the methanol mother liquor is collected in a methanol collection tank. After all the material in the crystallization vessel has been centrifuged, the washing valve is opened, and methanol is injected from the methanol storage tank for washing. The washed methanol enters the methanol collection tank along with the mother liquor. After washing, the centrifuge discharge is started, and the solid material enters the dissolving vessel connected to the centrifuge via the discharge pipeline through the centrifuge discharge flange. After the material transfer is complete, the flushing valve is opened, and a certain amount of methyl acetate is injected from the methyl acetate storage tank to flush the inside of the centrifuge and pipelines, removing any residual material. At this time, a certain amount of methyl acetate is injected from the methyl acetate storage tank into the dissolving vessel, and the dissolution operation begins after the injection is complete. Once all the material has dissolved, it is sent to the refining synthesis vessel, thus completing the entire refining process. The device has a simple overall structure, and the fully enclosed conveying operation can effectively avoid material exposure and reduce harm to the environment and personnel. Through the purification of the intermediate 3-(α-methoxy)methylenebenzofuran-2(3H)-one, the solvent anhydride, methyl acetate, and trimethyl orthoformate mixture are effectively removed, which has a good promoting effect on the next step of methyl 3,3-dimethyl-2-(2-hydroxyphenyl)propionate synthesis. Compared with the unrefined state, the amount of sodium methoxide and 4,6-dichloropyrimidine used is reduced at the same yield, which has the advantages of improving product quality and yield and reducing costs. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model.

[0017] In the diagram: 1. Refining synthesis reactor; 2. Desolventizing jacket; 3. Stirrer; 4. Synthesis discharge valve; 5. Synthesis discharge pipe; 6. Crystallization reactor; 7. Crystallization jacket; 8. Crystallization discharge valve; 9. Crystallization discharge pipe; 10. Belt-type scraper centrifuge; 11. Methanol storage tank; 12. Methanol injection valve; 13. Methanol injection pipe; 14. Methanol washing valve; 15. Methanol washing pipe; 16. Ethyl acetate storage tank; 17. Ethyl acetate flushing valve; 18. Ethyl acetate flushing pipe; 19. Methanol collection valve; 20. Methanol collection pipe; 21. Methanol collection tank; 22. Dissolving valve; 23. Discharge flange; 24. Discharge pipeline; 25. Dissolving reactor; 26. Refining synthesis reactor; 27. Flow meter; 28. Detailed Implementation

[0018] The following explanation, in conjunction with the accompanying drawings, will provide further details.

[0019] Figure 1 The apparatus shown is for refining 3-(α-methoxy)methylenebenzofuran-2(3H)-one, an intermediate of azoxystrobin, comprising a refining synthesis kettle 1, a solvent removal jacket 2, a stirrer 3, a synthesis discharge valve 4, a synthesis discharge pipe 5, a crystallization kettle 6, a crystallization jacket 7, a crystallization discharge valve 8, a crystallization discharge pipe 9, a belt-type scraper centrifuge 10, a methanol storage tank 11, a methanol injection valve 12, a methanol injection pipe 13, a methanol washing valve 14, a methanol washing pipe 15, an ethyl acetate storage tank 16, an ethyl acetate flushing valve 17, an ethyl acetate flushing pipe 18, a methanol collection valve 19, a methanol collection pipe 20, a methanol collection tank 21, a dissolving valve 22, a dissolving pipe 23, a discharge flange 24, a discharge pipeline 25, a dissolving kettle 26, a refining synthesis kettle 27, and a flow meter 28.

[0020] The intermediate synthesis reactor 1 is equipped with a desolvation jacket 2. The upper part of the intermediate synthesis reactor 1 is connected to a desolvation device. The lower part of the intermediate synthesis reactor 1 is connected to the upper feed of the crystallization reactor 6 via a synthesis discharge pipe 5 with a synthesis discharge valve 4. The crystallization reactor 6 is equipped with a crystallization jacket 7. The lower part of the crystallization reactor 6 is connected to a belt scraper centrifuge 10 via a crystallization discharge pipe 9 with a crystallization discharge valve 8. The lower part of the belt scraper centrifuge 10 is connected to a methanol collection tank 21 via a methanol collection pipe 20 with a methanol collection valve 19. The solid phase outlet at the bottom of the belt scraper centrifuge 10 is directly discharged to the dissolving reactor 26 via a discharge flange 24 and a discharge pipeline 25. The bottom of the dissolving reactor 26 is connected to the refining synthesis reactor 27 via a pipeline with a valve. The intermediate synthesis reactor, crystallization reactor, dissolving reactor, and refining synthesis reactor are all equipped with a stirrer 3.

[0021] The methanol storage tank 11 has two outlets. One outlet connects to the upper feed of the intermediate synthesis reactor 1 via a methanol injection pipe 13 equipped with a methanol injection valve 12. The other outlet connects to the upper feed of the belt-driven scraper centrifuge 10 via a methanol washing pipe 15 equipped with a methanol washing valve 14. The ethyl acetate storage tank 16 has two outlets. One outlet connects to the upper feed of the belt-driven scraper centrifuge 10 via an ethyl acetate washing pipe 18 equipped with an ethyl acetate washing valve 17. The other outlet connects to the upper feed of the dissolving reactor 26 via a dissolving pipe 23 equipped with a dissolving valve 22.

[0022] In this embodiment, the solvent removal device is an existing industrial process of heating, removing solvent, and condensing for recovery, which typically uses a series of condensers and solvent recovery tanks connected in series.

[0023] In this embodiment, flow meters 28 are connected to both the ethyl acetate rinsing tube and the dissolving tube to control the quantitative demand of ethyl acetate required for dissolving and refining the intermediate.

[0024] In this embodiment, each valve can be installed on the corresponding pipeline or on each reactor where the material is connected via the corresponding pipeline. In this embodiment, the solvent removal method is existing technology. The synthesis of the intermediate involves feeding raw materials into an intermediate synthesis reactor, which is not shown in the attached drawings. The intermediate synthesis reactor is not a refining technology but merely a chemical pipeline feeder based on existing technology. This embodiment of the present invention will not be described in detail.

Claims

1. A purification apparatus for azoxystrobin intermediates, comprising an intermediate synthesis vessel, a crystallization vessel, and a centrifuge, characterized in that: It also includes a refining synthesis reactor, a methanol storage tank, and an ethyl acetate storage tank. The intermediate synthesis reactor is equipped with a desolvation jacket, and a desolvation device is connected to the upper part of the intermediate synthesis reactor. The lower part of the intermediate synthesis reactor is connected to the upper feed of the crystallization reactor via a synthesis discharge pipe with a synthesis discharge valve. The crystallization reactor is equipped with a crystallization jacket, and the lower part of the crystallization reactor is connected to a centrifuge via a crystallization discharge pipe with a crystallization discharge valve. The lower part of the centrifuge is connected to a methanol collection tank. The bottom of the centrifuge is connected to a dissolving reactor via a pipe with a valve. The bottom of the dissolving reactor is connected to the refining synthesis reactor via a pipe with a valve. Both the intermediate synthesis reactor and the refining synthesis reactor are equipped with a stirrer. The methanol storage tank has two outlets: one is connected to the upper feed of the intermediate synthesis reactor via a pipe with a valve, and the other is connected to the upper feed of the centrifuge via a washing pipe with a washing valve. The ethyl acetate storage tank has two outlets: one is connected to the upper feed of the centrifuge via a washing pipe with a rinsing valve, and the other is connected to the upper feed of the dissolving reactor via a dissolving pipe with a dissolving valve.

2. The apparatus for refining azoxystrobin intermediates according to claim 1, characterized in that: The centrifuge is a belt-type scraper centrifuge.

3. The apparatus for refining azoxystrobin intermediates according to claim 1, characterized in that: The solvent removal device consists of a condenser and a solvent recovery tank connected in series at one or more stages.

4. The azoxystrobin intermediate refining apparatus according to claim 1, characterized in that: The desolventizing jacket is connected to steam.

5. The apparatus for refining azoxystrobin intermediates according to claim 1, characterized in that: The crystallization jacket is connected to tap water or condensate.

6. A purification apparatus for azoxystrobin intermediates according to claim 1 or 2, characterized in that: The solid phase outlet at the bottom of the centrifuge is directly discharged through the discharge flange into the discharge pipeline, which is directly connected to the upper part of the dissolving vessel.

7. The apparatus for refining azoxystrobin intermediates according to claim 1, characterized in that: The flushing tube and the dissolving tube are connected to flow meters.

8. The apparatus for refining azoxystrobin intermediates according to claim 1, characterized in that: The lower part of the centrifuge is connected to a methanol collection tank via a methanol collection pipe equipped with a methanol collection valve.

9. The apparatus for refining azoxystrobin intermediates according to claim 1, characterized in that: The crystallization vessel is equipped with a stirrer.

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