Synthesis process of herbicide intermediate

Abstract

The present invention relates to the technical field of compounds, particularly to a herbicide intermediate synthesis process, which comprises: adding a first solvent and thiourea into a reaction container, stirring, and mixing the first solvent and thiourea to prepare a first mixture; sequentially adding a first catalyst, 3-bromo-5, 5-dimethyl-4, 5-dihydroxyisoxazole and the first mixture into the reaction container, and carrying out a reaction so as to prepare a second reactant; adding process water I into the reaction container, stirring the process water I and the second reactant, standing for layering, taking out a lower-layer water phase, and putting the lower-layer water phase into a product bottle; adding process water II into the oil phase in the reaction container, stirring, standing for layering, and combining the lower-layer water phase with the water phase in the product bottle to prepare a 5, 5-dimethyl-4, 5-dihydroisoxazole-3-yl thiourea bromate water solution; according to the invention, the operation steps are simplified, the use of filtering equipment is avoided, and the production cost can be saved.

Description

Technical Field

[0001] The present invention relates to the technical field of compounds, and in particular to a synthesis process of a herbicide intermediate. Background Art

[0002] 5,5-Dimethyl-4,5-dihydroisoxazol-3-ylthiourea bromide is an important pesticide intermediate and can be used to produce sulfonepyraclostrobin. Sulfonepyraclostrobin is an isoxazole herbicide used as a pre-emergence treatment agent in many crop fields. After application, it can inhibit the growth of young roots and young shoots of weeds, thereby inhibiting the early growth of weed seedlings, destroying meristems and coleoptiles, and is an important potential inhibitor of VLCFA (very long side-chain fatty acids) biosynthesis in plants. Compared with acetochlor and isopropylamine, sulfonepyraclostrobin has a wide range of applications and high biological activity, and its unit area usage is about 9 times lower than that of acetochlor and chloroacetamide herbicides.

[0003] At present, the processes for synthesizing 5,5-dimethyl-4,5-dihydroisoxazole-3-ylthiourea bromate on the market mostly use 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole and thiourea as raw materials, react in solvents such as acetonitrile, and then obtain the product through steps such as crystallization filtration or desolventization and stratification. In the existing process, since post-treatment steps such as filtration are required, corresponding filtration equipment is required. However, since the filtration equipment occupies a large area and has high energy consumption, the production cost of 5,5-dimethyl-4,5-dihydroisoxazole-3-ylthiourea bromate is relatively high. Summary of the invention

[0004] The object of the present invention is to provide a synthesis process of a herbicide intermediate. When preparing 5,5-dimethyl-4,5-dihydroisoxazol-3-ylthiourea bromate, no desolventizing and filtering steps are required, the use of filtering equipment is eliminated, and production costs can be saved.

[0005] To achieve the above object, the present invention provides a synthesis process of a herbicide intermediate, comprising:

[0006] Adding a first solvent and thiourea into a reaction container and stirring the mixture to prepare a first mixture;

[0007] Adding the first catalyst, 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole and the first mixture into a reaction container in sequence to react, and ending the reaction when the content of 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole is less than 1%, to obtain a second reactant;

[0008] Add process water 1 to the reaction container, stir the process water 1 and the second reactant, let stand and separate, take out the lower aqueous phase and put it into the product bottle;

[0009] Add process water 2 to the oil phase in the reaction container, stir and let stand to separate the layers, combine the lower aqueous phase with the aqueous phase in the product bottle to obtain an aqueous solution of 5,5-dimethyl-4,5-dihydroisoxazol-3-ylthiourea bromate.

[0010] Wherein, the first solvent is any one or more of benzene, ether and ester solvents.

[0011] The first solvent and thiourea are added to the reaction container and stirred to obtain a first mixture. The stirring rate is 60-100 rpm, the stirring time is 18-21 hours, and the mixing temperature is 5-40°C.

[0012] Wherein, the first catalyst, 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole and the first mixture are sequentially added into the reaction container for reaction, and the reaction temperature is 5 to 40°C.

[0013] Wherein, the process water 1 is added into the reaction container, the process water 1 and the second reactant are stirred and then allowed to stand for stratification, the stirring rate is 60-90 rpm, and the stirring time is 0.5-1.5 h.

[0014] Wherein, the first catalyst is any one or more of aqueous hydrogen halide solution, sulfuric acid, and nitric acid, and the concentration range of the first catalyst is 10% to 70%.

[0015] The molar ratio of the 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole to thiourea is 1:1-1.5, and the molar ratio of the 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole to the first solvent is 1:6-9.

[0016] The molar ratio of the process water 1 to 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole is 22-17:1, and the molar ratio of the process water 2 to 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole is 12-7:1.

[0017] Wherein, the process water 1 is added into the reaction container, the process water 1 and the second reactant are stirred and then allowed to stand for stratification, and the temperature in the reaction container is 5-40°C.

[0018] Wherein, the process water 2 is added to the oil phase in the reaction container, and the mixture is allowed to stand for stratification after stirring, and the temperature in the reaction container is 5-40°C.

[0019] The synthesis process of a herbicide intermediate of the present invention adopts a layered extraction method to obtain a 5,5-dimethyl-4,5-dihydroisoxazol-3-ylthiourea bromate aqueous solution, which simplifies the operation difficulty. The oil phase after layering can be reused as a solvent, thereby reducing the generation of three wastes. The synthesis process of the present invention does not need to perform a desolventizing and filtering process, and directly obtains a 5,5-dimethyl-4,5-dihydroisoxazol-3-ylthiourea bromate aqueous solution by layering, which can be directly used in subsequent process flows without the need to prepare a solution again, thereby simplifying the operation steps, eliminating the use of filtering equipment, and saving production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0021] Figure 1 The present invention is a flow chart of a synthesis process of a herbicide intermediate. DETAILED DESCRIPTION

[0022] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0023] See also Figure 1 ,in, Figure 1 The present invention is a flow chart of a synthesis process of a herbicide intermediate.

[0024] The present invention provides a synthesis process of a herbicide intermediate, comprising:

[0025] S1. adding a first solvent and thiourea into a reaction container and stirring the mixture to prepare a first mixture;

[0026] Wherein, the first solvent is any one or more of benzene, ether and ester solvents.

[0027] The first solvent and thiourea are added into the reaction container and stirred to prepare a first mixture after the first solvent and thiourea are mixed. The stirring rate is 60-100 rpm, the stirring time is 18-21 hours, and the mixing temperature is 5-40°C.

[0028] S2. sequentially adding the first catalyst, 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole and the first mixture into a reaction container to react, and when the content of 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole is less than 1%, the reaction is terminated to obtain a second reactant;

[0029] Wherein, the first catalyst is any one or more of aqueous hydrogen halide solution, sulfuric acid, and nitric acid, and the concentration range of the first catalyst is 10% to 70%.

[0030] The first catalyst, 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole and the first mixture are sequentially added into the reaction container for reaction at a reaction temperature of 5 to 40°C.

[0031] The molar ratio of the 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole to thiourea is 1:1-1.5, and the molar ratio of the 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole to the first solvent is 1:6-9.

[0032] S3: adding process water 1 to the reaction container, stirring the process water 1 and the second reactant, standing and separating, taking out the lower aqueous phase and putting it into the product bottle;

[0033] Wherein, the process water 1 is added into the reaction container, the process water 1 and the second reactant are stirred and then allowed to stand for stratification, the stirring rate is 60-90 rpm, and the stirring time is 0.5-1.5 h.

[0034] The process water 1 is added into the reaction container, the process water 1 and the second reactant are stirred and then allowed to stand for stratification, and the temperature in the reaction container is 5-40°C.

[0035] S4: Add process water 2 to the oil phase in the reaction container, stir and allow to stand for stratification, combine the lower aqueous phase with the aqueous phase in the product bottle to obtain an aqueous solution of 5,5-dimethyl-4,5-dihydroisoxazol-3-ylthiourea bromate.

[0036] The molar ratio of the process water 1 to 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole is 22-17:1, and the molar ratio of the process water 2 to 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole is 12-7:1.

[0037] The process water 2 is added to the oil phase in the reaction container, and the mixture is allowed to stand for stratification after stirring. The temperature in the reaction container is 5-40°C.

[0038] In the embodiment of the present invention, a first solvent and thiourea are added to a four-necked bottle, stirred at a speed of 60 to 100 rpm for 18 to 21 hours, while maintaining the temperature in the container at 5 to 40° C., and then a certain amount of 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole is added dropwise, and the temperature in the container is maintained at 5 to 50° C. to react. During sampling, when the content of 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole is less than 1%, the reaction is terminated.

[0039] Add process water 1 to a four-necked bottle, keep the temperature in the container at 5-40°C, stir at a speed of 60-90 rpm for 0.5-1.5 hours, let stand and separate, put the lower aqueous phase into a product bottle, then add process water 2 to the oil phase in the four-necked bottle, keep the temperature in the container at 5-40°C, stir at a speed of 60-90 rpm for 0.5-1.5 hours, let stand and separate, put the lower aqueous phase into the product bottle, and obtain a product 5,5-dimethyl-4,5-dihydroisoxazol-3-ylthiourea bromate aqueous solution, which can be used as a herbicide intermediate for the subsequent synthesis of sulfonepyraclostrobin.

[0040] For a better understanding of the present invention, a specific synthesis process is used below for illustration:

[0041] First, add 349g toluene and 42g thiourea to a four-necked bottle, start stirring, keep the temperature between 20 and 30°C, drop 52g HCl with a concentration of 36%, then drop 100g 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole, keep the temperature between 25 and 30°C, and react for 17 hours. Take samples for control, and when the content of 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole is less than 1%, the reaction is over.

[0042] Next, add 200 g of water to the four-necked bottle, keep the temperature between 20 and 25° C., stir for 1 hour and let stand to separate, take the upper oil phase to an extraction bottle, add 100 g of water, keep the temperature between 20 and 25° C., stir for 1 hour and let stand to separate, take the lower aqueous phase and combine it with the aqueous phase in the four-necked bottle to obtain the product 5,5-dimethyl-4,5-dihydroisoxazol-3-ylthiourea bromate aqueous solution, which can be used for the subsequent synthesis of sulfonepyraclostrobin.

[0043] The synthesis process of a herbicide intermediate of the present invention adopts a layered extraction method to obtain a 5,5-dimethyl-4,5-dihydroisoxazol-3-ylthiourea bromate aqueous solution, which simplifies the operation difficulty. The oil phase after layering can be reused as a solvent, thereby reducing the generation of three wastes. The synthesis process of the present invention does not need to perform a desolventizing and filtering process, and directly obtains a 5,5-dimethyl-4,5-dihydroisoxazol-3-ylthiourea bromate aqueous solution by layering, which can be directly used in subsequent process flows without the need to prepare a solution again, thereby simplifying the operation steps, eliminating the use of filtering equipment, and saving production costs.

[0044] What is disclosed above is only one or more preferred embodiments of the present application, and cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of implementing the above embodiments and equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A process for synthesizing a herbicide intermediate, characterized in that: include: Adding a first solvent and thiourea into a reaction container and stirring the mixture to prepare a first mixture; Adding the first catalyst, 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole and the first mixture into a reaction container in sequence to react, and ending the reaction when the content of 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole is less than 1%, to obtain a second reactant; Add process water 1 to the reaction container, stir the process water 1 and the second reactant, let stand and separate, take out the lower aqueous phase and put it into the product bottle; Add process water 2 to the oil phase in the reaction container, stir and let stand to separate the layers, combine the lower aqueous phase with the aqueous phase in the product bottle to obtain an aqueous solution of 5,5-dimethyl-4,5-dihydroisoxazol-3-ylthiourea bromate.

2. The synthesis process of a herbicide intermediate according to claim 1, characterized in that: The first solvent is any one or more of benzene, ether, and ester solvents.

3. The synthesis process of a herbicide intermediate according to claim 1, characterized in that: The first solvent and thiourea are added into the reaction container and stirred to prepare a first mixture after the first solvent and thiourea are mixed. The stirring rate is 60-100 rpm, the stirring time is 18-21 hours, and the mixing temperature is 5-40°C.

4. The synthesis process of a herbicide intermediate according to claim 1, characterized in that: The first catalyst, 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole and the first mixture are sequentially added into the reaction container for reaction at a reaction temperature of 5 to 40°C.

5. The synthesis process of a herbicide intermediate according to claim 1, characterized in that: The process water 1 is added into the reaction container, and the process water 1 and the second reactant are stirred and then allowed to stand for stratification, the stirring rate is 60-90 rpm, and the stirring time is 0.5-1.5 h.

6. The process for synthesizing a herbicide intermediate according to claim 1, characterized in that: The first catalyst is any one or more of a hydrogen halide aqueous solution, sulfuric acid, and nitric acid, and the concentration range of the first catalyst is 10% to 70%.

7. The process for synthesizing a herbicide intermediate according to claim 1, characterized in that: The molar ratio of the 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole to thiourea is 1:1-1.5, and the molar ratio of the 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole to the first solvent is 1:6-9.

8. The process for synthesizing a herbicide intermediate according to claim 1, characterized in that: The molar ratio of the process water 1 to 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole is 22-17:1, and the molar ratio of the process water 2 to 3-bromo-5,5-dimethyl-4,5-dihydroxyisoxazole is 12-7:

1.

9. The process for synthesizing a herbicide intermediate according to claim 1, characterized in that: The process water 1 is added into the reaction container, the process water 1 and the second reactant are stirred and then allowed to stand for stratification, and the temperature in the reaction container is 5-40°C.

10. The process for synthesizing a herbicide intermediate according to claim 1, characterized in that: The process water 2 is added to the oil phase in the reaction container, and the mixture is allowed to stand for stratification after stirring. The temperature in the reaction container is 5-40°C.

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