Pyraclostrobin sustained-release agent and preparation method thereof

Abstract

The invention relates to a pyraclostrobin slow-release agent and a preparation method thereof, the pyraclostrobin slow-release agent comprises a pyraclostrobin slow-release component, a dispersing agent, a thickening agent, a defoaming agent, a preservative and a pH regulator, the pyraclostrobin slow-release component comprises pyraclostrobin and an organic framework material, and the organic framework material comprises ferric chloride, a modifier and halloysite nanotubes. The application has the effect of improving the prevention and control performance of pyraclostrobin on crops, is green and environment-friendly, and reduces the pollution and damage phenomena on aquatic animals and plants.

Description

Technical Field

[0001] The present application relates to the field of fungicides, and in particular to a pyraclostrobin sustained-release agent and a preparation method thereof. Background Art

[0002] Pyraclostrobin is a methoxyacrylate fungicide that inhibits mitochondrial respiration to cause cell death. It has protective, therapeutic, and leaf osmotic conduction effects, preventing a variety of diseases caused by fungi on crops. It can also induce the victory phenomenon in many crops, especially cereals, to promote rapid growth of crops.

[0003] Using pyraclostrobin directly on crops can easily affect the growth environment of aquatic animals and other animals in the ecological environment, thereby destroying the ecological environment. Summary of the invention

[0004] In order to improve the environmental friendliness of pyraclostrobin, the present application provides a pyraclostrobin sustained-release agent and a preparation method thereof.

[0005] The present application provides a pyraclostrobin sustained-release agent and a preparation method thereof using the following technical solutions: In the first aspect, the present application provides a pyraclostrobin sustained-release agent, which adopts the following technical solution: A pyraclostrobin sustained-release agent comprises a pyraclostrobin sustained-release component, a dispersant, a thickener, a defoaming agent, a preservative and a pH regulator. The pyraclostrobin sustained-release component comprises pyraclostrobin and an organic framework material. The raw materials of the organic framework material comprise ferric chloride, a modifier and halloysite nanotubes.

[0006] By adopting the above technical scheme, pyraclostrobin is loaded onto an organic skeleton material, which can further increase the contact time between the medicinal material and the crop leaves. At the same time, the phenomenon of excessive degradation rate of the drug due to the influence of the external environment can be reduced, and the drug can be slowly released. The organic skeleton material is mainly composed of halloysite nanotubes. Halloysite nanotubes have a unique microstructure and good biocompatibility, and are a green and environmentally friendly nanomaterial with potential prospects. Using halloysite nanotubes as a carrier, pyraclostrobin can be loaded and pyraclostrobin can be stably loaded. The halloysite nanotubes are then modified with metal materials to improve the dispersibility and stability of the halloysite nanotubes, so that the utilization rate and drug loading rate of the prepared organic skeleton material are improved, so that the stability and control performance of the system are further improved. At the same time, the slow-released pyraclostrobin can act on crops in a targeted manner, reduce pollution to the environment, and is conducive to the development of environmentally friendly agriculture.

[0007] Preferably, the organic framework material is prepared by the following method: N,N-dimethylformamide and ethylene glycol are mixed to obtain a composite mixed solution, anhydrous ferric chloride and a modifier are added to the composite mixed solution, ultrasonic treatment is performed, and then the solution is heated under oil bath conditions, and halloysite nanotubes are added under ultrasonic dispersion conditions to obtain an organic framework material.

[0008] By adopting the above technical scheme, an organic framework material is synthesized by an in-situ growth method, and the hydroxyl groups on the surface of the halloysite nanotubes interact with the carboxyl groups of the ligands, thereby improving the stability of the organic framework material, and effectively improving the dispersion performance and compatibility in the solvent, and effectively reducing the contact angle of the system, so that the adhesion performance of pyraclostrobin on crop leaves is further improved, so that the crops can further absorb the drug, thereby improving the stability of the drug.

[0009] Preferably, the modifier comprises 1,3,5-benzenetricarboxylic acid.

[0010] By adopting the above technical solution and using 1,3,5-benzenetricarboxylic acid as a modifier, a rod-shaped nanostructured organic framework material is prepared, which can further improve the dispersion performance of the organic framework material in the system, thereby improving the stability of the prepared pyraclostrobin sustained-release agent.

[0011] Preferably, the mass ratio of the ferric chloride, 1,3,5-benzenetricarboxylic acid and halloysite nanotubes is 1:1.48:(0.48-0.58).

[0012] By adopting the above technical solution, preferably the mass ratio of ferric chloride, 1,3,5-benzenetricarboxylic acid and halloysite nanotubes is within the above range, which can further improve the comprehensive performance of the prepared organic framework material.

[0013] Preferably, the oil bath heating temperature is 88-92°C.

[0014] By adopting the above technical solution, preferably the oil bath temperature is within the above range, the stability of the prepared organic framework material can be further improved.

[0015] Preferably, the pyraclostrobin sustained-release component is prepared by the following method: Pyraclostrobin is added to dimethyl sulfoxide, stirred evenly, and then added to the organic framework material. After evacuation, the material is stirred under vacuum, washed by centrifugation, and dried to obtain the pyraclostrobin sustained-release component.

[0016] By adopting the above technical scheme, pyraclostrobin is loaded in the micropores of halloysite nanotubes to improve the stability of pyraclostrobin. The organic framework material is loaded with drugs and has good sustained-release properties, which can reduce the occurrence of rapid degradation of drugs due to environmental influences. At the same time, the contact performance between the organic framework material and crop leaves is greatly improved, thereby further improving the absorption effect of the crop leaves on the drug.

[0017] Preferably, the mass ratio of pyraclostrobin to the organic framework material is (1.4-1.6):1.

[0018] By adopting the above technical solution, preferably the mass ratio between pyraclostrobin and the organic framework material is within the above range, which can further improve the comprehensive performance of the pyraclostrobin sustained-release component.

[0019] In a second aspect, the present application provides a method for preparing a pyraclostrobin sustained-release agent, using the following technical solution: A method for preparing a pyraclostrobin sustained-release agent comprises the following steps: The pyraclostrobin slow-release component, a dispersant, a thickener, a defoamer, a preservative and a solvent are mixed and dispersed to prepare the pyraclostrobin slow-release agent.

[0020] In summary, the present application includes at least one of the following beneficial technical effects: 1. Pyraclostrobin is loaded on an organic skeleton material. The organic skeleton material can reduce the phenomenon that the drug is degraded too quickly due to external influences, and can slowly release the drug, and can increase the contact time between the drug and the leaf crops. The organic skeleton material is mainly composed of halloysite nanotubes, has a unique microstructure and good biocompatibility, and is a green and environmentally friendly nanomaterial with potential prospects. It can load pyraclostrobin, and then the halloysite nanotubes are modified by metal materials, which can further improve the dispersibility and stability of the halloysite nanotubes, so that the utilization rate and drug loading rate of the prepared organic skeleton material are further improved, thereby improving the overall stability of the system. At the same time, the pyraclostrobin sustained-release agent prepared in the present application can protect the growth environment of aquatic animals during use, and can also maintain the drug properties and stability in a high temperature environment; 2. The rod-shaped organic framework material prepared by the solvothermal method can be better dispersed in the system, thereby making the prepared pyraclostrobin sustained-release agent more stable. DETAILED DESCRIPTION

[0021] The present application is further described in detail below with reference to the embodiments: Raw material description: All raw materials in the examples can be obtained from commercial sources; the thickener is PEG-80 glyceryl tallow ester, the defoamer is DF-830, the preservative is sodium benzoate, and the dispersant is lignin.

[0022] Example 1 Preparation of organic framework materials: N,N-dimethylformamide (CAS No.: 68-12-2) and ethylene glycol are mixed in a volume ratio of 1:1 to obtain a composite mixed solution, anhydrous ferric chloride and a modifier 1,3,5-benzenetricarboxylic acid (CAS No.: 554-95-0) are added to the composite mixed solution, and ultrasonic treatment is performed for 15 minutes, and the solution becomes an orange clear solution. The solution is then heated in an oil bath at 88°C for 2 hours, and halloysite nanotubes are added under ultrasonic dispersion conditions to obtain an organic framework material; wherein the mass ratio of anhydrous ferric chloride, 1,3,5-benzenetricarboxylic acid and halloysite nanotubes is 1:1.48:0.48.

[0023] Preparation of pyraclostrobin sustained-release component: Pyraclostrobin (CAS No.: 175013-18-0) was added to dimethyl sulfoxide, stirred evenly and then added to the organic framework material prepared above, vacuumed and kept for 30 minutes, then stirred for 48 hours under vacuum, centrifuged and washed with ethanol, and finally dried at 60° C. for 24 hours to obtain a pyraclostrobin sustained-release component; wherein the mass ratio between pyraclostrobin and the organic framework material was 1.4:1.

[0024] Preparation of pyraclostrobin sustained-release formulation: A pyraclostrobin slow-release component, a dispersant, a thickener, a defoamer, a preservative and a solvent are mixed and dispersed for 30 minutes to prepare a pyraclostrobin slow-release agent, wherein the pyraclostrobin slow-release component accounts for 50wt%, the dispersant accounts for 3.5wt%, the thickener accounts for 1.3wt%, the defoamer accounts for 0.1wt%, the preservative accounts for 0.1wt%, and the remainder is the solvent and unavoidable impurities; wherein the solvent is obtained by mixing ethanol and acetone in a volume ratio of 1:1.

[0025] Example 2 Preparation of organic framework materials: N,N-dimethylformamide and ethylene glycol are mixed in a volume ratio of 1:1 to obtain a composite mixed solution, anhydrous ferric chloride and a modifier 1,3,5-benzenetricarboxylic acid are added to the composite mixed solution, and ultrasonic treatment is performed for 15 minutes, and the solution becomes an orange clear solution. The solution is then heated in an oil bath at 92°C for 2 hours, and halloysite nanotubes are added under ultrasonic dispersion conditions to obtain an organic framework material; wherein the mass ratio of anhydrous ferric chloride, 1,3,5-benzenetricarboxylic acid and halloysite nanotubes is 1:1.48:0.58.

[0026] Preparation of pyraclostrobin sustained-release component: Pyraclostrobin is added to dimethyl sulfoxide, stirred evenly, and then added to the organic framework material prepared above, vacuumed and kept for 30 minutes, then stirred for 48 hours under vacuum, centrifuged and washed with ethanol, and finally dried at 60°C for 24 hours to obtain a pyraclostrobin sustained-release component; wherein the mass ratio between pyraclostrobin and the organic framework material is 1.6:1.

[0027] Preparation of pyraclostrobin sustained-release formulation: A pyraclostrobin slow-release component, a dispersant, a thickener, a defoamer, a preservative and a solvent are mixed and dispersed for 30 minutes to prepare a pyraclostrobin slow-release agent, wherein the pyraclostrobin slow-release component accounts for 50wt%, the dispersant accounts for 3.5wt%, the thickener accounts for 1.3wt%, the defoamer accounts for 0.1wt%, the preservative accounts for 0.1wt%, and the remainder is the solvent and unavoidable impurities; wherein the solvent is obtained by mixing ethanol and acetone in a volume ratio of 1:1.

[0028] Example 3 Preparation of organic framework materials: N,N-dimethylformamide and ethylene glycol are mixed in a volume ratio of 1:1 to obtain a composite mixed solution, anhydrous ferric chloride and a modifier 1,3,5-benzenetricarboxylic acid are added to the composite mixed solution, and ultrasonic treatment is performed for 15 minutes, the solution becomes an orange clear solution, and then the solution is heated in an oil bath at 90°C for 2 hours, and halloysite nanotubes are added under ultrasonic dispersion conditions to obtain an organic framework material; wherein the mass ratio of anhydrous ferric chloride, 1,3,5-benzenetricarboxylic acid and halloysite nanotubes is 1:1.48:0.53.

[0029] Preparation of pyraclostrobin sustained-release component: Pyraclostrobin is added to dimethyl sulfoxide, stirred evenly, and then added to the organic framework material prepared above, vacuumed and maintained for 30 minutes, then stirred for 48 hours under a vacuum environment, centrifuged and washed with ethanol, and finally dried at 60°C for 24 hours to obtain a pyraclostrobin sustained-release component; wherein the mass ratio between pyraclostrobin and the organic framework material is 1.5:1.

[0030] Preparation of pyraclostrobin sustained-release formulation: A pyraclostrobin slow-release component, a dispersant, a thickener, a defoamer, a preservative and a solvent are mixed and dispersed for 30 minutes to prepare a pyraclostrobin slow-release agent, wherein the pyraclostrobin slow-release component accounts for 50wt%, the dispersant accounts for 3.5wt%, the thickener accounts for 1.3wt%, the defoamer accounts for 0.1wt%, the preservative accounts for 0.1wt%, and the remainder is the solvent and unavoidable impurities; wherein the solvent is obtained by mixing ethanol and acetone in a volume ratio of 1:1.

[0031] Example 4 Example 4 is based on Example 3. The difference between Example 4 and Example 3 is that when preparing the organic framework material in Example 4, the mass ratio of ferric chloride, 1,3,5-benzenetricarboxylic acid and halloysite nanotubes is 1:1.48:0.4.

[0032] Example 5 Example 5 is based on Example 3. The difference between Example 5 and Example 3 is that when preparing the organic framework material in Example 5, the mass ratio of ferric chloride, 1,3,5-benzenetricarboxylic acid and halloysite nanotubes is 1:1.48:0.7.

[0033] Example 6 Example 6 is based on Example 3. The difference between Example 6 and Example 3 is that when preparing the pyraclostrobin sustained-release component, the mass ratio between pyraclostrobin and the organic framework material is 1.2:1.

[0034] Example 7 Example 7 is based on Example 3. The difference between Example 7 and Example 3 is that when preparing the pyraclostrobin sustained-release component, the mass ratio between pyraclostrobin and the organic framework material is 1.8:1.

[0035] Example 8 Example 8 is based on Example 3. The difference between Example 8 and Example 3 is that when preparing the organic framework material, the oil bath temperature is 80°C.

[0036] Example 9 Example 9 is based on Example 3. The difference between Example 9 and Example 3 is that when preparing the organic framework material, the oil bath temperature is 100°C.

[0037] Comparative Example 1 Comparative Example 1 is based on Example 3, and in Comparative Example 1, the pyraclostrobin sustained-release component is replaced with common pyraclostrobin.

[0038] Comparative Example 2 Comparative Example 2 is based on Example 3, and the organic framework material in Comparative Example 2 is halloysite nanotubes.

[0039] Performance testing The following performance tests were performed on the samples of Examples 1-9 and Comparative Examples 1-2: (1) Prevention and control effect The experiment was conducted during the flowering and fruiting period of cucumbers, when cucumbers were at their peak. The pesticide was applied three times, once every 10 days, on both sides of the leaves. The water was diluted to 600 liters / hectare. Random sampling was conducted in each plot, with 2 plants checked at each point, for a total of 8 plants. All leaves of each plant were investigated, and the total number of leaves, the number of diseased leaves, and the disease level were recorded. The disease index and control effect were calculated based on the data recorded in the investigation, and the test results were filled in Table 1.

[0040] Disease classification method: Level 0: no disease; Level 1: The lesion area accounts for less than 5% of the entire leaf area; Level 3: The lesion area accounts for 6%-10% of the entire leaf area; Level 5: The lesion area accounts for 11%-25% of the entire leaf area; Level 7: The lesion area accounts for 26%-50% of the entire leaf area; Level 9: The lesion area accounts for more than 50% of the total leaf area.

[0041] (2) Particle size and distribution test The prepared pyraclostrobin nanocapsules were diluted with pure water to 0.5% (w / w), and ultrasonically vibrated evenly. The hydrated particle size and PDI of the pyraclostrobin nanocapsules were measured by a Malvern particle size analyzer at room temperature. Each sample was measured 3 times, the average value was taken, and its standard deviation was calculated.

[0042] Table 1: Test results of Examples 1-9 and Comparative Examples 1-2 Table 2 Performance test results of Examples 1-9 and Comparative Examples 1-2 Test items Average particle size / d.nm PDI Appearance Example 1 394.6 0.26 No precipitated water Example 2 375.2 0.26 No precipitated water Example 3 362.8 0.25 No precipitated water Example 4 748.9 0.36 No precipitated water Example 5 735.4 0.35 No precipitated water Example 6 974.6 0.40 No precipitated water Example 7 958.3 0.39 No precipitated water Example 8 551.6 0.31 No precipitated water Example 9 531.0 0.30 No precipitated water Comparative Example 1 1989.6 0.63 Water separation 19% Comparative Example 2 1458.1 0.55 10% water separation Data analysis Combined with Table 1, it can be seen that the control effect of the pyraclostrobin sustained-release agent prepared in Examples 1-3 shows that the pyraclostrobin sustained-release agent prepared in the present application has a good preventive effect; combined with Table 2, it can be seen that the average particle size of the pyraclostrobin sustained-release agent prepared in the present application is 400 nm or less, the average PDI is 0.3 or less, and there is no water precipitation phenomenon, indicating that the pyraclostrobin sustained-release agent prepared in the present application has good performance.

[0043] The mass ratios of ferric chloride, 1,3,5-benzenetricarboxylic acid and halloysite nanotubes in Examples 4 and 5 are not within the range defined in the present application. When the content of halloysite nanotubes is too much, it is difficult to further improve the modification effect of the halloysite nanotubes, and it is difficult to obtain a higher specific surface area of ​​the halloysite nanotubes, which limits the drug loading amount and thus makes it difficult to further improve the use capacity of the pyraclostrobin sustained-release component. When the content of the halloysite nanotubes is too little, the modification of the halloysite nanotubes is too much, resulting in an excessive specific surface area of ​​the halloysite nanotubes, which reduces the overall stability of the halloysite nanotubes. Therefore, the overall performance of pyraclostrobin is also affected, so the performance of Examples 4 and 5 are both reduced.

[0044] The mass ratio between pyraclostrobin and the organic framework in Examples 6 and 7 is not within the range defined in the present application. When the content of pyraclostrobin is too high, it is difficult to evenly load all of the pyraclostrobin into the halloysite nanotubes. Therefore, there is still some free-loaded pyraclostrobin in the system, which affects the overall stability of the system. When the content of pyraclostrobin is too low, the effective components in the pyraclostrobin sustained-release agent decrease, preventing the effect from decreasing. Therefore, the performance of Examples 6 and 7 decreases.

[0045] In Examples 8 and 9, when preparing organic skeleton materials, the oil bath temperature is not within the range specified in the present application. When the oil bath temperature during preparation is too high or too low, it will affect the overall performance of the system. Therefore, the performance of Examples 8 and 9 is reduced.

[0046] In Comparative Example 1, the pyraclostrobin sustained-release component was replaced with ordinary pyraclostrobin. The unloaded pyraclostrobin was affected by the environment during use, which accelerated the decomposition rate and made it difficult to contact with the leaves more stably. Therefore, the control performance of Comparative Example 1 was reduced.

[0047] In Comparative Example 2, the organic framework material is replaced with ordinary halloysite nanotubes. The specific surface area of ​​the untreated halloysite nanotubes is difficult to further increase, and it is difficult to load more pyraclostrobin. At the same time, the compatibility in the system is difficult to improve, and the contact stability with the leaves is reduced. Therefore, the control performance in Comparative Example 2 is reduced.

[0048] This specific embodiment is only an explanation of the present application, and it is not a limitation of the present application. Through the above description, relevant staff can make various changes and modifications without deviating from the technical idea of ​​the present application. The technical scope of the present application is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A pyraclostrobin sustained-release agent, characterized in that: The invention comprises a pyraclostrobin slow-release component, a dispersant, a thickener, a defoamer, a preservative and a pH regulator. The pyraclostrobin slow-release component comprises pyraclostrobin and an organic framework material. The raw materials of the organic framework material comprise ferric chloride, a modifier and halloysite nanotubes.

2. The pyraclostrobin sustained-release agent according to claim 1, characterized in that: The organic framework material is prepared by the following method: N,N-dimethylformamide and ethylene glycol are mixed to obtain a composite mixed solution, anhydrous ferric chloride and a modifier are added to the composite mixed solution, ultrasonic treatment is performed, and then the solution is heated under oil bath conditions, and halloysite nanotubes are added under ultrasonic dispersion conditions to obtain an organic framework material.

3. A pyraclostrobin sustained-release agent according to claim 2, characterized in that: The modifier includes 1,3,5-benzenetricarboxylic acid.

4. A pyraclostrobin sustained-release agent according to claim 3, characterized in that: The mass ratio of the ferric chloride, 1,3,5-benzenetricarboxylic acid and the halloysite nanotubes is 1:1.48:(0.48-0.58).

5. The pyraclostrobin sustained-release agent according to claim 2, characterized in that: The oil bath heating temperature is 88-92°C.

6. The pyraclostrobin sustained-release agent according to claim 2, characterized in that: The pyraclostrobin sustained-release component is prepared by the following method: Pyraclostrobin is added to dimethyl sulfoxide, stirred evenly, and then added to the organic framework material. After evacuation, the material is stirred under vacuum, washed by centrifugation, and dried to obtain the pyraclostrobin sustained-release component.

7. A pyraclostrobin sustained-release agent according to claim 6, characterized in that: The mass ratio of pyraclostrobin to the organic framework material is (1.4-1.6):

1.

8. A method for preparing the pyraclostrobin sustained-release agent according to any one of claims 1 to 7, characterized in that: The steps include: The pyraclostrobin slow-release component, dispersant, thickener, defoamer, preservative and solvent are mixed and dispersed to prepare the pyraclostrobin slow-release agent.

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