Preparation method of tebuconazole nano pesticide with leaf surface adhesiveness as well as product and application of tebuconazole nano pesticide

Abstract

The invention discloses a preparation method of a tebuconazole nano-pesticide with leaf surface adhesiveness as well as a product and application of the tebuconazole nano-pesticide. The preparation method comprises the following steps: adding a zinc nitrate aqueous solution into a methanol solution of dimethylimidazole, stirring, and adding an N, N-dimethylformamide solution of tebuconazole; centrifuging and drying a lower-layer solid to obtain the tebuconazole nano pesticide which is not coated with the tannic acid; and adding the tannic acid aqueous solution into the tebuconazole nano-pesticide aqueous solution which is not coated with the tannic acid, stirring, centrifuging and drying to obtain the tebuconazole nano-pesticide which takes the tannic acid coated organic metal framework material as the carrier. The tebuconazole nano pesticide prepared by the invention has obvious slow release performance and excellent plant leaf surface adhesion performance, and has the advantages of simple preparation process, easily available raw materials and the like.

Description

Technical Field

[0001] The invention relates to a preparation method of a tebuconazole nanopesticide with leaf surface adhesion, a product thereof and an application thereof, and belongs to the field of functional pesticide preparation development. Background Art

[0002] In recent years, pesticides have been widely used in agricultural production as an important means to control the occurrence and spread of crop diseases and pests and promote crop yield and income. However, traditional pesticide formulations have problems such as low leaf deposition rate, poor leaf adhesion and unstable active ingredients, which not only cause a large amount of pesticide waste, but also pose huge risks to ecological environmental safety and human health. Therefore, improving the adhesion of pesticides on target crops and reducing their loss is an important method to improve the utilization rate of pesticides and protect the ecological environment.

[0003] Nanopesticides are an important means to improve the adhesion of pesticides on crop leaves. Wet grinding is the main method for preparing nanopesticides. This method can increase the dispersion of poorly soluble pesticides in the aqueous phase, enhance their permeability and adhesion on plant leaves, and increase bioavailability. However, due to the poor monodispersity and stability of wet grinding, it is difficult to achieve sustained release performance. Therefore, it is of great significance to develop a leaf-adhesive tebuconazole nanopesticide with excellent performance. Summary of the invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to provide a preparation method of a tebuconazole nanopesticide with leaf adhesion, its product and application.

[0005] Technical solution: To solve the above technical problems, the present invention provides a method for preparing a tebuconazole nanopesticide with leaf adhesion, which is mainly prepared by the following steps:

[0006] (1) A methanol solution of dimethylimidazole and an aqueous solution of zinc nitrate are mixed, and an N,N-dimethylformamide solution of tebuconazole is added, and after centrifugation, washing, and drying, the obtained solid is a tebuconazole nanopesticide not coated with tannic acid;

[0007] (2) adding the tannic acid aqueous solution to the tebuconazole nanopesticide aqueous solution not coated with tannic acid, stirring, centrifuging and drying to obtain the tebuconazole nanopesticide with the tannic acid coated organic metal framework material as the carrier.

[0008] Wherein, the concentration of the methanol solution of dimethylimidazole in step (1) is 3-5wt%.

[0009] Wherein, the concentration of the zinc nitrate aqueous solution in step (1) is 20-40 g / L.

[0010] Wherein, the concentration of the tannic acid aqueous solution in step (2) is 70-100 mM.

[0011] The invention also provides a tebuconazole nanopesticide with leaf surface adhesion prepared by the method.

[0012] The present invention also provides the use of the tebuconazole nanopesticide with leaf surface adhesion in improving the utilization rate of the tebuconazole nanopesticide.

[0013] The present invention also provides application of the tebuconazole nanopesticide with leaf surface adhesion in controlling crop diseases and insect pests.

[0014] Among them, acidic conditions are conducive to the release of the pesticide tebuconazole.

[0015] In the prior art, tannic acid coating is mostly performed by reacting its own phenolic hydroxyl group with other substances or by utilizing its own adhesive properties. The present invention utilizes the tannic acid to easily react with metal zinc ions and coats it on the outer layer of the nanopesticide in a simple manner to form a new composite material, thereby improving the stability and adhesion of the nanopesticide.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0017] (1) The present invention utilizes the metal ion-organic molecule coordination synthesis method, Zn 2+ The metal ion is a metal ion, and dimethylimidazole is a ligand. The metal ion and the organic ligand are coordinated and self-assembled in the solution to form an organic metal framework without the need for other reaction conditions.

[0018] (2) The present invention relies on Zn 2+ The metal coordination of ions and dimethylimidazole ligands forms a porous network structure, which contains no harmful substances such as surfactants and cross-linking agents. In addition, Zn is an element required for crop growth and is environmentally friendly.

[0019] (3) The present invention relies on tannic acid and Zn 2+ Through the chelation effect, tannic acid molecules can directly form a coating layer on the surface of metal-organic framework materials, thereby effectively increasing the adhesion of pesticides on crop leaves;

[0020] (4) The preparation process of the tebuconazole nanopesticide of the present invention is simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 TEM image of the tebuconazole nanopesticide without tannic acid coating in the comparative example;

[0022] Figure 2 This is the TEM image of the tannic acid-coated tebuconazole nanopesticide of Example 1. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0024] Reagents and sources: Tebuconazole (Teb) was provided by Jiangsu Aijin Crop Science and Technology Group Co., Ltd., zinc nitrate hexahydrate (Zn(NO3)2·6(H2O)) and N,N-dimethylformamide (DMF) were purchased from Nanjing Chemical Reagent Co., Ltd., dimethylimidazole was purchased from Shanghai MacLean Biochemical Technology Co., Ltd., tannic acid (TA) was purchased from Shanghai Lingfeng Chemical Reagent Co., Ltd., and methanol and ethanol were purchased from Wuxi Yasheng Chemical Co., Ltd.

[0025] Example 1

[0026] A tebuconazole nanopesticide with a tannic acid-coated organic metal framework material as a carrier is prepared by the following steps:

[0027] Step (1): adding 90.00 mL of a 3.67 wt % dimethylimidazole methanol solution to 50.00 mL of a 30.00 g / L zinc nitrate aqueous solution and stirring to prepare a mixed solution A;

[0028] Step (2): adding 10.00 mL of a 10 wt% solution of tebuconazole in N,N-dimethylformamide to the mixed solution A, and stirring to obtain a mixed solution B;

[0029] Step (3): After the mixed solution B is centrifuged, washed and dried, the obtained solid is the prepared tebuconazole nanopesticide not coated with tannic acid.

[0030] Step (4): Tannic acid coating: prepare 80.00 mM tannic acid aqueous solution and add it to 2.00 g / L tebuconazole nanopesticide aqueous solution which is not coated with tannic acid, and stir to obtain a mixed solution C; the volume ratio of the tannic acid aqueous solution to the tebuconazole nanopesticide aqueous solution is 1:500.

[0031] Step (5): centrifuging the mixed solution C and drying it at -80°C to obtain tannic acid-coated tebuconazole nanopesticide.

[0032] Example 2

[0033] Step (1): adding 90.00 mL of a 3 wt % dimethylimidazole methanol solution to 50.00 mL of a 30.00 g / L zinc nitrate aqueous solution and stirring to prepare a mixed solution A;

[0034] Step (2): adding 10.00 mL of a 10 wt % solution of tebuconazole in N,N-dimethylformamide to the mixed solution A, and stirring to obtain a mixed solution B;

[0035] Step (3): After the mixed solution B is centrifuged, washed and dried, the obtained solid is the prepared tebuconazole nanopesticide not coated with tannic acid.

[0036] Step (4): Tannic acid coating: prepare 80.00 mM tannic acid aqueous solution and add it to 2.00 g / L tebuconazole nanopesticide aqueous solution which is not coated with tannic acid, and stir to obtain a mixed solution C; the volume ratio of the tannic acid aqueous solution to the tebuconazole nanopesticide aqueous solution is 1:500.

[0037] Step (5): centrifuging the mixed solution C and drying it at -80°C to obtain tannic acid-coated tebuconazole nanopesticide.

[0038] Example 3

[0039] Step (1): adding 90.00 mL of a 5 wt% methanol solution of dimethylimidazole to 50.00 mL of a 30.00 g / L aqueous zinc nitrate solution, and stirring to prepare a mixed solution A;

[0040] Step (2): adding 10.00 mL of a 10 wt % solution of tebuconazole in N,N-dimethylformamide to the mixed solution A, and stirring to obtain a mixed solution B;

[0041] Step (3): After the mixed solution B is centrifuged, washed and dried, the obtained solid is the prepared tebuconazole nanopesticide not coated with tannic acid.

[0042] Step (4): Tannic acid coating: prepare 80.00 mM tannic acid aqueous solution and add it to 2.00 g / L tebuconazole nanopesticide aqueous solution which is not coated with tannic acid, and stir to obtain a mixed solution C; the volume ratio of the tannic acid aqueous solution to the tebuconazole nanopesticide aqueous solution is 1:500.

[0043] Step (5): centrifuging the mixed solution C and drying it at -80°C to obtain tannic acid-coated tebuconazole nanopesticide.

[0044] Example 4

[0045] Step (1): adding 90.00 mL of a 3.67 wt% dimethylimidazole methanol solution to 50.00 mL of a 20.00 g / L zinc nitrate aqueous solution, and stirring to prepare a mixed solution A;

[0046] Step (2): adding 10.00 mL of a 10 wt % solution of tebuconazole in N,N-dimethylformamide to the mixed solution A, and stirring to obtain a mixed solution B;

[0047] Step (3): After the mixed solution B is centrifuged, washed and dried, the obtained solid is the prepared tebuconazole nanopesticide not coated with tannic acid.

[0048] Step (4): Tannic acid coating: prepare 80.00 mM tannic acid aqueous solution and add it to 2.00 g / L tebuconazole nanopesticide aqueous solution which is not coated with tannic acid, and stir to obtain a mixed solution C; the volume ratio of the tannic acid aqueous solution to the tebuconazole nanopesticide aqueous solution is 1:500.

[0049] Step (5): centrifuging the mixed solution C and drying it at -80°C to obtain tannic acid-coated tebuconazole nanopesticide.

[0050] Example 5

[0051] Step (1): adding 90.00 mL of a 3.67 wt% methanol solution of dimethylimidazole to 50.00 mL of a 40.00 g / L aqueous zinc nitrate solution, and stirring to prepare a mixed solution A;

[0052] Step (2): adding 10.00 mL of a 10 wt % solution of tebuconazole in N,N-dimethylformamide to the mixed solution A, and stirring to obtain a mixed solution B;

[0053] Step (3): After the mixed solution B is centrifuged, washed and dried, the obtained solid is the prepared tebuconazole nanopesticide not coated with tannic acid.

[0054] Step (4): Tannic acid coating: prepare 80.00 mM tannic acid aqueous solution and add it to 2.00 g / L tebuconazole nanopesticide aqueous solution which is not coated with tannic acid, and stir to obtain a mixed solution C; the volume ratio of the tannic acid aqueous solution to the tebuconazole nanopesticide aqueous solution is 1:500.

[0055] Step (5): centrifuging the mixed solution C and drying it at -80°C to obtain tannic acid-coated tebuconazole nanopesticide.

[0056] Example 6

[0057] Step (1): adding 90.00 mL of a 3.67 wt% methanol solution of dimethylimidazole to 50.00 mL of a 30.00 g / L aqueous zinc nitrate solution, and stirring to prepare a mixed solution A;

[0058] Step (2): adding 10.00 mL of a 10 wt % solution of tebuconazole in N,N-dimethylformamide to the mixed solution A, and stirring to obtain a mixed solution B;

[0059] Step (3): After the mixed solution B is centrifuged, washed and dried, the obtained solid is the prepared tebuconazole nanopesticide not coated with tannic acid.

[0060] Step (4): Tannic acid coating: prepare a 70.00 mM tannic acid aqueous solution and add it to a 2.00 g / L tebuconazole nanopesticide aqueous solution that is not coated with tannic acid, and stir to obtain a mixed solution C; the volume ratio of the tannic acid aqueous solution to the tebuconazole nanopesticide aqueous solution is 1:500.

[0061] Step (5): centrifuging the mixed solution C and drying it at -80°C to obtain tannic acid-coated tebuconazole nanopesticide.

[0062] Example 7

[0063] Step (1): adding 90.00 mL of a 3.67 wt% methanol solution of dimethylimidazole to 50.00 mL of a 30.00 g / L aqueous zinc nitrate solution, and stirring to prepare a mixed solution A;

[0064] Step (2): adding 10.00 mL of a 10 wt % solution of tebuconazole in N,N-dimethylformamide to the mixed solution A, and stirring to obtain a mixed solution B;

[0065] Step (3): After the mixed solution B is centrifuged, washed and dried, the obtained solid is the prepared tebuconazole nanopesticide not coated with tannic acid.

[0066] Step (4): Tannic acid coating: prepare a 100.00 mM tannic acid aqueous solution and add it to a 2.00 g / L tebuconazole nanopesticide aqueous solution that is not coated with tannic acid, and stir to obtain a mixed solution C; the volume ratio of the tannic acid aqueous solution to the tebuconazole nanopesticide aqueous solution is 1:500.

[0067] Step (5): centrifuging the mixed solution C and drying it at -80°C to obtain tannic acid-coated tebuconazole nanopesticide.

[0068] Example 8

[0069] Step (1): adding 90.00 mL of a 6 wt % dimethylimidazole methanol solution to 50.00 mL of a 50.00 g / L zinc nitrate aqueous solution and stirring to prepare a mixed solution A;

[0070] Step (2): adding 10.00 mL of a 10 wt % solution of tebuconazole in N,N-dimethylformamide to the mixed solution A, and stirring to obtain a mixed solution B;

[0071] Step (3): After the mixed solution B is centrifuged, washed and dried, the obtained solid is the prepared tebuconazole nanopesticide not coated with tannic acid.

[0072] Step (4): Tannic acid coating: prepare 80.00 mM tannic acid aqueous solution and add it to 2.00 g / L tebuconazole nanopesticide aqueous solution which is not coated with tannic acid, and stir to obtain a mixed solution C; the volume ratio of the tannic acid aqueous solution to the tebuconazole nanopesticide aqueous solution is 1:500.

[0073] Step (5): centrifuging the mixed solution C and drying it at -80°C to obtain tannic acid-coated tebuconazole nanopesticide.

[0074] Example 9

[0075] Step (1): adding 90.00 mL of a 6 wt % dimethylimidazole methanol solution to 50.00 mL of a 50.00 g / L zinc nitrate aqueous solution and stirring to prepare a mixed solution A;

[0076] Step (2): adding 10.00 mL of a 10 wt % solution of tebuconazole in N,N-dimethylformamide to the mixed solution A, and stirring to obtain a mixed solution B;

[0077] Step (3): After the mixed solution B is centrifuged, washed and dried, the obtained solid is the prepared tebuconazole nanopesticide not coated with tannic acid.

[0078] Step (4): Tannic acid coating: prepare a 105.00 mM tannic acid aqueous solution and add it to a 2.00 g / L tebuconazole nanopesticide aqueous solution that is not coated with tannic acid, and stir to obtain a mixed solution C; the volume ratio of the tannic acid aqueous solution to the tebuconazole nanopesticide aqueous solution is 1:500.

[0079] Step (5): centrifuging the mixed solution C and drying it at -80°C to obtain tannic acid-coated tebuconazole nanopesticide.

[0080] Table 1 Concentration of each substance in Examples 1 to 9

[0081]

[0082] Comparative Example

[0083] Step (1): adding 90.00 mL of a 3.67 wt% methanol solution of dimethylimidazole to 50.00 mL of a 30.00 g / L aqueous zinc nitrate solution, and stirring to prepare a mixed solution A;

[0084] Step (2): adding 10.00 mL of a 10 wt % solution of tebuconazole in N,N-dimethylformamide to the mixed solution A, and stirring to obtain a mixed solution B;

[0085] Step (3): After the mixed solution B is centrifuged, washed and dried, the obtained solid is the prepared tebuconazole nanopesticide not coated with tannic acid.

[0086] Performance testing methods

[0087] (1)TEM:

[0088] Transmission electron microscopy (TEM, JEM-1400, JEOL Ltd.) was used to examine the morphology of the samples;

[0089] (2) pH responsiveness:

[0090] First, 5.00 mg of the tannic acid-coated tebuconazole nanopesticide of the embodiment was weighed, and the 5.00 mg was placed in a dialysis bag, placed in a sample bottle with a cover, and 100.00 mL of a mixed solution of ethanol and water (V 乙醇 :V 水 =7:3, pH 5, 7 and 9 respectively), put it in a shaker, set the shaker temperature to 25°C, test the absorbance value of the solution at intervals, and calculate the drug concentration in the solution according to the standard curve; three parallel experiments;

[0091] (3) Adhesion to plant leaves:

[0092] Botrytis cinerea was used as the pathogen, and the Botrytis cinerea (Bio-81601) used in the experiment was purchased from the China Microbial Strain Query Network and subcultured in the laboratory. Live plant pot experiments were carried out with Chinese cabbage as a model plant. Select the Chinese cabbage with good growth, stick the leaves on a flat plate, clean the dust on the leaf surface, and dry naturally. Prepare tebuconazole suspension, the tannic acid-coated tebuconazole nanopesticide of the embodiment, and the tebuconazole nanopesticide of the uncoated tannic acid of the comparative example, spray with the 0.50mg / L effective concentration of tebuconazole as the standard, and use the Chinese cabbage leaves treated with deionized water as a control. The leaves of the application were divided into two groups, one group of which was washed and cleaned with 10.00mL deionized water simulated rainwater, and the other group was not processed. After the leaf surface was dried, the bacterial cake was taken off at the edge of the culture dish covered with Botrytis cinerea with a 5.00mm puncher, and was attached to the surface of the Chinese cabbage leaves, waiting for the onset of disease.

[0093] (4) Standard curve

[0094] First, 5 mg of the pesticide tebuconazole was dissolved in 100.00 mL of a mixed solution of ethanol and water (V 乙醇 :V 水 =7:3, pH 5, 7 and 9 respectively) to obtain a 50.00 mg / L stock solution. Take a series of drug stock solutions and dilute them with a mixed solution of ethanol and water (V 乙醇 :V 水 =7:3), obtain 5, 10, 15, 20, 25 mg / L drug solutions, measure absorbance values, record results at 221 nm using an ultraviolet spectrophotometer and draw a standard curve.

[0095] (5) Cumulative release rate:

[0096] First, the drug concentration in the solution is obtained according to (2) in the performance test method, and the drug concentration is substituted into equation (1) to obtain the cumulative release rate;

[0097]

[0098] Among them, C t is the concentration of tebuconazole in the solution at that moment; V i The volume of solution taken out each time is 4 mL; V is the total volume of the buffer solution, 100 mL; M is the content of tebuconazole loaded in the tannic acid-coated tebuconazole nanopesticide.

[0099] Test result analysis:

[0100] Depend on Figure 1 The test results show that the tebuconazole nanopesticide without tannic acid coating in the comparative example is in the form of dodecahedron with good size consistency.

[0101] Depend on Figure 2 The test results and Figure 1 The comparison shows that due to the interaction between tannic acid and Zn 2+ By cooperating on the surface of the organic metal framework, tannic acid molecules can form a coating layer on the surface of the organic metal framework and release H + The Zn-N bond in the organic metal framework is destroyed to form macropores. The obtained tannic acid-coated tebuconazole nanopesticide is based on the tannic acid-coated organic metal framework material as a carrier. From the TEM image, it can be observed that the metal-organic framework material has an obvious coating layer on the outside, and the others are basically similar.

[0102] Table 2 Standard curves of the pesticide tebuconazole at pH 5, 7, and 9

[0103] pH Standard curve equation <![CDATA[R 2 ]]> 5 Y=0.0032x+0.0064 0.9889 7 Y=0.0064x-0.025 0.9755 9 Y=0.0082x-0.0334 0.9807

[0104] Table 3 Release conditions of the embodiments and comparative examples at pH = 7 (ethanol-water system)

[0105]

[0106]

[0107] Combining Examples 1 to 7, the comparative example and Table 3, it can be seen that the pesticides prepared in Examples 1 to 7 have a cumulative release rate lower than that of the comparative example after the cumulative release for 30 hours, indicating that after the outer layer of the organic metal framework is coated with tannic acid, the drug action time is prolonged and the sustained release effect of the pesticide is achieved.

[0108] By comparing the test results of Examples 1 to 7 and Examples 8 to 9, it can be seen that when the concentration of dimethylimidazole is 3 to 5wt%, the concentration of zinc nitrate hexahydrate is 20 to 40g / L, and the concentration of tannic acid is between 70 and 100mM, the cumulative release rate is lower than that of the comparative example, and the sustained release effect of the pesticide can be achieved. When the added amount is large, the dispersion of the nanocarrier in the pesticide is insufficient, and the tannic acid is easy to destroy the carrier structure, thereby affecting the release operation of the loaded tebuconazole.

[0109] Table 4 Cumulative release rate of the embodiment at different pH (PBS system)

[0110]

[0111]

[0112] As shown in Table 4, the cumulative release rate of tebuconazole nanopesticide coated with tannic acid is about 70% at pH = 5 for 40 hours, about 40% at pH = 7 for 40 hours, and about 20% at pH = 9 for 40 hours, which shows that under acidic pH conditions, the cumulative release rate of tebuconazole is the largest in the same time, indicating that the tebuconazole nanopesticide coated with tannic acid has pH-responsive release performance, and the low pH environment accelerates the release rate of tebuconazole in the system. This is mainly because the dissolution of the outer layer coated tannic acid is accelerated under low pH conditions, thereby promoting the release of the inner layer encapsulated drug.

[0113] Table 5 Corrosion degree of Example 1 and Comparative Example to Botrytis cinerea before and after simulated rainwater scouring

[0114] sample No flushing 10mL water flush Teb 100％ 100％ Example 1 37.83％ 55.64％ Comparative Example 50.84％ 80.65％

[0115] As shown in Table 5, the present invention adds tannic acid and relies on the reaction between tannic acid and Zn 2+ The tannic acid molecules can directly form a coating layer on the surface of the metal-organic framework material through chelation, providing multiple sites for forming hydrogen bonds, and the prepared nanopesticide has excellent adhesion properties. In particular, with the increase of the amount of rainwater scouring, the corrosion degree of the comparative example is greater than that of the embodiment, and the difference in corrosion before and after scouring is large. After TA is wrapped, the nanopesticide has a better control effect on Botrytis cinerea. This result shows that the tebuconazole nanopesticide with the organic metal framework as the carrier wrapped by tannic acid has very good adhesion properties on the cabbage leaf surface.

Claims

1. A method for preparing a tebuconazole nanopesticide with leaf adhesion, characterized in that: The following steps are involved: (1) A methanol solution of dimethylimidazole and an aqueous solution of zinc nitrate are mixed, and an N,N-dimethylformamide solution of tebuconazole is added, and after centrifugation, washing, and drying, the obtained solid is a tebuconazole nanopesticide not coated with tannic acid; (2) adding the tannic acid aqueous solution to the tebuconazole nanopesticide aqueous solution not coated with tannic acid, stirring, centrifuging and drying to obtain the tebuconazole nanopesticide with the tannic acid coated organic metal framework material as the carrier.

2. The method for preparing the tebuconazole nanopesticide according to claim 1, characterized in that: The concentration of the methanol solution of dimethylimidazole in step (1) is 3-5wt%.

3. The method for preparing the tebuconazole nanopesticide according to claim 1, characterized in that: The concentration of the zinc nitrate aqueous solution in step (1) is 20-40 g / L.

4. The method for preparing the tebuconazole nanopesticide according to claim 1, characterized in that: The concentration of the tannic acid aqueous solution in step (2) is 70-100 mM.

5. A tebuconazole nanopesticide with leaf surface adhesion prepared by the method according to any one of claims 1 to 4.

6. Use of the tebuconazole nanopesticide with leaf surface adhesion according to claim 5 in improving the utilization rate of the tebuconazole nanopesticide.

7. Use of the tebuconazole nanopesticide with leaf-adhesive properties as claimed in claim 5 in controlling crop diseases and insect pests.

8. The use according to claim 7, characterized in that: Release of the pesticide tebuconazole under acidic conditions.

Images