阅读说明：本技术 一种啶虫脒与有机酸的共晶及其制备方法、用途 (Co-crystal of acetamiprid and organic acid, preparation method and application thereof ) 是由 白光耀 董凤英 葛家成 刘桂娟 邢阳阳 胡堂路 孙鹏 刘明东 于 2021-11-08 设计创作，主要内容包括：本发明涉及化合物晶型领域,具体涉及一种啶虫脒共晶及其制备方法、用途,所述啶虫脒共晶包含：啶虫脒以及有机酸；其中所述啶虫脒与有机酸的摩尔比为10:1～1:10；本发明还提供了上述啶虫脒共晶的制备方法和用途。本发明的技术方案以丁二酸或酒石酸等有机酸为共晶形成物、与啶虫脒形成共晶体,具有熔点高、水溶解度值高、水溶解速率高的优点,尤其适合应用于农药制剂生产过程中。(The invention relates to the field of compound crystal forms, in particular to an acetamiprid eutectic and a preparation method and application thereof, wherein the acetamiprid eutectic comprises the following components: acetamiprid and organic acids; wherein the molar ratio of the acetamiprid to the organic acid is 10: 1-1: 10; the invention also provides a preparation method and application of the acetamiprid eutectic. According to the technical scheme, organic acids such as succinic acid or tartaric acid and the like are used as eutectic formers and form eutectic with acetamiprid, so that the pesticide composition has the advantages of high melting point, high water solubility value and high water solubility rate, and is particularly suitable for being applied to the production process of pesticide preparations.)

1. An acetamiprid cocrystal, comprising: acetamiprid and organic acids; wherein the molar ratio of the acetamiprid to the organic acid is 10: 1-1: 10; the organic acid is succinic acid or tartaric acid.

2. A co-crystal according to claim 1, wherein the molar ratio of acetamiprid to organic acid is 2:1 to 1: 2.

3. A co-crystal according to claim 2, wherein the molar ratio of acetamiprid to organic acid is 1:1 to 1: 2; the preferred molar ratio is 1: 1.

4. Co-crystal according to any of claims 1 to 3, characterized in that the organic acid, when succinic acid, shows in the spectrum at least 4 of the following diffraction peaks given in 2 θ values: 15.038 DEG + -0.2, 18.096 DEG + -0.2, 20.037 DEG + -0.2, 21.916 DEG + -0.2, 22.585 DEG + -0.2, 24.650 DEG + -0.2, 26.060 DEG + -0.2, 27.116 DEG + -0.2, 30.385 DEG + -0.2, 31.503 DEG + -0.2, 32.320 DEG + -0.2, 38.442 DEG + -0.2, 40.649 DEG + -0.2.

5. A co-crystal according to any of claims 1 to 3, wherein the organic acid is tartaric acid and exhibits in the spectrum at least 4 of the following diffraction peaks given in 2 Θ values: 8.716 DEG + -0.2, 12.370 DEG + -0.2, 15.183 DEG + -0.2, 17.675 DEG + -0.2, 18.668 DEG + -0.2, 19.100 DEG + -0.2, 20.672 DEG + -0.2, 21.585 DEG + -0.2, 22.039 DEG + -0.2, 22.941 DEG + -0.2, 23.281 DEG + -0.2, 23.834 DEG + -0.2, 24.875 DEG + -0.2, 25.587 DEG + -0.2, 26.833 + -0.2, 29.217 DEG + -0.2, 30.566 DEG + -0.2, 32.957 DEG + -0.2, 35.341 DEG + -0.2, 36.293 DEG + -0.2, 37.684 DEG + -0.2, 40.527 DEG + -0.2.

6. A process for the preparation of a co-crystal according to claim 1, characterized in that acetamiprid is mixed with succinic acid or tartaric acid, an alcoholic solvent is added, the mixture is stirred with or without heating and then filtered, the filtrate is left to stand and the solid is collected as the co-crystal.

7. The method according to claim 6, wherein the heating condition is heating at 30 to 50 ℃; the alcohol solvent is any one or a mixture of methanol, ethanol, propanol or butanol; preferably methanol or ethanol;

the solid-liquid ratio of the mixture of the acetamiprid and the organic acid to the alcohol solvent is (0.3-0.6) g (3-10) mL.

8. An agricultural formulation comprising an effective amount of an acetamiprid cocrystal according to any one of claims 1 to 5; preferably, the composition also comprises an agriculturally acceptable preparation carrier or a preparation auxiliary agent.

9. A method for controlling pests, which comprises applying a pesticidally effective amount of the acetamiprid cocrystal according to any one of claims 1 to 5 or the agricultural formulation according to claim 8 to the pests and/or their habitat and/or to the plants and/or plant propagules.

10. Use of an acetamiprid cocrystal according to any one of claims 1 to 5 or an agricultural formulation according to claim 8 for controlling pests.

Technical Field

The invention belongs to the technical field of compound crystal preparation, and particularly relates to an acetamiprid and organic acid eutectic crystal, and a preparation method and application of the eutectic crystal.

Background

Acetamiprid is a novel broad-spectrum insecticide with a certain acaricidal activity, belongs to a novel chloronicotinyl insecticide, and is developed by Nippon Caoda corporation. Acetamiprid interferes with the stimulation and conduction of the insect nervous system by acting on a nicotine acetylcholine receptor at the synaptic site of the insect nervous system, causes the obstruction of the nervous system channels, causes the accumulation of neurotransmitter acetylcholine at the synaptic site, and leads to paralysis and eventual death of the insect. Acetamiprid is one of the most widely used excellent insecticides in neonicotinoids, has the characteristics of high efficiency and broad spectrum, and can be widely used for crops such as fruit trees, tea, vegetables, cotton and the like.

As a novel pesticide, acetamiprid is popular since the beginning and is affirmed by market and agricultural practitioners, but in practical application, acetamiprid also has the defects of poor water solubility, low melting point and the like, and has certain influence on the practical application. Therefore, how to simply and effectively improve the physicochemical properties of the acetamiprid is an important factor for restricting the further development of the acetamiprid. The currently common method for changing the property of the medicine generally needs to change the structure of the medicine, add an auxiliary agent and the like, so that the cost is high, and the performance of the practical application of the medicine is influenced due to the change of the structure of part of the medicine. In recent years, the pharmaceutical cocrystal technology has received attention from researchers due to its excellent performance in improving the physicochemical properties of drugs, improving the bioavailability of drugs, and prolonging the lifetime of existing drugs. The pharmaceutical co-crystal is a new pharmaceutical entity formed by combining a pharmaceutical active ingredient with a co-crystal form through non-covalent bonds such as hydrogen bonds. The pharmaceutical co-crystal not only can improve the physicochemical property of the drug on the premise of not changing the covalent structure of the drug, but also can realize the combined medication at the molecular level, thereby being widely concerned by academia and industry.

Succinic acid is also called succinic acid, is a compound widely applied to industries such as food, medicine and the like, has the characteristics of safety and environmental protection, is safe to human bodies and animals, has low cost, and is suitable for eutectic transformation of pesticide raw materials; tartaric acid is an organic acid occurring in nature, is present in various plants, and is also one of the main organic acids in wine. Tartaric acid is an excellent co-crystal former, which has the advantages of high water solubility, low toxicity and the like. Therefore, the acetamiprid-tartaric acid eutectic is prepared by combining the acetamiprid and tartaric acid in a eutectic mode on the premise of not changing the covalent structure of the acetamiprid. The eutectic effectively improves the physicochemical properties of the acetamiprid, improves the water solubility and the melting point of the acetamiprid, enhances the stability and the processability of the acetamiprid, and lays a foundation for the further development and application of the acetamiprid.

Disclosure of Invention

The invention aims to overcome the inconvenience caused by the lower water solubility and the lower melting point of the acetamiprid in the prior art in the preparation and storage processes of pesticide preparations. The method for changing the properties of the pesticide preparation usually needs to change the structure, add an auxiliary agent and the like, has high cost, and influences the performance of practical application of the pesticide preparation due to the change of the structure of part of methods.

In order to achieve the technical purpose, the invention provides the following technical scheme: an acetamiprid cocrystal, comprising: acetamiprid and organic acids; wherein the molar ratio of the acetamiprid to the organic acid is 10: 1-1: 10; the organic acid is succinic acid or tartaric acid.

Further, the molar ratio of the acetamiprid to the organic acid is 2: 1-1: 2.

Further, the molar ratio of the acetamiprid to the organic acid is 1: 1-1: 2; the preferred molar ratio is 1: 1.

Further, when the organic acid is succinic acid, at least 4 of the following diffraction peaks given by 2 θ values are displayed in the spectrum: 15.038 DEG + -0.2, 18.096 DEG + -0.2, 20.037 DEG + -0.2, 21.916 DEG + -0.2, 22.585 DEG + -0.2, 24.650 DEG + -0.2, 26.060 DEG + -0.2, 27.116 DEG + -0.2, 30.385 DEG + -0.2, 31.503 DEG + -0.2, 32.320 DEG + -0.2, 38.442 DEG + -0.2, 40.649 DEG + -0.2.

Further, when the organic acid is tartaric acid, at least 4 of the following diffraction peaks given in 2 θ values are shown in the spectrum: 8.716 DEG + -0.2, 12.370 DEG + -0.2, 15.183 DEG + -0.2, 17.675 DEG + -0.2, 18.668 DEG + -0.2, 19.100 DEG + -0.2, 20.672 DEG + -0.2, 21.585 DEG + -0.2, 22.039 DEG + -0.2, 22.941 DEG + -0.2, 23.281 DEG + -0.2, 23.834 DEG + -0.2, 24.875 DEG + -0.2, 25.587 DEG + -0.2, 26.833 + -0.2, 29.217 DEG + -0.2, 30.566 DEG + -0.2, 32.957 DEG + -0.2, 35.341 DEG + -0.2, 36.293 DEG + -0.2, 37.684 DEG + -0.2, 40.527 DEG + -0.2.

The invention also provides a preparation method of the cocrystal, which comprises the steps of mixing acetamiprid and succinic acid or tartaric acid, adding an alcohol solvent, stirring under heating or non-heating conditions, filtering, standing the filtrate, and collecting a solid as the cocrystal.

Further, the heating condition is heating at 30-50 ℃; the alcohol solvent is any one or a mixture of methanol, ethanol, propanol or butanol; preferably methanol or ethanol;

the solid-liquid ratio of the mixture of the acetamiprid and the organic acid to the alcohol solvent is (0.3-0.6) g (3-10) mL.

The invention also provides an agricultural formulation comprising an effective amount of an acetamiprid cocrystal as described above; preferably, the composition also comprises an agriculturally acceptable preparation carrier or a preparation auxiliary agent.

The invention also provides a method of controlling pests, which comprises applying a pesticidally effective amount of an acetamiprid cocrystal as described above or an agricultural formulation as described above to the pests and/or their habitat and/or to the plants and/or to the plant propagules.

The invention also provides the use of an acetamiprid cocrystal as described above or an agricultural formulation as described above for controlling pests.

Due to the adoption of the technology, compared with the prior art, the invention has the remarkable advantages that:

1) according to the technical scheme, succinic acid and tartaric acid are used as eutectic formers and form eutectic with acetamiprid, so that the eutectic has the advantages of high melting point, high water solubility value and high water solubility rate, particularly the melting point is increased to be higher than 126 ℃, the water solubility is increased to be higher than 9.0g/L, the dissolution rate in water is greatly increased, the eutectic is suitable for being applied to the production process of pesticide preparations, and the inconvenience caused by the low water solubility and the low melting point of the acetamiprid in the prior art in the preparation and storage processes of the pesticide preparations is solved;

2) according to the preparation method of the acetamiprid eutectic, the solvent volatilization method and the cooling method are adopted to prepare the high-purity eutectic, and PXRD, melting point measurement and other related characterization and dissolution rate tests are performed on the eutectic, so that the prepared acetamiprid-succinic acid and acetamiprid-tartaric acid eutectic has high purity and crystallinity, can be kept stable for a long time without deterioration, is simple in preparation process and low in cost, and is suitable for large-scale production.

Drawings

FIG. 1 is a PXRD spectrum of acetamiprid-succinic acid eutectic of the present invention;

FIG. 2 is a comparison graph of PXRD spectra of acetamiprid-succinic acid eutectic, acetamiprid and succinic acid;

FIG. 3 is a PXRD pattern of cocrystals of acetamiprid-tartaric acid according to the present invention;

FIG. 4 is a comparison graph of PXRD patterns of the acetamiprid-tartaric acid eutectic, acetamiprid and tartaric acid;

FIG. 5 is a comparison graph of dissolution rates of acetamiprid-succinic acid eutectic crystal and acetamiprid in water;

fig. 6 is a graph comparing dissolution rates of acetamiprid-tartaric acid eutectic and acetamiprid in water.

Detailed Description

In order to make the technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments.

Example 1

The preparation method of the acetamiprid-succinic acid eutectic crystal is implemented according to the following steps:

putting 2.226g of acetamiprid raw material medicine and 1.180g of succinic acid into a round-bottom flask according to the molar ratio of 1:1, adding 50mL of methanol into the round-bottom flask, heating and stirring the mixed powder and the methanol in a water bath at 50 ℃ for 3h, filtering, standing and volatilizing the filtrate for 3 days, and collecting a solid phase substance to obtain acetamiprid-succinic acid eutectic and white crystal powder. The test is carried out by using an X-ray diffractometer model D8 of German BRUKER company, the test conditions are that the Cu-Kalpha target tube voltage is 40kV, the tube current is 10mA, the scanning speed is 2 DEG/min, and the PXRD diffraction pattern of the product is shown in figure 1.

The PXRD characteristic diffraction peaks of the acetamiprid-succinic acid eutectic of the embodiment appear at 15.038 °, 18.096 °, 20.037 °, 21.916 °, 22.585 °, 24.650 °, 26.060 °, 27.116 °, 30.385 °, 31.503 °, 32.320 °, 38.442 °, and 40.649 °. As shown in fig. 2, when compared with PXRD of acetamiprid bulk drug and succinic acid bulk drug, the obtained acetamiprid-succinic acid eutectic has significant changes in characteristic diffraction peak position and diffraction intensity, indicating that a new phase is generated.

The melting point of the eutectic compound is 126.3 ℃ and the melting point of the acetamiprid is 102 ℃ by using a Shanghai Jiahang WRS-1C type melting point tester, which shows that compared with the acetamiprid, the melting point of the acetamiprid in the eutectic is increased by 24.3 ℃, and the stability of the acetamiprid is greatly promoted.

Example 2

The preparation method of the acetamiprid-succinic acid eutectic crystal is implemented according to the following steps:

putting 2.226g of acetamiprid raw material medicine and 1.180g of succinic acid into a round-bottom flask according to the molar ratio of 1:1, adding 30mL of methanol into the round-bottom flask, heating and stirring the mixed powder and the methanol in a water bath at 50 ℃ for 2h, filtering, cooling the filtrate to room temperature, separating out a solid phase, and collecting the solid phase to obtain acetamiprid-succinic acid eutectic and white crystal powder. The measurement was carried out using an X-ray diffractometer model D8 from BRUKER, Germany under the conditions of a Cu-K.alpha.target tube voltage of 40kV, a tube current of 10mA, and a scanning speed of 2 DEG/min, and the PXRD diffraction pattern of the product was the same as that of example 1. The melting point was the same as in example 1.

Example 3

The preparation method of the acetamiprid-succinic acid eutectic crystal is implemented according to the following steps:

putting 2.226g of acetamiprid raw material medicine and 1.180g of succinic acid into a round-bottom flask according to the molar ratio of 1:1, adding 80mL of ethanol into the round-bottom flask, heating and stirring the mixed powder and the ethanol in a water bath at 50 ℃ for 3h, filtering, cooling the filtrate to room temperature, separating out a solid phase, and collecting the solid phase to obtain acetamiprid-succinic acid eutectic and white crystal powder. The measurement was carried out using an X-ray diffractometer model D8 from BRUKER, Germany under the conditions of a Cu-K.alpha.target tube voltage of 40kV, a tube current of 10mA, and a scanning speed of 2 DEG/min, and the PXRD diffraction pattern of the product was the same as that of example 1. The melting point was the same as in example 1.

Example 4

The preparation method of the acetamiprid-succinic acid eutectic crystal is implemented according to the following steps:

putting 2.226g of acetamiprid raw material medicine and 1.180g of succinic acid into a round-bottom flask according to the molar ratio of 1:1, adding 100mL of ethanol into the round-bottom flask, heating and stirring the mixed powder and the ethanol in a water bath at 50 ℃ for 2h, filtering, standing and volatilizing the filtrate for 5 days, and collecting a solid phase substance to obtain acetamiprid-succinic acid eutectic and white crystal powder. The measurement was carried out using an X-ray diffractometer model D8 from BRUKER, Germany under the conditions of a Cu-K.alpha.target tube voltage of 40kV, a tube current of 10mA, and a scanning speed of 2 DEG/min, and the PXRD diffraction pattern of the product was the same as that of example 1. The melting point was the same as in example 1.

Example 5

The preparation method of the acetamiprid-tartaric acid eutectic is implemented according to the following steps:

putting 2.226g of acetamiprid raw material medicine and 1.500g of tartaric acid into a round-bottom flask according to the molar ratio of 1:1, adding 50mL of methanol into the mixed powder, heating and stirring the mixed powder and the methanol in a water bath kettle at the temperature of 30 ℃ for 3h, filtering, standing the filtrate for 4 days to volatilize the solvent, and collecting a solid phase substance to obtain acetamiprid-tartaric acid eutectic and white crystalline powder. The test is carried out by using an X-ray diffractometer model D8 of German BRUKER company, the test conditions are that the Cu-Kalpha target tube voltage is 40kV, the tube current is 10mA, the scanning speed is 2 DEG/min, and the PXRD diffraction pattern of the product is shown in figure 3.

The PXRD characteristic diffraction peaks of the acetamiprid-tartaric acid eutectic of the embodiment appear at 15.038 °, 18.096 °, 20.037 °, 21.916 °, 22.585 °, 24.650 °, 26.060 °, 27.116 °, 30.385 °, 31.503 °, 32.320 °, 38.442 °, and 40.649 °. As shown in fig. 4, when compared with PXRD of acetamiprid bulk drug and tartaric acid bulk drug, the obtained acetamiprid-tartaric acid eutectic has significant changes in characteristic diffraction peak position and diffraction intensity, indicating that a new phase is generated.

The melting point of the eutectic compound is 132.0 ℃ measured by using a Shanghai Jiahang WRS-1C type melting point instrument, and is improved by 30.0 ℃ compared with the melting point of acetamiprid at 102 ℃, which shows that the eutectic can further improve the stability of the acetamiprid, and has certain advantages for the storage and preparation of the acetamiprid.

Example 6

The preparation method of the acetamiprid-tartaric acid eutectic is implemented according to the following steps:

putting 2.226g of acetamiprid raw material medicine and 1.500g of tartaric acid into a round-bottom flask according to the molar ratio of 1:1, adding 60mL of ethanol into the mixed powder, heating and stirring the mixed powder and the ethanol in a water bath at 50 ℃ for 5h, filtering while hot, cooling the filtrate to room temperature, and collecting a solid phase substance to obtain acetamiprid-tartaric acid eutectic and white crystalline powder. The test was carried out using an X-ray diffractometer model D8 from BRUKER, Germany, under the test conditions of a Cu-K.alpha.target tube voltage of 40kV, a tube current of 10mA, and a scanning speed of 2 DEG/min, and the product had a PXRD diffraction pattern identical to that of example 5 and a melting point identical to that of example 5.

Example 7

The acetamiprid-succinic acid eutectic solubility test:

the dissolution rates of the acetamiprid-succinic acid eutectic sample and the acetamiprid are respectively measured in water by an excessive powder dissolution rate method. Respectively placing an excessive acetamiprid-succinic acid eutectic sample and an acetamiprid sample with equal weight into 2 eggplant-shaped flasks with the volume of 100mL, placing the eggplant-shaped flasks into a water bath kettle, simultaneously adding 20mL of water and starting timing, wherein the water bath temperature is 25 +/-0.5 ℃. The test lasted 180 minutes, and 0.5mL was sampled at 1, 2, 3, 4, 5, 10, 15, 30, 60, 120, 180 minutes, with the results shown in FIG. 5.

As can be seen from the figure, the maximum solubility of the acetamiprid-succinic acid eutectic in water is 9095mg/L higher than that of the acetamiprid 4250mg/L, which shows that the pharmaceutical eutectic can improve the solubility of the acetamiprid, and research results provide scientific basis for improving the bioavailability of the acetamiprid and further exerting the insecticidal effect of the acetamiprid.

Example 8

Solubility test of acetamiprid-tartaric acid cocrystal:

the dissolution rates of the acetamiprid-tartaric acid eutectic sample and the acetamiprid are respectively measured in an aqueous solution by an excessive powder dissolution rate method. Respectively placing an excessive acetamiprid-tartaric acid eutectic sample and an excessive acetamiprid sample with equal weight into 2 eggplant-shaped flasks with the volume of 100mL, placing the eggplant-shaped flasks into a water bath kettle, simultaneously adding 20mL of water and starting timing, wherein the water bath temperature is 25 +/-0.5 ℃. The test lasted 180 minutes, and 0.5mL was sampled at 1, 2, 3, 4, 5, 10, 15, 30, 60, 120, 180 minutes, with the results shown in FIG. 6.

As can be seen from the figure, the maximum solubility 10575mg/L of the acetamiprid-tartaric acid eutectic in water is higher than 4250mg/L of acetamiprid, which shows that the pharmaceutical eutectic can improve the solubility of the acetamiprid, and research results provide scientific basis for improving the bioavailability of the acetamiprid and further exerting the insecticidal effect of the acetamiprid.

Example 9

Insecticidal activity test of acetamiprid-succinic acid eutectic:

1) the preparation method of the acetamiprid-succinic acid eutectic-containing water dispersible granule comprises the following steps:

adding 30g of white carbon black, 765.2g of acetamiprid-succinic acid eutectic crystal (the molar ratio is 1:1), 40g of dispersant NNO, 40g of naphthalenesulfonate formaldehyde condensate and 40g of nekal BX into 84.8g of kaolin, mixing, adding 200mL of water after jet milling, kneading, granulating, drying and screening to obtain the water dispersible granule.

2) The preparation method of the water dispersible granule containing acetamiprid and succinic acid comprises the following steps:

adding 30g of white carbon black, 500g of acetamiprid, 265.2g of succinic acid, 40g of dispersant NNO, 40g of naphthalene sulfonate formaldehyde condensate and 40g of nekal BX into 84.8g of kaolin, mixing, adding 200mL of water after jet milling, kneading, granulating, drying and screening to obtain the water dispersible granule.

3) The preparation method of the acetamiprid-containing water dispersible granule comprises the following steps:

adding 30g of white carbon black, 500g of acetamiprid, 40g of dispersant NNO, 40g of naphthalenesulfonate formaldehyde condensate and 40g of nekal BX into 350g of kaolin, mixing, adding 200mL of water after airflow crushing, kneading, granulating, drying and screening to prepare the water dispersible granule.

4) The preparation method of the acetamiprid-oxalic acid eutectic-containing water dispersible granule comprises the following steps:

adding 30g of white carbon black, 702g of acetamiprid-oxalic acid eutectic (the molar ratio is 1:1), 40g of dispersant NNO, 40g of naphthalenesulfonate formaldehyde condensate and 40g of nekal BX into 148g of kaolin, mixing, adding 200mL of water after jet milling, kneading, granulating, drying and screening to obtain the water dispersible granule.

5) And (3) insecticidal activity test:

the insecticidal activity of the acetamiprid-succinic acid eutectic-containing water dispersible granules on tea plant lesser leafhoppers is determined according to the national standard GB/T17980.56-2004, the insecticide is applied in the peak of the emergence period of tea lesser leafhopper nymphs, experiments are carried out according to the dosage of 3g of preparation per mu, 50 liters of water is added per mu for spraying leaf surfaces, water dispersible granules containing acetamiprid and succinic acid are additionally used in a control group 1, water dispersible granules containing acetamiprid are used in a control group 2, water dispersible granules containing acetamiprid-oxalic acid eutectic are used in a control group 3, the specific test method is as described above, and the test result 7 days after insecticide application is as follows: the acetamiprid-succinic acid eutectic test group control effect is 95.3%, the control 1 group control effect is 90.5%, the control 2 group control effect is 90.3%, and the control 3 group control effect is 91.2%.

Example 10

Insecticidal activity test of acetamiprid-tartaric acid eutectic:

1) the preparation method of the acetamiprid-tartaric acid eutectic-containing water dispersible granule comprises the following steps:

837g acetamiprid-tartaric acid eutectic (the molar ratio is 1:1), 45g lignosulfonate, 40g sodium dodecyl benzene sulfonate and 45g sodium polycarboxylate are added into 33g kaolin, mixed, subjected to jet milling, added with 200mL of water, kneaded, granulated, dried and sieved to prepare the water dispersible granule.

2) The preparation method of the water dispersible granule containing acetamiprid and tartaric acid comprises the following steps:

adding 500g acetamiprid, 337g tartaric acid, 45g lignosulfonate, 40g sodium dodecyl benzene sulfonate and 45g sodium polycarboxylate into 33g kaolin, mixing, performing jet milling, adding 200mL of water, kneading, granulating, drying and screening to obtain the water dispersible granule.

3) The preparation method of the acetamiprid-containing water dispersible granule comprises the following steps:

500g acetamiprid, 45g lignosulfonate, 40g sodium dodecyl benzene sulfonate and 45g sodium polycarboxylate are added into 370g kaolin, mixed, subjected to jet milling, added with 200mL of water, kneaded, granulated, dried and sieved to prepare the water dispersible granule.

4) The preparation method of the acetamiprid-oxalic acid eutectic-containing water dispersible granule comprises the following steps:

adding 702g acetamiprid-oxalic acid eutectic (the molar ratio is 1:1), 45g lignosulfonate, 40g sodium dodecyl benzene sulfonate and 45g sodium polycarboxylate into 168g kaolin, mixing, adding 200mL of water after airflow crushing, kneading, granulating, drying and screening to obtain the water dispersible granule.

5) And (3) insecticidal activity test:

the insecticidal activity of the acetamiprid-tartaric acid eutectic-containing water dispersible granules on tea plant lesser leafhoppers is determined according to the national standard GB/T17980.56-2004, the insecticide is applied in the full-growth period of tea lesser leafhopper nymphs, experiments are carried out according to the dosage of 3g of preparation/mu, 50 liters of water is added per mu for leaf surface spraying, in addition, a control group 1 uses the acetamiprid-tartaric acid-containing water dispersible granules, a control group 2 uses the acetamiprid-containing water dispersible granules, and a control group 3 uses the acetamiprid-oxalic acid eutectic-containing water dispersible granules, the specific test methods are as described above, and the experiment result 7 days after the insecticide is as follows: the control effect of the acetamiprid-tartaric acid eutectic test group is 96.7%, the control effect of the control 1 group is 91.1%, the control effect of the control 2 group is 90.6%, and the control effect of the control 3 group is 92.4%.

The above-mentioned embodiments are merely preferred embodiments of the present invention, and should not be construed as limiting the present invention, and the scope of the present invention should be defined by the claims, and equivalents including technical features of the claims, i.e., equivalent modifications within the scope of the present invention.