Preparation method of aminopyralid soluble liquid

Abstract

The invention discloses a preparation method of aminopyralid soluble liquid, and mainly relates to the technical field of herbicides. Compared with the prior art, the aminopyralid soluble liquid has the advantages that water-insoluble aminopyralid raw medicine is prepared into the soluble liquid, and the soluble liquid is in a molecular / ionic form in the solution after being diluted with water during use, so that medicine components have high penetrability and permeability, and the efficacy utilization rate is increased. Moreover, the problem of insufficient storage stability of aminopyralid is solved, and the aminopyralid dispersible tablet has good wetting and dispersing effects and permeation and absorption performance and has the characteristics of convenience in storage and use at an application end. Furthermore, aminopyralid is modified, and the storage stability, the soil permeation and absorption performance and the controlled release performance of the aminopyralid soluble liquid in practical application are improved at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of herbicides, and particularly relates to a preparation method of a picloram soluble concentrate. Background Art

[0002] Picloram is a new type of pyridine carboxylic acid herbicide that is safe, low-toxic, non-carcinogenic and environmentally friendly. No other products that affect soil and water quality have been found in its metabolism except for CO2. It is suitable for weed control in diverse terrains. Picloram belongs to a synthetic hormone-type herbicide. It can be rapidly absorbed by plant stems, leaves and roots. In sensitive plants, it induces an epinastic response in plants, resulting in the stagnation of plant growth and rapid necrosis. In the prior art, good effects have been achieved by combining picloram with other herbicide products such as glufosinate, sethoxydim, quinclorac, etc. Common dosage forms of herbicides include granule agents, aqueous agents, soluble concentrates, etc. The soluble concentrate forms a true solution of the active ingredient of the pesticide after being diluted with water.

[0003] The storage stability problem of picloram soluble concentrate is usually related to the chemical properties of the technical material and storage conditions. During storage, it may be affected by environmental factors such as temperature, humidity, light and oxidation, which may cause the decomposition or deterioration of the technical material, thus affecting the activity and stability of its active ingredient. In practical applications, good permeability means that the picloram technical material can more effectively penetrate through the soil layer and reach the roots of plants, thereby controlling the target weeds and reducing volatilization and loss. The soil conditions in China are diverse, and there are significant differences in soil pH values. In the areas north of the Yangtze River, the soil is mostly neutral and alkaline, and the pH value is usually between 7.0 and 8.5. In the areas south of the Yangtze River, the soil is mostly acidic or strongly acidic, usually between 5.0 and 6.5, and the soil pH value in some individual areas can be as low as 4.0. In an acidic soil environment, the application of herbicides can be controlled and released by using the soil pH value.

[0004] CN105104375A discloses a herbicidal composition containing glycerol. The main components of the raw materials are calculated by mass fraction as follows: glycerol 8 - 97%, herbicide A 2 - 60%, surfactant 0.1 - 20%, filler B 0.5 - 30%. Among them, herbicide A can be picloram, and filler B can be selected from one or several of the following: water, soybean oil, corn oil, methyl oleate, rapeseed oil, turpentine, kitchen waste oil, aromatic hydrocarbon solvents, mineral oil, diesel oil, machine oil, sec-butyl acetate, solvent oil, monohydric or polyhydric alcohols with less than 10 carbon atoms. The herbicidal composition provided by this invention is used for spraying and foliage treatment to control weeds. A large amount of glycerol is added to the formula, and the moisture-absorbing and moisturizing properties of glycerol are utilized to improve the wetting and absorption of the active ingredient on the target, thereby reducing the dosage of the drug and improving the control effect.

[0005] CN105828609A discloses a herbicidal composition comprising imazapic, clopyralid, and optionally, demethylated metsulfuron-methyl acid. This composition can be diluted with an inert carrier such as water before post-emergence, foliar application to exposed weed and crop leaves, or can be directly applied as a dry or liquid formulation to flooded paddy fields or other aquatic environments. This invention improves broad-spectrum weed control, selectivity, minimal crop damage, storage stability, ease of operation, and higher activity against weeds.

[0006] The solutions reported in the above patent documents can improve the moisture retention to enhance the control effect and solve the storage stability problem, but cannot simultaneously solve issues such as storage stability, soil penetration and absorption, controlled release performance, etc., to improve the weed control effect and biological utilization rate. Summary of the Invention

[0007] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to improve the storage stability and soil penetration and absorption performance of the clopyralid soluble liquid agent, as well as the controlled release performance of the clopyralid soluble liquid agent in practical applications.

[0008] To achieve the above object, the present invention provides a method for preparing a clopyralid soluble liquid agent.

[0009] The preparation method of the clopyralid soluble liquid agent includes the following steps:

[0010] (1) Add the modified clopyralid technical material to water and stir for 0.5 - 1 hour;

[0011] (2) Add an alkali and continue to stir for 1 - 2 hours until completely dissolved;

[0012] (3) Add a synergist and continue to stir for 0.5 - 1 hour;

[0013] (4) Add a dye, an antifreeze, and a preservative and continue to stir for 0.5 - 1 hour;

[0014] (5) Heat to 35 - 45 °C and stir for 1 - 2 hours. After the appearance is clear and transparent, detect and fill to obtain the clopyralid soluble liquid agent.

[0015] The preparation method of the modified clopyralid technical material in step (1) is as follows:

[0016] M1 Add the clopyralid technical material and carboxymethyl-β-cyclodextrin to water, add sodium hydroxide to adjust the pH to 7 - 8, stir for 1 - 2 hours, centrifuge, wash the filter cake with absolute ethanol 2 - 4 times, and dry at 80 - 100 °C to obtain carboxymethyl-β-cyclodextrin loaded with clopyralid technical material;

[0017] M2 added the carboxymethyl-β-cyclodextrin loaded with picloram technical to an aqueous citric acid solution, added N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, continued stirring for 2 - 6 hours, dropped an aqueous guar gum solution and continued stirring for 2 - 4 hours, centrifuged, washed the filter cake with water 2 - 4 times, and dried to obtain the modified picloram technical.

[0018] Specifically, the preparation method of the picloram soluble concentrate comprises the following steps, by weight:

[0019] (1) Add 5 - 40 parts of the modified picloram technical to 10 - 70 parts of water, and stir for 0.5 - 1 hour;

[0020] (2) Add 2 - 4 parts of alkali, and continue stirring for 1 - 2 hours until completely dissolved;

[0021] (3) Add 5 - 20 parts of synergist, and continue stirring for 0.5 - 1 hour;

[0022] (4) Add 1 - 2 parts of dye, 2 - 10 parts of antifreeze, and 1 - 3 parts of preservative, and continue stirring for 0.5 - 1 hour;

[0023] (5) Heat to 35 - 45 °C and stir for 1 - 2 hours. After the appearance is clear and transparent, detect and fill to obtain the picloram soluble concentrate.

[0024] The preparation method of the modified picloram technical in step (1) is as follows, by weight:

[0025] M1 added 20 - 40 parts of picloram technical and 2 - 6 parts of carboxymethyl-β-cyclodextrin to 200 - 400 parts of water, added sodium hydroxide to adjust the pH to 7 - 8, stirred for 1 - 2 hours, centrifuged, washed the filter cake with absolute ethanol 2 - 4 times, and dried at 80 - 100 °C to obtain the carboxymethyl-β-cyclodextrin loaded with picloram technical;

[0026] M2 added 20 - 40 parts of the carboxymethyl-β-cyclodextrin loaded with picloram technical to 300 - 500 parts of an aqueous citric acid solution, added 3 - 6 parts of N-hydroxysuccinimide and 5 - 15 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, continued stirring for 2 - 6 hours, dropped 400 - 600 parts of an aqueous guar gum solution and continued stirring for 2 - 4 hours, centrifuged, washed the filter cake with water 2 - 4 times, and dried to obtain the modified picloram technical.

[0027] The alkali in step (2) is any one or a mixture of sodium hydroxide, sodium carbonate, ammonia water, dimethylamine, and isopropylamine.

[0028] In step (3), the synergist is any one or a mixture of polyoxyethylene lauryl ether, polyoxyethylene castor oil ether, polyoxyethylene tallow amine, polyoxyethylene oleate, polyoxyethylene dodecyl alcohol ether, dodecyl glucoside, octadecyl dimethyl amine oxide, and sodium oleoyl methyl taurate.

[0029] In step (4), the dye is any one of red, yellow, blue, purple, green, and black.

[0030] In step (4), the antifreeze is any one or a mixture of ethanol, ethylene glycol, isopropanol, sodium chloride, sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium carbonate, and sodium hydroxide.

[0031] In step (4), the preservative is any one or a mixture of benzoic acid, sodium benzoate, sorbic acid, potassium sorbate, and propyl p-hydroxybenzoate.

[0032] In step M2, the citric acid aqueous solution is a 10-15 wt% citric acid aqueous solution.

[0033] In step M2, the guar gum aqueous solution is a 2-6 wt% guar gum aqueous solution.

[0034] The picloram soluble concentrate of the present invention makes the picloram technical, which is insoluble in water, into a soluble concentrate. When used, after dilution with water, it is in a molecular / ionic form in the solution, making the drug components have strong penetrability and permeability, and improving the drug efficacy utilization rate. And it solves the problem of insufficient storage stability of picloram, has good wetting and dispersing effects and penetration and absorption properties, and has the characteristics of convenient storage and use at the application end. Further, the present invention also modifies picloram. By forming a stable inclusion complex between picloram technical and carboxymethyl-β-cyclodextrin, and then forming an active ester intermediate through the chemical activation of N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and further covalently coating with guar gum on the surface of the drug molecule to form a modified picloram technical. At the same time, it improves the storage stability and soil penetration and absorption properties, as well as the controlled release performance of the picloram soluble concentrate in practical applications.

[0035] In the present invention, an alkali is used to adjust the pH value and improve solubility, while neutralizing acidic substances to ensure the chemical stability of the solution. The synergist added is a surfactant, which helps to improve the adhesion of clopyralid to plant leaves or rhizomes and enhance the weed control effect by improving the physical properties such as wettability, dispersibility and permeability of the soluble concentrate. The main function of the dye is to provide an easily recognizable color, which can serve as a reminder or warning, facilitating the user to identify and distinguish different products during use. The antifreeze is used to lower the freezing point of the solution to ensure that the product does not freeze under low temperature conditions, thus maintaining its fluidity and usability. The antifreeze can also act as an auxiliary stabilizer to help maintain the stability of the solution at different temperatures. The preservative functions to inhibit the growth of microorganisms and prevent the solution from spoiling or deteriorating during storage and use. By maintaining the chemical and biological stability of the solution, the preservative helps to extend the shelf life of the product and ensure its safety and effectiveness during use.

[0036] As a macromolecular natural polysaccharide, guar gum can form a high-viscosity solution in water. In the present invention, it is covalently coated on the surface of carboxymethyl-β-cyclodextrin molecules loaded with clopyralid technical through an ester bond. The technical of clopyralid is effectively encapsulated by using the cavity structure of carboxymethyl-β-cyclodextrin to obtain a modified clopyralid technical, protecting the release of the technical, increasing the storage stability, and achieving precise controlled release under pH stimulation, which provides important assistance for the targeting of clopyralid soluble concentrate in practical applications. There are a large number of hydroxyl groups in the guar gum molecular chain, and these hydroxyl groups can form hydrogen bonds with water molecules to increase the viscosity of water. In the practical application of clopyralid soluble concentrate, when it is irrigated on the soil surface, it can improve the wetting and moisture retention of the soil surface. Water molecules are more likely to evenly cover the surface of soil particles, reducing the surface tension of water, making the dilution of clopyralid soluble concentrate easier to penetrate into the deep layer of the soil rather than forming runoff on the surface. The downward penetration helps to promote the root absorption of target weeds and improve the utilization efficiency of clopyralid soluble concentrate in weed control applications.

[0037] Carboxymethyl β-cyclodextrin is a cyclodextrin derivative with a unique structure. It retains the cavity structure of cyclodextrin, and at the same time, its water solubility is improved through carboxymethylation. This not only enhances its ability to interact with drug molecules but also improves its stability and biocompatibility in the body. The cyclic structure and hydrophilic modification of carboxymethyl-β-cyclodextrin enhance the solubility of picloram technical in water, enabling it to more effectively load and disperse picloram technical molecules in the diluent, which helps the uniform distribution and deep penetration of picloram technical molecules in the soil. At the same time, as a carrier in the present invention, by loading picloram technical into the cavity structure, its cyclic structure can form a stable inclusion complex with the drug, reducing the direct contact between drug molecules and the external environment, thereby reducing the risk of flocculation or precipitation caused by temperature changes. The high viscosity property of guar gum helps to slow down the migration and diffusion of drug molecules, reducing the aggregation or phase separation phenomenon caused by thermal stress, thus maintaining the stability and uniformity of the drug, achieving the storage stability of picloram soluble concentrate under low-temperature, normal-temperature or high-temperature environments, reducing the losses and risks during storage or transportation, lowering costs, and enhancing market competitiveness.

[0038] The combined action of N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide is to chemically activate the carboxyl group and promote the coupling of carboxymethyl-β-cyclodextrin and guar gum to form an active ester bond. The 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide activating reagent realizes covalent binding with other molecules by generating an ester intermediate. N-hydroxysuccinimide rapidly hydrolyzes in solution to generate an active ester intermediate. Using their combined action, guar gum is coated on the surface of carboxymethyl-β-cyclodextrin molecules loaded with picloram technical, and the technical drug is encapsulated in the cavity of carboxymethyl-β-cyclodextrin. Under acidic conditions, the ester bond between the carboxyl group of carboxymethyl-β-cyclodextrin and the hydroxyl group of guar gum is unstable, which causes guar gum to dissociate from the surface of carboxymethyl-β-cyclodextrin, opening the protection of picloram technical and enabling picloram technical to diffuse and release from the hydrophobic cavity of carboxymethyl-β-cyclodextrin, indicating that the modified picloram technical has an acid-responsive release behavior, with reduced release in alkaline and neutral environments, achieving the controlled release of picloram soluble concentrate.

[0039] Advantages of the present invention:

[0040] Compared with the prior art, the picloram soluble concentrate of the present invention makes the picloram technical which is hardly soluble in water into a soluble concentrate. When in use, after dilution with water, it exists in molecular / ionic form in the solution, making the drug components have strong penetrability and permeability, and improving the drug efficacy utilization rate. Moreover, the problem of insufficient storage stability of picloram is solved. It has good wetting and dispersing effects and penetration and absorption properties, and has the characteristics of convenient storage and use at the application end. Further, the present invention also modifies picloram, while improving the storage stability and soil penetration and absorption properties, as well as the controlled release performance of the picloram soluble concentrate in actual application. Detailed implementation manners

[0041] The technical solutions of the present invention will be described clearly and completely below. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0042] The parameters and sources of the specific chemical substances used in the embodiments are as follows:

[0043] Picloram technical: pesticide grade, with a content of 97%, CAS No. 150114-71-9, manufactured by Wuhan Shuer Biotechnology Co., Ltd., model shuer.

[0044] Castor oil polyoxyethylene ether: CAS No. 61791-12-6.

[0045] Dodecyl glucoside: CAS No. 110615-47-9.

[0046] Sodium oleoyl methyl taurate: CAS No. 137-20-2.

[0047] Carboxymethyl-β-cyclodextrin: CAS No. 218269-34-2.

[0048] N-Hydroxysuccinimide: CAS No. 6066-82-6.

[0049] 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide: CAS No. 1892-57-5.

[0050] Guar gum: CAS No. 9000-30-0.

[0051] Blue dye: manufactured by Jinan Longsheng Dye Chemical Co., Ltd., model LS-blue pesticide dye.

[0052] Example 1

[0053] A preparation method of picloram soluble concentrate comprises the following steps:

[0054] (1) Add 20 g of modified picloram technical to 55 g of water and stir for 0.5 hour;

[0055] (2) Add 1 g of sodium hydroxide and 2 g of isopropylamine, and continue stirring for 1.5 hours until completely dissolved;

[0056] (3) Add 5 g of castor oil polyoxyethylene ether, 4 g of dodecyl glucoside, and 4 g of sodium oleoyl methyl taurate, and continue stirring for 1 hour;

[0057] (4) Add 2 g of blue dye, 2 g of sodium chloride, 3 g of sodium dihydrogen phosphate, and 2 g of benzoic acid, and continue stirring for 0.5 hour;

[0058] (5) Heat to 40 °C and stir for 1.5 hours. After the appearance is clear and transparent, detect and fill to obtain the picloram soluble concentrate.

[0059] The preparation method of the modified picloram technical in the step (1) is as follows:

[0060] M1 Add 25 g of picloram technical and 4 g of carboxymethyl-β-cyclodextrin to 250 g of water, adjust the pH to 7 with sodium hydroxide, stir for 2 hours, centrifuge, wash the filter cake with absolute ethanol twice, and dry at 90 °C to obtain carboxymethyl-β-cyclodextrin loaded with picloram technical;

[0061] M2 Add 25 g of carboxymethyl-β-cyclodextrin loaded with picloram technical to 400 g of 10 wt% citric acid aqueous solution, add 5 g of N-hydroxysuccinimide and 10 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, continue stirring for 4 hours, dropwise add 500 g of 4 wt% guar gum aqueous solution and continue stirring for 4 hours, centrifuge, wash the filter cake with water twice, and dry to obtain the modified picloram technical.

[0062] Example 2

[0063] A preparation method of picloram soluble concentrate comprises the following steps:

[0064] (1) Add 20 g of modified picloram technical to 55 g of water and stir for 0.5 hour;

[0065] (2) Add 1 g of sodium hydroxide and 2 g of isopropylamine, and continue stirring for 1.5 hours until completely dissolved;

[0066] (3) Add 5 g of castor oil polyoxyethylene ether, 4 g of dodecyl glucoside, and 4 g of sodium oleoyl methyl taurate, and continue stirring for 1 hour;

[0067] (4) Add 2 g of blue dye, 2 g of sodium chloride, 3 g of sodium dihydrogen phosphate, and 2 g of benzoic acid, and continue stirring for 0.5 hour;

[0068] (5) Heat to 40 °C and stir for 1.5 hours. After the appearance is clear and transparent, perform detection and filling to obtain the said picloram soluble concentrate.

[0069] The preparation method of the modified picloram technical material in the said step (1) is as follows:

[0070] Add 25 g of picloram technical material and 4 g of carboxymethyl-β-cyclodextrin to 250 g of water, add sodium hydroxide to adjust the pH to 7, stir for 2 hours, centrifuge, wash the filter cake with absolute ethanol twice, and dry at 90 °C to obtain the modified picloram technical material.

[0071] Example 3

[0072] A preparation method of a picloram soluble concentrate comprises the following steps:

[0073] (1) Add 20 g of modified picloram technical material to 55 g of water, and stir for 0.5 hour;

[0074] (2) Add 1 g of sodium hydroxide and 2 g of isopropylamine, and continue stirring for 1.5 hours until completely dissolved;

[0075] (3) Add 5 g of castor oil polyoxyethylene ether, 4 g of dodecyl glucoside, and 4 g of sodium oleoyl methyl taurate, and continue stirring for 1 hour;

[0076] (4) Add 2 g of blue dye, 2 g of sodium chloride, 3 g of sodium dihydrogen phosphate, and 2 g of benzoic acid, and continue stirring for 0.5 hour;

[0077] (5) Heat to 40 °C and stir for 1.5 hours. After the appearance is clear and transparent, perform detection and filling to obtain the said picloram soluble concentrate.

[0078] The preparation method of the modified picloram technical material in the said step (1) is as follows:

[0079] Add 25 g of picloram technical material to 400 g of 10 wt% citric acid aqueous solution, stir for 4 hours, dropwise add 500 g of 4 wt% guar gum aqueous solution and continue stirring for 4 hours, centrifuge, wash the filter cake with water twice, and dry to obtain the modified picloram technical material.

[0080] Example 4

[0081] A preparation method of a picloram soluble concentrate comprises the following steps:

[0082] (1) Add 20 g of picloram technical material to 55 g of water, and stir for 0.5 hour;

[0083] (2) Add 1 g of sodium hydroxide and 2 g of isopropylamine, and continue stirring for 1.5 hours until completely dissolved;

[0084] (3) Add 5 g of castor oil polyoxyethylene ether, 4 g of dodecyl glucoside, and 4 g of sodium N-methyl oleoyl taurate, and continue stirring for 1 hour;

[0085] (4) Add 2 g of blue dye, 2 g of sodium chloride, 3 g of sodium dihydrogen phosphate, and 2 g of benzoic acid, and continue stirring for 0.5 hour;

[0086] (5) Heat to 40 °C and stir for 1.5 hours. After the appearance is clear and transparent, test and fill to obtain the said picloram soluble concentrate.

[0087] Test Example 1

[0088] Add the picloram soluble concentrates obtained by the preparation methods of Examples 1-4 to water at a ratio of 1:10, and stir for 20 minutes to obtain the diluted solutions of the picloram soluble concentrates of Examples 1-4. Divide 900 g of the diluted solutions of the picloram soluble concentrates to be tested in each example into 3 1000 mL conical flasks, with 300 g of the test sample in each flask. Add acid regulator and base regulator respectively to adjust the pH of the test sample to 8.5, 7.0, and 6.5. The acid-base regulators are 10 wt% hydrochloric acid aqueous solution and 15 wt% sodium hydroxide aqueous solution; test the cumulative release amounts in alkaline, neutral, and acidic environments after 2 hours, and the summary is shown in Table 1.

[0089] Table 1 Controlled Release Test Results in Different pH Environments

[0090] Example 1 Example 2 Example 3 Example 4 pH = 8.5 0.005 g / mL 0.013 g / mL 0.010 g / mL 0.009 g / mL pH = 7.0 0.005 g / mL 0.015 g / mL 0.013 g / mL 0.011 g / mL pH = 6.5 0.016 g / mL 0.014 g / mL 0.012 g / mL 0.010 g / mL

[0091] In Test Example 1, the diluted solutions of the picloram soluble concentrates of Examples 1-4 were placed in alkaline, neutral, and acidic environments respectively for dissolution and release amount tests. As can be seen from the above table, the cumulative release amount of picloram in Example 1 in the acidic environment with pH = 6.5 is higher than that in alkaline and neutral environments. The reason is that under acidic conditions, the ester bond between the carboxyl group of carboxymethyl-β-cyclodextrin and the hydroxyl group of guar gum is unstable, which will cause the dissociation of guar gum from the surface of carboxymethyl-β-cyclodextrin, opening the protection of the picloram technical material, and enabling the picloram technical material to diffuse and release from the hydrophobic cavity of carboxymethyl-β-cyclodextrin, indicating that the modified picloram technical material has an acidic-responsive release behavior and reduces release in alkaline and neutral environments. While the diluted solutions of the picloram soluble concentrates of Examples 2-4 maintain almost equal release amounts in different pH environments and do not have an acidic-responsive release behavior.

[0092] Test Example 2

[0093] The soluble liquid agent of clopyralid obtained by the preparation methods of Examples 1-4 was added to water at a ratio of 1:10, and after stirring for 20 minutes, the diluted solution of the soluble liquid agent of clopyralid in Examples 1-4 was obtained. 1000 g of the test soil was filled into a PVC pipe with an inner diameter of 10 cm and a height of 30 cm, and gently tamped to make the soil height 20 cm and the density 1.5 g / cm3, with no gaps between the soils; the test soil was selected from brown soil, with a pH of 5.0-6.0 and a water content of 20%. Weigh 10 g of the diluted solution of the soluble liquid agent of clopyralid in Examples 1-4, and evenly spray it on the surface of the test soil in the PVC pipe. After 6 hours, the soil column was intercepted in segments with a height of 5 cm per segment, and the clopyralid content in each segment of the soil column was measured. If detected, it was determined that the diluted solution of the soluble liquid agent of clopyralid in this example had penetrated to this depth, and the final penetration depth and the clopyralid content at this depth were recorded. 3 groups of controls were set for each example, and the test data were averaged and summarized as shown in Table 2.

[0094] Table 2 Results of Simulated Soil Penetration Test

[0095] Example 1 Example 2 Example 3 Example 4 Penetration depth 15 - 20 cm 15 - 20 cm 15 - 20 cm 10 - 15 cm Content 87.5％ 70.4％ 78.0％ 65.2％

[0096] As can be seen from the above table, the penetration depths of the diluted solutions of the soluble liquid agent of clopyralid in Examples 1-3 were all 15-20 cm in the simulated soil penetration test, and the penetration depth of Example 4 was 10-15 cm. The difference was that in Example 1, the clopyralid technical was modified by carboxymethyl-β-cyclodextrin and guar gum, in Example 2, the clopyralid technical was modified by carboxymethyl-β-cyclodextrin, and in Example 3, the clopyralid technical was modified by guar gum. The wettability of the modified clopyralid technical on the soil was improved to a certain extent, which helped the downward permeability. Example 4 was the directly added clopyralid technical, and its downward penetration effect was lower than that of the modified clopyralid technical. Among Examples 1-3, under the same penetration time and the same penetration depth, in Examples 2-3, only a single component of carboxymethyl-β-cyclodextrin and guar gum was added. The clopyralid content in the soil column of this section at 15-20 cm in Example 1 was significantly higher than that in Examples 2-3. The reason was the combined action of carboxymethyl-β-cyclodextrin and guar gum in Example 1. During the soil penetration process, guar gum dissociated from the surface of carboxymethyl-β-cyclodextrin. When sprayed on the surface of the test soil in the PVC pipe, it could improve the wetting and moisture retention of the soil surface, reduce the surface tension of water, and make the diluted solution of the soluble liquid agent of clopyralid penetrate deeper into the soil faster. At the same time, the cyclic structure and hydrophilic modification of carboxymethyl-β-cyclodextrin enhanced the solubility of the clopyralid technical in water, enabling it to more effectively load and disperse the clopyralid technical molecules in the diluted solution, which helped the uniform distribution and deep penetration of the clopyralid technical molecules in the soil.

[0097] Test Example 3

[0098] Take the aminopyralid soluble concentrate obtained by the preparation methods of Examples 1-4 as the test samples, and store them at 10°C, 25°C, 35°C, and 45°C for 5 days respectively. Observe whether there is precipitation or flocculation. If the number of precipitates and flocs is 0, it is determined to be clear, that is, the storage stability is good at this temperature; if the number of precipitates and flocs is 0-5, it is determined to be slightly turbid at this temperature, that is, the storage stability is average; if the number of precipitates and flocs is ≥6, it is determined to be turbid, that is, the storage stability is poor at this temperature. Set 3 controls for each temperature group, and take the average value of the test data. The summary is shown in Table 3.

[0099] Table 3 Test results of storage stability at different temperatures

[0100] Example 1 Example 2 Example 3 Example 4 10℃ Clear Slightly turbid Slightly turbid Turbid 25℃ Clear Clear Clear Clear 35℃ Clear Clear Slightly turbid Slightly turbid 45℃ Clear Slightly turbid Slightly turbid Turbid

[0101] In Test Example 3, the aminopyralid soluble concentrate obtained by the preparation methods of 1-4 was subjected to storage stability tests at 10°C, 25°C, 35°C, and 45°C respectively. In contrast, in the aminopyralid soluble concentrate of Example 3, aminopyralid was not added with a carrier for loading and modification. In Examples 2 and 3, carboxymethyl-β-cyclodextrin and guar gum were used to modify the aminopyralid technical, but the improvement of stability by one-step simple modification was not significant. However, Example 1 showed a good clear state at all test temperatures, indicating excellent storage stability. The cavity structure of carboxymethyl-β-cyclodextrin effectively encapsulated the aminopyralid molecules, reducing their direct contact with the external environment and lowering the risk of flocculation or precipitation caused by temperature changes. The wrapping of guar gum helped to slow down the migration and diffusion of drug molecules, reducing the aggregation or phase separation phenomenon caused by thermal stress, thereby maintaining the stability and uniformity of the drug and achieving the storage stability of the aminopyralid soluble concentrate in low-temperature, normal-temperature or high-temperature environments.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a clopyralid soluble concentrate, characterized in that, It includes the following steps: (1) Add the modified aminopyralid technical material to water and stir for 0.5 - 1 hour; (2) Add an alkali and continue to stir for 1 - 2 hours until completely dissolved; (3) Add a synergist and continue to stir for 0.5 - 1 hour; (4) Add a dye, an antifreeze, and a preservative and continue to stir for 0.5 - 1 hour; (5) Heat to 35 - 45 °C and stir for 1 - 2 hours. After the appearance is clear and transparent, conduct detection and filling to obtain the aminopyralid soluble concentrate; The preparation method of the modified aminopyralid technical material in the step (1) is as follows: M1 Add the aminopyralid technical material and carboxymethyl-β-cyclodextrin to water, add sodium hydroxide to adjust the pH to 7 - 8, stir for 1 - 2 hours, centrifuge, wash the filter cake with absolute ethanol 2 - 4 times, and dry at 80 - 100 °C to obtain the carboxymethyl-β-cyclodextrin loaded with aminopyralid technical material; M2 Add the carboxymethyl-β-cyclodextrin loaded with aminopyralid technical material to an aqueous citric acid solution, add N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, continue to stir for 2 - 6 hours, dropwise add an aqueous guar gum solution and continue to stir for 2 - 4 hours, centrifuge, wash the filter cake with water 2 - 4 times, and dry to obtain the modified aminopyralid technical material.

2. The preparation method of the picloram soluble concentrate according to claim 1, characterized in that, The dosage of each component in the preparation method is in parts by weight: (1) Add 5 - 40 parts of the modified aminopyralid technical material to 10 - 70 parts of water and stir for 0.5 - 1 hour; (2) Add 2 - 4 parts of an alkali and continue to stir for 1 - 2 hours until completely dissolved; (3) Add 5 - 20 parts of a synergist and continue to stir for 0.5 - 1 hour; (4) Add 1 - 2 parts of a dye, 2 - 10 parts of an antifreeze, and 1 - 3 parts of a preservative and continue to stir for 0.5 - 1 hour; (5) Heat to 35 - 45 °C and stir for 1 - 2 hours. After the appearance is clear and transparent, conduct detection and filling to obtain the aminopyralid soluble concentrate; The preparation method of the modified aminopyralid technical material in the step (1) is as follows, in parts by weight: M1 Add 20 - 40 parts of the aminopyralid technical material and 2 - 6 parts of carboxymethyl-β-cyclodextrin to 200 - 400 parts of water, add sodium hydroxide to adjust the pH to 7 - 8, stir for 1 - 2 hours, centrifuge, wash the filter cake with absolute ethanol 2 - 4 times, and dry at 80 - 100 °C to obtain the carboxymethyl-β-cyclodextrin loaded with aminopyralid technical material; M2 Add 20 - 40 parts of the carboxymethyl-β-cyclodextrin loaded with aminopyralid technical material to 300 - 500 parts of an aqueous citric acid solution, add 3 - 6 parts of N-hydroxysuccinimide and 5 - 15 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, continue to stir for 2 - 6 hours, dropwise add 400 - 600 parts of an aqueous guar gum solution and continue to stir for 2 - 4 hours, centrifuge, wash the filter cake with water 2 - 4 times, and dry to obtain the modified aminopyralid technical material.

3. The preparation method of the picloram soluble concentrate according to claim 1 or 2, characterized in that, The alkali in the step (2) is any one or a mixture of sodium hydroxide, sodium carbonate, ammonia water, dimethylamine, and isopropylamine.

4. The preparation method of the picloram soluble concentrate according to claim 1 or 2, characterized in that, In the step (3), the synergist is any one or a mixture of polyoxyethylene lauryl ether, polyoxyethylene castor oil ether, polyoxyethylene tallow amine, polyoxyethylene oleate, polyoxyethylene dodecyl alcohol ether, dodecyl glucoside, octadecyl dimethyl amine oxide, sodium oleoyl methyl taurate.

5. The method for preparing the picloram soluble concentrate according to claim 1 or 2, characterized in that, In the step (4), the dye is any one of red, yellow, blue, purple, green, and black.

6. The preparation method of the picloram soluble concentrate according to claim 1 or 2, characterized in that In the step (4), the antifreeze is any one or a mixture of ethanol, ethylene glycol, isopropanol, sodium chloride, sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium carbonate, and sodium hydroxide.

7. The preparation method of the picloram soluble concentrate according to claim 1 or 2, characterized in that, In the step (4), the preservative is any one or a mixture of benzoic acid, sodium benzoate, sorbic acid, potassium sorbate, and propyl p-hydroxybenzoate.

8. The preparation method of the picloram soluble concentrate according to claim 1 or 2, characterized in that In the step M2, the citric acid aqueous solution is a 10-15 wt% citric acid aqueous solution.

9. The method for preparing the picloram soluble concentrate according to claim 1 or 2, characterized in that, In the step M2, the guar gum-aqueous solution is a 2-6 wt% guar gum-aqueous solution.