Pollution-free insecticide and preparation method thereof

Abstract

The invention discloses a preparation method of a pollution-free insecticide, which comprises the following steps: dissolving permethrin in first vegetable oil, the mass fraction of permethrin in the first vegetable oil being 0.5-2.0%, and the first vegetable oil being castor oil; the azadirachtin is dissolved in second vegetable oil, the mass fraction of the azadirachtin in the second vegetable oil is 0.2%-1.5%, and the second vegetable oil is soybean oil; s2, mixing the permethrin castor oil solution obtained in S1 with the azadirachtin soybean oil solution obtained in S2, adding an emulsifier polyoxyethylated castor oil, and stirring to form an oil phase mixture; dissolving phenyl salicylate in deionized water to form a water phase; dropwise adding the water phase into the oil phase mixture, and stirring to obtain the pollution-free insecticide. The insecticidal composition has a good insecticidal effect, can reduce adverse effects on the environment and non-target organisms, and meets the requirements of pollution-free prevention and control of crops.

Description

Technical Field

[0001] The present invention relates to the technical field related to pesticides, and more particularly to a pollution-free pesticide and a preparation method thereof. Background Art

[0002] In agricultural production, pest control is crucial for ensuring crop yield and quality. Pollution-free pesticides, due to their combined insecticide efficacy and environmental friendliness, have become a key focus of current pesticide research and development. However, existing methods for preparing pollution-free pesticides still face several challenges in terms of active ingredient stability, formulation physical properties, and environmental compatibility, resulting in some pesticides failing to achieve their intended effects.

[0003] First, the solubility and stability of active ingredients are particularly prominent. Pyrethroid compounds (such as permethrin) and botanical active ingredients (such as azadirachtin) often present challenges in dissolving and stabilizing in solvents due to their inherent physical and chemical properties. Permethrin is prone to crystallization in conventional solvents due to temperature fluctuations, resulting in uneven dispersion of the active ingredient and affecting its efficacy. Azadirachtin, on the other hand, is sensitive to light and oxygen and prone to degradation during storage and use, leading to a decrease in active ingredient content and a significant decrease in insecticidal efficacy over time. The root cause of these problems lies in the structural limitations of the active ingredients themselves and the insufficient stabilization effect of traditional solvent systems. Solvent substitution alone cannot achieve a balanced balance of solubility and stability. Second, achieving synergistic enhancement and uniform dispersion in compounded systems presents technical bottlenecks. When compounding active ingredients with different mechanisms of action (such as permethrin and azadirachtin), compatibility and emulsification dispersion of the two in the solvent must be addressed. Traditional emulsification processes often suffer from poor interfacial stability between the oil and aqueous phases due to a single emulsifier and crude addition methods, leading to stratification and demulsification, which compromise the uniformity and application efficacy of the formulation. Furthermore, synergists (such as phenyl salicylate) suffer from low solubility and dispersion efficiency in the aqueous phase, easily forming particle agglomerates that prevent them from fully inhibiting pest metabolic enzymes, resulting in a failure to effectively release the synergistic effects of the formulation. Furthermore, the environmental friendliness and safety of formulations still need to be improved. Although some technologies have attempted to replace traditional organic solvents with vegetable oils, failure to optimize solvent handling during the dissolution of active ingredients can lead to adverse reactions between the natural components of the vegetable oil and the active substance, or oxidation and deterioration of the solvent itself can compromise formulation stability. Furthermore, existing technologies lack effective control of the active ingredient's crystal form, photoprotection, and antioxidant measures, making the formulation susceptible to physical or chemical changes during storage due to changes in external conditions (such as temperature and light). This not only shortens shelf life but also increases potential risks to non-target organisms (such as bees and soil microorganisms) during application.

[0004] Therefore, it is necessary to design a technical solution that can overcome the above-mentioned defects. Summary of the Invention

[0005] One object of the present invention is to provide a pollution-free insecticide and a preparation method thereof, which not only has a good insecticidal effect but also can reduce adverse effects on the environment and non-target organisms, meeting the requirements of pollution-free control of crops.

[0006] To achieve these objects and other advantages of the present invention, according to one aspect of the present invention, there is provided a method for preparing a pollution-free insecticide, comprising: S1: dissolving permethrin in a first vegetable oil, wherein the mass fraction of permethrin in the first vegetable oil is 0.5% to 2.0%, and the first vegetable oil is castor oil; S2: dissolving azadirachtin in a second vegetable oil, wherein the mass fraction of azadirachtin in the second vegetable oil is 0.2% to 1.5%, and the second vegetable oil is soybean oil; S3: mixing the permethrin castor oil solution obtained in S1 with the azadirachtin soybean oil solution obtained in S2, adding emulsifier polyoxyethylene castor oil, and stirring to form an oil phase mixture, wherein the mass fraction of the polyoxyethylene castor oil in the oil phase mixture is 3.0% to 8.0%; S4: dissolving phenyl salicylate in deionized water to form an aqueous phase, wherein the mass fraction of phenyl salicylate in the deionized water is 0.05% to 0.2%; S5: The water phase of S4 is added dropwise to the oil phase mixture of S3 and stirred to obtain a pollution-free pesticide.

[0007] Furthermore, in S1, it also includes: preheating castor oil to 50-60°C, and adding 5-10% of the mass of permethrin as an amphiphilic cosolvent propylene glycol dicaprylate; dissolving the permethrin with high-speed shear stirring at 2000-3000 rpm under nitrogen protection; after dissolution, cooling to 25°C at a gradient rate of 0.5-1°C / min, and keeping the temperature for aging for 30 minutes.

[0008] Furthermore, the method further includes: during the gradient cooling process, injecting nanocrystalline seeds accounting for 0.01-0.05% of the mass of the oil phase into the system, where the nanocrystalline seeds are chlorpyrifos-propylene glycol dicaprylate / caprate eutectic particles modified with stearic acid, and the particle size is 50-100 nm; after heat preservation and aging, heating to 40°C at 0.8-1.2°C / min, maintaining for 10 minutes, and then cooling to 25°C for a second time at 0.3-0.5°C / min.

[0009] Furthermore, in S2, it also includes: pre-mixing and grinding azadirachtin and β-cyclodextrin in a molar ratio of 1:2-1:3 to form an inclusion compound; dispersing the inclusion compound in soybean oil preheated to 40-45°C, and adding 0.3% rosemary extract; and gently stirring at 400-600 rpm under a red light environment with a wavelength >520nm until completely dispersed.

[0010] Furthermore, in S2, it also includes: pre-mixing and grinding are carried out in a closed argon environment, and the inner wall of the grinding jar is covered with a polytetrafluoroethylene coating; a variable amplitude vibration mode is adopted during grinding: the amplitude is 0.5-1.0 mm and the frequency is 35 Hz in the first 5 minutes, and the amplitude is 2.0-3.0 mm and the frequency is 15 Hz in the next 5 minutes; when the inclusion compound is dispersed in soybean oil, the viscosity of the oil phase is controlled to be 120-150 cP, and the temperature is immediately lowered to 30°C at a rate of 0.5-1.0°C / s after dispersion.

[0011] Furthermore, in S3, it also includes: dividing the polyoxyethylene castor oil into three equal parts; adding the polyoxyethylene castor oil into the first part to the permethrin castor oil solution obtained in S1, and stirring at 50-55°C and 800-1000 rpm for 5 minutes to form a pre-emulsified oil phase A; adding the polyoxyethylene castor oil into the second part to the azadirachtin soybean oil solution obtained in S2, and stirring at 45-50°C and 600-800 rpm for 5 minutes to form a pre-emulsified oil phase B; mixing the pre-emulsified oil phases A and B, adding the third part of the polyoxyethylene castor oil, and stirring at a high shear rate of 2000-3000 rpm for 10 minutes to form an oil phase mixture; maintaining the shear state, cooling the system to 30°C at a rate of 2-3°C / min.

[0012] Furthermore, in S4, it also includes: pre-dissolving 0.1-0.2% hydroxypropyl-β-cyclodextrin in deionized water; melt-blending phenyl salicylate and triethyl citrate in a ratio of 10:1, and then adding the deionized water in which the hydroxypropyl-β-cyclodextrin is dissolved; and homogenizing at a pressure of 0.2-0.3 MPa for 10 minutes.

[0013] Furthermore, the homogenization treatment is carried out in two stages: the first stage: circulate treatment at a pressure of 0.8-1.0 MPa for 3 minutes, and control the temperature at 35-38°C; the second stage: switch to a pressure of 0.1-0.2 MPa, increase the temperature to 50-55°C at a rate of 10°C / min, and maintain for 5 minutes.

[0014] Furthermore, in S5, it also includes: the aqueous phase is added dropwise using a pulse injection mode: high-speed dropwise addition lasts for 10 seconds, pauses for 5 seconds, and the cycle is completed; the system is maintained in a microfluidizer during the entire dropwise addition process, with an inlet pressure of 50-80 bar and an outlet pressure controlled by a back pressure valve at 20-30 bar; immediately after the dropwise addition, 0.5-1.0% (v / v) food-grade nitrogen is introduced to replace the headspace oxygen, and the mixture is shaken and degassed under a vacuum of -0.09 MPa.

[0015] According to another aspect of the present invention, there is also provided a pollution-free pesticide, which is prepared by the method according to any one of claims 1 to 9.

[0016] The present invention has at least the following beneficial effects: The present invention forms a stable pollution-free insecticide by dissolving permethrin in castor oil and azadirachtin in soybean oil, and then mixing and emulsifying with an aqueous phase containing phenyl salicylate. The use of vegetable oils such as castor oil and soybean oil to replace traditional organic solvents reduces the toxicity of the formulation from the raw material level, reduces the adverse effects on the environment and non-target organisms, and meets the environmental protection requirements of pollution-free prevention and control. Permethrin and azadirachtin are stably dissolved in the corresponding vegetable oils respectively, avoiding the problem of active ingredient separation caused by the poor compatibility of a single solvent. After the two are compounded, a system with both rapid contact killing and long-term pest control is formed. The addition of phenyl salicylate can assist in inhibiting the activity of pest metabolic enzymes and enhance the persistence of drug efficacy. The use of an emulsifier promotes the uniform mixing of the oil phase and the aqueous phase to form a stable emulsion system, solves the problems of stratification and demulsification caused by interfacial tension differences in the compounding process, ensures that the active ingredients can be evenly dispersed when applied, and improves the adhesion and penetration effect of the liquid on the crop surface. The overall process steps are clear and the raw material ratio is scientific. It does not require complex equipment or special reaction conditions, and is easy to operate in industrial production. It provides a practical technical solution for the preparation of pollution-free insecticides with both high-efficiency insecticidal performance and environmentally friendly characteristics.

[0017] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flowchart of an embodiment of the present application. DETAILED DESCRIPTION

[0019] The present invention is described in further detail below so that those skilled in the art can implement the invention with reference to the description.

[0020] It should be understood that terms such as "having," "comprising," and "including" used in the embodiments of this application do not exclude the presence or addition of one or more other elements or combinations thereof. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are intended only to explain the relative positional relationships and movement of components in a specific posture. If the specific posture changes, the directional indications will also change accordingly. When an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element through an intervening element. References to "first," "second," etc. in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features designated as "first" or "second" may explicitly or implicitly include at least one of such features.

[0021] It should be noted that the technical solutions between the various embodiments of the present application can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0022] like Figure 1 As shown, the embodiment of the present application provides a method for preparing a pollution-free insecticide, comprising: S1: dissolving permethrin in a first vegetable oil, wherein the mass fraction of permethrin in the first vegetable oil is 0.5% to 2.0%, and the first vegetable oil is castor oil; S2: dissolving azadirachtin in a second vegetable oil, wherein the mass fraction of azadirachtin in the second vegetable oil is 0.2% to 1.5%, and the second vegetable oil is soybean oil; S3: mixing the permethrin castor oil solution obtained in S1 with the azadirachtin soybean oil solution obtained in S2, adding emulsifier polyoxyethylene castor oil, and stirring to form an oil phase mixture, wherein the mass fraction of polyoxyethylene castor oil in the oil phase mixture is 3.0% to 8.0%; S4: dissolving phenyl salicylate in deionized water to form an aqueous phase, wherein the mass fraction of phenyl salicylate in deionized water is 0.05% to 0.2%; S5: adding the aqueous phase of S4 dropwise to the oil phase mixture of S3, and stirring to obtain the pollution-free insecticide. For example, permethrin in S1, as a pyrethroid active ingredient, can be dissolved in castor oil by stirring. Castor oil, as a natural plant oil, can be a commercially available food-grade or pharmaceutical-grade product. The mass fraction of permethrin in castor oil can be specifically selected to be 0.5%, 1.0%, or 2.0%. The dissolution process can be carried out in a thermostatic container with a stirring function, stirring at 200-500 rpm at room temperature until completely dissolved. Azadirachtin in S2, as a plant-derived active ingredient, is dissolved in soybean oil preheated to 30-40°C. The soybean oil is also a commercially available refined grade product. The mass fraction of azadirachtin can be selected to be 0.2%, 0.8%, or 1.5%. Low-speed stirring is used during dissolution to avoid destruction of the active ingredient. After mixing the two solutions in S3, polyoxyethylene castor oil is added as an emulsifier. Its mass fraction can be selected as 3.0%, 5.5% or 8.0%. The stirring can be carried out using a common electric stirrer in the laboratory at a speed of 800-1500 rpm for 10-20 minutes to evenly disperse the emulsifier in the oil phase. Phenyl salicylate in S4 is used as a synergist. When dissolved in deionized water, the water can be heated to 40-50°C. The mass fraction of phenyl salicylate can be selected as 0.05%, 0.1% or 0.2%. It is stirred with a magnetic stirrer until it is completely dissolved to form an aqueous phase. In S5, the aqueous phase is slowly added to the oil phase mixture using a separatory funnel. Stirring is continued during the addition process. The stirring speed is controlled at 300-600 rpm until a uniform emulsion is formed. In the present embodiment, permethrin castor oil solution and azadirachtin soybean oil solution are first prepared respectively, then mixed and an emulsifier is added to form the oil phase, and after preparing the phenyl salicylate aqueous phase, the two are mixed and stirred. This method avoids the toxicity problem of traditional organic solvents by selecting castor oil and soybean oil as solvents. Polyoxyethylene castor oil effectively promotes the uniform mixing of oil phase and water as an emulsifier, forming a stable emulsion system. After phenyl salicylate is dissolved in the aqueous phase, it mixes with the oil phase to assist in enhancing the insecticidal effect. With respect to the traditional method of not adopting vegetable oil and specific emulsification process, this embodiment raw material selection is environmentally friendly, not only has a good insecticidal effect, but also can reduce the adverse effects on the environment and non-target organisms, meets the requirement of pollution-free prevention and control of crops.

[0023] In another embodiment, in S1, the process further includes: preheating castor oil to 50-60°C, and adding 5-10% of the mass of permethrin as an amphiphilic cosolvent propylene glycol dicaprylate; dissolving the permethrin with high-speed shear stirring at 2000-3000 rpm under nitrogen protection; and cooling to 25°C at a gradient rate of 0.5-1°C / min after dissolution, and aging the mixture for 30 minutes. For example, castor oil, as the first vegetable oil, can be preheated to 50°C, 55°C, or 60°C using a constant temperature heating device before dissolving permethrin, allowing the castor oil to reach a suitable temperature for dissolution. The amphiphilic cosolvent, propylene glycol dicaprylate, is added in an amount of 5%, 7.5%, or 10% of the mass of permethrin to enhance the solubility of permethrin in castor oil. The dissolution process is carried out in a reaction vessel with a nitrogen inlet port. A protective atmosphere is formed by continuously introducing nitrogen to prevent permethrin from reacting with oxygen in the air during dissolution. A high-speed shear mixer capable of providing a rotational speed of 2000 rpm, 2500 rpm, or 3000 rpm is used for stirring, accelerating the dissolution of permethrin through the intense shearing action. After dissolution is complete, a gradient cooling program is initiated, slowly cooling the solution to 25°C at a rate of 0.5°C / min, 0.75°C / min, or 1°C / min, and then incubating at this temperature for 30 minutes to allow the solution system to reach a stable state. In the present embodiment, steps such as preheating, addition of cosolvent, nitrogen protection, high-speed shear stirring, gradient cooling and heat preservation and aging are added. First, castor oil is preheated to a specified temperature, a certain proportion of propylene glycol dicaprylate is added, and permethrin is fully dissolved by high-speed shear stirring under nitrogen protection, and then slowly cooled and heat-insulated and aged. Such operation can improve the dissolution efficiency and dissolution stability of permethrin in castor oil. The addition of cosolvent improves the dissolution environment of permethrin, nitrogen protection avoids oxidation reaction, high-speed shear stirring accelerates the dissolution process, and gradient cooling and heat preservation and aging help to form a stable solution system, providing a more uniform and stable oil phase raw material for the subsequent mixed emulsification step. Compared with the conventional dissolution method without these treatments, the precipitation problem that may occur in storage and use of permethrin can be reduced, and the overall stability of the preparation is improved. In another embodiment, the method further comprises: injecting nanocrystalline seeds accounting for 0.01-0.05% of the mass of the oil phase into the system during the gradient cooling process, wherein the nanocrystalline seeds are chlorpyrifos-propylene glycol dicaprylate / caprate eutectic particles modified with stearic acid and having a particle size of 50-100 nm; after heat preservation and aging, heating to 40°C at a rate of 0.8-1.2°C / min, maintaining for 10 minutes, and then cooling to 25°C for a second time at a rate of 0.3-0.5°C / min. For example, during the gradient cooling process, when the system temperature drops to a certain stage, nanocrystalline seeds can be injected into the reaction vessel via a metering pump, with the dosage being 0.01%, 0.03%, or 0.05% of the mass of the oil phase. The nanocrystalline seeds are stearic acid-modified chlorfenapyr-propylene glycol dicaprylate / caprate cocrystal particles, with a particle size controlled at 50nm, 75nm, or 100nm. These nanocrystalline seeds can serve as crystal nuclei in the solution, guiding chlorfenapyr to form a specific crystal structure. After the thermal aging is completed, the temperature is increased to 40°C at a rate of 0.8°C / min, 1.0°C / min, or 1.2°C / min, and maintained at this temperature for 10 minutes to allow the crystal structure in the system to dissolve and reorganize to a certain extent. Subsequently, the temperature is lowered again to 25°C at a rate of 0.3°C / min, 0.4°C / min, or 0.5°C / min to further optimize the crystal growth environment. The preparation process for stearic acid-modified permethrin-propylene glycol dicaprylate / caprate cocrystal microparticles is as follows: Permethrin and propylene glycol dicaprylate / caprate were added to anhydrous ethanol in a mass ratio of 1:3 and sonicated at 50°C until clear, forming a 10% (w / v) mixed solution. Stearic acid, representing 10% of the cocrystal mass, was then dissolved in tetrahydrofuran and slowly added dropwise to the solution. Stirring was continued at 60°C for 30 minutes. The interaction between the hydrophobic chains of the stearic acid molecules and the cocrystal surface resulted in uniform adsorption of the stearic acid molecules via van der Waals forces, forming a surface modification layer. The solution was then cooled at a rate of 0.5°C / min to 25°C, and permethrin microcrystals (50-100 nm in size) representing 0.1% of the solution mass were added as seeds. The mixture was maintained for 1 hour to induce uniform nucleation and avoid the formation of coarse crystals. The temperature was then raised to 40°C at a rate of 0.8°C / min and maintained for 15 minutes to allow initial nucleation growth. The temperature was then lowered a second time to 25°C at a rate of 0.3°C / min. Temperature field regulation promoted uniform growth of the eutectic particles, keeping the average particle size at approximately 80 nm. Finally, the ethanol was separated by vacuum filtration, washed three times with deionized water to remove impurities, and vacuum dried at 40°C for 24 hours to obtain eutectic particles coated with stearic acid. XRD analysis confirmed the eutectic structure of permethrin and propylene glycol dicaprylate / decanoate. The surface modification layer exhibited uniform thickness and significantly improved dispersion stability in the oil phase, providing key nanocrystal seeds for the subsequent crystal form control of insecticide formulations.

[0024] In this embodiment, nanocrystalline seed injection and secondary temperature field control steps are added. Specific nanocrystalline seeds are added during gradient cooling, and then, through temperature maintenance and secondary cooling, the crystal growth process of the solution system is finely regulated. The addition of nanocrystalline seeds can provide more crystal nuclei for the crystallization of permethrin, avoiding the formation of coarse crystals, and the secondary temperature field control helps to homogenize and stabilize the crystal structure. Compared with the method of only performing gradient cooling and heat preservation and aging, this treatment method can more effectively control the crystal morphology and distribution of permethrin in the oil phase, reduce the possibility of crystal agglomeration and precipitation, and enable the formed solution system to maintain better stability during long-term storage, laying a more solid foundation for the subsequent preparation of uniform and stable insecticide formulations. In another embodiment, S2 further includes: pre-mixing and grinding azadirachtin and β-cyclodextrin in a molar ratio of 1:2-1:3 to form an inclusion complex; dispersing the inclusion complex in soybean oil preheated to 40-45° C., and adding 0.3% rosemary extract; and gently stirring at 400-600 rpm under a red light environment with a wavelength >520 nm until completely dispersed. For example, azadirachtin, as a plant-derived active ingredient, is premixed with β-cyclodextrin in a molar ratio of 1:2, 1:2.5 or 1:3, and then placed in a grinding device for grinding. The grinding device can be a planetary grinder or a vibration grinder commonly used in the laboratory. The two are fully contacted by grinding to form an inclusion compound, which can improve the stability of azadirachtin. Soybean oil, as the second vegetable oil, is first preheated to 40°C, 42.5°C or 45°C in a water bath heating device, and then the inclusion compound obtained by grinding is added to the preheated soybean oil. At the same time, rosemary extract accounting for 0.3% of the system mass is added. Rosemary extract contains antioxidant ingredients that help protect azadirachtin. The dispersion process is carried out under a red light environment with a wavelength greater than 520nm. A red LED lamp can be used as a light source to create specific lighting conditions to prevent azadirachtin from decomposing under strong light. The stirring is performed using an electric stirrer with an adjustable speed at a gentle speed of 400 rpm, 500 rpm or 600 rpm until the inclusion compound is completely dispersed in the soybean oil to form a uniform solution. In the present embodiment, the steps of pre-mixing grinding, inclusion compound preparation, soybean oil preheating, rosemary extract addition and gentle stirring under red light environment are added. First, azadirachtin and beta-cyclodextrin are ground to form an inclusion compound, the inclusion compound of cyclodextrin is utilized to improve the stability of azadirachtin, and then the inclusion compound is dispersed in preheated soybean oil, and rosemary extract is added to enhance the antioxidant effect, and gentle stirring is ensured to be uniformly dispersed under red light environment. This treatment method can effectively reduce the degradation of azadirachtin caused by factors such as light and oxygen during the preparation process relative to the conventional method of directly dissolving azadirachtin in soybean oil. The formation of the inclusion compound and the addition of rosemary extract provide dual protection for azadirachtin. The red light environment avoids the influence of harmful light, and gentle stirring ensures the dispersion effect, making the existence state of azadirachtin in soybean oil more stable, thereby improving the activity retention rate of azadirachtin in the whole insecticide preparation and the long-term storage performance of the preparation.

[0025] In another embodiment, S2 further includes: pre-mixing and grinding in a closed argon environment, and the inner wall of the grinding jar is covered with a polytetrafluoroethylene coating; a variable amplitude vibration mode is adopted during grinding: the amplitude is 0.5-1.0 mm and the frequency is 35 Hz in the first 5 minutes, and the amplitude is 2.0-3.0 mm and the frequency is 15 Hz in the next 5 minutes; when the inclusion compound is dispersed in soybean oil, the viscosity of the oil phase is controlled to be 120-150 cP, and the temperature is immediately lowered to 30°C at a rate of 0.5-1.0°C / s after dispersion. For example, the premixed grinding process is carried out in a closed grinding device with an argon inlet port. Argon can be continuously introduced through an argon cylinder to maintain an inert environment in the tank. The inner wall of the grinding tank is sprayed with a polytetrafluoroethylene coating, and a commercially available stainless steel grinding tank with treated inner wall can be used. The variable amplitude vibration mode is specifically as follows: for the first 5 minutes, the amplitude of the vibration mill is set to 0.5mm, 0.75mm or 1.0mm, and the frequency is 35Hz. The particles of azadirachtin and β-cyclodextrin are broken by high-frequency and small-amplitude vibration; for the next 5 minutes, the amplitude is adjusted to 2.0mm, 2.5mm or 3.0mm, and the frequency is 15Hz. Low-frequency and large-amplitude vibration is used to promote material mixing. Before dispersing the inclusion complex, preheat the soybean oil to 40-45°C. Monitor the oil phase viscosity with a viscometer and control it at 120 cP, 135 cP, or 150 cP. Use an electric stirrer at 400-600 rpm during dispersion. Immediately after dispersion, turn on the refrigeration device and cool it to 30°C at a rate of 0.5°C / s, 0.75°C / s, or 1.0°C / s. A reactor with a temperature control function can be used to achieve rapid cooling. In this embodiment, the premixed grinding and dispersion process is optimized. A closed argon environment prevents azadirachtin from contacting and oxidizing with oxygen, a polytetrafluoroethylene coating prevents adsorption or contamination of the material by the inner wall of the grinding jar, and a variable amplitude vibration mode first crushes and then mixes, thereby improving the inclusion efficiency. Controlling the viscosity of the oil phase and rapidly cooling the temperature can stabilize the dispersion state of the inclusion compound in the soybean oil and prevent the inclusion compound from dissociating or agglomerating. Compared with conventional grinding and dispersion processes, this treatment method can more effectively protect the activity of azadirachtin, reduce degradation losses during the preparation process, make the inclusion compound more uniform, provide a more stable azadirachtin soybean oil solution for the subsequent emulsification step, and help improve the long-term storage performance and active ingredient retention rate of the entire insecticide formulation. In another embodiment, in S3, the steps further include: dividing polyoxyethylene castor oil into three equal parts; adding the first part of polyoxyethylene castor oil to the permethrin castor oil solution obtained in S1, and stirring at 50-55° C. and 800-1000 rpm for 5 minutes to form a pre-emulsified oil phase A; adding the second part of polyoxyethylene castor oil to the azadirachtin soybean oil solution obtained in S2, and stirring at 45-50° C. and 600-800 rpm for 5 minutes to form a pre-emulsified oil phase B; mixing the pre-emulsified oil phases A and B, adding the third part of polyoxyethylene castor oil, and stirring at a high shear speed of 2000-3000 rpm for 10 minutes to form an oil phase mixture; maintaining the shear state, cooling the system to 30° C. at a rate of 2-3° C. / min. For example, polyoxyethylene castor oil is divided equally by mass into three portions, each comprising 1%-2.67% of the total mass of the oil phase mixture (corresponding to the total amount in claim 3.0%-8.0%). The first portion is added with a permethrin castor oil solution, heated to 50°C, 52.5°C, or 55°C using a thermostatic stirring device, and stirred at 800 rpm, 900 rpm, or 1000 rpm for 5 minutes to allow the emulsifier to initially coat the permethrin oil droplets. The second portion is added with azadirachtin soybean oil solution, heated to 45°C, 47.5°C, or 50°C, and stirred at 600 rpm, 700 rpm, or 800 rpm for 5 minutes to form a pre-emulsified oil phase B. After mixing phases A and B, the third portion of emulsifier is added, and the mixture is sheared for 10 minutes using a high-speed shearing machine at 2000 rpm, 2500 rpm, or 3000 rpm to ensure uniform distribution of the emulsifier. During the shearing process, the system temperature is maintained by a cold water bath or a temperature control jacket, and the temperature is lowered to 30°C at a rate of 2°C / min, 2.5°C / min or 3°C / min. A shear kettle with a temperature control function can be used to achieve temperature control. In this embodiment, the emulsifier is added in stages and the temperature and stirring rate at different stages are controlled. The emulsifier is added to the two oil phases and the mixed phase in three portions in sequence. Through pre-emulsification and high-speed shearing at different temperatures, the emulsifier forms a multi-layer stable emulsion film on the surface of the oil droplets. Low-temperature shearing and gradient cooling further consolidate the emulsion interface structure, avoiding emulsifier failure or oil phase aggregation at high temperatures. Compared with the conventional method of adding an emulsifier at one time, this staged emulsification process can more accurately control the emulsification process, improve the dispersion uniformity and interfacial stability of the oil phase mixture, reduce the risk of demulsification during subsequent mixing with the aqueous phase, and make the particle size distribution of the formed oil phase mixture narrower after emulsification, laying the foundation for the preparation of a stable O / W emulsion, and helping to improve the long-term storage stability of the insecticide formulation and the dispersion effect during application. In another embodiment, S4 further includes: pre-dissolving 0.1-0.2% hydroxypropyl-β-cyclodextrin in deionized water; melt-blending phenyl salicylate and triethyl citrate at a ratio of 10:1, and then adding the deionized water in which the hydroxypropyl-β-cyclodextrin is dissolved; and homogenizing at a pressure of 0.2-0.3 MPa for 10 minutes. For example, commercially available purified water or laboratory-made ultrapure water can be used as deionized water. First, 0.1%, 0.15% or 0.2% of hydroxypropyl-β-cyclodextrin is added to the water and stirred with a magnetic stirrer until completely dissolved. Phenyl salicylate and triethyl citrate are weighed in a mass ratio of 10:1, placed in a melting kettle, heated to 100-120°C, stirred to form a uniform blend, and added to an aqueous solution containing hydroxypropyl-β-cyclodextrin after cooling to 50-60°C. A high-pressure homogenizer is used for homogenization, with a pressure setting of 0.2MPa, 0.25MPa or 0.3MPa and a processing time of 10 minutes. It can be processed in batches to ensure that the material is fully homogenized. During the homogenization process, the temperature is controlled at 30-40°C by jacket water to avoid high temperature destroying the activity of the ingredients. In this embodiment, hydroxypropyl-β-cyclodextrin solubilization and melt blending homogenization treatment are added. Hydroxypropyl-β-cyclodextrin, as a water-soluble inclusion material, can increase the solubility of phenyl salicylate in water, and melt blending causes phenyl salicylate and triethyl citrate to form a molecular-level mixture, thereby enhancing the stability of the synergist. High-pressure homogenization treatment breaks up the agglomerated particles to form nano-scale aqueous phase particles, thereby improving the compatibility of the aqueous phase and the oil phase when mixed. This treatment method, relative to the conventional method of directly dissolving phenyl salicylate, can effectively solve the problem of its low solubility in water and easy precipitation. Phenyl salicylate is evenly dispersed in the aqueous phase through solubilization and homogenization processes, ensuring that the synergistic ingredients are fully exerted when subsequently mixed with the oil phase, thereby contributing to improving the synergistic insecticidal effect and formulation stability of the insecticide. In another embodiment, in S4, the homogenization treatment is carried out in two stages: the first stage: circulate treatment at a pressure of 0.8-1.0 MPa for 3 minutes, and control the temperature at 35-38°C; the second stage: switch to a pressure of 0.1-0.2 MPa, increase the temperature to 50-55°C at a rate of 10°C / min, and maintain for 5 minutes. Exemplarily, a high-pressure homogenizer with pressure and temperature control functions is used for processing. In the first stage, the pressure is adjusted to 0.8MPa, 0.9MPa or 1.0MPa, and the material is circulated in the homogenizer for 3 minutes. The temperature is maintained at 35°C, 36.5°C or 38°C by jacket water cooling, and the coarse particles of the blend of phenyl salicylate and triethyl citrate are broken up by high-pressure shear force. In the second stage, the pressure is reduced to 0.1MPa, 0.15MPa or 0.2MPa, and the heating device is turned on to heat it to 50°C, 52.5°C or 55°C at a rate of 10°C / min, and maintained for 5 minutes to further optimize the surface morphology of the particles at low pressure and high temperature to reduce particle agglomeration. During the homogenization process, the parameters are monitored in real time by pressure gauges and temperature sensors to ensure stable execution of the two-stage process. In this embodiment, the homogenization process is optimized in stages. The first stage uses high pressure and low temperature to crush the particles, while the second stage uses low pressure and high temperature to optimize the dispersion state. This combination of two stages not only ensures the material's crushing efficiency but also avoids the overheating failure that may occur with a single high-pressure treatment. Compared to traditional single-pressure homogenization methods, this segmented homogenization process can more precisely control the particle size and distribution of the aqueous phase particles, allowing phenyl salicylate to form a more stable nanoscale dispersion system in the aqueous phase. This improves interfacial compatibility when mixed with the oil phase, helps improve the uniformity and long-lasting efficacy of the entire insecticide formulation, and reduces stratification caused by particle agglomeration during storage. In another embodiment, S5 further includes: the aqueous phase is added dropwise using a pulse injection mode: high-speed dropwise addition lasts for 10 seconds, pauses for 5 seconds, and the cycle is completed; the system is maintained in a microfluidizer during the entire dropwise addition process, with an inlet pressure of 50-80 bar and an outlet pressure controlled by a back pressure valve at 20-30 bar; immediately after the dropwise addition, 0.5-1.0% (v / v) food-grade nitrogen is introduced to replace the oxygen in the headspace, and the mixture is shaken and degassed under a vacuum of -0.09 MPa. For example, a peristaltic pump or a liquid separator with a pulse control function is used for the dropwise addition of the aqueous phase, and a high-speed dropwise acceleration rate of 5-10 mL / s is set. After each dropwise addition of 10 seconds, there is a pause of 5 seconds to ensure that the aqueous phase enters the oil phase mixture in an intermittent manner. During the dropwise addition process, the oil phase mixture circulates in a microfluidizer, and the inlet pressure is adjusted to 50 bar, 65 bar or 80 bar. The outlet pressure is controlled to 20 bar, 25 bar or 30 bar by a back pressure valve, so that the oil and water phases are fully mixed under the action of high-pressure microjets. After the dropwise addition is completed, food-grade nitrogen is immediately introduced from the top of the reactor at a ventilation volume of 0.5%, 0.75% or 1.0% (v / v) of the headspace volume of the system to replace the oxygen therein. The vacuum system is then turned on and the reactor is shaken at a vacuum degree of -0.09 MPa for 5-10 minutes to remove bubbles introduced during the mixing process. In this embodiment, pulse dripping, micro-jet homogenization circulation, nitrogen replacement and vacuum degassing processes are added. Pulse dripping avoids local uneven emulsification caused by concentrated injection of the water phase, and the high-pressure circulation of the micro-jet homogenization ensures sufficient shear mixing of the oil and water phases to form a uniform emulsion. Nitrogen replacement and vacuum degassing remove oxygen and bubbles in the system, reducing the risk of oxidation of active ingredients and unstable factors in the emulsion. Compared with conventional dripping and stirring mixing methods, this treatment method can more effectively control the emulsion particle size and distribution, improve the emulsion stability, and reduce the possibility of oxidation and deterioration during storage, so that the prepared insecticide preparation is improved in appearance uniformity, long-term storage stability and environmental safety, which helps to ensure the efficacy and ecological safety during application.

[0026] The embodiments of the present application also provide a pollution-free insecticide obtained from the above embodiments. Specifically, the preparation process includes: dissolving 1.0% permethrin by mass in castor oil preheated to 55°C, adding 7.5% of the mass of permethrin to propylene glycol dicaprylate as a cosolvent, stirring at 2500rpm under nitrogen protection until dissolved, then cooling at a gradient of 0.75°C / min and injecting 0.03% of the mass of the oil phase into nanocrystal seeds, and obtaining a stable permethrin oil phase after heating and cooling twice; grinding and inclusion of azadirachtin and β-cyclodextrin in an argon environment at a molar ratio of 1:2.5, and dispersing Rosemary extract is added to soybean oil preheated to 42.5°C and stirred at 500 rpm under red light until uniform. Polyoxyethylene castor oil is added to the two oil phases and the mixed phase in three portions, and the oil phase mixture is formed through pre-emulsification and high-speed shearing at different temperatures and rotation speeds. Phenyl salicylate and triethyl citrate are melt-blended and dissolved in deionized water containing hydroxypropyl-β-cyclodextrin, and the aqueous phase is formed through a two-stage homogenization treatment. Finally, the aqueous phase is dripped into the oil phase in a pulsed mode, circulated and mixed in a microfluidizer, and the finished product is obtained through nitrogen displacement and vacuum degassing. Permethrin can be dissolved in castor oil using a reactor equipped with temperature control and a nitrogen port. The castor oil preheat temperature is 50°C, 55°C, or 60°C. The cosolvent dosage is 5%, 7.5%, or 10% of the permethrin mass. The high-speed shear stirring speed can be set to 2000 rpm, 2500 rpm, or 3000 rpm. Azadirachtin and β-cyclodextrin are ground in a sealed, polytetrafluoroethylene-coated tank under argon to maintain an inert atmosphere. The grinding process uses a variable-mode vibration with an amplitude of 0.75 mm and a frequency of 35 Hz for the first 5 minutes, followed by an amplitude of 2.5 mm and a frequency of 15 Hz for the last 5 minutes. The emulsifier, polyoxyethylene castor oil, was added in three equal portions. The pre-emulsification temperatures were controlled at 50-55°C (permethrin oil phase) and 45-50°C (azadirachtin oil phase), respectively. The stirring speeds were 800-1000 rpm and 600-800 rpm, respectively. After mixing, the high-speed shear speed was 2000-3000 rpm. To prepare the aqueous phase, the mass fraction of hydroxypropyl-β-cyclodextrin in deionized water was 0.1%, 0.15%, or 0.2%. Phenyl salicylate and triethyl citrate were blended in a 10:1 ratio. The homogenization process consisted of two stages: high-pressure crushing and low-pressure optimization. The pressure and temperature were precisely controlled within the corresponding ranges. The addition process utilized pulse injection combined with microfluidization, with an inlet pressure of 50-80 bar and an outlet pressure of 20-30 bar. Degassing was achieved through food-grade nitrogen displacement and -0.09 MPa vacuum oscillation. In the present embodiment, the overall preparation method integrates the processes such as active ingredient dissolution optimization, inclusion stabilization, segmented emulsification, homogeneous dispersion and degassing protection, and each step parameter selects specific values ​​within the scope of the claim limit. By the green solvent system of castor oil and soybean oil, the toxicity problem of traditional organic solvents is avoided, the emulsification of polyoxyethylene castor oil and the inclusion technology of cyclodextrin improve the stability and dispersion uniformity of active ingredients, and the synergistic effect of phenyl salicylate and the synergistic effect of the composite system ensure insecticidal effect. Relative to the conventional method without adopting these processes, the insecticide prepared by this embodiment reduces active ingredient precipitation and degradation during storage, and the emulsion system formed is not easy for stratification and demulsification, and the equipment and materials used in the production process are all commercially available conventional types, and process steps are coherent and controllable, and a practical path is provided for industrialized production, and the obtained insecticide has both high-efficiency insecticidal performance and environmentally friendly characteristics, meets the actual needs of pollution-free prevention and control.

[0027] The following describes the method with reference to specific embodiments.

[0028] Example 1: Preparation method of pollution-free pesticide: S1: Preparation of permethrin castor oil solution 1. Preheating and cosolvent addition: Pour castor oil into a reaction vessel equipped with a temperature control device and a nitrogen inlet port, heat to 55°C, add propylene glycol dicaprylate (7.5% by weight of permethrin), an amphiphilic cosolvent, and stir until initially mixed.

[0029] 2. Nitrogen protection and high-speed dissolution: Introduce nitrogen into the container to maintain an inert environment, start the high-speed shear mixer (speed 2500 rpm), add permethrin and stir until completely dissolved. The mass fraction of permethrin in castor oil is 1.0%.

[0030] 3. Gradient cooling and seed control: After dissolution is completed, the temperature is gradually lowered to 25°C at a rate of 0.75°C / min. During the cooling process, nanocrystalline seeds (permethrin-propylene glycol dicaprylate / caprate eutectic particles modified with stearic acid, particle size 50-100nm) accounting for 0.03% of the oil phase mass are injected; after cooling to 25°C, the mixture is kept warm for 30 minutes, then the temperature is increased to 40°C at a rate of 1.0°C / min, maintained for 10 minutes, and then cooled to 25°C for a second time at a rate of 0.4°C / min to form a stable permethrin castor oil solution.

[0031] S2: Preparation of Azadirachtin-Soybean Oil Solution 1. Pre-grinding of inclusion complex: Place azadirachtin and β-cyclodextrin in a 1:2.5 molar ratio into a sealed grinding jar (with a polytetrafluoroethylene coating on the inner wall). Maintain an inert environment with argon gas and grind with variable amplitude vibration: 0.75 mm amplitude and 35 Hz frequency for the first 5 minutes, and 2.5 mm amplitude and 15 Hz frequency for the next 5 minutes to form the azadirachtin-β-cyclodextrin inclusion complex.

[0032] 2. Inclusion complex dispersion and protection: Preheat soybean oil to 42.5°C, control the oil phase viscosity to 135 cP, add the inclusion complex and 0.3% of rosemary extract by mass, and stir at 500 rpm under red light with a wavelength >520 nm until completely dispersed. After dispersion, immediately cool to 30°C at a rate of 0.75°C / s to form an azadirachtin soybean oil solution.

[0033] S3: Oil phase mixture preparation 1. Add emulsifier in stages: Divide polyoxyethylene castor oil into three equal parts. Add permethrin castor oil solution into the first part and stir at 52.5°C and 900 rpm for 5 minutes to form pre-emulsified oil phase A. Add azadirachtin soybean oil solution into the second part and stir at 47.5°C and 700 rpm for 5 minutes to form pre-emulsified oil phase B.

[0034] 2. Mixing and high-speed shearing: Mix the pre-emulsified oil phases A and B, add the third portion of polyoxyethylene castor oil (emulsifier content in the oil phase mixture is 5.5% by mass), and stir at 2500 rpm for 10 minutes to form an oil phase mixture. Maintaining the shear state, cool the mixture to 30°C at a rate of 2.5°C / min.

[0035] S4: Preparation of phenyl salicylate aqueous phase 1. Solubilization and blending: Pre-dissolve 0.15% hydroxypropyl-β-cyclodextrin in deionized water and stir until completely dissolved. Melt-blend phenyl salicylate and triethyl citrate in a 10:1 mass ratio (heat to 100-120°C until uniform). Cool to 55°C and then add the above aqueous solution.

[0036] 2. Two-stage homogenization: The mixed solution was transferred to a high-pressure homogenizer. In the first stage, the mixture was circulated at 0.9 MPa for 3 minutes and the temperature was controlled at 36.5°C. In the second stage, the pressure was switched to 0.15 MPa, and the temperature was increased to 52.5°C at a rate of 10°C / min and maintained for 5 minutes to form an aqueous phase (phenyl salicylate mass fraction in deionized water 0.1%).

[0037] S5: Emulsion preparation and post-processing 1. Pulse addition and homogenization: The water phase is added to the oil phase mixture through a pulse injection device (high-speed addition for 10 seconds, pause for 5 seconds, and cycle until completion). The system is kept circulating in the microfluidizer during the entire addition process. The inlet pressure is 65 bar and the outlet pressure is controlled by a back pressure valve at 25 bar.

[0038] 2. Degassing and protection: After the addition is completed, immediately introduce 0.75% (v / v) food-grade nitrogen to replace the oxygen in the headspace, then shake and degas for 5-10 minutes under a vacuum of -0.09 MPa to obtain the pollution-free pesticide.

[0039] Comparative Example 1: During S1, permethrin was dissolved in acetone, a traditional organic solvent, instead of castor oil, and neither azadirachtin nor phenyl salicylate was added. The remaining parameters and process were identical to those in the implementation flow. Specifically, S1 used acetone as the solvent (instead of castor oil), with a permethrin concentration of 1.0%. S2 (preparing the soybean oil solution without azadirachtin) was omitted. S4 omitted the phenyl salicylate solution (using pure deionized water). S3 simply mixed the permethrin acetone solution with deionized water (without an emulsifier). Comparative Example 2: During S1, castor oil was not preheated, propylene glycol dicaprylate cosolvent was not added, and nanocrystal seeds were not injected. After dissolution, the temperature was directly lowered to 25°C without temperature increase or secondary cooling. The remaining parameters and process were identical to the implementation flow. Specifically, permethrin was directly dissolved in castor oil at room temperature (25°C), with low-speed stirring (500 rpm, not high-speed shear), and the temperature control steps of "gradient cooling → heating → secondary cooling" were omitted. Comparative Example 3: In S2, azadirachtin was dissolved directly in soybean oil without premixing and grinding with β-cyclodextrin, dispersing under red light, or adding rosemary extract. All other parameters and processes were identical to those in the implementation process. Specifically, azadirachtin was added directly to room-temperature soybean oil (not preheated to 42.5°C), with standard stirring (1000 rpm, not gentle stirring at 400-600 rpm), and the process was performed under natural light (including UV light). Comparative Example 4: In S3, the polyoxyethylene castor oil was not added in three equal portions. Instead, it was added all at once to the mixture of the permethrin castor oil solution and the azadirachtin soybean oil solution. The remaining parameters and process were identical to those in the implementation flow. Specifically, the emulsifier was added all at once to the mixed oil phase, without preparing pre-emulsified oil phases A and B. The mixture was stirred uniformly at room temperature (25°C) and 1000 rpm (without temperature control at 50-55°C / 45-50°C or gradient shearing at 800-3000 rpm). Comparative Example 5: During S5, the aqueous phase was not added dropwise using a pulsed injection mode, the microfluidizer was not used for circulation during the addition process, and nitrogen exchange and vacuum degassing were not performed after the addition. All other parameters and processes were identical to the implementation flow. Specifically, the aqueous phase was quickly poured into the oil phase all at once through a separatory funnel (not in the "high-speed addition for 10 seconds followed by a 5-second pause" pulse mode), mixed using a standard agitator (300 rpm), and filled directly after the addition (without deoxygenation and degassing). Control group: The conventional preparation process of commercially available permethrin emulsifiable concentrate is adopted, and the specific steps are as follows: Dissolution of active ingredient: Dissolve 5% permethrin directly in 60% acetone and stir magnetically at room temperature (25°C) for 10 minutes until clear; Emulsifier addition: Add 15% calcium dodecylbenzenesulfonate at once and stir at 800 rpm for 5 minutes; Water phase mixing: Pour deionized water (20%) into the oil phase system through a separatory funnel at once and mix with a conventional stirrer (300 rpm) for 5 minutes; Preparation molding: Fill directly into plastic bottles.

[0040] Performance tests were performed on the above Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, and the control group, and the results are shown in the following table.

[0041] Comparative Example 1 did not use green solvents such as castor oil and soybean oil during preparation, nor did it compound azadirachtin and phenyl salicylate. Instead, permethrin was dissolved in toxic acetone without adding an emulsifier. This resulted in its acute oral toxicity LD50 dropping to 80 mg / kg, far below the safety level of Example 1. The acetone residue also polluted soil and water bodies. Because it only contains a single active ingredient, permethrin, its lasting effect on aphids is only 5 days. After 6 consecutive uses, the resistance multiple reaches 3.5 times, which is significantly higher than the 1.2 times of Example 1. In comparison, Example 1 reduces the toxicity of the formulation from the source by replacing the organic solvent with vegetable oil. After compounding azadirachtin, a synergistic effect of contact killing and long-term pest control is formed, which not only increases the biodegradation rate to more than 90%, but also delays the development of resistance through the complementary mechanism of the two components, solving the core problem of high toxicity and short effect of traditional emulsifiable concentrates.

[0042] In Comparative Example 2, when preparing the permethrin castor oil solution, castor oil was not preheated, propylene glycol dicaprylate cosolvent and nanocrystal seeds were not added, and gradient temperature field control was not performed. Permethrin was only dissolved by stirring at low speed at room temperature. This resulted in the formation of coarse crystals after the permethrin was dissolved. After 6 months, the content retention rate dropped to 75%, which was much lower than the 95% in Example 1. The average particle size of the emulsion reached 850nm, and the stratification rate after 14 days of heat storage at 54°C was 28%, both of which were significantly higher than Example 1. Example 1 reduces the crystallization energy barrier of permethrin by using a cosolvent, uses nanocrystal seeds to induce the formation of uniform crystals of 50-100nm, and promotes uniform crystal growth through multi-stage temperature field control, effectively avoiding crystal agglomeration and precipitation, controlling the emulsion particle size at 180nm, and reducing the heat storage stratification rate to 2%, ensuring the long-term stability of permethrin in the oil phase, and solving the industry problem of temperature-sensitive crystallization.

[0043] In Comparative Example 3, when treating azadirachtin, it was not pre-mixed and ground with β-cyclodextrin to form an inclusion complex, nor was it dispersed under a red light environment, and no rosemary extract was added. The azadirachtin was directly dissolved in soybean oil. This resulted in rapid degradation of azadirachtin due to photooxidation during preparation and storage. After 6 months, the content retention rate was only 65%, far lower than 88% in Example 1. The duration of effect on pests was shortened to 10 days, and the antifeedant activity was significantly reduced. Example 1, through grinding and inclusion at a molar ratio of 1:2.5, utilized the molecular capsule structure of β-cyclodextrin to isolate photooxidation, combined with a red light environment to avoid ultraviolet damage and the antioxidant effect of rosemary extract, reduced the photolysis rate of azadirachtin from 50% / 24h to <5%, effectively solving the problem of easy degradation and unstable activity of plant-derived ingredients, and ensuring its long-term pest control effect.

[0044] In comparative example 4, when preparing the oil phase mixture, polyoxyethylene castor oil was not added in three portions in stages, but was added to the mixed oil phase at one time, and pre-emulsification and high-speed shearing at different temperatures and speeds were not performed, but only uniform stirring was performed at room temperature. This caused the emulsifier to be unevenly dispersed in the two oil phases, and the average particle size of the formed emulsion reached 450nm, the absolute value of the Zeta potential was only 28mV, and the 54°C thermal storage stratification rate was 20%, all of which were higher than those in Example 1. In Example 1, the emulsifier was added to the permethrin oil phase, the azadirachtin oil phase and the mixed phase in three portions in sequence, and pre-emulsified at 50-55°C and 45-50°C respectively, and then subjected to high-speed shearing at 2000-3000rpm to form a multi-layer emulsion film with uniform thickness, controlling the emulsion particle size at 180nm, and increasing the absolute value of the Zeta potential to 38mV, which significantly enhanced the interfacial stability, solved the technical bottlenecks of uneven emulsification and easy demulsification of the compound system, and ensured the uniform dispersion of the active ingredient in the oil phase.

[0045] Comparative Example 5 did not adopt the pulse injection mode and microjet homogenization during aqueous phase addition and post-processing, and nitrogen replacement and vacuum degassing were not performed after addition. It was directly filled only after ordinary stirring and mixing. This resulted in phenyl salicylate particles with a particle size of 380 nm, much larger than the 100 nm or less of Example 1, slow release of the synergist, a shortened duration of effect of 15 days, and a large amount of microbubbles and oxygen remaining in the system. After 6 months, the oxidative degradation rate of the active ingredient was 25% higher than that of Example 1. Example 1 achieved nanoscale uniform dispersion of the aqueous phase in the oil phase through the pulse mode of “high-speed dropwise addition for 10 seconds + pause for 5 seconds” and microjet homogenization at an inlet pressure of 65 bar. Combined with 0.75% food-grade nitrogen to replace headspace oxygen and -0.09 MPa vacuum degassing, the oxygen content of the system was reduced to less than 0.1%, effectively avoiding the oil droplet aggregation and active ingredient oxidation caused by bubble residues, and improving the storage stability and drug efficacy persistence of the preparation.

[0046] The control group adopted the traditional emulsifiable concentrate preparation process, with acetone as the solvent, single permethrin as the active ingredient, and a one-time emulsifier added. The process was rough and no stability optimization was performed. Its acute oral toxicity LD50 was only 50 mg / kg, which was far lower than the safety standard of Example 1. The stratification rate at 54°C was 40%, and the permethrin content retention rate was only 60% after 6 months. The effective period for aphids was 7 days, and the resistance multiple was 4.0 times after 6 consecutive uses. All performances were significantly inferior to Example 1. Example 1 formed a complete technical system from raw material selection, component stabilization, emulsion preparation to post-processing through the synergistic effect of core technologies such as green solvent compounding, seed regulation, inclusion technology, gradient emulsification and homogenization degassing, which systematically solved the problems of high toxicity, short effect, instability and rapid drug resistance in the control group, and achieved significant improvements in toxicity, stability, efficacy and environmental friendliness.

[0047] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A method for preparing a pollution-free pesticide, characterized in that: include: S1: dissolving permethrin in a first vegetable oil, wherein the mass fraction of permethrin in the first vegetable oil is 0.5% to 2.0%, and the first vegetable oil is castor oil; S2: dissolving azadirachtin in a second vegetable oil, wherein the mass fraction of azadirachtin in the second vegetable oil is 0.2% to 1.5%, and the second vegetable oil is soybean oil; S3: mixing the permethrin castor oil solution obtained in S1 with the azadirachtin soybean oil solution obtained in S2, adding polyoxyethylene castor oil as an emulsifier, and stirring to form an oil phase mixture, wherein the mass fraction of the polyoxyethylene castor oil in the oil phase mixture is 3.0% to 8.0%; S4: dissolving phenyl salicylate in deionized water to form an aqueous phase, wherein the mass fraction of phenyl salicylate in the deionized water is 0.05% to 0.2%; S5: The aqueous phase of S4 is added dropwise to the oil phase mixture of S3, and stirred to obtain a pollution-free pesticide.

2. The method for preparing the pollution-free pesticide according to claim 1, wherein: In S1, also included: Preheat castor oil to 50-60°C and add propylene glycol dicaprylate, an amphiphilic cosolvent, at a concentration of 5-10% by weight of permethrin; Under nitrogen protection, dissolve permethrin at a high shear stirring speed of 2000-3000 rpm; After dissolution, the temperature was lowered to 25°C at a gradient of 0.5-1°C / min and kept warm for 30 minutes.

3. The method for preparing the pollution-free pesticide according to claim 2, wherein: Also includes: During the gradient cooling process, nanocrystalline seeds accounting for 0.01-0.05% of the oil phase mass are injected into the system. The nanocrystalline seeds are chlorpyrifos-propylene glycol dicaprylate / caprate eutectic particles modified with stearic acid, with a particle size of 50-100nm; after thermal aging, the temperature is raised to 40°C at 0.8-1.2°C / min, maintained for 10 minutes, and then cooled to 25°C for the second time at 0.3-0.5°C / min.

4. The method for preparing the pollution-free pesticide according to claim 1, wherein: In S2, it also includes: Azadirachtin and β-cyclodextrin were premixed and ground in a molar ratio of 1:2-1:3 to form an inclusion complex; The inclusion compound was dispersed in soybean oil preheated to 40-45°C and 0.3% rosemary extract was added; Under red light with a wavelength >520nm, stir gently at 400-600 rpm until completely dispersed.

5. The method for preparing the pollution-free pesticide according to claim 4, wherein: In S2, it also includes: Premix grinding was performed in a closed argon atmosphere, and the inner wall of the grinding jar was covered with polytetrafluoroethylene coating; The variable amplitude vibration mode is used during grinding: the amplitude is 0.5-1.0mm and the frequency is 35Hz in the first 5 minutes, and the amplitude is 2.0-3.0mm and the frequency is 15Hz in the last 5 minutes; When the inclusion compound is dispersed in soybean oil, the viscosity of the oil phase is controlled to be 120-150 cP, and the temperature is immediately lowered to 30° C. at a rate of 0.5-1.0° C. / s after dispersion.

6. The method for preparing the pollution-free pesticide according to claim 1, wherein: In S3, it also includes: Divide the polyoxyethylene castor oil into three equal parts; The first portion of polyoxyethylene castor oil was added to the permethrin castor oil solution obtained in S1, and stirred at 50-55°C and 800-1000 rpm for 5 minutes to form a pre-emulsified oil phase A; In the second step, polyoxyethylene castor oil was added to the azadirachtin soybean oil solution obtained in S2 and stirred at 45-50°C and 600-800 rpm for 5 minutes to form a pre-emulsified oil phase B; Mix the pre-emulsified oil phases A and B, add the third portion of polyoxyethylene castor oil, and stir at high shear speed of 2000-3000 rpm for 10 minutes to form an oil phase mixture; While maintaining the shear state, the system was cooled to 30°C at a rate of 2-3°C / min.

7. The method for preparing the pollution-free pesticide according to claim 1, characterized in that: In S4, it also includes: Pre-dissolve 0.1-0.2% hydroxypropyl-β-cyclodextrin in deionized water; Phenyl salicylate and triethyl citrate were melt-blended at a ratio of 10:1, and then added to deionized water in which hydroxypropyl-β-cyclodextrin was dissolved; Homogenize at a pressure of 0.2-0.3 MPa for 10 minutes.

8. The method for preparing the pollution-free pesticide according to claim 7, wherein: The homogenization treatment is carried out in two stages: the first stage: circulate treatment at a pressure of 0.8-1.0 MPa for 3 minutes, and control the temperature at 35-38°C; the second stage: switch to 0.1-0.2 MPa pressure, increase the temperature to 50-55°C at a rate of 10°C / min, and maintain for 5 minutes.

9. The method for preparing the pollution-free pesticide according to claim 1, wherein: In S5, also included: The water phase was added dropwise using a pulse injection mode: high-speed addition lasted for 10 seconds, paused for 5 seconds, and cycled until completion; During the entire addition process, the system was kept circulating in the microfluidizer with an inlet pressure of 50-80 bar and a back pressure valve controlling the outlet pressure at 20-30 bar. Immediately after the addition, 0.5-1.0% (v / v) food-grade nitrogen was introduced to replace the oxygen in the headspace, and the mixture was shaken and degassed under a vacuum of -0.09 MPa.

10. A pollution-free pesticide, characterized in that: The method is prepared by any one of claims 1 to 9.

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