A dispersible oil suspension containing 2-methyl-4-chloropropionyl ester of isooctyl alcohol, atrazine and nicosulfuron and a preparation method thereof

Abstract

The application relates to the field of dispersible oil suspensions, and particularly discloses a dispersible oil suspension containing 2-methyl-4-chloro-6-ethylamino-4,6-dinitrophenyl acetate, atrazine and nicosulfuron and a preparation method thereof. The dispersible oil suspension containing 2-methyl-4-chloro-6-ethylammino-4,6-dinitrophenyl acetate, atrazine and nicosulfuron comprises the following raw materials in mass percentage: active component 33.7-38.3%, emulsifying component 14-18%, thickening agent 0.3-0.7%, and methyl oleate, which is supplemented to 100%; the active component comprises nicosulfuron, 2-methyl-4-chloro-6-ethylamino-4,6- dinitrophenyl acetate and atrazine; the mass percentage ratio of the nicosulfuron, 2-methyl-4-chloro-6-ethylammino-4,6- dinitrophenyl acetate and atrazine in the dispersible oil suspension is 3.6-4.4%:11.3-12.7%:18.8-21.2%. The application improves the weeding effect in corn fields by preparing the dispersible oil suspension containing 2-methyl-4-chloro-6-ethylamimo-4,6-dinitrophenyl acetate, atrazine and nicosulfuron, and reduces environmental pollution.

Description

Technical Field

[0001] This invention belongs to the field of dispersible oil suspensions, and more specifically relates to a dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine and nicosulfuron, and its preparation method. Background Technology

[0002] In agricultural production, weeds compete with crops for sunlight, water, and nutrients, severely impacting crop yields. The use of highly effective herbicides is a primary means of weed control. 2,4-D isooctyl ester is a type of 2,4-D herbicide; as a selective herbicide, it has good control effects on broadleaf weeds. Atrazine, a triazine herbicide, is effective in controlling annual grasses and broadleaf weeds in corn, sugarcane, and other crop fields. Nicosulfuron is a sulfonylurea herbicide with significant efficacy against common corn weeds such as barnyard grass and foxtail, and has high safety for corn. 2,4-D, atrazine, and nicosulfuron are widely used as highly effective herbicides for weed control in farmland.

[0003] However, traditional formulations of 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron are mostly emulsifiable concentrates or aqueous solutions. The organic solvents in emulsifiable concentrates and the large amount of cosolvents in aqueous solutions lead to environmental pollution. Furthermore, the aqueous solutions are prone to the release of active ingredients and stratification during long-term storage, resulting in decreased formulation stability and reduced efficacy.

[0004] Therefore, there is an urgent need to provide a dispersible oil suspension containing 2,4-D isooctyl ester, atrazine, and nicosulfuron, which has the characteristics of high-efficiency weed control and low environmental pollution. Summary of the Invention

[0005] To improve the stability and weed control effect of herbicides containing 2,4-D isooctyl ester, atrazine, and nicosulfuron, this application provides a dispersible oil suspension containing 2,4-D isooctyl ester, atrazine, and nicosulfuron, and a method for preparing the same.

[0006] In a first aspect, this application provides a dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron, employing the following technical solution: A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron, comprising the following raw materials in weight percentages: Active ingredient 33.7-38.3%, emulsifying component 14-18%, thickener 0.3-0.7%, methyl oleate to make up to 100%; The active ingredients include nicosulfuron, 2,4-methylchloroisooctyl ester and atrazine; The mass percentage of nicosulfuron, 2,4-methyl-4-chloroisooctyl ester and atrazine in the dispersible oil suspension is 3.6-4.4%:11.3-12.7%:18.8-21.2%.

[0007] By employing the above technical solution, using emulsified components to disperse nicosulfuron, 2,4-D isooctyl ester, and atrazine into methyl oleate, nicosulfuron exhibits good herbicidal effects against common grass weeds in cornfields. 2,4-D isooctyl ester can effectively control broadleaf weeds, and atrazine has both inhibitory and killing effects on annual grass weeds and broadleaf weeds. The combined use of these three components can kill weeds in cornfields over a large area, improving weed control efficiency. Furthermore, the combined use of nicosulfuron, 2,4-D isooctyl ester, and atrazine has a synergistic effect. The synergistic effect allows for better weed control at lower dosages, reducing the number of sprays and the amount of pesticide used, thus minimizing environmental pollution. The emulsifying component has an amphiphilic structure, which reduces the interfacial tension between oil and water, allowing the active ingredient to be uniformly dispersed in methyl oleate, forming a stable dispersible oil suspension system. The thickener increases the viscosity of methyl oleate, preventing pesticide deposition and polymerization, increasing the stability of the suspension system, and avoiding oil droplet aggregation and active ingredient deposition that could lead to local drug concentration imbalance, thereby improving the control effect.

[0008] Methyl oleate can form a similar compatibility with the waxy layer on the surface of weed leaves, reducing the surface tension of the pesticide solution, allowing the solution to fully penetrate the leaf surface, increasing the retention rate of the solution, and reducing the waste of active ingredients. Furthermore, methyl oleate can alter the permeability of the cell protoplasmic membrane, promoting the penetration of the solution into the weeds and preventing photodegradation of the solution on the leaf surface, thereby improving efficacy. In addition, after application, methyl oleate is decomposed by soil microorganisms into carbon dioxide, water, and small molecule fatty acids, avoiding inhibition of the soil microbial community and reducing environmental pollution.

[0009] Optionally, the mass percentage of nicosulfuron, 2,4-methyl-4-chloroisooctyl ester and atrazine in the dispersible oil suspension is 4%:12%:20%.

[0010] By adopting the above technical solution and optimizing the ratio of nicosulfuron, 2,4-methyl-4-chloroisooctyl ester and atrazine in the active components, the maximum control effect of weed removal in corn can be achieved.

[0011] Optionally, the emulsifying components are calcium dodecylbenzenesulfonate, tristyrylphenol polyoxyethylene ether, castor oil polyoxyethylene ether, and 150# solvent oil.

[0012] Optionally, the mass ratio of the calcium dodecylbenzenesulfonate, tristyrylphenol polyoxyethylene ether, castor oil polyoxyethylene ether, and 150# solvent oil is 1:1:1-3:1.

[0013] By adopting the above technical solutions, the viscosity of 150# solvent oil is low, which can dilute methyl oleate, reduce the resistance of oil phase dispersion into tiny droplets during emulsification, and improve emulsification efficiency. Calcium dodecylbenzenesulfonate, as an anionic surfactant, is adsorbed on the surface of oil droplets, giving the surface of the oil droplets a negative charge. The electrostatic repulsion between charges can prevent oil droplets from agglomerating and depositing in the suspension, maintaining the stability of the oil suspension. Tristyrene-phenol polyoxyethylene ether is a nonionic surfactant with a rigid structure. When the drug is diluted with water, the lipophilic aromatic ring structure at one end can be firmly locked on the surface of the oil droplets, while the polyoxyethylene ether chain at the other end forms a hydration layer in water. This, in conjunction with the electrostatic repulsion, further prevents oil droplet aggregation. Moreover, tristyrene-phenol polyoxyethylene ether can be tightly arranged with calcium dodecylbenzenesulfonate at the interface to form a dense and mechanically strong composite interfacial film, resisting external damage, increasing the stability of the suspension, avoiding imbalance of active component concentration, and thus improving drug efficacy.

[0014] Castor oil polyoxyethylene ether, as a nonionic surfactant, exhibits excellent compatibility in the oil phase and can effectively reduce interfacial tension, promoting the wetting, penetration, and spreading of the herbicide solution on the weed surface, increasing the absorption of active ingredients, and thus improving efficacy. Furthermore, castor oil polyoxyethylene ether, calcium dodecylbenzenesulfonate, and tristyrylphenol polyoxyethylene ether can mix at the interface, filling in the intermolecular gaps, increasing the density of the composite interfacial film, and further improving the stability of the suspension. In addition, nicosulfuron is prone to photodegradation in the oil phase; the polyoxyethylene ether chains of castor oil polyoxyethylene ether can adsorb free radicals in the environment, inhibiting the oxidative degradation of nicosulfuron and improving the utilization rate of active ingredients.

[0015] Optionally, the thickener is at least one of organoclay and polyamide wax.

[0016] By adopting the above technical solution, in the oil suspension, 2,4-methyl-4-chloroisooctyl ester is dissolved in methyl oleate, while nicosulfuron and atrazine are uniformly dispersed in the methyl oleate system in the form of small particles. Organocarboxylic acid and polyamide wax, as thickeners, interact with each other in the methyl oleate through interlayer hydrophobic groups to form a three-dimensional network gel structure, which increases the viscosity of methyl oleate, avoids the sedimentation and agglomeration of active components, and improves the dispersion stability of the oil suspension.

[0017] Optionally, the dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron further includes silicone-modified silica powder, wherein the mass ratio of the silicone-modified silica powder to the active component is 0.6-0.8:30-40. The preparation method of the organosilicon-modified silica powder includes the following steps: (1) Add nano-titanium dioxide and polycarboxylate to ethanol and stir evenly to obtain nano-titanium dioxide dispersion; (2) Add silica to nano-titanium dioxide dispersion and stir evenly to obtain silica suspension; (3) Heat and stir the silica suspension at 55-65℃ for 30-40 minutes, add ammonia water, stir evenly, add organosilicon, react for 20-22 hours, filter, wash and dry to obtain organosilicon modified silica powder.

[0018] Optionally, the mass ratio of the nano-titanium dioxide, organosilicon, and precipitated silica is 0.3-0.5:0.7-0.9:1-2.

[0019] By employing the above technical solution, the thickener forms a three-dimensional network gel structure in methyl oleate, which can suspend particles. Silica, with its extremely high specific surface area and porous surface structure, can be tightly adsorbed onto the particle surface, increasing the steric hindrance of the particles and preventing particle collisions and aggregation. This synergistic effect with the network structure of the thickener improves the dispersion stability of the suspending agent. Furthermore, silica nanoparticles can fill the gaps in the three-dimensional network structure of the thickener, further increasing the stability of the suspending agent. Organosilicon can be rapidly adsorbed onto the liquid surface, reducing the surface tension of the system. When used in conjunction with porous silica, it promotes rapid spread of the herbicide solution on the surface of weed leaves, forming a hydrophobic protective film that prevents droplets from rolling off and being washed away by rain, thus prolonging the duration of the herbicide's effect. Furthermore, the lipophilic groups of organosilicon can lock the oil droplets in the herbicide solution, while the hydrophilic groups face the aqueous phase, increasing the dispersion stability of the oil suspension in the aqueous phase during application. In addition, titanium dioxide reduces the oxidative attack on nicosulfuron and atrazine by absorbing ultraviolet light and adsorbing water molecules and oxygen in the environment, preventing the degradation of nicosulfuron and atrazine, increasing the utilization rate of active ingredients, and improving the herbicidal effect.

[0020] Secondly, this application provides a method for preparing a dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron, comprising the following steps: (1) Add nicosulfuron, 2,4-methyl-4-chloroisooctyl ester and atrazine to methyl oleate, mix well, and prepare a mixture; (2) Add the emulsified components to the mixture, shear, add thickener, shear for 5-10 minutes to obtain a dispersible oil suspension.

[0021] By adopting the above technical solution, the emulsifier uniformly disperses nicosulfuron, 2,4-methylchloroisooctyl ester and atrazine into methyl oleate, promoting the dispersion of active components into tiny oil droplets. The subsequent addition of thickener prevents the oil droplets from agglomerating and improves the stability of the oil suspension. Shearing preparation breaks the oil solution into fine and uniform oil droplets, increasing the uniformity of the drug solution in the oil suspension. The operation is simple and conducive to subsequent industrial production.

[0022] Optionally, in step (2), after adding a thickener and shearing for 5-10 minutes, silicone-modified silica is added and sheared to obtain a dispersible oil suspension.

[0023] By adopting the above technical solution, the synergistic effect of organosilicon-modified silica and thickener further prevents oil droplet aggregation, avoids the deposition of active components, and increases the stability of oil suspension, thereby improving the weeding effect.

[0024] In summary, this application has the following beneficial effects: 1. This application preferably uses a combination of nicosulfuron, 2,4-D isooctyl ester and atrazine. The emulsifying components disperse nicosulfuron, 2,4-D isooctyl ester and atrazine into methyl oleate. The three components work synergistically to improve the weeding effect and reduce the amount of herbicide used. Methyl oleate also has excellent biocompatibility, avoiding inhibition of the proliferation of soil microorganisms and reducing environmental pollution.

[0025] 2. This application uses a combination of calcium dodecylbenzenesulfonate, tristyrylphenol polyoxyethylene ether, and castor oil polyoxyethylene ether to emulsify and disperse the active components into methyl oleate, forming stable micro oil droplets. Furthermore, castor oil polyoxyethylene ether can prevent the oxidative degradation of nicosulfuron and improve the utilization rate of the active components.

[0026] 3. This application uses organosilicon-modified silica powder. Silica can increase the dispersion stability of active components in the oil phase, and the amphiphilic structure of organosilicon can prevent oil droplet aggregation and improve the dispersion stability of oil droplets in the aqueous phase. When used in combination with silica, it forms a hydrophobic protective film on the liquid surface, which improves the duration of herbicide action. In addition, the addition of titanium dioxide avoids photodegradation of nicosulfuron and atrazine, thus improving the herbicidal effect. Detailed Implementation

[0027] The following embodiments provide a further detailed description of this application.

[0028] Example of preparation of organosilicon-modified silica powder

[0029] The nano-titanium dioxide with a particle size of 20nm was purchased from Ningbo Luofei Nanotechnology Co., Ltd., with the product number LF-titanium dioxide-N20; the organosilicon was purchased from Momentive Advanced Materials Group, with the product number Silquest A-1230; and the silica with a particle size of 20nm was purchased from Zhejiang Yamei Nanotechnology Co., Ltd., with the product number SiO2-0020.

[0030] Preparation Example 1 (1) Add 0.5g of nano-titanium dioxide and 0.3g of polycarboxylate to 50g of ethanol and stir evenly to obtain a nano-titanium dioxide dispersion; (2) Add 2g of silica to the nano-titanium dioxide dispersion and stir evenly to obtain silica suspension; (3) Heat and stir the silica suspension at 60°C for 35 min, add 7 ml of ammonia water, stir evenly, add 0.9 g of organosilicon, react for 20 h, filter, wash, and dry at 60°C for 24 h to obtain organosilicon modified silica powder.

[0031] Preparation Example 2 (1) Add 0.3g of nano-titanium dioxide and 0.2g of polycarboxylate to 50g of ethanol and stir evenly to obtain a nano-titanium dioxide dispersion; (2) Add 1g of silica to the nano-titanium dioxide dispersion and stir evenly to obtain silica suspension; (3) Heat and stir the silica suspension at 60°C for 35 min, add 5 ml of ammonia water, stir evenly, add 0.7 g of organosilicon, react for 20 h, filter, wash, and dry at 60°C for 24 h to obtain organosilicon modified silica powder.

[0032] Preparation Example 3 (1) Add 2g of silica to 50g of ethanol and stir until homogeneous to obtain silica suspension; (2) Heat and stir the silica suspension at 60°C for 35 min, add 7 ml of ammonia water, stir evenly, add 0.9 g of organosilicon, react for 20 h, filter, wash, and dry at 60°C for 24 h to obtain organosilicon modified silica powder.

[0033] Example

[0034] In the following examples, the organic bentonite was purchased from Shanghai Baoyang Baoxin Biotechnology Co., Ltd., product number BX0161; and the 150# solvent oil was purchased from Shenyang Elapex Chemical Co., Ltd., CAS number 64742-94-5.

[0035] Examples 1-4: A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron, with the raw material amounts shown in Table 1, and the thickener being organobentonite. The preparation method of the above-mentioned dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron includes the following steps: (1) Add nicosulfuron, 2,4-methyl-4-chloroisooctyl ester and atrazine to methyl oleate, mix well, and prepare a mixture; (2) Add calcium dodecylbenzenesulfonate, tristyrylphenol polyoxyethylene ether and castor oil polyoxyethylene ether to 150# solvent oil, grind and mix evenly to obtain emulsified components; (3) Add the emulsified components to the mixture, and shear for 15 minutes at 10,000 rpm using a high-speed shearing machine. Add the thickener and shear for 15 minutes at 10,000 rpm to obtain a dispersible oil suspension.

[0036] Example 5: A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine and nicosulfuron, differing from Example 1 in that, in step (3), the emulsifying component is added to the mixture, and the mixture is sheared for 15 minutes at 10,000 rpm using a high-speed shearing machine. After adding a thickener, the mixture is sheared for 15 minutes at 10,000 rpm. Then, silicone-modified silica powder is added, and the mixture is sheared for 30 minutes at 10,000 rpm to obtain the dispersible oil suspension. The silicone-modified silica powder is prepared using the method described in Example 1 of silicone-modified silica powder preparation.

[0037] Table 1. Raw material dosage of dispersible oil suspensions in Examples 1-5

[0038] Example 6: A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine and nicosulfuron, which differs from Example 5 in that the organosilicon-modified silica powder is prepared by the method in Example 2 of Organosilicon-modified silica powder preparation.

[0039] Example 7: A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron, differing from Example 5 in that the organosilicon-modified silica powder is prepared using the method described in Example 3 of Organosilicon-modified silica powder preparation.

[0040] Example 8: A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron, differing from Example 5 in that the organosilicon-modified silica powder is replaced by silica-supported titanium dioxide powder in an equal amount. The preparation method of the silica-supported titanium dioxide powder is as follows: (1) Add 0.5g of nano-titanium dioxide and 0.3g of polycarboxylate to 50g of ethanol and stir evenly to obtain a nano-titanium dioxide dispersion; (2) Add 2g of silica to the nano-titanium dioxide dispersion, stir evenly, filter, wash, and dry at 60℃ for 24h to obtain silica-loaded titanium dioxide powder.

[0041] Example 9: A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine and nicosulfuron, which differs from Example 5 in that the organosilicon-modified silica powder is replaced by silica powder in an equal amount.

[0042] Example 10: A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine and nicosulfuron, differing from Example 1 in that tristyrylphenol polyoxyethylene ether is replaced by an equal amount of calcium dodecylbenzenesulfonate.

[0043] Example 11: A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine and nicosulfuron, differing from Example 1 in that calcium dodecylbenzenesulfonate is replaced by an equal amount of tristyrylphenol polyoxyethylene ether.

[0044] Example 12: A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine and nicosulfuron, differing from Example 1 in that castor oil polyoxyethylene ether is replaced by an equal amount of calcium dodecylbenzenesulfonate.

[0045] Example 13: A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron, differing from Example 1 in that tristyrylphenol polyoxyethylene ether and calcium dodecylbenzenesulfonate are replaced by castor oil polyoxyethylene ether in equal amounts.

[0046] Example 14: A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron, differing from Example 1 in that tristyrylphenol polyoxyethylene ether and castor oil polyoxyethylene ether are replaced by calcium dodecylbenzenesulfonate in equal amounts.

[0047] Example 15: A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron, differing from Example 1 in that calcium dodecylbenzenesulfonate and castor oil polyoxyethylene ether are replaced by tristyrylphenol polyoxyethylene ether in equal amounts.

[0048] Comparative Example 1: A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine and nicosulfuron, which differs from Example 1 in that no thickener is added.

[0049] Comparative Example 2: The dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron was replaced by an equal amount of nitro-nicosulfuron-atrazine dispersible oil suspension; the effective content of the nitro-nicosulfuron-atrazine dispersible oil suspension was 36%, and it was purchased from Shandong Dongyuan Biotechnology Co., Ltd.

[0050] Comparative Example 3: The dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron was replaced by an equal amount of nicosulfuron-atrazine dispersible oil suspension; the effective content of the nicosulfuron-atrazine dispersible oil suspension was 36%, and it was purchased from Shandong Taiyang Biotechnology Co., Ltd.

[0051] Performance testing Dispersible oil suspensions containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron were prepared according to the methods in the examples and comparative examples, and their performance was tested according to the following methods. The test results are recorded in Tables 2-4.

[0052] 1. pH value: The test shall be conducted in accordance with GB / T 1601-1993 "Determination of pH value of pesticides".

[0053] 2. Dispersion stability: Dispersion stability is measured in accordance with HG / T 2467.11-2003 *Code for Writing of Standards for Pesticide Suspension Emulsions*. The test procedure is as follows: At room temperature (23±2°C), add standard hard water to the 240mL graduation mark in two 250mL graduated cylinders respectively, add 5g of the test sample dropwise to each cylinder with a pipette. Keep the pipette as close to the water surface as possible during dropwise addition, and do not immerse it below the water surface. Finally, add standard hard water to the 250mL graduation mark. Wear cotton gloves, take the middle part of the cylinder as the axis, invert the cylinder up and down 30 times, ensure that the liquid in the cylinder flows gently without backflushing, and each inversion takes 2s. Use one cylinder for the precipitation and cream test, and the other cylinder for the redispersion test, observe the initial dispersibility of the dispersion, the dispersibility after standing for a period of time and the dispersibility after redispersion. The measurement result is qualified if it meets the following requirements: (1) Initial dispersibility: 0min dispersibility: complete dispersion; 30min dispersibility: precipitation ≤ 2.0mL, cream or floating oil ≤ 2.0mL; (2) Redispersibility: 24h dispersibility: complete dispersion; 24.5h dispersibility: precipitation ≤ 1.0mL, cream or floating oil ≤ 1.0mL.

[0054] 3. Suspension rate: The detection is carried out with reference to GB / T 14825-2006 *Method for the Determination of Suspension Rate of Pesticides*.

[0055] 4. Pourability: The detection is carried out with reference to GB / T 31737-2015 *Determination of Pourability of Pesticides*.

[0056] 5. Heat storage stability: The detection is carried out with reference to GB / T 19136-2021 *Method for Determination of Heat Storage Stability of Pesticides*. The test procedure is as follows: Seal the test sample in a glass bottle, store it in a constant temperature oven at 54±2°C for 14d, take it out, place it in a desiccator, and cool it to room temperature. Complete the determination of specified items such as the mass fraction of active ingredients within 24h. Commercial original packaging can also be directly used for the heat storage test. The product is qualified if the relative decomposition rate of the active ingredient content is less than 5.0%, and the pH value and emulsion stability still meet the standard requirements.

[0057] 6. Low temperature stability: The detection is carried out in accordance with the "suspension preparations" section of GB / T 19137-2003 *Method for Determination of Low Temperature Stability of Pesticides*. The test procedure is as follows: Take 80mL of the test sample and place it in a 100mL beaker, cool it to (0±2)°C in a refrigerator, keep it for 1h, stir once every 15min for 15s each time, and observe whether there is any change in appearance. Put the beaker back to the refrigerator, and continue to stand for 7d at (0±2)°C. After 7d, take out the beaker, restore it to room temperature, and test necessary physical and chemical indicators such as sieve analysis and suspension rate. The product is qualified if the volume of the precipitated substance does not exceed 0.3mL, and no visible particles or oily substances can be observed after slight stirring.

[0058] 7. Wetting Time: The test was conducted according to GB / T 5451-2001 "Determination of Wetting Properties of Pesticide Wettable Powders". The standard hard water was prepared using the steps in "5.2 Preparation Method Two". Experimental steps: Take 100 mL ± 1 mL of standard hard water and pour it into a 250 mL beaker. Place this beaker in a constant temperature water bath at 25℃ ± 1℃, ensuring the liquid level is flush with the water bath surface. When the hard water reaches 25℃ ± 1℃, weigh 5 g ± 0.1 g of the sample (the sample should be a representative, uniform powder, and clumps or agglomerates are not allowed). Place the sample on a watch glass and pour the entire sample evenly onto the liquid surface of the beaker from a position flush with the rim, without excessively disturbing the liquid surface. Immediately start timing with a stopwatch when adding the sample until the sample is completely wetted (the fine powder film remaining on the liquid surface is negligible). Record the wetting time (accurate to the second). Repeat this process 5 times and take the average value as the wetting time of the sample.

[0059] 8. Field Trial: The trial was conducted in cornfields with moderate fertility, where weeds were at the 3-5 leaf stage at the time of application, and where no other herbicides had been used prior to application. A two-stage dilution method was used to prepare the herbicide solution. After transferring the solution to the sprayer, the soil was thoroughly shaken to ensure a uniform solution. The entire plant was sprayed evenly. The control area was sprayed with clean water first, followed by the treatment areas (examples and comparative examples). The concentration was increased gradually, with each plot in each treatment area being sprayed evenly. The sprayer was rinsed with clean water before each application of different herbicides. The water usage was 50L per acre, and the herbicide dosage was 90ml per acre, with intervals of 7 days. d. Spraying was carried out twice. On the day of the first application, the weather at the test site was cloudy, with an air temperature of 19.4℃, a relative humidity of 85.9%, and a wind speed of 0.7m / s. On the day of the second application, the weather at the test site was cloudy, with an air temperature of 21.8℃, a relative humidity of 72.5%, and a wind speed of 0.6m / s. The plant control efficiency was recorded 7 days after the first application and 7 days after the second application. The weed control efficiency was calculated using the following formula: Plant control efficiency (%) = ((number of weeds in the control area - number of weeds in the treatment area) / number of weeds in the control area) * 100%.

[0060] Table 2. Performance test results of the dispersible oil suspension prepared in Example 1

[0061] Table 3 shows the dispersion stability test results of the dispersible oil suspensions prepared in the Examples and Comparative Example 1.

[0062] Table 4. Performance test results of suspensions in Examples 2-3 and Comparative Examples 2-3

[0063] As can be seen from Table 3, the dispersible oil suspensions containing 2,4-chloroisooctyl ester, atrazine, and nicosulfuron prepared in Examples 1-9 of this application have good dispersion stability. However, the dispersible oil suspensions containing 2,4-chloroisooctyl ester, atrazine, and nicosulfuron prepared in Examples 10-12 show decreased dispersion stability due to the partial absence of emulsifying components. This indicates that the combined use of calcium dodecylbenzenesulfonate, tristyrylphenol polyoxyethylene ether, and castor oil polyoxyethylene ether helps to improve the dispersibility of the active components. The dispersible oil suspensions containing 2,4-chloroisooctyl ester, atrazine, and nicosulfuron prepared in Examples 13-15 and Comparative Example 1 show unsatisfactory dispersion stability due to the lack of emulsifying components or thickeners, resulting in the separation of the active components.

[0064] As can be seen from Table 4, the dispersible oil suspensions containing 2,4-chloroisooctyl ester, atrazine, and nicosulfuron prepared in Examples 1-4 of this application have good wetting properties and control effects. In Examples 5 and 6, organosilicon-modified silica powder was added during the preparation of the dispersible oil suspensions containing 2,4-chloroisooctyl ester, atrazine, and nicosulfuron. Compared with Example 1, the dispersible oil suspensions prepared in Examples 5-6 have improved wetting properties and control effects. This is because silica increases the suspension of the formulation, organosilicon improves the wetting properties, and titanium dioxide prevents the degradation of the active ingredients.

[0065] In Examples 10-12, during the preparation of dispersible oil suspensions containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron, only two of the following were added as emulsifiers: calcium dodecylbenzenesulfonate, tristyrylphenol polyoxyethylene ether, and castor oil polyoxyethylene ether. Compared to Example 1, the wetting properties of the dispersible oil suspensions containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron prepared in Examples 10-12 decreased, resulting in a reduced control effect.

[0066] Comparative Examples 2 and 3 used nitrile-atrazine-dispersible oil suspension and nicosulfuron-dispersible oil suspension, respectively, instead of the dispersible oil suspension containing 2,4-chloroisooctyl ester, atrazine, and nicosulfuron. Compared with Example 1, the control effect of the suspensions prepared in Comparative Examples 2 and 3 was reduced, mainly because their wetting properties were lower than those of the dispersible oil suspension prepared in this application.

[0067] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron, characterized in that, Raw materials including the following percentages by mass: Active ingredient 33.7-38.3%, emulsifying component 14-18%, thickener 0.3-0.7%, methyl oleate to make up to 100%; The active ingredients include nicosulfuron, 2,4-methylchloroisooctyl ester and atrazine; The mass percentage of nicosulfuron, 2,4-methyl-4-chloroisooctyl ester and atrazine in the dispersible oil suspension is 3.6-4.4%:11.3-12.7%:18.8-21.2%.

2. The dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron according to claim 1, characterized in that, The mass percentage ratio of nicosulfuron, 2,4-methyl-4-chloroisooctyl ester and atrazine in the dispersible oil suspension is 4%:12%:20%.

3. The dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron according to claim 1, characterized in that, The emulsifying components are calcium dodecylbenzenesulfonate, tristyrylphenol polyoxyethylene ether, castor oil polyoxyethylene ether, and 150# solvent oil.

4. The dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron according to claim 3, characterized in that, The mass ratio of the calcium dodecylbenzenesulfonate, tristyrylphenol polyoxyethylene ether, castor oil polyoxyethylene ether, and 150# solvent oil is 1:1:1-3:

1.

5. The dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron according to claim 1, characterized in that, The thickener is at least one of organoclay and polyamide wax.

6. The dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron according to claim 1, characterized in that, The dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron also includes silicone-modified silica powder, wherein the mass ratio of the silicone-modified silica powder to the active component is 0.6-0.8:30-40. The preparation method of the organosilicon-modified silica powder includes the following steps: (1) Add nano-titanium dioxide and polycarboxylate to ethanol and stir evenly to obtain nano-titanium dioxide dispersion; (2) Add silica to nano-titanium dioxide dispersion and stir evenly to obtain silica suspension; (3) Heat and stir the silica suspension at 55-65℃ for 30-40 minutes, add ammonia water, stir evenly, add organosilicon, react for 20-22 hours, filter, wash and dry to obtain organosilicon modified silica powder.

7. The dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron according to claim 6, characterized in that, The mass ratio of nano-titanium dioxide, organosilicon, and precipitated silica is 0.3-0.5:0.7-0.9:1-2.

8. A method for preparing a dispersible oil suspension containing 2,4-methylchloroisooctyl ester, atrazine, and nicosulfuron according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Add nicosulfuron, 2,4-methyl-4-chloroisooctyl ester and atrazine to methyl oleate, mix well, and prepare a mixture; (2) Add the emulsified components to the mixture, shear, add thickener, shear for 5-10 minutes to obtain a dispersible oil suspension.

9. The method for preparing a dispersible oil suspension containing 2,4-methyl-4-chloroisooctyl ester, atrazine, and nicosulfuron according to claim 8, characterized in that, In step (2), after adding thickener and shearing for 5-10 minutes, add organosilicon-modified silica and shear to obtain a dispersible oil suspension.

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