Mesotrione soybean oil suspending agent and preparation process thereof

Abstract

The invention discloses a mesotrione soybean oil suspending agent and a preparation process thereof, and relates to the technical field of pesticides. The mesotrione soybean oil suspending agent is prepared from the following raw materials in percentage by mass: 15 to 25 percent of mesotrione active compound, 8 to 16 percent of auxiliary agent, 10 to 25 percent of methyl oleate, 2 to 5 percent of solvent, 0.1 to 3 percent of auxiliary material, 0.1 to 0.2 percent of pH regulator and the balance of soybean oil. The preparation method of the mesotrione soybean oil suspending agent specifically comprises the following steps: uniformly mixing the raw materials of the mesotrione soybean oil suspending agent, and shearing at a high shearing rate for 5-15 minutes; and sanding the mesotrione soybean oil suspension with zirconia beads for 1-3 hours to obtain the mesotrione soybean oil suspension. Experimental results show that the mesotrione soybean oil suspending agent provided by the invention has relatively good suspension property and emulsifying property.

Description

Technical Field

[0001] The invention relates to the technical field of pesticides, in particular to a mesotrione soybean oil suspension concentrate and a preparation process thereof. Background Art

[0002] Mesotrione is a highly effective HPPD inhibitor herbicide, primarily used to control broadleaf weeds and some grass weeds in corn fields. Its mechanism of action is to inhibit the enzyme p-hydroxyphenylpyruvate dioxygenase (HPPD) in plants, thereby affecting carotenoid biosynthesis, causing weed bleaching and eventual death. Mesotrione is widely used due to its advantages, including low application rates, low soil residues, and safety for the environment and subsequent crops.

[0003] However, when mesotrione is directly prepared or used, due to its low solubility in water (0.16 mg / mL at 20°C), it is impossible to form a uniform solution and cannot effectively kill weeds. Secondly, mesotrione used directly may not be able to stably adhere to the surface of weeds and can be easily washed away by rainwater, reducing the weed control effect.

[0004] To improve the dispersibility of mesotrione in water, the existing technology often uses a dispersion medium to prepare the original pesticide as a suspension concentrate. This formulation improves the dispersibility of the original pesticide, making it easier to mix with water, forming a uniform solution, thereby enhancing herbicidal efficacy and pesticide utilization efficiency. However, mesotrione suspensions currently have many problems, such as: 1. The stability of mesotrione preparations is not ideal. It cannot maintain a milky white liquid state with good fluidity for a long time. It is easy to aggregate and separate oil, resulting in solidification, bottoming, and becoming viscous. 2. The preparation is inconvenient to store and use; 3. The preparation system is unstable and prone to sedimentation, causing solidification and bottoming.

[0005] In summary, it is of great significance to solve the above problems and prepare a mesotrione soybean oil suspension concentrate and its preparation process. Summary of the Invention

[0006] The object of the present invention is to provide a mesotrione soybean oil suspension concentrate and a preparation process thereof, so as to solve the problems raised in the prior art.

[0007] To achieve the above object, the present invention provides the following technical solutions: A mesotrione soybean oil suspension concentrate comprises the following raw materials, calculated by mass: 15-25% mesotrione technical, 8-16% adjuvant, 10-25% methyl oleate, 2-5% solvent, 0.1-3% auxiliary material, 0.1-0.2% pH regulator, and the remainder being soybean oil.

[0008] Preferably, the pH adjuster is citric acid, and the pH of the mesotrione soybean oil suspension concentrate is 3-4.

[0009] Among them, pH has a great influence on the decomposition rate of mesotrione technical. When the pH is 3-4, it is relatively stable and the decomposition rate is less than 5%.

[0010] Preferably, the solvent includes one or more of 150# solvent oil, dichloromethane, and glycerin; and the auxiliary material includes one or more of organic bentonite and white carbon black.

[0011] The auxiliary agent is 7210-C, which includes the following substances, calculated by mass: 1 to 5 parts of fatty alcohol polyoxyethylene ether, 1 to 3 parts of styrene phenol polyoxyethylene ether, 1 to 2 parts of phenolic resin polyoxyethylene ether, and 1 to 3 parts of fatty alcohol ether phosphate.

[0012] Among them, the selection of additives is divided into three steps: emulsification, dispersion, and wetting and penetration: (1) The emulsification part is similar to the emulsifiable concentrate formulation, and is made of a compound of anionic emulsifiers and nonionic emulsifiers. This not only increases the emulsification and dispersion ability, but also reduces the amount of emulsifier used. Anionic surfactants can make the surface of solid particles have the same charge and repel each other, preventing particle aggregation. Nonionic and nonionic surfactants are compounded to form a dense protective film on the surface adsorption surface of the particles in a molecular state, repelling each other by the effect of steric hindrance. (2) Dispersants are substances that can reduce the aggregation of solid or liquid particles in the dispersion system. According to the structure of surfactants, surfactants are usually divided into linear and network structures. From the perspective of dispersion performance alone, linear surfactants are not as good as network surfactants in dispersion. They better reflect steric hindrance and can solve the phenomenon of particle self-aggregation and solidification. For example, the OP series and 600# series have stronger dispersion ability than the BY series and AEO series. (3) Wetting and penetrating agents are substances that increase the contact of the drug-containing liquid with the solid surface of the treatment object (plants, pests, etc.), causing it to wet and penetrate or accelerate the wetting and penetration process. Commonly used wetting and penetrating agents include fatty alcohol polyoxyethyl ether, nonylphenol polyoxyethyl ether, octylphenol polyoxyethyl ether, octanol polyoxyethyl ether, and some imported wetting and penetrating agents, such as Dow's. Based on the above understanding, different nonionic and anionic, different dispersants, and different wetting and penetrating agent varieties are selected for compounding in the research of mesotrione dispersible oil suspension. Different compounding can improve the superiority of performance, increase dispersion, and speed up the wetting and penetration time.

[0013] Preferably, the mesotrione soybean oil suspension concentrate further comprises 5-10% modified soybean oil.

[0014] Preferably, the preparation method of the modified soybean oil is: (1) Preparation of the modifier: Add 2-allyl-1,3-cyclohexanedione to acetone, stir evenly, add mercapto-triethylene glycol-amino and benzoin dimethyl ether, stir under ultraviolet light for 3-4 hours, purify, and evaporate to obtain the modifier; (2) Add epoxidized soybean oil and modifier into acetone and fully dissolve them. Stir at 80-90 °C for 70-80 h under nitrogen atmosphere, purify, and evaporate to obtain modified soybean oil.

[0015] The modifier comprises the following raw materials, calculated by mass: 4 to 6 parts of 2-allyl-1,3-cyclohexanedione, 25 to 28 parts of mercapto-triethylene glycol-amino, and 1 to 2 parts of benzoin dimethyl ether; The modified soybean oil comprises the following raw materials, calculated by mass: 9 to 11 parts of epoxidized soybean oil and 23 to 25 parts of a modifier.

[0016] Preferably, the preparation process of the mesotrione soybean oil suspension concentrate comprises the following steps: uniformly mixing the raw materials of the mesotrione soybean oil suspension concentrate, first shearing them at a high shear rate for 5 to 15 minutes; and then sand-milling them with zirconium oxide beads for 1 to 3 hours to obtain the mesotrione soybean oil suspension concentrate.

[0017] Preferably, the high shear rate parameter is 2000-4000 r / min; the mass ratio of the mesotrione soybean oil suspension concentrate raw material to the zirconium oxide beads is 100:150; the particle fineness of the mesotrione soybean oil suspension concentrate is 2-6 μm; and the temperature of the sand milling process should be controlled to be less than 30°C.

[0018] Compared with the prior art, the present invention has the following advantages: (1) Emulsification and dispersion performance is an important indicator for evaluating dispersible oil suspensions. Selecting a suitable surfactant can control the suspension rate of mesotrione, improve its emulsification in water, reduce oil separation, and increase its viscosity. The surfactants of the present invention, i.e., adjuvants, include emulsifiers, dispersants, wetting and penetrating agents, and polymer network surfactants. The added emulsifier is a compound of anionic emulsifiers and nonionic emulsifiers. This not only increases the emulsification and dispersion ability, but also reduces the amount of emulsifier used. Anionic surfactants can make the surface of solid particles carry the same charge and repel each other, preventing particle aggregation. The combination of anions and nonionics forms a dense protective film on the surface adsorption surface of the particles in a molecular state, repelling each other by the effect of steric hindrance. Adding a dispersant helps reduce the aggregation of solid or liquid particles in the dispersed system and improve the suspension performance. Adding a wetting and penetrating agent increases the wetting and penetration speed of the dispersible oil suspension, thereby increasing its permeability and improving its efficacy. Adding a high molecular surfactant with a network structure can improve the stability of the preparation. When combined with organic bentonite or white carbon black, it can increase viscosity and reduce stratification, thereby solving problems such as bottom consolidation.

[0019] (2) The present invention uses methyl oleate and soybean oil as dispersion media, allowing the solid technical drug to be presented in liquid form even when it is insoluble in organic solvents. Methyl oleate has a relatively low density, and when used as a dispersible oil suspension medium, the density difference between it and the solid is relatively large. Therefore, the present invention adds 150# solvent oil, which has a relatively high density, or soybean oil, which has a relatively high viscosity, as a solvent, and mixes it with methyl oleate in different ratios to improve the viscosity or density, thereby reducing stratification of the preparation.

[0020] (2) The present invention also replaces part of the soybean oil in the dispersion medium with epoxy soybean oil, and uses a modifier synthesized from 2-allyl-1,3-cyclohexanedione and mercapto-triethylene glycol-amino to modify it, and then compound it with soybean oil. The benefits are as follows: the main structure of mesotrione is a benzoylcyclohexanedione skeleton, and 2-allyl-1,3-cyclohexanedione has a similar cyclohexanedione structure, which can improve the compatibility between the dispersion medium and mesotrione and promote the dispersion of the drug in the suspension; the epoxy soybean oil has multiple active units and can be grafted with more triethylene glycol structures, which helps to greatly enhance its hydrophilic and lipophilic properties, further enhancing the dispersion of the drug, and its network structure can also form a protective layer around the drug particles. This protective layer prevents aggregation and precipitation between drug particles through steric hindrance, thereby improving the stability of the suspension. At the same time, the flexibility and hydrophilicity of its molecular chain help to reduce the viscosity of the suspension, making it easy to flow and pump.

[0021] Preferably, the present invention also studies the effects of process and formulation on mesotrione preparations: (1) Influence of sand mill temperature: According to our experimental data, the lower the sand milling temperature, the better the sand milling effect and the smaller the particle size of the solid technical drug. It is better when the technical drug solid content is not very high below 35 degrees; while in the case of high content or multi-component compounding, it is recommended to keep the sand milling temperature below 30 degrees. The higher the sand milling temperature, the greater the impact on the formulation system, which will cause thickening, paste formation, etc., and once this is formed, the result is irreversible; (2) The effect of particle size on the formulation system: The smaller the particle size, the better the emulsification performance and drug efficacy, and the slower the particle settling rate. It is best to grind the solid raw drug to a smaller particle size without overheating during the production process. Currently, the best results on the market can reach 3um, and 5um is better. Most of the formulations on the market that ensure stability are between 8 and 9um.

[0022] (3) The influence of viscosity and fluidity: The greater the viscosity, the worse the relative fluidity, and the better the fluidity, the smaller the relative viscosity, and the two are inversely proportional. In order to achieve the best oil separation range while ensuring storage stability, this places extremely high demands on the process and formulation. Large-scale production needs to adjust the optimal state that suits its own process. There are many factors that affect fluidity, such as poor antifreeze properties of the dispersion medium or excessive viscosity of the system. The inherent problems of the drug itself may also affect whether it is suitable for use as a dispersible oil suspension.

[0023] (4) The impact of the effective content of the active ingredient on the formulation system: The formulation of high-content system has always been a problem for dispersible suspending agents. It is easy to solidify, agglomerate, and flocculate at high temperatures. At present, we have found some suitable dispersants after a large number of tests and screening of suitable dispersants. At present, high-content formulations with a content of less than 40% are relatively stable when stored at room temperature for half a year. They will not solidify after 14 days of hot storage and can be restored after shaking. The viscosity is slightly higher, and the higher the content, the higher the dispersion requirements. The emulsification performance will be weakened in all aspects. When the amount of emulsifier remains unchanged. The formulation of high-content system needs to be further studied. In particular, the multi-component high-content system is not very stable. The requirements for the control of raw materials for process products are very high. DETAILED DESCRIPTION

[0024] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0025] It should be noted that the purchase manufacturers of all raw materials involved in the present invention are not subject to any special restrictions and exemplarily include: auxiliary agent: 7210-C, ingredients including: fatty alcohol polyoxyethylene ether, styrene phenol polyoxyethylene ether, phenolic resin polyoxyethylene ether, fatty alcohol ether phosphate, all of the above raw materials belong to the company's products Nanjing Taihua Chemical Co., Ltd.; 2-allyl-1,3-cyclohexanedione, CAS: 42738-68-1, provided by Jinjinle (Hunan) Chemical Co., Ltd.; mercapto-triethylene glycol-amino, CAS: 1189760-69-7, provided by Shandong Dongde New Materials Co., Ltd., epoxidized soybean oil, CAS: 8013-07-8, provided by Nantong Runfeng Petrochemical Co., Ltd.

[0026] In the following examples, parts by mass are used and all raw materials are commercially available.

[0027] The following examples include the following steps: each example is to weigh each raw material according to the formula in the table, then uniformly mix the raw materials, first shear at a high shear rate for 10 minutes; then sand mill with zirconium oxide beads for 2 hours to obtain a mesotrione soybean oil suspension concentrate.

[0028] Among them, the auxiliary agent is 7210-C, which includes the following substances in parts by mass: 3 parts of fatty alcohol polyoxyethylene ether, 2 parts of styrene phenol polyoxyethylene ether, 2 parts of phenolic resin polyoxyethylene ether, and 2 parts of fatty alcohol ether phosphate.

[0029] Among them, in Examples 18 to 20: the modified soybean oil preparation method comprises the following steps: (1) Preparation of the modifier: Add 5 parts of 2-allyl-1,3-cyclohexanedione to 75 parts of acetone, stir evenly, add 26 parts of mercapto-triethylene glycol-amino and 1.5 parts of benzoin dimethyl ether, stir under ultraviolet light for 3.5 hours, purify, and evaporate to obtain the modifier; (2) 10 parts of epoxidized soybean oil and 24 parts of modifier were added to 80 parts of acetone and fully dissolved. The mixture was stirred at 85°C for 75 hours under a nitrogen atmosphere, purified, and evaporated to obtain modified soybean oil.

[0030] Examples 1 to 5: Table - Examples 1 to 5

[0031] Examples 6 to 10: Table - Examples 6 to 10

[0032] Examples 11 to 15: Table - Examples 11 to 15

[0033] Examples 16-20: Table - Examples 16 to 20

[0034] Performance test: (1) According to GB / T 19136-2021 "Determination of thermal storage stability of pesticides", the samples of Examples 1 to 15 were stored at room temperature for 14 days and in a constant temperature box at 54℃±2℃ for 14 days, and the oil separation was measured. The experimental data are shown in Table 1; (2) The suspension rate of Examples 16 to 20 was tested: After each sample was treated according to the performance test (1) hot storage method, it was added into water to observe the emulsification and dispersion, and judged as excellent, good, or poor. Then, according to GB / T 14825-2023 "Determination of suspension rate of pesticides", 25% mesotrione suspension concentrate was weighed and prepared into 250mL suspension. The suspension was transferred to a 250mL measuring cylinder, and 25mL of the suspension at the bottom was taken for measurement. The suspension rate was calculated. The experimental data are shown in Table 2 as the suspension rate.

[0035] Table 1

[0036] Table 2

[0037] Conclusion: (1) As can be seen from Table 1, in the nitrate OD0001~OD0003, the pure methyl oleate system has a low viscosity and a lot of oil separation. It is easy to cause solidification, flocculation, and severe stratification when stored for a long time; the pure soybean oil system has a high viscosity and is easy to paste, the discharge material is viscous and the discharge loss is large. It becomes frozen during hot storage and can be restored after shaking, but the oil separation rate is low; the pure white oil system has a moderate viscosity and poor dispersion in the emulsified water state, and the hot storage oil separation is also high, which is not suitable for use; Therefore, the nitrate OD0007~OD00010 tried to use a compound dispersion medium, and supplemented it with 150# solvent oil, dichloromethane, and glycerol as solvents, but the oil separation rate of the suspending agent was still poor; Therefore, the present invention explored the content of mesotrione at 25%, From Table 1, OD00011~OD00015, it can be seen that when the content of mesotrione is 25%, the mixed compound system formed by 15% methyl oleate, 15% 150# solvent oil and soybean oil has moderate viscosity, little oil separation and good storage, so the proportioning is based on this; (2) From Table 2, it can be seen that compared with mesotrione OD006, mesotrione OD007 adds 3.5% 150# solvent oil, and the performance of the suspension agent is enhanced. It may be that the density of 150# solvent oil and mesotrione is close, which can further improve the surface tension and thixotropy of the suspension agent; From OD008, it can be seen that a part of soybean oil has been modified into the cyclohexanedione skeleton and the active agent structure, and the suspension agent of the suspension agent is further enhanced.

[0038] In summary, the present invention successfully provides a mesotrione soybean oil suspension concentrate and a preparation process thereof through ratio adjustment research, which has good suspension and emulsification effects. At the same time, since there is no relevant product certificate for 25% mesotrione on the market, the present invention can also be regarded as a technical reserve, which can provide inspiration for other technical materials. Through experiments on other technical materials, the viscosity of the formula can be adjusted to improve the suspension rate, and the stratification of some technical materials with high density can be reduced and the suspension rate can be improved.

[0039] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A mesotrione soybean oil suspension concentrate, characterized in that: The mesotrione soybean oil suspension concentrate comprises the following raw materials: by mass fraction, 15-25% of mesotrione technical, 8-16% of adjuvant, 10-25% of methyl oleate, 2-5% of solvent, 0.1-3% of auxiliary material, 0.1-0.2% of pH regulator, and the rest is soybean oil.

2. A mesotrione soybean oil suspension concentrate according to claim 1, characterized in that: The pH regulator is citric acid, and the pH of the mesotrione soybean oil suspension concentrate is 3-4.

3. The mesotrione soybean oil suspension concentrate according to claim 1, wherein: The solvent includes one or more of 150# solvent oil, dichloromethane, and glycerin; and the auxiliary material includes one or more of organic bentonite and white carbon black.

4. The mesotrione soybean oil suspension concentrate according to claim 1, wherein: The auxiliary agent is 7210-C, which includes the following substances, calculated by mass: 1 to 5 parts of fatty alcohol polyoxyethylene ether, 1 to 3 parts of styrene phenol polyoxyethylene ether, 1 to 2 parts of phenolic resin polyoxyethylene ether, and 1 to 3 parts of fatty alcohol ether phosphate.

5. The mesotrione soybean oil suspension concentrate according to claim 1, wherein: The mesotrione soybean oil suspension concentrate further comprises 5-10% of modified soybean oil.

6. The mesotrione soybean oil suspension concentrate according to claim 5, characterized in that: The preparation method of the modified soybean oil is: (1) Preparation of the modifier: Add 2-allyl-1,3-cyclohexanedione to acetone, stir evenly, add mercapto-triethylene glycol-amino and benzoin dimethyl ether, stir under ultraviolet light for 3-4 hours, purify, and evaporate to obtain the modifier; (2) Add epoxidized soybean oil and modifier into acetone and fully dissolve them. Stir at 80-90 °C for 70-80 h under nitrogen atmosphere, purify, and evaporate to obtain modified soybean oil.

7. The mesotrione soybean oil suspension concentrate according to claim 6, characterized in that: The modifier comprises the following raw materials, calculated by mass: 4 to 6 parts of 2-allyl-1,3-cyclohexanedione, 25 to 28 parts of mercapto-triethylene glycol-amino, and 1 to 2 parts of benzoin dimethyl ether; The modified soybean oil comprises the following raw materials, calculated by mass: 9 to 11 parts of epoxidized soybean oil and 23 to 25 parts of a modifier.

8. A process for preparing a mesotrione soybean oil suspension concentrate according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: uniformly mixing raw materials of mesotrione soybean oil suspension concentrate, first shearing them at a high shear rate for 5 to 15 minutes; and then sand-milling them with zirconium oxide beads for 1 to 3 hours to obtain the mesotrione soybean oil suspension concentrate.

Images