A picoxystrobin-difenoconazole microemulsion and its preparation method

Abstract

The present invention provides a picoxystrobin-difenoconazole microemulsion, characterized by comprising the following ingredients by weight: 5-15% picoxystrobin, 5-15% difenoconazole, 5-25% organic solvent, 1-10% cosolvent, 10-30% surfactant, 0.01-0.1% defoamer, 1-10% antifreeze, and 100% water. The microemulsion prepared by the present invention can meet water quality requirements in different regions, has excellent antifreeze effects, making it suitable for storage conditions in northern winters, and improves the biological activity of the agent, reduces the dosage of pesticides, and is environmentally friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of pesticides, in particular to a picoxystrobin-difenoconazole microemulsion and a preparation method thereof. Background Art

[0002] Pesticides are the primary means of combating agricultural and forestry diseases, insect pests, and weeds, ensuring increased agricultural production and income. They are also a key tool for public health pest control, contributing to human health and safety. For a long time, the irrational use of chemical pesticides has led to a series of difficult-to-solve problems, including excessive pesticide residues in agricultural products, ecological pollution, the development of pesticide resistance in pests, and threats to human health. Furthermore, the high cost, high risk, and long production cycles of new pesticides make it difficult to meet the demand for highly effective and safe pesticides in the short term. Therefore, the research on pesticide formulations is a crucial aspect of pesticide development. A well-designed formulation maximizes the effectiveness of the active ingredient, ensuring maximum target coverage, reducing pesticide dosage, facilitating its use, and minimizing environmental impact.

[0003] Pesticide microemulsions (MEs) are a new pesticide formulation developed in the 1970s. They are transparent, single-phase liquid formulations using water as the dispersion medium, with no or minimal organic solvents, and containing appropriate amounts of surfactants and other adjuvants. By replacing large amounts of organic solvents with water, microemulsions reduce environmental stress during production and after application, making them an environmentally friendly pesticide formulation.

[0004] Picoxystrobin belongs to the strobilurin class of fungicides, inhibiting mitochondrial respiration through electron transfer between cytochrome b and C1. Difenoconazole, a triazole fungicide, acts by inhibiting ergosterol biosynthesis in pathogenic cells, exhibiting protective and therapeutic effects and possessing strong systemic conductivity.

[0005] Patent document CN108522517 A discloses the use of a fungicide composition containing picoxystrobin and difenoconazole to reduce or prevent infection of peanuts by Cercospora arachidis and Cercospora arachidis. The patent describes the formulations as wettable powders, emulsifiable concentrates, suspension concentrates, suspoemulsions, microcapsules, seed coatings, microemulsions, aqueous emulsions, water-dispersible granules, foams, ointments, aerosols, ultra-low volume sprays, and granules. There are no examples of preparing microemulsions. Patent document CN102204544A discloses a synergistic fungicide composition containing picoxystrobin, but the formulation does not disclose a microemulsion. A search of the pesticide information website reveals only suspension concentrates among the known combinations of picoxystrobin and difenoconazole (PD20200926, PD20182962, PD20182939, and PD20182391). In addition, during the early development of the suspension concentrate formulation of picoxystrobin + difenoconazole, no matter how the types or proportions of adjuvants were adjusted, the particle size would increase significantly. Moreover, whether at room temperature or after hot storage experiments, there was a phenomenon of paste formation or obvious crystal precipitation, posing a high risk in storage and transportation.

[0006] To meet the water quality requirements of different regions, enhance the product's antifreeze effect so that it can adapt to the storage conditions in northern winters, and improve the biological activity of the agent and reduce the dosage of pesticides, our company has developed a picoxystrobin-difenoconazole microemulsion product. Summary of the Invention

[0007] The purpose of the present invention is to provide a picoxystrobin-difenoconazole microemulsion and a preparation method thereof, so as to enhance the antifreeze effect of the preparation, improve the biological activity of the preparation, and meet the water quality requirements of different regions.

[0008] The present invention provides the following technical solutions:

[0009] A picoxystrobin-difenoconazole microemulsion comprises the following ingredients in percentage by weight: 5-15% of picoxystrobin, 5-15% of difenoconazole, 5-25% of an organic solvent, 1-10% of a cosolvent, 10-30% of a surfactant, 0.01-0.1% of a defoamer, 1-10% of an antifreeze agent, and water to make up to 100%.

[0010] A picoxystrobin-difenoconazole microemulsion comprises the following ingredients in percentage by weight: 8-12% of picoxystrobin, 8-12% of difenoconazole, 5-25% of an organic solvent, 1-10% of a cosolvent, 10-30% of a surfactant, 0.01-0.1% of a defoamer, 1-10% of an antifreeze agent, and water to make up to 100%.

[0011] A picoxystrobin-difenoconazole microemulsion comprises the following ingredients in percentage by weight: 10% of picoxystrobin, 10% of difenoconazole, 5-25% of an organic solvent, 1-10% of a cosolvent, 10-30% of a surfactant, 0.01-0.1% of a defoaming agent, 1-10% of an antifreeze agent, and water to make up to 100%.

[0012] The organic solvent is selected from at least one of vegetable oil solvents, coal tar cracking products, petroleum cracking solvents and synthetic environmentally friendly solvents;

[0013] The cosolvent is selected from at least one of propylene carbonate, ethanol, dimethyl sulfoxide, and N,N-dimethylacetamide;

[0014] The surfactant is selected from at least one of dodecylphenol polyoxyethylene ether, hydroxypolyethylene oxide Ethylan NS-500LQ, agricultural milk series, Tween series, castor oil polyoxyethylene ether, and fatty amine polyoxyethylene ether;

[0015] The defoaming agent is selected from at least one of polyoxypropylene glycerol ether and silicone;

[0016] The antifreeze agent is selected from at least one of ethylene glycol and glycerol;

[0017] The water is selected from tap water, distilled water or deionized water.

[0018] A picoxystrobin-difenoconazole microemulsion comprises the following steps: dissolving picoxystrobin technical and difenoconazole technical in an organic solvent and a cosolvent according to formulation requirements, then adding a surfactant and other auxiliary agents, mixing and stirring to dissolve the mixture to form an oil phase; directly adding water to the oil phase under stirring at 60-200 r / min, stirring for 15-45 minutes to obtain a transparent liquid; and then conducting quality testing.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] The microemulsion prepared by the present invention can meet the water quality requirements of different regions, has excellent antifreeze effect, and can adapt to the storage conditions in northern winter. It can also improve the biological activity of the agent, reduce the dosage of pesticides, and be environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 : Preparation 1 was stored at -10°C for 14 days without crystal precipitation

[0022] Figure 2 : Preparation 1 is stable after dilution with 2 times hard water and 200 times tap water DETAILED DESCRIPTION

[0023] 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.

[0024] The present invention will be further explained below with reference to specific embodiments.

[0025] Example 1 20% Picoxystrobin·Difenoconazole Microemulsion Formulation

[0026] The invention comprises the following components in percentage by weight: 10% of picoxystrobin, 10% of difenoconazole, 5-25% of an organic solvent, 1-10% of a cosolvent, 10-30% of a surfactant, 0.01-0.1% of a defoaming agent, 1-10% of an antifreeze agent, and water to make up to 100%.

[0027] The organic solvent is selected as light aromatic solvent naphtha s-150;

[0028] The cosolvent is selected from one or more of ethanol, isobutanol, propylene carbonate, and N,N-dimethylacetamide;

[0029] The surfactant is selected from one or more of dodecylphenol polyoxyethylene ether, hydroxy polyethylene oxide (Ethylan NS-500LQ), tristyrylphenol polyoxyethylene polyoxypropylene ether, calcium dodecylbenzenesulfonate, and Agrilan 755;

[0030] Defoaming agent: polyoxypropylene glycerol ether;

[0031] Antifreeze: ethylene glycol

[0032] The water selected is: deionized water.

[0033] The preparation method is as follows: according to the formula requirements, picoxystrobin technical and difenoconazole technical are dissolved in an organic solvent and a cosolvent, and then a surfactant and other auxiliary agents are added, mixed, stirred and dissolved to form an oil phase; under stirring at 100 r / min, tap water is directly added to the oil phase and stirred for 30 minutes to obtain a transparent liquid.

[0034] The specific formulation composition is shown in Table 1-2.

[0035] Table 1 20% picoxystrobin·difenoconazole microemulsion formulation (emulsifier variables)

[0036]

[0037] Table 2 20% picoxystrobin·difenoconazole microemulsion formulation (cosolvent variables)

[0038]

[0039]

[0040] Example 2: Determination of the transparent temperature range of 20% picoxystrobin·difenoconazole microemulsion

[0041] Transparency Temperature Range Test: Conducted in accordance with HG / T 2467.10-2003. Place 10 mL of sample in a 25 mL test tube and stir up and down with a stirring rod. Gradually cool the sample in an ice bath until turbidity or freezing occurs. The temperature at this turning point is the lower limit of the transparency temperature, t1. Place the test tube in a water bath and slowly heat it at a rate of 2°C / min. Record the temperature at which turbidity occurs, which is the upper limit of the transparency temperature, t2. The transparency temperature range is t1-t2.

[0042] Test results: As shown in Table 3, the transparent temperature range of formulation 1 is -12-60°C, the transparent temperature range of formulation 5 is -11-60°C, and the transparent temperature ranges of formulations 2-4 and 6-10 are relatively narrow.

[0043] According to the formula analysis of formulas 1, 5 and formulas 2-4, the selection of a composite surfactant of dodecylphenol polyoxyethylene ether and hydroxypolyethylene oxide as the surfactant in the microemulsion can enhance the antifreeze effect of the microemulsion and can adapt to the storage conditions in northern winter.

[0044] According to the comparative analysis of formula 1 and formulas 6-10, the selection of ethanol and propylene carbonate composite cosolvent in the microemulsion can enhance the antifreeze effect of the microemulsion and adapt to the storage conditions in northern winter.

[0045] Table 3 Transparent temperature range of 20% picoxystrobin·difenoconazole microemulsion

[0046]

[0047]

[0048] Example 3: Stability test of 20% picoxystrobin·difenoconazole microemulsion

[0049] Thermal storage stability test: carried out in accordance with GB / T 19136-2021.

[0050] Low temperature stability test: carried out in accordance with GB / T 19137-2003.

[0051] Test Results: As shown in Table 4, the choice of excipients in the microemulsion formulation significantly affects the thermal storage stability and low-temperature stability of the formulation. Formulations 1, 4, 5, 6, and 7 can produce products with acceptable stability.

[0052] Table 4 Stability test of 20% picoxystrobin·difenoconazole microemulsion

[0053]

[0054] Example 4 -10°C cold storage stability test of 20% picoxystrobin·difenoconazole microemulsion.

[0055] According to the low-temperature stability requirements of GB / T 19137-2003, pesticide formulations must be stored at 0°C for 7 days without crystallization or precipitation. To enhance the product's frost resistance and adapt it to winter storage conditions in northern China, destructive testing was conducted during development. Following the validation conditions of 14 days of cold storage at -10°C, the microemulsion formulations of Formulations 1 and 5 were stable without crystal precipitation after 14 days of storage at -10°C. Formulations 2-4, 6-9 exhibited varying degrees of crystal precipitation after 14 days of storage at -10°C. Figure 1 The formulation 1 shown did not precipitate crystals after being stored at a low temperature of -10°C for 14 days.

[0056] Example 5 Dilution stability determination of 20% picoxystrobin·difenoconazole microemulsion

[0057] The liquid preparation was diluted with 2 times hard water and 200 times tap water, and its emulsion stability was observed within 1 hour. Figure 2 As shown, formulation 1 is stable in 2x hard water and 200x dilution with tap water, meeting the water quality requirements of different regions. Formulations 2-4 and 6-9 are not stable.

[0058] Example 6 Preparation 1 Formulation Performance Test

[0059] Table 5: Comparison of Preparation 1 before and after hot and cold storage

[0060]

[0061] Example 7: Field efficacy of 20% picoxystrobin-difenoconazole microemulsion against watermelon anthracnose

[0062] Test agents: Preparation 1, Preparation 5; PD20182391 (40% benzyl chloride and chlorpyrifos suspension); PD20200926 (30% benzyl chloride and chlorpyrifos suspension)

[0063] Test method: The test was set up with test agents and control treatments (Table 5), with 4 repetitions and random arrangement of plots. Watermelon seedlings were sprayed with pesticides twice in succession at the early stage of disease. A backpack manual sprayer was used to evenly spray the whole plant at a water consumption of 750 L / hm2.

[0064] Investigation and Statistics: This experiment was conducted 14 days after the last application of the pesticide. Five random survey points were surveyed in each plot, with three stems and 10 leaves from each stem inspected from top to bottom. The number of diseased leaves at each level was recorded, and the disease index and control efficacy were calculated. The DMRT method was used to determine the significance of differences between treatments.

[0065] The grading standards for watermelon anthracnose (based on leaves) are:

[0066] Level 0: no lesions;

[0067] Level 1: The lesion area accounts for less than 5% of the entire leaf area;

[0068] Level 3: The lesion area accounts for 6% to 10% of the entire leaf area;

[0069] Level 5: The lesion area accounts for 11% to 25% of the entire leaf area;

[0070] Level 7: The lesion area accounts for 26% to 50% of the entire leaf area;

[0071] Level 9: The lesion area accounts for more than 50% of the entire leaf area.

[0072] Calculation is performed according to the following formula:

[0073]

[0074]

[0075] Where: CK is the disease index of the control area after drug application; PT is the disease index of the treated area after drug application.

[0076] Test results: As shown in Table 6, compared with the existing registered suspension concentrate, the microemulsion prepared by the present invention can improve its control effect on watermelon anthracnose.

[0077] Table 6: Field efficacy of 20% picoxystrobin·difenoconazole microemulsion against watermelon anthracnose

[0078]

[0079]

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same.

Claims

1. A picoxystrobin-difenoconazole microemulsion, characterized in that: The invention comprises the following components in percentage by weight: 5-15% of picoxystrobin, 5-15% of difenoconazole, 5-25% of an organic solvent, 1-10% of a cosolvent, 10-30% of a surfactant, 0.01-0.1% of a defoaming agent, 1-10% of an antifreeze agent, and water to make up to 100%; The organic solvent is s-150 solvent oil; The cosolvents are ethanol and propylene carbonate; The surfactant is selected from dodecylphenol polyoxyethylene ether and EthylanNS-500LQ; The defoaming agent is: polyoxypropylene glycerol ether; The antifreeze agent is: ethylene glycol; The water is: deionized water.

2. The picoxystrobin-difenoconazole microemulsion according to claim 1, characterized in that: Picoxystrobin 8-12%, difenoconazole 8-12%.

3. The picoxystrobin-difenoconazole microemulsion according to claim 2, characterized in that: Picoxystrobin 10%, difenoconazole 10%.

4. The picoxystrobin-difenoconazole microemulsion according to claim 3, characterized in that: Picoxystrobin 10%, difenoconazole 10%, dodecylphenol polyoxyethylene ether 20%, Ethylan NS-500LQ 4%, s-150 solvent oil 10%, ethanol 4%, propylene carbonate 2%, polyoxypropylene glycerol ether 0.01%, ethylene glycol 2%, deionized water to 100%; Alternatively, 10% picoxystrobin, 10% difenoconazole, 17% dodecylphenol polyoxyethylene ether, 7% Ethylan NS-500LQ, 10% s-150 solvent oil, 4% ethanol, 2% propylene carbonate, 0.01% polyoxypropylene glycerol ether, 2% ethylene glycol, and deionized water are added to make up 100%.

5. Use of the picoxystrobin-difenoconazole microemulsion according to any one of claims 1 to 4 for preventing and controlling crop diseases, characterized in that: The crop diseases are watermelon vine blight, banana leaf spot and watermelon anthracnose.

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