Flonicamid nanoemulsion, preparation method and application thereof

Abstract

The application provides a flonicamid nanoemulsion as well as a preparation method and application thereof, and relates to the technical field of pesticides.The flonicamid nanoemulsion comprises the following raw materials in percentage by mass: 1.0-3.0% of flonicamid, 9.0-20.0% of an organic solvent, 4.5-10.0% of an emulsifier, 1.0-2.0% of a dispersing agent, 0-3.0% of an antifoaming agent, and the rest of water.The flonicamid nanoemulsion prepared by the application has excellent wetting property and insecticidal effect, and is high in safety and long in duration of drug efficacy.

Description

Technical Field

[0001] This invention relates to the field of pesticide technology, and in particular to a flonicamid nanoemulsion, its preparation method, and its application. Background Technology

[0002] Agricultural pests cause reduced crop yields and decreased quality, severely restricting agricultural development. Pest-related grain losses account for approximately 30% of total annual production. While traditional chemical pesticides can control pests to a certain extent and for specific periods, their sole use leads to severe plant damage, environmental pollution, pesticide residues, the death of natural enemies, and a rapid increase in pest resistance, resulting in continuously rising pesticide concentrations and higher control costs.

[0003] Flupyradifurone is a novel, low-toxicity pyridine amide insecticide, chemically known as N-cyanomethyl, and its technical grade is a white powder. Besides its excellent contact and stomach poison effects, flupyradifurone has a unique mechanism of action: it can rapidly deter pests from feeding. Aphids and other piercing-sucking insects, after ingesting plant sap containing flupyradifurone, will quickly stop sucking the sap, producing no excrement within one hour, and ultimately die from starvation. However, it is harmless to aquatic plants and animals and has extremely high safety for humans and livestock. Currently, flupyradifurone formulations contain a high amount of organic components, causing significant environmental pollution, and the wettability of the solution is not ideal, hindering its penetration into plants for absorption and translocation.

[0004] Nanoemulsions, also known as nano-emulsions, are translucent, isotropic, milky liquid formulations composed of water, organic solvents, emulsifiers, and dispersants in specific proportions. They possess thermodynamic stability and are isotropic. Nanoemulsions typically have a particle size of 20–500 nm and exhibit good wettability and permeability. Currently, there is no research on flonicamid nanoemulsions; therefore, developing a safe and highly effective flonicamid nanoemulsion is a current research hotspot. Summary of the Invention

[0005] In view of this, the present invention provides a flonicamid nanoemulsion, its preparation method, and its application. The flonicamid nanoemulsion of the present invention improves the wetting properties and insecticidal activity of flonicamid in pesticides.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] The purpose of this invention is to provide a flonicamid nanoemulsion comprising the following raw materials in weight percentages:

[0008] Flupyradifurone 1.0%~3.0%, organic solvent 9.0%~20.0%, emulsifier 4.5%~10.0%, dispersant 1.0%~2.0%, defoamer 0~3.0%, the remainder is water.

[0009] Preferably, the organic solvent is at least one of cyclohexanone and rosin-based vegetable oil (ND-60, purchased from Fujian Nord Biotechnology Co., Ltd.).

[0010] Preferably, the emulsifier is at least one of G-103 and G100A. G-103 is a styrene-acrylic acid copolymer, purchased from Shenzhen Tai New Material Technology Development Co., Ltd.

[0011] More preferably, the emulsifier is a mixture of G-103 and G100A in a mass ratio of 3:2.

[0012] Preferably, the dispersant is sodium dodecylbenzenesulfonate.

[0013] Preferably, the defoamer is an organosilicone defoamer.

[0014] Another object of the present invention is to provide a method for preparing the flupyradifurone nanoemulsion, comprising the following steps:

[0015] (1) Weigh the raw materials according to the proportion, then add the weighed emulsifier and flonicamid to the organic solvent, disperse evenly to obtain the oil phase, and set aside;

[0016] (2) Add the weighed dispersant to water and disperse it evenly to obtain an aqueous phase for later use;

[0017] (3) The aqueous phase is magnetically stirred. During the stirring process, the oil phase is added dropwise to the aqueous phase. An antifoaming agent is added and stirring is continued to form a uniformly dispersed emulsion, which is flonicamid nanoemulsion.

[0018] Preferably, the stirring speed in step (3) is 500-800 r / min and the stirring time is 2-8 h.

[0019] This invention also provides the application of the aforementioned flonicamid nanoemulsion as an insecticide. The pests include, but are not limited to, aphids.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention provides a flonicamid nanoemulsion, specifically prepared using flonicamid, organic solvents, emulsifiers, dispersants, defoamers, and water as raw materials. The flonicamid nanoemulsion prepared by this invention exhibits excellent wetting properties and insecticidal effects, while also demonstrating high safety and a long-lasting efficacy. Attached Figure Description

[0022] Figure 1 This is a particle size distribution diagram of the flonicamid nanoemulsion described in Example 1;

[0023] Figure 2 The surface tension of treatment 1, treatment 2, and ultrapure water was determined using the platinum plate method;

[0024] Figure 3 The surface tension of treatment 1, treatment 2 and ultrapure water was determined using the pendant drop method.

[0025] Figure 4 The contact angle of treatment 1 was determined using the seat drop method;

[0026] Figure 5 The contact angle of treatment 2 was determined using the seat drop method;

[0027] Figure 6 To determine the contact angle of ultrapure water using the seat drop method. Detailed Implementation

[0028] The present invention will be further described below with reference to the embodiments. The 20% flupyradifurone suspension concentrate was purchased from Qingdao Runsheng Agricultural Chemical Co., Ltd.

[0029] Example 1

[0030] A flupyradifurone nanoemulsion comprises the following raw materials in weight percentages:

[0031] The composition includes 1.38% flonicamid, 19.84% organic solvent (cyclohexanone:ND-60 = 8:2, volume ratio), 8.55% emulsifier, 1.39% sodium dodecylbenzenesulfonate dispersant, 0.2% silicone defoamer, and the remainder is ultrapure water. The emulsifier is a mixture of G-103 and G100A in a mass ratio of 3:2.

[0032] The preparation method of the above-mentioned flonicamid nanoemulsion of the present invention comprises the following steps:

[0033] (1) Weigh the raw materials according to the proportion, then add the weighed emulsifier and flonicamid to the organic solvent, disperse evenly to obtain the oil phase, and set aside;

[0034] (2) Add the weighed dispersant sodium dodecylbenzenesulfonate to ultrapure water, disperse evenly to obtain an aqueous phase, and set aside for later use;

[0035] (3) The aqueous phase is magnetically stirred at 800 r / min for 8 h. During the stirring process, the oil phase is added dropwise to the aqueous phase, and an organosilicon defoamer is added and stirred continuously to form a uniformly dispersed emulsion, which is flonicamid nanoemulsion.

[0036] Example 2

[0037] A flupyradifurone nanoemulsion comprises the following raw materials in weight percentages:

[0038] The composition includes 2.05% flupyradifurone, 14.96% organic solvent (cyclohexanone:ND-60 = 9:1, volume ratio), 8.47% emulsifier, 1.33% sodium dodecylbenzenesulfonate dispersant, 0.2% silicone defoamer, and the remainder is ultrapure water. The emulsifier is a mixture of G-103 and G100A in a mass ratio of 3:2.

[0039] The preparation method of the above-mentioned flupyradifurone nanoemulsion of the present invention is the same as that in Example 1.

[0040] Example 3

[0041] A flupyradifurone nanoemulsion comprises the following raw materials in weight percentages:

[0042] The composition includes 2.66% flupyradifurone, 9.97% organic solvent (cyclohexanone), 8.37% emulsifier, 1.36% sodium dodecylbenzenesulfonate dispersant, 0.2% silicone defoamer, and the remainder is ultrapure water. The emulsifier is a mixture of G-103 and G100A in a mass ratio of 3:2.

[0043] The preparation method of the above-mentioned flupyradifurone nanoemulsion of the present invention is the same as that in Example 1.

[0044] Experimental Example 1: Solvent Screening

[0045] The solubility of flonicamid technical grade was compared by adding it to different solvents, as shown in Table 1. The results showed that flonicamid had the best solubility in cyclohexanone, followed by ND-60. One or a mixture of cyclohexanone and ND-60 were selected as solvents.

[0046] Table 1. Solubility of flupyradifurone in different solvents

[0047]

[0048] Experimental Example 2: Screening of Emulsifiers

[0049] The emulsifier of the organic solvent was replaced while the rest remained unchanged. An emulsion was prepared and left at room temperature for 7 days and 60 days. The state of the emulsion was recorded, as shown in Table 2.

[0050] Table 2

[0051]

[0052] Note: EL-40 is castor oil polyoxyethylene ether, purchased from Shandong Yousuo Huagong Technology Co., Ltd.; A-7 is cetearyl alcohol polyoxyethylene 7 ether, purchased from Nantong Chenrun Chemical Co., Ltd.; N-300 is diethylaminoethyl cellulose, purchased from Shenzhen Tai New Material Technology Development Co., Ltd.; G-103 is styrene-acrylic acid copolymer, purchased from Shenzhen Tai New Material Technology Development Co., Ltd.; Agricultural Emulsion 602# is phenethylphenol polyoxyethylene (10) ether, purchased from Xingtai Yancheng Chemical Additives Co., Ltd.; D101 is ammonium polyacrylate and C13-C16 isoparaffin copolymer, purchased from Shenzhen Tai New Material Technology Development Co., Ltd.; Agrilian 1015 is mainly composed of fatty alcohol phosphate esters, purchased from Nanjing Jierun Technology Co., Ltd.; ADSEE AB600 is mainly composed of alkoxyamines, purchased from Nanjing Jierun Technology Co., Ltd.

[0053] Experimental Example 3: Particle Size Determination

[0054] The particle size of the flonicamid nanoemulsion prepared in Example 1 was determined. Specifically, the particle size of the emulsion was measured using a Malvern Zetasizer Nano ZS90 laser particle size analyzer. Water was used as the medium, and the emulsion was ultrasonically dispersed for 3 min. The prepared emulsion, which had been left to stand for 12 h, was then added to the instrument, and the particle size was measured.

[0055] The flonicamid nanoemulsion described in Example 1 has an average particle size of 207 nm and good uniformity. Nanoemulsions typically have particle sizes ranging from 20 to 500 nm, and this emulsion's particle size falls within the range of nanoemulsions. (See [link to example 1]). Figure 1 .

[0056] Experimental Example 4: Determination of Surface Tension and Contact Angle

[0057] Treatment 1: Take 1g of the flonicamid nanoemulsion prepared in Example 1 and add it to ultrapure water to make a total of 100g, then stir until homogeneous;

[0058] Treatment 2: Dilute 20% flonicamid suspension until the effective flonicamid content is the same as in Treatment 1, and add ultrapure water to make up to 100g.

[0059] Treatment 3: Take 100g of ultrapure water as a blank control.

[0060] The surface tension of the emulsion was determined using both the plate method and the pendant drop method. The plate method was performed using a KRUSS K100 instrument. This method has a shorter measurement time and the plate remains relatively stable after contact with the reagent; however, the reagent can alter the wettability of the plate, leading to some measurement error. Measurements were set to 30 s, 1 Hz, with a 1-s interval, and repeated three times. The pendant drop method was performed using a KRUSS DSA100 instrument. This method is more accurate, but the measurement time is longer. A SY-3601 syringe with a diameter of 1.826 mm was used, with each aspiration of 10 μL, a measurement time of 120 s, a 1-s interval, and repeated three times. The average of the three replicates was compared, and the results are shown in [Figure number missing]. Figure 2 and Figure 3 The average surface tension of treatment 1 was 36.61 mN / m, the surface tension of treatment 2 was 52.11 mN / m, and the maximum surface tension of ultrapure water was 72.53 mN / m.

[0061] The contact angle was determined using the KRUSS DSA100 (KRUSS Scientific Instruments) via the seated drop method. Cotton cotyledons were prepared into strips and fixed onto a glass slide, leaf surface facing upwards, for titration. A syringe with a diameter of 0.516 mm was used, and 2 μL was drawn each time at an FPS of 50. A total of 30 measurements were performed, each lasting 10 minutes, repeated three times. (See attached table). Figure 4 The measured contact angles were divided into left and right contact angles, and the average of the two was taken. The average of the three replicates was taken. The average contact angle of treatment 1 was 28.63°, the average contact angle of treatment 2 was 36.78°, and the contact angle of the blank control was 34.34°.

[0062] Experimental Example 5: Indoor Bioassay

[0063] The bioactivity of the emulsion was determined by immersion method in accordance with the agricultural industry standard of the People's Republic of China, "Guidelines for Indoor Bioassay Testing of Pesticides". The flonicamid nanoemulsion of Example 1 and the commercially available flonicamid suspension (control group) were successively diluted with water to obtain flonicamid concentrations of 80 mg / L, 40 mg / L, 20 mg / L, 10 mg / L, 5 mg / L, and 2.5 mg / L, respectively.

[0064] Cotton aphids and cotton cotyledons were immersed in the diluted pesticide solution for 10 seconds, then air-dried and placed in petri dishes. Each concentration was replicated three times, with each replicate using 20 cotton aphids and 1 cotton cotyledon. Ultrapure water was used as a blank control. The petri dishes were then incubated in an incubator at 25±1℃, 65%-70% relative humidity, and a photoperiod of 14:10 (light:dark). Results were collected and toxicity parameters were calculated after 24 hours. The ability of cotton aphids to crawl normally was used as the criterion for mortality, and the LC50 was calculated. 50 See Table 3.

[0065] Table 3 Poisoning Equations

[0066]

[0067] Experiment Example 6: Field Efficacy Determination

[0068] The field efficacy trial was conducted at the Dong Experimental Farm in Baibi Town, Anyang City, Henan Province, with geographical coordinates of 114°30′35″E, 36°05′05″N. Cotton was sown on April 27, 2021, with a row spacing of 0.80 m, a plant spacing of 0.24 m, and a planting density of 55,000 plants / hm². 2 The field trial consisted of four treatments, each replicated three times, arranged in a randomized block design. Each plot contained 15 cotton plants, for a total of 12 plots. A single, manual sprayer was used to apply the pesticide evenly to the entire plant, ensuring uniform coverage on both sides of the leaves, with a slight amount of pesticide dripping down in streams. Overspraying and missed areas were avoided. The control plot was sprayed with the same amount of water. The treatment plot used 7.5g of pesticide, while the control plot used 0.75g. To theoretically achieve different levels of control efficacy, the flonicamid nanoemulsions prepared in Examples 1-3 were diluted 200 times before use in the field efficacy trial. No other pesticides were sprayed in any of the experimental plots during the trial. The control efficacy against aphids is shown in Table 4. The control group used a commercially available 20% flonicamid suspension diluted 200 times.

[0069] Table 4. Control efficacy of different concentrations of pesticides against cotton aphids in the field.

[0070]

[0071] It can be seen that 3 days after application, the flupyridine nanoemulsion in Example 3 had the highest control efficacy; 7 days after application, the control efficacy of Example 2 and 20% flupyridine suspension was comparable.

[0072] The above description is a further detailed explanation of the present invention in conjunction with specific preferred embodiments. It should not be considered that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the present invention, and all of these should be considered to fall within the scope of patent protection determined by the submitted claims.

Claims

1. A flonicamid nanoemulsion, characterized in that, Composed of the following raw materials by mass percentage: Flupyradifurone 1.38%, organic solvent 19.84%, emulsifier 8.55%, sodium dodecylbenzenesulfonate dispersant 1.39%, silicone defoamer 0.2%, the remainder being ultrapure water; The emulsifier is a mixture of G-103 and G100A in a mass ratio of 3:2; The organic solvent is composed of cyclohexanone and pine resin-based vegetable oil ND-60 in a volume ratio of 8:2; The preparation method of the flonicamid nanoemulsion includes the following steps: (1) Weigh the raw materials according to the proportion, then add the weighed emulsifier and flonicamid to the organic solvent, disperse evenly to obtain the oil phase, and set aside; (2) Add the weighed dispersant sodium dodecylbenzenesulfonate to ultrapure water and disperse it evenly to obtain an aqueous phase for later use; (3) The aqueous phase is magnetically stirred at 800 r / min for 8 h. During the stirring process, the oil phase is added dropwise to the aqueous phase, and an organosilicon defoamer is added and stirred continuously to form a uniformly dispersed emulsion, which is flonicamid nanoemulsion.

2. The application of the flupyradifurone nanoemulsion according to claim 1 as an insecticide.

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