Nano pesticide adjuvant and application thereof

Abstract

The invention discloses a nano pesticide adjuvant, the nano pesticide adjuvant comprises ulmic acid and a quaternary ammonium salt type cationic surface active agent which is polyquaternium-7, the mass ratio of the ulmic acid to pesticide active ingredients is (1-10): 1, and the quaternary ammonium salt type cationic surface active agent accounts for 0.1-2% of the percentage content of a pesticide preparation; a stable nano-pesticide preparation can be prepared from the nano-pesticide adjuvant, and the nano-pesticide adjuvant is simple in preparation process and suitable for being used in agriculture.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticides, and in particular relates to a nano auxiliary agent for improving the activity of pesticides and application thereof. Background Art

[0002] Compared with traditional pesticides, nanopesticides have the characteristics of small particle size, excellent dispersion performance, high target transmission effect, controlled release, and easy absorption. They can significantly reduce the application amount of pesticide active ingredients and have become a hot topic of current research. It is a pesticide formulation that uses functional materials and nanotechnology to make the active ingredients of pesticides exist stably in a nanoscale dispersed state in the formulation and dispersion system, and exerts application performance that is different from conventional formulations when used. Its excellence has attracted more and more attention. By regulating the structure and function of the carrier material and constructing a nano drug delivery system that delays the release of pesticides, the repeated application of pesticides can be greatly reduced.

[0003] Nano-herbicides usually have high weed control activity and are good for the environment. Compared with traditional herbicides, nano-herbicides show better spreading, adhesion and longer release time on the leaf surface, and can control the release of fatty acids. Whether nanomaterials are suitable for processing nano-herbicides needs to consider factors such as their size, morphology, crystal structure, and chemical composition. Summary of the invention

[0004] The purpose of the present invention is to provide a nano pesticide adjuvant in view of the deficiencies of the prior art. The adjuvant is used in combination with palmitic acid and a quaternary ammonium salt cationic surfactant to prepare a stable nano pesticide preparation, which has a simple preparation process and is suitable for use in agriculture.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A nano pesticide adjuvant comprises palmitic acid and a quaternary ammonium salt type cationic surfactant.

[0007] Preferably, as a preferred embodiment, the preparation method of palmitic acid comprises the following steps:

[0008] Pig manure or straw is subjected to alkaline pyrolysis with 0.5 mol / L sodium hydroxide, and then separated and collected through a 4000-8000 Dalton dialysis bag to obtain palmitic acid with a molecular weight of 4000-8000 Dalton.

[0009] Preferably, as a preferred embodiment, the quaternary ammonium salt cationic surfactant is polyquaternium-7.

[0010] Preferably, as a better embodiment, the mass ratio of palmitic acid to the active ingredient of the pesticide in the nano pesticide adjuvant is 1-10:1, and the percentage of the quaternary ammonium salt cationic surfactant in the pesticide preparation is 0.1-2%.

[0011] Another object of the present invention is to provide an application of a nano pesticide adjuvant, wherein the nano pesticide adjuvant is applied to the preparation of herbicide nano pesticides.

[0012] Preferably, as a preferred embodiment, the herbicide is 2,4-dichlorophenoxyacetic acid.

[0013] Another object of the present invention is to provide an application method of the nano pesticide adjuvant, comprising the following steps:

[0014] S1 dissolves the herbicide in an alkaline solution to obtain a mixed solution A;

[0015] S2 dissolves the palmitic acid in the mixed solution A. If it does not dissolve, continue to add sodium hydroxide solution; ultrasonicate for 10-20 minutes to obtain a mixed solution B;

[0016] S3: Add a rotor to the mixed solution B, adjust the speed to 500-800 rpm, and uniformly add 0.1-0.5 M HCl to the beaker at a rate of 1-5 mL / min for 20-60 min until the pH of the solution is less than 2.0, and continue the reaction for 20-60 min;

[0017] S4 continues to add stabilizer quaternary ammonium salt type cationic surfactant polyquaternium salt-7 to make the stabilizer content 0.5-1.5%, and continues the reaction for 0.5-2h to obtain the nano pesticide herbicide.

[0018] Preferably, as a preferred embodiment, the pH of the alkaline aqueous solution in step S1 is greater than 10, and the alkaline aqueous solution can be obtained by adjusting the pH using sodium hydroxide or potassium hydroxide, but cannot be obtained by adjusting the pH using calcium hydroxide.

[0019] Preferably, as a better embodiment, the mass ratio of palmitic acid to herbicidal active ingredient in step S2 is 1-0:1.

[0020] Preferably, as a preferred embodiment, the preparation method of palmitic acid is: pig manure or straw is subjected to alkaline solution pyrolysis using 0.5 mol / L sodium hydroxide, and then palmitic acid with a molecular weight of 4000-8000 Daltons is separated and collected through a 4000-8000 Dalton dialysis bag.

[0021] Preferably, as a preferred embodiment, the molecular weight of the palmitic acid is 4000-8000.

[0022] Another object of the present invention is to provide a nanopesticide prepared by using a nanopesticide adjuvant.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The nanopesticide prepared by the nanopesticide adjuvant of the present invention has reliable nanoparticle synthesis, high pesticide loading rate and high stability, and can significantly improve the use effect of the active ingredients of the pesticide. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention. The following specific implementation methods further describe the present invention.

[0026] Unless otherwise specified, the chemical substances of the present invention can be purchased from the market.

[0027] 1. Preparation Example

[0028] 1. Embodiment 1

[0029] A method for preparing a nanopesticide comprises the following steps:

[0030] S1 dissolves 2,4-dichlorophenoxyacetic acid in an alkaline aqueous solution with a pH value greater than 10 to obtain a mixed solution A;

[0031] S2: Pig manure is pyrolyzed with 0.5 mol / L sodium hydroxide, and then separated and collected by dialysis bag with a molecular weight of 4000-8000 Daltons. The 4000-8000 Daltons of palmitic acid are dissolved in mixed solution A, and ultrasonicated for 15 minutes to obtain mixed solution B; the mass of the palmitic acid is 8 times the mass of 2,4-dichlorophenoxyacetic acid in step S1.

[0032] S3: Add a rotor to the mixed solution B, adjust the speed to 600 rpm, and uniformly add 0.25 M HCl to the beaker at a rate of 5 mL / min for 60 min until the pH of the solution is less than 2.0. Continue the reaction for 60 min.

[0033] S4 continues to add stabilizer quaternary ammonium salt type cationic surfactant polyquaternium-7 to make the stabilizer content 1.0%, and continues the reaction for 1.0h to obtain nano pesticide.

[0034] 2. Comparative Example 1

[0035] A method for preparing a nanopesticide comprises the following steps:

[0036] S1: dissolving nitenpyram in an alkaline aqueous solution with a pH value greater than 10 to obtain a mixed solution A;

[0037] S2: using 0.5 mol / L sodium hydroxide to perform alkaline pyrolysis on pig manure, and then separating and collecting palmitic acid with a molecular weight of 4000-8000 Daltons through a dialysis bag of 4000-8000 Daltons. The palmitic acid with a molecular weight of 4000-8000 Daltons is dissolved in mixed solution A, and ultrasonicated for 15 minutes to obtain a mixed solution B; the mass of the palmitic acid is 8 times that of nitenpyram in step S1.

[0038] S3: Add a rotor to the mixed solution B, adjust the speed to 600 rpm, and uniformly add 0.25 M HCl to the beaker at a rate of 5 mL / min for 60 min until the pH of the solution is less than 2.0. Continue the reaction for 60 min.

[0039] S4 continues to add stabilizer quaternary ammonium salt type cationic surfactant polyquaternium-7 to make the stabilizer content 1.0%, and continues the reaction for 1.0h to obtain nano pesticide.

[0040] 3. Comparative Example 2

[0041] A method for preparing a nanopesticide comprises the following steps:

[0042] S1 dissolves bialaphos in an alkaline aqueous solution with a pH value greater than 10 to obtain a mixed solution A;

[0043] S2: using 0.5 mol / L sodium hydroxide to perform alkaline pyrolysis on pig manure, and then separating and collecting palmitic acid with a molecular weight of 4000-8000 Daltons through a 4000-8000 Daltons dialysis bag. The palmitic acid with a molecular weight of 4000-8000 Daltons is dissolved in mixed solution A, and ultrasonicated for 15 minutes to obtain mixed solution B; the mass of the palmitic acid is 8 times that of the bialaphos in step S1.

[0044] S3: Add a rotor to the mixed solution B, adjust the speed to 600 rpm, and uniformly add 0.25 M HCl to the beaker at a rate of 5 mL / min for 60 min until the pH of the solution is less than 2.0. Continue the reaction for 60 min.

[0045] S4 continues to add stabilizer quaternary ammonium salt type cationic surfactant polyquaternium-7 to make the stabilizer content 1.0%, and continues the reaction for 1.0h to obtain nano pesticide.

[0046] 4. Comparative Example 4

[0047] A method for preparing a nanopesticide comprises the following steps:

[0048] S1 dissolves 2,4-dichlorophenoxyacetic acid in an alkaline aqueous solution with a pH value greater than 10 to obtain a mixed solution A;

[0049] S2: Pig manure is pyrolyzed with 0.5 mol / L sodium hydroxide, and then separated and collected by dialysis bag with a molecular weight of 4000-8000 Daltons. The 4000-8000 Daltons of palmitic acid are dissolved in mixed solution A, and ultrasonicated for 15 minutes to obtain mixed solution B; the mass of the palmitic acid is 8 times the mass of 2,4-dichlorophenoxyacetic acid in step S1.

[0050] S3: Add a rotor to the mixed solution B, adjust the speed to 600 rpm, and uniformly add 0.25 M HCl to the beaker at a rate of 5 mL / min for 60 min until the pH of the solution is less than 2.0. Continue the reaction for 60 min.

[0051] S4: Continue to add the stabilizer neutral surfactant polyoxyethylene-8-octylphenyl ether to make the stabilizer content be 1.0%, and continue the reaction for 1.0h to obtain the nano pesticide.

[0052] 2. Determination of pesticide properties

[0053] The morphology of the nanopesticide particles prepared in Example 1 and Comparative Examples 2-4 was observed by scanning electron microscopy. If spherical particles were present, the synthesis was successful; if spherical particles were not present, the synthesis failed; the reaction system was subjected to solid-liquid separation, and the concentration of the pesticide in the liquid phase was analyzed by liquid chromatograph; the solid phase sample was extracted by acetonitrile (solid-liquid ratio = 1:100) + ultrasonic crushing extraction, and the concentration of the pesticide was analyzed by liquid chromatograph; the loading rate of the pesticide was calculated according to the liquid and solid phase pesticide concentrations. If the loading rate was low, the synthesis failed. The average particle size of the pesticide was measured by a nanoparticle size Zeta potential analyzer on the synthesized pesticide particle suspension. According to the method for determining the thermal storage stability of pesticides (GBT19136-2021), the changes in the particle size and concentration of the pesticide particles were observed through a 14-day 54-degree thermal storage experiment to determine the stability of the pesticide.

[0054] Table 1 Nanopesticides prepared by different treatments

[0055]

[0056] It can be seen from Table 1 that the nano pesticide adjuvant of the present invention can be used to prepare qualified nano pesticides for a specific pesticide active ingredient 2,4-dichlorophenoxyacetic acid; however, when the same pesticide adjuvant is used, the active ingredient is replaced with nitenpyram or bialaphos, and nanoparticles cannot be successfully synthesized; and when the stabilizer polyquaternium-7 in the nano pesticide adjuvant is replaced with polyoxyethylene-8-octylphenylphenol ether, the pesticide active ingredient is 2,4-dichlorophenoxyacetic acid, and nanoparticles cannot be successfully synthesized.

[0057] Table 2 Particle size and loading rate of nanopesticides prepared in Example 1

[0058] deal with Pesticide particle size Pesticide loading rate Example 1 60-70nm 94.9％

[0059] As can be seen from Table 2, the nanopesticide adjuvant of the present invention is applied to the pesticide active ingredient 2,4-dichlorophenoxyacetic acid to prepare a nanopesticide with a particle size between 60-70 nm and a pesticide loading of 94.9%, which proves that the nanoparticle synthesis method of the present invention is reliable.

[0060] Table 3 Effects of different surfactants on pesticide particle size, loading rate and thermal storage stability

[0061]

[0062] The cationic surfactant polyquaternium-7 in Example 1 and Comparative Example 4 was replaced with the neutral surfactant polyoxyethylene-8-octylphenyl ether, and the particle size, loading rate and thermal storage stability of 2,4-dichlorophenoxyacetic acid were observed. The results are shown in Table 3.

[0063] According to the method for determining the thermal storage stability of pesticides (GBT19136-2021), after a 14-day thermal storage experiment at 54 degrees, the particle size of the 2,4-dichlorophenoxyacetic acid pesticide particles in Example 1 did not change significantly, and remained at 60-80nm, and the active ingredients of the pesticide did not show any rupture and release phenomenon; while in Comparative Example 4, after using the neutral surfactant polyoxyethylene-8-octylphenyl ether, the particle size of the 2,4-dichlorophenoxyacetic acid pesticide increased to 557nm after 14 days of thermal storage, and the pesticide loading rate decreased from 95.4% to 75.2%, and the active ingredients of the pesticide also showed release. The above results indicate that the specific nano-pesticide adjuvant of the present invention is used to prepare a specific type of nano-pesticide with active ingredients of pesticides, and the stability is high and the synthesis method is reliable.

[0064] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A nano pesticide adjuvant, characterized in that: The nano pesticide adjuvant comprises palmitic acid and a quaternary ammonium salt type cationic surfactant.

2. A nano pesticide adjuvant according to claim 1, characterized in that: The quaternary ammonium salt type cationic surfactant is polyquaternium-7.

3. A nano pesticide adjuvant according to claim 1, characterized in that: The preparation method of the palmitic acid comprises the following steps: Pig manure or straw is subjected to alkaline pyrolysis with 0.5 mol / L sodium hydroxide, and then separated and collected through a 4000-8000 Dalton dialysis bag to obtain palmitic acid with a molecular weight of 4000-8000 Dalton.

4. A nano pesticide adjuvant according to claim 1, characterized in that: The mass ratio of palmitic acid to the active ingredient of the pesticide is 1-10:1, and the percentage of the quaternary ammonium salt type cationic surfactant in the pesticide preparation is 0.1-2%.

5. The use of the nano pesticide adjuvant according to claim 1, characterized in that: The nano pesticide adjuvant is used for preparing herbicide nano pesticides.

6. The use according to claim 5, characterized in that: The herbicide is 2,4-dichlorophenoxyacetic acid.

7. The application method of the nano pesticide adjuvant according to claim 1, characterized in that: The steps include: S1 dissolves the herbicide in an alkaline solution to obtain a mixed solution A; S2 dissolves the palmitic acid in the mixed solution A. If it does not dissolve, continue to add sodium hydroxide solution; ultrasonicate for 10-20 minutes to obtain a mixed solution B; S3: Add a rotor to the mixed solution B, adjust the speed to 500-800 rpm, and uniformly add 0.1-0.5 M HCl to the beaker at a rate of 1-5 mL / min for 20-60 min until the pH of the solution is less than 2.0, and continue the reaction for 20-60 min; S4 continues to add stabilizer quaternary ammonium salt type cationic surfactant polyquaternium-7 to make the stabilizer content 0.5-1.5%, and continues the reaction for 0.5-2h to obtain the nano pesticide herbicide.

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