Hexazinone-based environment-friendly pesticide and preparation method thereof

Abstract

The invention relates to the technical field of pesticides, in particular to a hexazinone-based environment-friendly pesticide and a preparation method thereof. Comprising the following steps: step 1, placing amino-modified mesoporous silica in a core component solution containing hexazinone, and carrying out ultrasonic dispersion, stirring treatment, filtration and freeze-drying to obtain drug-loaded mesoporous silica; step 2, adding drug-loaded mesoporous silica and proline-based chitosan into deionized water in a nitrogen atmosphere, carrying out ultrasonic dispersion, adjusting the pH value to 5.5-6.5, stirring at 45-55 DEG C for 12-20 hours, centrifuging, washing and drying; therefore, the hexazinone-based environment-friendly pesticide is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of pesticides, in particular to an environmentally friendly pesticide based on hexazinone and a preparation method thereof. Background Art

[0002] With the continuous development of the pesticide industry, the environment has become increasingly polluted, and people's environmental awareness has gradually increased. Cyclozinone, as a highly efficient and low-toxic herbicide, is widely used in forestry, agriculture and other fields. In the prior art, the traditional method of preparing cyclozinone will produce a large amount of by-products and waste. In addition, the existing pesticides do not have sustained-release properties, resulting in excessive pesticide dosage in the early stage, affecting the soil environment, and facing the problem of rapid attenuation of pesticide efficacy in the later stage, and the prevention and control effect is greatly reduced. Improper handling will also seriously pollute the environment and cause irreversible problems.

[0003] In summary, it is of great significance to prepare an environmentally friendly pesticide based on cyclohexazinone. Summary of the invention

[0004] The object of the present invention is to provide an environmentally friendly pesticide based on hexazinone and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: A method for preparing an environmentally friendly pesticide based on hexazinone, comprising the following steps: Step 1: placing the amino-modified mesoporous silica in a core component solution containing hexazinone, ultrasonically dispersing and stirring, filtering, and freeze-drying to obtain drug-loaded mesoporous silica; Step 2: Under a nitrogen atmosphere, add drug-loaded mesoporous silica and proline-based chitosan into deionized water, ultrasonically disperse, adjust the pH to 5.5-6.5, stir at 45-55°C for 12-20 hours, centrifuge, wash, and dry to obtain an environmentally friendly pesticide.

[0006] More optimally, the core component solution containing hexazinone includes the following components: by mass, 6 to 8 parts of hexazinone, 3 to 4 parts of dimethyltetrachloridone, 2 to 3 parts of chlorpyrifos methyl, 1 to 2 parts of mesotrione, and 60 to 70 parts of ethanol aqueous solution.

[0007] In a further embodiment, the ethanol aqueous solution includes ethanol and deionized water in a mass ratio of 1 to 1.2:1.

[0008] The solution includes hexazinone, dimethoate, chlorpyrifos methyl and mesotrione as core ingredients, with hexazinone providing the main weed control effect. When dimethoate is used in combination with hexazinone, dimethoate can expand the weed control spectrum, enhance the control effect on broadleaf weeds, and improve the overall weed control efficiency. The addition of chlorpyrifos methyl can further enhance the control ability against specific weeds, and improve the targeting and effect of the herbicide. When mesotrione is used in combination with ingredients such as hexazinone, the control range of grass weeds can be expanded, and the comprehensiveness and durability of the herbicide can be improved.

[0009] More optimally, the raw materials of the drug-loaded mesoporous silica include amino-modified mesoporous silica and a core component solution containing cyclohexanone in a mass ratio of 1:3 to 3.5.

[0010] More optimally, the preparation method of the amino-modified mesoporous silica is: add mesoporous silica, 3-aminopropyltrimethoxysilane, and N,N-dimethylhexadecylamine into deionized water and disperse them evenly, perform hydrothermal treatment at 100-120°C for 12-24 hours, acid wash, water wash, alcohol wash, and dry to obtain amino-modified mesoporous silica.

[0011] More optimally, the amino-modified mesoporous silica comprises the following components: by mass, 6 to 9 parts of mesoporous silica, 2 to 3 parts of 3-aminopropyltrimethoxysilane, 0.3 to 0.5 parts of N,N-dimethylhexadecylamine, and 30 to 40 parts of deionized water.

[0012] Among them, the pore expansion treatment of mesoporous silica is conducive to the addition of the core component solution, while the amino-modified mesoporous silica enhances the drug loading capacity and improves the sustained-release performance of pesticides; the amino-modified mesoporous silica has stronger adsorption capacity and more stable pore structure, protecting the pesticide molecules. In addition, amino-modified mesoporous silica can be degraded in nature and is very environmentally friendly. As a carrier, it can reduce the loss and volatilization of pesticides and reduce the negative impact on the environment; at the same time, amino-modified mesoporous silica is a biocompatible material with low toxicity and good stability in the body. By further modifying the sustained-release group on its surface, the drug delivery effect of pesticides can be improved.

[0013] More optimally, in step 2, the environmentally friendly pesticide includes the following components: 3 to 5 parts of drug-loaded mesoporous silica, 2 to 3 parts of proline-based chitosan, and 30 to 40 parts of deionized water, by mass.

[0014] More optimally, the pore size of the mesoporous silica is 5-7 nm, and the specific surface area is 600-700 m 2 / g.

[0015] More optimally, the preparation process of the proline-based chitosan is: S1-2: (1) Add proline and pyridine to acetonitrile, stir at room temperature until dissolved, slowly add benzyloxycarboxylic acid chloride at 20-30°C for 50-80 min, then react at 30-35°C for 20-30 h, extract, wash, dry and concentrate to obtain Cbz-proline for later use; (2) Add chitosan to DMF to obtain chitosan solution for later use; S2-2: (1) Dissolve Cbz-proline and propionic acid in DMF, add diisopropylcarbodiimide and chitosan solution in turn, mix well, add potassium carbonate to adjust the pH to 7-8; react at 0-5°C for 1-3 hours, then react at 20-30°C for 1-2 days, filter and wash to obtain Cbz-proline chitosan; (2) Add Cbz-proline chitosan to THF, add 1-1.5vt% dilute hydrochloric acid dropwise to adjust the pH to 2-4, stir at room temperature for 8-10 hours to remove the protecting group, neutralize, filter and purify to obtain proline chitosan.

[0016] Among them, by adding chitosan, it can be loaded on the surface of mesoporous silica loaded with cyclozinone, which can effectively prevent the rapid degradation and loss of cyclozinone in the environment, thereby improving the stability and durability of the pesticide and extending its efficacy period. In addition, chitosan has bioadhesive properties and can selectively adhere to the surface of plant leaves or soil particles, thereby enhancing the sustained release of the pesticide. Hydrogen bonds and electrostatic interactions can be formed between the chitosan layer and the amino groups on the surface of amino-modified mesoporous silica. This interaction helps to control the release rate of the drug and achieve a controlled release effect. This controlled release mechanism can control the release amount of pesticides according to the growth cycle of the plant and the occurrence of pests and diseases, reducing the waste of pesticides and environmental pollution.

[0017] In a further scheme, an alkyl chain is introduced into the chitosan chain segment to further reduce the direct impact of external factors on the cyclozinone molecule, thereby improving the stability of the drug, the bioavailability of the drug, the uniformity of distribution and the sustained release of the drug; by introducing amide bonds through proline modification and adjusting the structure and properties of the modified chitosan, the drug release rate can be controlled so that the drug is released at a constant rate within a specific time, thereby improving the utilization rate of the drug and the sustained release performance of the drug.

[0018] More optimally, the Cbz-proline comprises the following components: by weight, 3-4 parts of proline, 1-2 parts of pyridine, 30-40 parts of acetonitrile, and 5-6 parts of benzyloxycarboxylic acid chloride; the concentration of the chitosan solution is 18-22 g / L; The proline-based chitosan comprises the following components: by mass: 3-4 parts of Cbz-proline, 5-6 parts of diisopropylcarbodiimide, 4-5 parts of chitosan solution, 2-3 parts of propionic acid, and 30-40 parts of DMF; The proline-based chitosan comprises Cbz-proline-based chitosan and THF in a mass ratio of 1:15-20.

[0019] The preparation method of the hexazinone comprises the following steps: S1-3: Add N,N-dimethyl-N'-methyl-N'-alkoxyacylguanidine and cyclohexylamine to tetrahydrofuran, react at 60-100° C. for 3-5 hours, distill for 1-2 hours, cool, and filter to obtain an intermediate; S2-3: Add the intermediate, pyridine and triethylamine to dichloromethane, stir for 2 to 3 hours at -10 to 5°C, add an acylating agent and a composite catalyst to react for 2 to 3 hours, and take out to obtain intermediate A; S3-3: Add triethylamine and composite catalyst to intermediate A, react at 60-100°C for 1-2 hours, neutralize, wash with water, distill, filter, add hexane for crystallization, and obtain cycloazinone.

[0020] The intermediate raw material comprises the following components: by mass, 10 to 12 parts of N,N-dimethyl-N'-methyl-N'-alkoxyacylguanidine, 4 to 5 parts of cyclohexylamine, and 30 to 40 parts of tetrahydrofuran; The intermediate A raw material comprises the following components: by mass, 10-12 parts of the intermediate, 1-2 parts of pyridine, 2-3 parts of triethylamine, 30-40 parts of dichloromethane, 2.5-3.5 parts of acylating agent, and 1-2 parts of composite catalyst; The hexazinone raw material comprises the following components: by weight, 3-4 parts of triethylamine, 1-2 parts of composite catalyst, 20-25 parts of intermediate A, and 8-10 parts of hexane; The acylating agent comprises acetyl chloride and oxalyl chloride in a mass ratio of 2 to 2.5:1; The composite catalyst comprises zinc acetate and copper chloride in a mass ratio of 1-1.5:1-1.2.

[0021] Among them, the hexazinone prepared by introducing the preparation method has a high purity, and the high-purity product can more effectively exert its efficacy in the subsequent use process, reducing the environmental risks caused by excessive use; the use of a composite catalyst has higher activity and selectivity, reduces the amount of catalyst and reaction time, and reduces production costs and environmental burdens. In addition, the preparation process selects low-toxic raw materials, mild reaction conditions, distillation, filtration and crystallization in the reaction steps, etc., which can effectively separate the target product and by-products from the reaction mixture, improve the utilization rate of raw materials, and reduce the generation of waste.

[0022] More optimally, an environmentally friendly pesticide is prepared by a method for preparing an environmentally friendly pesticide based on hexazinone.

[0023] Compared with the prior art, the present invention has the following beneficial effects: 1. The cycloazinone prepared in the scheme has a high purity, which can improve the efficacy and reduce environmental risks. The use of composite catalysts reduces the amount of catalysts and reaction time, reducing costs and environmental burdens; at the same time, low-toxic raw materials are selected, the reaction is carried out under mild conditions, and the products are efficiently separated by means of distillation, filtration, crystallization, etc., which improves the utilization rate of raw materials and reduces waste emissions.

[0024] 2. In the scheme, amino-modified mesoporous silica is used to enhance the loading capacity of cyclohexanone, improve the adsorption capacity, and thus improve the utilization rate of pesticides, protect pesticide molecules, and has good degradability and is environmentally friendly, which can reduce pesticide loss and volatilization and improve the accuracy and effect of pesticides.

[0025] 3. The introduction of alkyl chains through chitosan in the scheme can improve the stability of cycloazinone, and the introduction of amide bonds through proline modification can regulate the release rate, thereby improving the drug utilization rate and sustained-release performance. It is used in amino-modified mesoporous silica loaded with cycloazinone to enhance the stability and durability of pesticides and prolong the efficacy. Its bioadhesion improves sustained-release properties, and interacts with amino groups to achieve controlled release, reducing waste and pollution. DETAILED DESCRIPTION

[0026] 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, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that the following parts are by mass, and all raw materials involved in the present invention are purchased from manufacturers without any special restrictions. Examples include: In the following examples, methyltriethoxysilane has a purity of 99%, CAS No. 2031-67-6, and is purchased from Shanghai Youpeng Chemical Co., Ltd.; the pore size of mesoporous silica is 6 nm, and the item No. is 2748670, purchased from Beijing Bailingwei Technology Co., Ltd.

[0028] In the following scheme, the acylating agent includes acetyl chloride and oxalyl chloride in a mass ratio of 2.3:1; the composite catalyst includes zinc acetate and cupric chloride in a mass ratio of 1.3:1.1.

[0029] The specific preparation process of cycloazinone is as follows: (1) 11 parts of N,N-dimethyl-N'-methyl-N'-alkoxyacylguanidine and 4.5 parts of cyclohexylamine are added to 35 parts of tetrahydrofuran, reacted at 80°C for 4 hours, distilled for 1.5 hours, cooled and filtered to obtain an intermediate; (2) 11 parts of the intermediate, 1.5 parts of pyridine and 2.5 parts of triethylamine are added to 35 parts of dichloromethane, stirred at -2°C for 2.5 hours, 3 parts of acylating agent and 3 parts of composite catalyst are added to react for 2.5 hours, taken out to obtain intermediate A; (3) 3.5 parts of triethylamine and 1.5 parts of composite catalyst are added to 22 parts of intermediate A, reacted at 80°C for 1.5 hours, neutralized, washed with water, distilled, filtered, and 9 parts of hexane are added to crystallize to obtain cycloazinone.

[0030] The core component solution containing hexazinone includes the following components: by weight, 7 parts of hexazinone, 3.5 parts of dimethyltetrachloridone, 2.5 parts of chlorpyrifos methyl, 1.5 parts of mesotrione, and 65 parts of ethanol aqueous solution. The ethanol aqueous solution includes ethanol and deionized water in a mass ratio of 1.1:1.

[0031] Example 1: A method for preparing an environmentally friendly pesticide based on hexazinone, comprising the following steps: S1: (1) Add 7.5 parts of mesoporous silica, 2.5 parts of 3-aminopropyltrimethoxysilane, and 0.4 parts of N,N-dimethylhexadecylamine to 35 parts of deionized water and disperse them evenly, perform hydrothermal treatment at 110°C for 18 hours, acid wash, water wash, alcohol wash, and dry to obtain amino-modified mesoporous silica; (2) Place the amino-modified mesoporous silica in a core component solution containing cyclohexane, the mass ratio of the amino-modified mesoporous silica to the core component solution of cyclohexane is 1:3.2, perform ultrasonic dispersion, stirring treatment, filtration, and freeze-drying to obtain drug-loaded mesoporous silica; S2: (1) Add 3.5 parts of proline and 1.5 parts of pyridine to 35 parts of acetonitrile, stir at room temperature until dissolved, slowly add 5.5 parts of benzyloxycarboxylic acid chloride at 25°C for 65 minutes, then react at 32°C for 25 hours, extract, wash, dry and concentrate to obtain Cbz-proline for later use; (2) Add chitosan to DMF to obtain a 20 g / L chitosan solution for later use; (3) Dissolve 3.5 parts of Cbz-proline and 2.5 parts of propionic acid in DMF, add 5.5 parts of diisopropylcarbodiimide in turn. amine, 4.5 parts of 20g / L chitosan solution, mixed evenly, added potassium carbonate to adjust the pH to 7.5; reacted at 2°C for 2 hours, then reacted at 25°C for 1.5 days, filtered and washed to obtain Cbz-proline chitosan; (4) added Cbz-proline chitosan to THF, the mass ratio of Cbz-proline chitosan to THF was 1:18, added 1.2vt% dilute hydrochloric acid to adjust the pH to 3, stirred at room temperature for 9 hours to remove the protecting group, neutralized, filtered, and purified to obtain proline chitosan; S3: Under nitrogen atmosphere, 4 parts of drug-loaded mesoporous silica and 2.5 parts of proline-based chitosan were added to 35 parts of deionized water, ultrasonically dispersed, the pH was adjusted to 6, stirred at 50°C for 18 hours, centrifuged, washed and dried to obtain an environmentally friendly pesticide.

[0032] Example 2: A method for preparing an environmentally friendly pesticide based on hexazinone, comprising the following steps: S1: (1) Add 7.5 parts of mesoporous silica, 2.5 parts of 3-aminopropyltrimethoxysilane, and 0.4 parts of N,N-dimethylhexadecylamine to 35 parts of deionized water and disperse them evenly, perform hydrothermal treatment at 110°C for 18 hours, acid wash, water wash, alcohol wash, and dry to obtain amino-modified mesoporous silica; (2) Place the amino-modified mesoporous silica in a core component solution containing cyclohexane, the mass ratio of the amino-modified mesoporous silica to the core component solution of cyclohexane is 1:3.2, perform ultrasonic dispersion, stirring treatment, filtration, and freeze-drying to obtain drug-loaded mesoporous silica; S2: (1) Add 3 parts of proline and 1 part of pyridine to 30 parts of acetonitrile, stir at room temperature until dissolved, slowly add 5 parts of benzyloxycarboxylic acid chloride at 20°C for reaction for 50 minutes, then react at 30°C for 20 hours, extract, wash, dry and concentrate to obtain Cbz-proline for use; (2) Add chitosan to DMF to obtain 20 g / L chitosan solution for use; (3) Dissolve 3 parts of Cbz-proline and 2 parts of propionic acid in DMF, add 5 parts of diisopropylcarbodiimide, 4 parts of 20g / L chitosan solution, mix evenly, add potassium carbonate to adjust the pH to 7.5; react at 0℃ for 1 hour, then react at 20℃ for 1.5 days, filter and wash to obtain Cbz-proline chitosan; (4) add Cbz-proline chitosan to THF, the mass ratio of Cbz-proline chitosan to THF is 1:18, add 1vt% dilute hydrochloric acid to adjust the pH to 3, stir at room temperature for 8 hours to remove the protecting group, neutralize, filter and purify to obtain proline chitosan; S3: Under nitrogen atmosphere, 3 parts of drug-loaded mesoporous silica and 2 parts of proline-based chitosan were added to 30 parts of deionized water, ultrasonically dispersed, the pH was adjusted to 5.5, stirred at 45°C for 12 hours, centrifuged, washed and dried to obtain environmentally friendly pesticides.

[0033] Example 3: A method for preparing an environmentally friendly pesticide based on hexazinone, comprising the following steps: S1: (1) Add 7.5 parts of mesoporous silica, 2.5 parts of 3-aminopropyltrimethoxysilane, and 0.4 parts of N,N-dimethylhexadecylamine to 35 parts of deionized water and disperse them evenly, perform hydrothermal treatment at 110°C for 18 hours, acid wash, water wash, alcohol wash, and dry to obtain amino-modified mesoporous silica; (2) Place the amino-modified mesoporous silica in a core component solution containing cyclohexane, the mass ratio of the amino-modified mesoporous silica to the core component solution of cyclohexane is 1:3.2, perform ultrasonic dispersion, stirring treatment, filtration, and freeze-drying to obtain drug-loaded mesoporous silica; S2: (1) Add 4 parts of proline and 2 parts of pyridine to 40 parts of acetonitrile, stir at room temperature until dissolved, slowly add 6 parts of benzyloxycarboxylic acid chloride at 30°C for 80 minutes, then react at 35°C for 30 hours, extract, wash, dry and concentrate to obtain Cbz-proline for later use; (2) Add chitosan to DMF to obtain a 20 g / L chitosan solution for later use; (3) Dissolve 4 parts of Cbz-proline and 3 parts of propionic acid in DMF, add 6 parts of diisopropylcarbodiimide, 5 parts of 2 0g / L chitosan solution, mix evenly, add potassium carbonate to adjust the pH to 7.5; react at 5°C for 3 hours, then react at 30°C for 1.5 days, filter and wash to obtain Cbz-proline chitosan; (4) add Cbz-proline chitosan to THF, the mass ratio of Cbz-proline chitosan to THF is 1:18, add 1.5vt% dilute hydrochloric acid to adjust the pH to 3, stir at room temperature for 10 hours to remove the protecting group, neutralize, filter and purify to obtain proline chitosan; S3: Under nitrogen atmosphere, 5 parts of drug-loaded mesoporous silica and 3 parts of proline-based chitosan were added to 40 parts of deionized water, ultrasonically dispersed, the pH was adjusted to 6.5, stirred at 55°C for 20 hours, centrifuged, washed and dried to obtain environmentally friendly pesticides.

[0034] Comparative Example 1: Based on Example 1, ordinary chitosan was used to prepare the product, and the other processes remained unchanged, specifically: S1: (1) Add 7.5 parts of mesoporous silica, 2.5 parts of 3-aminopropyltrimethoxysilane, and 0.4 parts of N,N-dimethylhexadecylamine to 35 parts of deionized water and disperse them evenly, perform hydrothermal treatment at 110°C for 18 hours, acid wash, water wash, alcohol wash, and dry to obtain amino-modified mesoporous silica; (2) Place the amino-modified mesoporous silica in a core component solution containing cyclohexane, the mass ratio of the amino-modified mesoporous silica to the core component solution of cyclohexane is 1:3.2, perform ultrasonic dispersion, stirring treatment, filtration, and freeze-drying to obtain drug-loaded mesoporous silica; S2: Under nitrogen atmosphere, 4 parts of drug-loaded mesoporous silica and 2.5 parts of chitosan were added to 35 parts of deionized water, ultrasonically dispersed, the pH was adjusted to 6, stirred at 50°C for 18 hours, centrifuged, washed and dried to obtain environmentally friendly pesticides.

[0035] Comparative Example 2: Based on Example 1, the ratio of Cbz-proline, propionic acid, diisopropylcarbodiimide, and 20 g / L chitosan solution in Cbz-proline-based chitosan was changed, and the other processes remained unchanged, specifically: S1: (1) Add 7.5 parts of mesoporous silica, 2.5 parts of 3-aminopropyltrimethoxysilane, and 0.4 parts of N,N-dimethylhexadecylamine to 35 parts of deionized water and disperse them evenly, perform hydrothermal treatment at 110°C for 18 hours, acid wash, water wash, alcohol wash, and dry to obtain amino-modified mesoporous silica; (2) Place the amino-modified mesoporous silica in a core component solution containing cyclohexane, the mass ratio of the amino-modified mesoporous silica to the core component solution of cyclohexane is 1:3.2, perform ultrasonic dispersion, stirring treatment, filtration, and freeze-drying to obtain drug-loaded mesoporous silica; S2: (1) Add 3.5 parts of proline and 1.5 parts of pyridine to 35 parts of acetonitrile, stir at room temperature until dissolved, slowly add 5.5 parts of benzyloxycarboxylic acid chloride at 25°C for 65 minutes, then react at 32°C for 25 hours, extract, wash, dry and concentrate to obtain Cbz-proline for later use; (2) Add chitosan to DMF to obtain a 20 g / L chitosan solution for later use; (3) Dissolve 2.5 parts of Cbz-proline and 3.5 parts of propionic acid in DMF, add 6 parts of diisopropylcarbodiimide in turn. amine, 4 parts of 20g / L chitosan solution, mixed evenly, added potassium carbonate to adjust the pH to 7.5; reacted at 2°C for 2 hours, then reacted at 25°C for 1.5 days, filtered and washed to obtain Cbz-proline chitosan; (4) added Cbz-proline chitosan to THF, the mass ratio of Cbz-proline chitosan to THF was 1:18, added 1.2vt% dilute hydrochloric acid to adjust the pH to 3, stirred at room temperature for 9 hours to remove the protecting group, neutralized, filtered, and purified to obtain proline chitosan; S3: Under nitrogen atmosphere, 4 parts of drug-loaded mesoporous silica and 2.5 parts of proline-based chitosan were added to 35 parts of deionized water, ultrasonically dispersed, the pH was adjusted to 6, stirred at 50°C for 18 hours, centrifuged, washed and dried to obtain an environmentally friendly pesticide.

[0036] Comparative Example 3: Based on Example 1, the product was prepared directly using mesoporous silica, and the other processes remained unchanged, specifically: S1: placing mesoporous silica in a core component solution containing hexazinone, wherein the mass ratio of the mesoporous silica to the core component solution containing hexazinone is 1:3, ultrasonically dispersing and stirring, filtering, and freeze-drying to obtain drug-loaded mesoporous silica; S2: (1) Add 3.5 parts of proline and 1.5 parts of pyridine to 35 parts of acetonitrile, stir at room temperature until dissolved, slowly add 5.5 parts of benzyloxycarboxylic acid chloride at 25°C for 65 minutes, then react at 32°C for 25 hours, extract, wash, dry and concentrate to obtain Cbz-proline for later use; (2) Add chitosan to DMF to obtain a 20 g / L chitosan solution for later use; (3) Dissolve 3.5 parts of Cbz-proline and 2.5 parts of propionic acid in DMF, add 5.5 parts of diisopropylcarbodiimide in turn. amine, 4.5 parts of 20g / L chitosan solution, mixed evenly, added potassium carbonate to adjust the pH to 7.5; reacted at 2°C for 2 hours, then reacted at 25°C for 1.5 days, filtered and washed to obtain Cbz-proline chitosan; (4) added Cbz-proline chitosan to THF, the mass ratio of Cbz-proline chitosan to THF was 1:18, added 1.2vt% dilute hydrochloric acid to adjust the pH to 3, stirred at room temperature for 9 hours to remove the protecting group, neutralized, filtered, and purified to obtain proline chitosan; S3: Under nitrogen atmosphere, 4 parts of drug-loaded mesoporous silica and 2.5 parts of proline-based chitosan were added to 35 parts of deionized water, ultrasonically dispersed, the pH was adjusted to 6, stirred at 50°C for 18 hours, centrifuged, washed and dried to obtain an environmentally friendly pesticide.

[0037] Comparative Example 4: Based on Example 1, hexazinone was prepared using the prior art, and the rest of the process remained unchanged, specifically: S1: Preparation of cyclohexanone: Add 3.5 parts of dimethylamine aqueous solution to 5 parts of 3-cyclohexyl-6-methylthio-1-methyl-1,3,5-triazine-2,4-(1H,3H)-dione toluene solution, adjust the pH value to 7.5, then react at 28°C for 3.5 hours, distill off the solvent at 125°C to obtain mixture A; add 10 parts of n-hexane to 2 parts of mixture A, react at 50°C for 30 minutes, filter, wash and dry to obtain cyclohexanone.

[0038] Testing experiment: The performance of an environmentally friendly pesticide based on cyclohexazinone prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was tested: (1) Sustained release effect test: The environmentally friendly pesticide based on cyclohexazinone prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was used to kill weeds, and the weeding effect was observed ten days and thirty days after application.

[0039]

[0040] Table 1 Result analysis: According to the data analysis in Table 1, it can be seen that the present invention enhances the efficacy and reduces the risk to the environment by preparing high-purity cycloazinone. The use of low-toxic raw materials and mild reaction conditions, combined with efficient separation technology, not only improves the utilization rate of raw materials, but also significantly reduces waste emissions; the loading capacity of mesoporous silica for cycloazinone is enhanced by amino modification, and has a stronger adsorption capacity. The carrier has excellent degradability and environmental friendliness, reduces the loss and volatilization of pesticides, and further improves the accuracy and effect of pesticide use; the stability, solubility, dispersion and bioavailability of cycloazinone are improved by chitosan modification, and the release rate and sustained release are regulated by alkyl chain and proline modification. Combined with drug-loaded mesoporous silica, it enhances stability and durability. Chitosan is renewable and degradable, environmentally friendly and reduces pollution.

[0041] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing an environmentally friendly pesticide based on hexazinone, characterized in that: The following steps are involved: Step 1: placing the amino-modified mesoporous silica in a core component solution containing hexazinone, ultrasonically dispersing and stirring, filtering, and freeze-drying to obtain drug-loaded mesoporous silica; Step 2: Under a nitrogen atmosphere, add drug-loaded mesoporous silica and proline-based chitosan into deionized water, ultrasonically disperse, adjust the pH to 5.5-6.5, stir at 45-55°C for 12-20 hours, centrifuge, wash, and dry to obtain an environmentally friendly pesticide.

2. The method for preparing an environmentally friendly pesticide based on hexazinone according to claim 1, characterized in that: The core component solution containing hexazinone includes the following components: by weight, 6 to 8 parts of hexazinone, 3 to 4 parts of dimethyltetrachloridone, 2 to 3 parts of chlorpyrifos methyl, 1 to 2 parts of mesotrione, and 60 to 70 parts of ethanol aqueous solution.

3. The method for preparing an environmentally friendly pesticide based on hexazinone according to claim 1, characterized in that: The raw materials of the drug-loaded mesoporous silica include amino-modified mesoporous silica and a core component solution containing cyclohexanone in a mass ratio of 1:3-3.

5.

4. The method for preparing an environmentally friendly pesticide based on hexazinone according to claim 1, characterized in that: The preparation method of the amino-modified mesoporous silica is as follows: mesoporous silica, 3-aminopropyltrimethoxysilane and N,N-dimethylhexadecylamine are added to deionized water and dispersed evenly, hydrothermally treated at 100-120° C. for 12-24 hours, acid-washed, water-washed, alcohol-washed, and dried to obtain the amino-modified mesoporous silica.

5. A method for preparing an environmentally friendly pesticide based on hexazinone according to claim 4, characterized in that: The amino-modified mesoporous silica comprises the following components: by weight, 6-9 parts of mesoporous silica, 2-3 parts of 3-aminopropyltrimethoxysilane, 0.3-0.5 parts of N,N-dimethylhexadecylamine, and 30-40 parts of deionized water.

6. The method for preparing an environmentally friendly pesticide based on hexazinone according to claim 1, characterized in that: In step 2, the environmentally friendly pesticide includes the following components: 3 to 5 parts of drug-loaded mesoporous silica, 2 to 3 parts of proline-based chitosan, and 30 to 40 parts of deionized water, by mass.

7. The method for preparing an environmentally friendly pesticide based on hexazinone according to claim 4, characterized in that: The mesoporous silica has a pore size of 5-7 nm and a specific surface area of ​​600-700 m 2 / g.

8. The method for preparing an environmentally friendly pesticide based on hexazinone according to claim 6, characterized in that: The preparation process of the proline chitosan is: S1-2: (1) Add proline and pyridine to acetonitrile, stir at room temperature until dissolved, slowly add benzyloxycarboxylic acid chloride at 20-30°C for 50-80 min, then react at 30-35°C for 20-30 h, extract, wash, dry and concentrate to obtain Cbz-proline for later use; (2) Add chitosan to DMF to obtain chitosan solution for later use; S2-2: (1) Dissolve Cbz-proline and propionic acid in DMF, add diisopropylcarbodiimide and chitosan solution in turn, mix well, add potassium carbonate to adjust the pH to 7-8; react at 0-5°C for 1-3 hours, then react at 20-30°C for 1-2 days, filter and wash to obtain Cbz-proline chitosan; (2) Add Cbz-proline chitosan to THF, add 1-1.5vt% dilute hydrochloric acid dropwise to adjust the pH to 2-4, stir at room temperature for 8-10 hours to remove the protecting group, neutralize, filter and purify to obtain proline chitosan.

9. The method for preparing an environmentally friendly pesticide based on hexazinone according to claim 8, characterized in that: The Cbz-proline comprises the following components: by weight, 3-4 parts of proline, 1-2 parts of pyridine, 30-40 parts of acetonitrile, and 5-6 parts of benzyloxycarboxylic acid chloride; The concentration of the chitosan solution is 18-22 g / L; The proline-based chitosan comprises the following components: by mass, 3-4 parts of Cbz-proline, 5-6 parts of diisopropylcarbodiimide, 4-5 parts of chitosan solution, 2-3 parts of propionic acid, and 30-40 parts of DMF; The proline-based chitosan comprises Cbz-proline-based chitosan and THF in a mass ratio of 1:15-20.

10. An environmentally friendly pesticide prepared by the method for preparing an environmentally friendly pesticide based on hexazinone according to any one of claims 1 to 9.

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