Long-acting diazinon production process

Abstract

The invention discloses a long-acting diazinon production process which comprises the following steps: preparing the following raw materials in parts by mass: 10-20 parts of diazinon technical with the content of more than or equal to 98%, 15-30 parts of a solvent, 5-10 parts of an emulsifier, 3-8 parts of a slow release agent, 0.5-2 parts of an antioxidant and 2-5 parts of a dispersing agent; by adding chitosan, sodium alginate, beta-cyclodextrin and other slow-release agents and carrying out a specific slow-release treatment process, diazinon and the slow-release agents are fully combined, the lasting period of the product is remarkably prolonged, and the pesticide application frequency is reduced; due to the addition of the antioxidant 2, 6-butylated hydroxytoluene and triphenyl phosphite, the oxidation reaction of the diazinon active compound in the production, storage and use processes is effectively inhibited, and the diazinon active compound is prevented from being decomposed and deteriorated; through the synergistic effect of the emulsifying agent and the dispersing agent, the diazinon active compound, the sustained-release agent and other components are uniformly dispersed in a system to form a stable emulsion or dispersion system, so that not only is the mixing uniformity in the production process facilitated, but also the uniformity and stability of the pesticide effect can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticide production, and particularly relates to a long-acting diazinon production process. Background Art

[0002] Diazinon is a broad-spectrum organophosphorus insecticide with contact, stomach poison, fumigation and certain systemic effects. It has good control effects on many pests and is widely used in agricultural production.

[0003] In the existing technology, the traditional diazinon production process usually only mixes the diazinon technical with simple solvents and additives to produce a common dosage form of diazinon product. No sustained-release agent is added, and there is no dedicated sustained-release treatment process. At the same time, the use of antioxidants is not taken seriously or is used improperly.

[0004] However, since traditional diazinon products do not use sustained-release technology, diazinon is released quickly after application, and the effective insecticidal concentration is maintained for a short time, resulting in a short duration of effect and the need for frequent application. This not only significantly increases labor costs, but may also cause excessive pesticide residues in agricultural products due to multiple applications. In addition, due to the lack of effective antioxidant measures, diazinon technical is prone to oxidation reactions and decomposition and deterioration during production, storage and use, resulting in poor chemical stability of the product. The efficacy gradually decreases during the effective period, making it unable to stably play a role in pest control, affecting the control effect.

[0005] To this end, we propose a long-acting diazinon production process to solve the problems mentioned in the above background technology. Summary of the Invention

[0006] The object of the present invention is to provide a long-acting diazinon production process to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a long-acting diazinon production process, comprising the following steps:

[0008] S1. Raw material preparation: According to the mass ratio, prepare 10-20 parts of diazinon technical with a content of ≥98%, 15-30 parts of solvent, 5-10 parts of emulsifier, 3-8 parts of sustained-release agent, 0.5-2 parts of antioxidant, and 2-5 parts of dispersant;

[0009] S2, dissolving and mixing

[0010] Add diazinon technical into the reactor, then add the selected solvent, stir at 30-50℃ for 1-2 hours to completely dissolve the diazinon technical, then add the emulsifier, antioxidant and dispersant in sequence, and continue stirring for 30-60 minutes to ensure that all ingredients are evenly mixed;

[0011] S3, sustained-release treatment

[0012] Add the sustained-release agent to an appropriate amount of water, heat to 50-70°C and stir until completely dissolved to form a sustained-release agent solution, slowly dropwise add the sustained-release agent solution to the above mixed solution, keep stirring during the dropwise addition process, and control the dropwise addition time to 30-60 minutes. After the dropwise addition is completed, continue stirring and react for 2-4 hours to allow the diazinon and the sustained-release agent to fully combine to form a mixture with sustained-release properties;

[0013] S4, Concentration and Drying

[0014] The solvent in the mixture is distilled out and recovered by using a reduced pressure distillation method, and the distillation temperature is controlled at 50-70° C. until the solid content of the mixture reaches 50%-70%. The concentrated material is then spray-dried to obtain a long-acting diazinon product.

[0015] Preferably, the solvent is a mixture of one or more of cyclohexanone, toluene and xylene.

[0016] Preferably, the emulsifier is one or more of alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, and styrylphenol polyoxyethylene ether.

[0017] Preferably, the sustained-release agent is one or more of chitosan, sodium alginate, and β-cyclodextrin.

[0018] Preferably, the antioxidant is one or both of 2,6-di-tert-butyl-p-cresol and triphenyl phosphite.

[0019] Preferably, the dispersant is one or both of sodium lignin sulfonate and naphthalene sulfonate formaldehyde condensate.

[0020] Preferably, the stirring speed in S2 is 150-200 rpm.

[0021] Preferably, the drying temperature in S4 is controlled at 120-150°C.

[0022] Preferably, the pressure in S4 is between -0.08 and -0.06 MPa.

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

[0024] (1) By adding slow-release agents such as chitosan, sodium alginate, and β-cyclodextrin, and carrying out a specific slow-release treatment process, diazinon is fully combined with the slow-release agent. During actual use, diazinon is slowly released from the slow-release system, and can maintain an effective insecticide concentration for a long time, significantly extending the product's effective period, reducing the number of applications, and lowering labor costs;

[0025] (2) The addition of antioxidants 2,6-di-tert-butyl-p-cresol and triphenyl phosphite effectively inhibits the oxidation reaction of diazinon technical during production, storage and use, prevents its decomposition and deterioration, improves the chemical stability of the product, and ensures that the product always maintains good efficacy within its validity period;

[0026] (3) The synergistic effect of the emulsifier and dispersant allows the diazinon technical, sustained-release agent and other ingredients to be evenly dispersed in the system, forming a stable emulsion or dispersion system. This is not only beneficial to the mixing uniformity during the production process, but also ensures that the diazinon technical can be evenly dispersed in water during use, such as during the dilution spray process, thereby improving the uniformity and stability of the efficacy and avoiding the impact of excessively high or low local concentrations on the control effect. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] Example 1: The present invention provides a long-acting diazinon production process, comprising the following steps: S1, raw material preparation: according to the mass ratio, prepare 10-20 parts of diazinon technical with a content of ≥98%, 15-30 parts of solvent, 5-10 parts of emulsifier, 3-8 parts of sustained-release agent, 0.5-2 parts of antioxidant, and 2-5 parts of dispersant;

[0029] S2, dissolving and mixing

[0030] Add diazinon technical into the reactor, then add the selected solvent, stir at 30-50℃ for 1-2 hours to completely dissolve the diazinon technical, then add the emulsifier, antioxidant and dispersant in sequence, and continue stirring for 30-60 minutes to ensure that all ingredients are evenly mixed;

[0031] S3, sustained-release treatment

[0032] Add the sustained-release agent to an appropriate amount of water, heat to 50-70°C and stir until completely dissolved to form a sustained-release agent solution, slowly dropwise add the sustained-release agent solution to the above mixed solution, keep stirring during the dropwise addition process, and control the dropwise addition time to 30-60 minutes. After the dropwise addition is completed, continue stirring and react for 2-4 hours to allow the diazinon and the sustained-release agent to fully combine to form a mixture with sustained-release properties;

[0033] S4, Concentration and Drying

[0034] The solvent in the mixture is distilled out and recovered by using a reduced pressure distillation method, and the distillation temperature is controlled at 50-70° C. until the solid content of the mixture reaches 50%-70%. The concentrated material is then spray-dried to obtain a long-acting diazinon product.

[0035] The solvent is a mixture of one or more of cyclohexanone, toluene and xylene.

[0036] The emulsifier is one or more of alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, and styrylphenol polyoxyethylene ether.

[0037] The sustained-release agent is one or more of chitosan, sodium alginate, and beta-cyclodextrin.

[0038] The antioxidant is one or two of 2,6-di-tert-butyl-p-cresol and triphenyl phosphite.

[0039] The dispersant is one or two of sodium lignin sulfonate and naphthalene sulfonate formaldehyde condensate.

[0040] The stirring speed in S2 is 150-200 rpm.

[0041] The drying temperature in S4 is controlled at 120-150°C.

[0042] The pressure in S4 is between -0.08 and -0.06 MPa.

[0043] Example 2:

[0044] Raw material preparation: Weigh 12 parts of 98% diazinon technical, 20 parts of cyclohexanone, 6 parts of alkylphenol polyoxyethylene ether, 4 parts of chitosan, 1 part of 2,6-di-tert-butyl-p-cresol, and 3 parts of sodium lignin sulfonate.

[0045] Dissolution and mixing: Add diazinon technical to the reactor, add cyclohexanone, and stir at 40°C for 1.5 hours to completely dissolve it. Add alkylphenol polyoxyethylene ether, 2,6-di-tert-butyl-p-cresol, and sodium lignin sulfonate in sequence and stir for 45 minutes.

[0046] Sustained-release treatment: Add chitosan to an appropriate amount of water, heat to 60°C and stir to dissolve. Slowly add chitosan dropwise to the above mixed solution over 45 minutes. After the addition is complete, stir and react for 3 hours.

[0047] Concentration and drying: Recover the solvent by vacuum distillation, controlling the temperature at 60°C and the pressure at -0.07 MPa to a solid content of 60%. Spray drying is then performed at 130°C to obtain a long-acting diazinon product.

[0048] Example 3:

[0049] Raw material preparation: Weigh 15 parts of 99% diazinon technical, 25 parts of a mixed solvent of toluene and xylene (volume ratio 1:1), 8 parts of polyoxyethylene fatty acid ester, 6 parts of sodium alginate, 1.5 parts of triphenyl phosphite, and 4 parts of naphthalenesulfonate formaldehyde condensate.

[0050] Dissolution and mixing: Add diazinon technical to the reactor, add the mixed solvent, and stir at 45°C for 1.2 hours to completely dissolve it. Add fatty acid polyoxyethylene ester, triphenyl phosphite, and naphthalenesulfonate formaldehyde condensate in sequence and stir for 50 minutes.

[0051] Sustained-release treatment: Add sodium alginate to an appropriate amount of water, heat to 65°C and stir to dissolve. Slowly add it dropwise to the above mixed solution over 50 minutes. After the addition is complete, stir and react for 3.5 hours.

[0052] Concentration and drying: Recover the solvent by vacuum distillation, controlling the temperature at 65°C and the pressure at -0.075 MPa to a solid content of 65%. Spray drying is then performed at 140°C to obtain a long-acting diazinon product.

[0053] Table 1 is a table showing the test and comparison results of the process steps, solvent selection, sustained-release agent type, sustained-release agent type, antioxidant, dispersant, key process conditions and product sustained-release cycle of the long-acting diazinon of the present invention:

[0054]

[0055]

[0056] Table 2 is a comparative experimental result table of the sustained-release period (days), purity (%), solvent residue (ppm) and 30-day pesticide utilization rate (%) of the long-acting diazinon of the present invention:

[0057]

[0058]

[0059] From Table 2, it can be seen that the sustained-release period (days) of the present invention is higher than that of the prior art (i.e., the traditional process);

[0060] It can be seen from Table 2 that the purity (%) of the present invention is higher than that of the traditional process;

[0061] As shown in Table 2, the solvent residue (ppm) of the present invention is lower than that of the traditional process;

[0062] It can be seen from Table 2 that the 30-day pesticide utilization rate (%) of the present invention is relatively higher.

[0063] Specifically, when using:

[0064] Carefully selected diazinon technical with a content of ≥98% as the core insecticide ingredient ensures product efficacy. Solvent selection is crucial. Cyclohexanone, toluene, xylene, and their mixtures have good solubility, providing a suitable medium for the subsequent dissolution of diazinon technical, helping to evenly disperse the technical molecules and enhance their reactivity. Emulsifiers, such as alkylphenol polyoxyethylene ethers, fatty acid polyoxyethylene esters, and styrylphenol polyoxyethylene ethers, have a unique amphiphilic structure with one end being hydrophilic and the other end being lipophilic. During the subsequent mixing process, they can reduce the surface tension between the oil (diazinon technical and some adjuvants) and water (or other solvent systems), allowing the diazinon technical and other oily ingredients to be stably dispersed in the solvent, forming a uniform emulsion system and preventing stratification.

[0065] After adding diazinon technical into the reactor and adding solvent, control the temperature at 30-50℃ and stir for 1-2 hours. This temperature range can ensure that diazinon technical has a high solubility in the solvent and avoid the technical decomposition or excessive volatilization of the solvent due to excessive temperature. The stirring speed is controlled at 150-200 rpm. The appropriate stirring speed can increase the collision frequency between the technical and solvent molecules, accelerate the dissolution rate, and make the technical fully dissolved in the solvent. Then add emulsifier, antioxidant and dispersant in sequence and continue stirring for 30-60 minutes. The emulsifier forms micelle structures in the solution, encapsulating the diazinon technical molecules and further stabilizing the emulsion. The antioxidant, 2,6-di-tert-butyl-p-cresol or triphenyl phosphite, can capture free radicals in the system, preventing the diazinon technical from deteriorating due to oxidation during production and storage, thereby extending the product's shelf life. The dispersant, sodium lignin sulfonate or naphthalene sulfonate formaldehyde condensate, adsorbs on the surface of the diazinon technical particles, preventing the technical particles from agglomerating through electrostatic repulsion or steric hindrance, ensuring that all components are evenly dispersed in the system.

[0066] A sustained-release agent, such as chitosan, sodium alginate, or β-cyclodextrin, is added to an appropriate amount of water and heated to 50-70°C with stirring until completely dissolved. This temperature range promotes the full extension and dissolution of the sustained-release agent molecules in water, forming a uniform solution. The sustained-release agent solution is slowly added dropwise to the previously mixed solution over a controlled dropwise addition time of 30-60 minutes, with continuous stirring during the addition process. Stirring allows the sustained-release agent solution and the mixed solution to mix rapidly and evenly, while also promoting full contact between the sustained-release agent molecules and the diazinon technical molecules. After the dropwise addition is complete, stirring is continued for 2-4 hours. During this period, the sustained-release agent molecules bind to the diazinon technical molecules through physical adsorption, hydrogen bonding, or inclusion complexation. For example, β-cyclodextrin can utilize its internal hydrophobic cavity to encapsulate the diazinon molecules, forming a stable inclusion complex. Polymers such as chitosan and sodium alginate can form a polymer film with a certain barrier effect around the diazinon technical, thereby slowing the release rate of the diazinon in the external environment and achieving a long-lasting effect.

[0067] The solvent is recovered by distillation under reduced pressure, with the distillation temperature controlled at 50-70°C and the pressure at -0.08 to -0.06 MPa. The reduced pressure environment can lower the boiling point of the solvent, allowing it to volatilize in large quantities at a lower temperature, thereby preventing damage to the diazinon technical and other components caused by high temperature. As the solvent is continuously distilled, the solid content of the mixture gradually increases to 50% to 70%. The concentrated material is then spray-dried at a temperature controlled at 120-150°C. During the spray-drying process, the concentrated material is atomized into tiny droplets, which are fully contacted with hot air, and moisture in the droplets is rapidly evaporated, thereby obtaining a dry, powdered, long-acting diazinon product. This drying method can quickly remove moisture, maintain the chemical stability of the product, and simultaneously ensure that the product has good dispersibility and fluidity.

[0068] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A long-acting diazinon production process, characterized in that: The following steps are involved: S1. Raw material preparation: According to the mass ratio, prepare 10-20 parts of diazinon technical with a content of ≥98%, 15-30 parts of solvent, 5-10 parts of emulsifier, 3-8 parts of sustained-release agent, 0.5-2 parts of antioxidant, and 2-5 parts of dispersant; S2, dissolving and mixing Add diazinon technical into the reactor, then add the selected solvent, stir at 30-50℃ for 1-2 hours to completely dissolve the diazinon technical, then add the emulsifier, antioxidant and dispersant in sequence, and continue stirring for 30-60 minutes to ensure that all ingredients are evenly mixed; S3, sustained-release treatment Add the sustained-release agent to an appropriate amount of water, heat to 50-70°C and stir until completely dissolved to form a sustained-release agent solution, slowly dropwise add the sustained-release agent solution to the above mixed solution, keep stirring during the dropwise addition process, and control the dropwise addition time to 30-60 minutes. After the dropwise addition is completed, continue stirring and react for 2-4 hours to allow the diazinon and the sustained-release agent to fully combine to form a mixture with sustained-release properties; S4, Concentration and Drying The solvent in the mixture is distilled out and recovered by using a reduced pressure distillation method, and the distillation temperature is controlled at 50-70° C. until the solid content of the mixture reaches 50%-70%. The concentrated material is then spray-dried to obtain a long-acting diazinon product.

2. The process for producing long-acting diazinon according to claim 1, characterized in that: The solvent is a mixture of one or more of cyclohexanone, toluene and xylene.

3. The process for producing long-acting diazinon according to claim 1, characterized in that: The emulsifier is one or more of alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, and styrylphenol polyoxyethylene ether.

4. The process for producing long-acting diazinon according to claim 1, characterized in that: The sustained-release agent is one or more of chitosan, sodium alginate, and beta-cyclodextrin.

5. The process for producing long-acting diazinon according to claim 1, characterized in that: The antioxidant is one or two of 2,6-di-tert-butyl-p-cresol and triphenyl phosphite.

6. The process for producing long-acting diazinon according to claim 1, characterized in that: The dispersant is one or two of sodium lignin sulfonate and naphthalene sulfonate formaldehyde condensate.

7. The process for producing long-acting diazinon according to claim 1, characterized in that: The stirring speed in S2 is 150-200 rpm.

8. The process for producing long-acting diazinon according to claim 1, characterized in that: The drying temperature in S4 is controlled at 120-150°C.

9. The process for producing long-acting diazinon according to claim 1, characterized in that: The pressure in S4 is between -0.08 and -0.06 MPa.

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