Preparation method of slow-release insecticide

Abstract

The present invention belongs to the technical field of pesticide preparation, and specifically relates to a preparation method of a sustained-release pesticide. The preparation of the hydrotalcite precursor, the preparation of dimehypo and polymer monomer intercalated hydrotalcite, and the polymerization reaction in the hydrotalcite are carried out to obtain the sustained-release pesticide. The present invention prepares hydrotalcite containing dimehypo and polymer. The main component, dimehypo, is located between the hydrotalcite layers and is protected by the layer plates. Therefore, the sustained-release pesticide can be used in acidic or alkaline soils and has a relatively wide applicable temperature range; polymers of acrylate and styryl are introduced between the hydrotalcite layers, and acrylate polymers are introduced into the voids of the hydrotalcite particles, which can delay the diffusion rate of dimehypo out of the hydrotalcite, thereby achieving the effect of long-term sustained release.

Description

Technical Field

[0001] The invention belongs to the technical field of insecticide preparation, and particularly relates to a method for preparing a slow-release insecticide. Background Art

[0002] Pesticides are chemical agents used to control agricultural pests and urban pests, including organic pesticides, inorganic pesticides, botanical pesticides, mineral oil pesticides, microbial pesticides, etc. Pesticides have a long history of use, with large amounts used and a wide variety of varieties. Since the 20th century, with the rapid development of agriculture, the use of pesticides has also increased significantly. However, most pesticides will affect the ecosystem. Some directly harm the human body, while others will be concentrated in the food chain and pose potential hazards to the environment and the human body. Bisultap, with the molecular formula of C5H 11 NNa2O6S4, with a molecular weight of 355.384, is a nereid poison-type insecticide. Its mechanism of action is to bind to cholinergic synapses in ganglia, blocking synaptic transmission in the insect's central nervous system. It has contact, stomach, and systemic effects on pests, and also has some fumigant activity. It is suitable for controlling lepidopteran pests in crops such as rice, vegetables, and fruit trees. Dimehypo, with its advantages of high efficiency, low residue, broad insecticide spectrum, and no "three-hazard" effects, has become an important agricultural insecticide in my country and is widely used. However, disadvantages of dimehypo, such as its easy decomposition in acidic media and the need for regular spraying, have limited its application.

[0003] Layered Double Hydroxides (LDHs) is a type of anionic layered material with the chemical composition of [M 2+ 1-x M 3+ x (OH)2] x+ (A n- ) x / n mH2O, where M 2+ and M 3+ are divalent and trivalent metal cations located on the main layer, such as Mg 2+ 、Ni 2+ 、Zn 2+ Divalent cations and Al 3+ Cr 3+ 、Co 3+ 、Fe 3+ Trivalent cations such as A can form LDHs; n- is an interlayer anion, which may include inorganic anions, organic anions, complex anions, etc.; x is M 3+ / (M 2+ +M 3+) has a molar ratio of approximately 4:1 to 2:1; m is the number of interlayer water molecules. Its structure is similar to brucite Mg(OH)₂, with a main layer formed by the sharing of edges of MO₆ octahedra. The divalent metal cation M located on the layer board 2+ can be isomorphously substituted by a trivalent metal cation M with a similar ionic radius within a certain proportion range 3+ so that the layer board carries a positive charge. There are exchangeable anions between the layers to balance the positive charge on the layer board, making the overall structure of LDHs electrically neutral.

[0004] Chinese Patent CN 110622991 A discloses a slow-release phoxim pesticide and its preparation method. Utilizing the hydrophobic environment rich in delocalized π bonds provided by naphthaleneacetic acid between the layers of hydrotalcite, phoxim is assembled into the interlayer of hydrotalcite to prepare a hydrotalcite material intercalated with phoxim and naphthaleneacetic acid. When this material is immersed in water or soil, phoxim can be released for a long time, achieving the effect of slow release of this pesticide (insecticide). In this patent, since phoxim is a neutral molecule and it is difficult to enter the positively charged hydrotalcite layer board, the loading amount is relatively low, and the hindrance effect of naphthaleneacetic acid root is small, so the slow-release rate is relatively fast.

[0005] Chinese Patent CN101456929A discloses a styrene-acrylic / hydrotalcite-like nanocomposite emulsion and its preparation method. Using hydrotalcite modified by intercalation of nanoscale organic substances as the dispersed phase, styrene and acrylate as the monomers for the polymerization reaction, and acrylic acid as the functional monomer, while neutralizing the acidity of acrylic acid with an alkali, a styrene-acrylic / hydrotalcite-like nanocomposite emulsion is prepared by in-situ intercalation polymerization. In this patent, acrylate radicals undergo intercalation and polymerization reactions simultaneously in a relatively short time, the intercalation amount of acrylate radicals is relatively low, and because a large amount of polymerization monomers such as styrene and acrylate are added, most of the hydrotalcite is exfoliated. Summary of the Invention

[0006] The object of the present invention is to provide a preparation method of a slow-release insecticide, to prepare a hydrotalcite containing bisultap and a polymer. The main component, bisultap, is located between the layers of hydrotalcite and is protected by the layer board. Therefore, the slow-release insecticide can be used in acidic or alkaline soils and has a relatively wide applicable temperature range; introducing polymers of acrylate and styryl between the layers of hydrotalcite and introducing acrylate polymer into the voids of hydrotalcite particles can delay the diffusion rate of bisultap out of hydrotalcite, thereby achieving the effect of long-term slow release.

[0007] The preparation method of the slow-release insecticide described in the present invention includes the following steps:

[0008] (1) Preparation of the hydrotalcite precursor;

[0009] (2) Preparation of the hydrotalcite intercalated with bisultap and polymer monomers:

[0010] Dimehypo and a polymer monomer are dissolved in deionized water free of CO2 to obtain a solution, and then the hydrotalcite precursor obtained in step (1) is added to this solution. The reaction is carried out under heating and stirring under N2 protection, followed by washing and drying to obtain an intercalated hydrotalcite of dimehypo and the polymer monomer;

[0011] (3) Polymerization reaction in hydrotalcite:

[0012] Prepare an aqueous-ethanol solution of acrylate, add the intercalated hydrotalcite of dimehypo and the polymer monomer obtained in step (2) to the aqueous-ethanol solution of acrylate, then add potassium persulfate, soak, heat to 70 - 80 °C under N2 protection, react under stirring for 1 - 3 h, then raise the temperature to 85 - 90 °C, react under stirring for 2 - 4 h, wash the product and dry it to obtain a sustained-release insecticide.

[0013] The preparation method of the hydrotalcite precursor described in step (1) is to dissolve the soluble salt of M 2+ and the soluble salt of M 3+ in water free of CO2 to obtain solution A, and dissolve NaOH in water free of CO2 to obtain solution B; under the condition of N2 protection at room temperature, mix solution A and solution B, adjust the pH value to obtain a slurry; crystallize the slurry, wash it and dry it to obtain the hydrotalcite precursor.

[0014] The M 2+ is one of Mg 2+ , Ni 2+ or Zn 2+ , preferably Zn 2+ ; M 3+ is Al 3+ , the soluble salt of M 2+ is the hydrochloride salt of M 2+ or the nitrate salt of M 2+ , the soluble salt of M 3+ is the hydrochloride salt of M 3+ or the nitrate salt of M 3+ , the types of the soluble salt of M 2+ and the soluble salt of M 3+ in solution A are the same, the molar ratio of M 2+ to M 3+ is 2 - 3; the molar concentration of solution B is 1.0 - 5.0 M, adjusting the pH value is to adjust the pH value to 6 - 10 with a 0.1 - 5.0 M NaOH solution, the crystallization temperature is 60 - 90 °C, the crystallization time is 12 - 72 h, the drying temperature is 50 - 90 °C, and the drying time is 20 - 48 h.

[0015] The polymer monomer described in step (2) is one of sodium p-styrenesulfonate, sodium p-vinylbenzoate or sodium p-vinylphenylacetate.

[0016] The mass ratio of bisultap, polymer monomer and hydrotalcite precursor described in step (2) is 3.5 - 5:2 - 4:10.

[0017] The heating temperature described in step (2) is 50 - 70 °C, and the reaction time is 12 - 48 h.

[0018] The drying temperature described in step (2) is 50 - 90 °C, and the drying time is 20 - 48 h.

[0019] The acrylate described in step (3) is methyl acrylate or ethyl acrylate.

[0020] The volume ratio of water and ethanol described in step (3) is 1:2 - 3, and the concentration of acrylate in the water - ethanol solution of acrylate is 40 - 60 g / L.

[0021] The mass ratio of acrylate, bisultap and polymer monomer intercalated hydrotalcite to potassium persulfate described in step (3) is 4 - 6:10:0.25 - 0.5.

[0022] The soaking time described in step (3) is 2 - 4 h.

[0023] The drying temperature described in step (3) is 50 - 90 °C, and the drying time is 20 - 48 h.

[0024] In the present invention, a hydrotalcite precursor is first prepared, and bisultap and polymer monomer are intercalated into the hydrotalcite precursor to obtain a hydrotalcite co - intercalated with bisultap and polymer monomer. Then, the hydrotalcite and potassium persulfate are fully soaked in a water - ethanol solution of acrylate, and a polymerization reaction occurs upon heating to obtain a slow - release insecticide containing a hydrotalcite of bisultap and polymer.

[0025] The chemical formula of the slow - release insecticide prepared by the present invention is as follows:

[0026] [(M 2+ ) 1-x (M 3+ ) x (OH)2] x+ (BS 2- ) a (D - ) b (E) c ·mH2O

[0027] Among them, x = 0.25 - 0.33, 2a + b = x, m = 3 - 6, c = 0.6 - 1, m is the number of interlayer crystal water molecules, M 2+ is a divalent metal ion, M 3+ is a trivalent metal ion, BS 2- is the bisultap anion, D -One of them is sulfonate styrene (VBS), acrylate benzoate (VBA) or acrylate phenylacetate (VBAA), and E is methyl acrylate (MA) or ethyl acrylate (EA).

[0028] The preparation method of the sustained-release insecticide described in the present invention includes the following specific steps:

[0029] (1) Preparation of hydrotalcite precursor:

[0030] Dissolve the soluble salt of M 2+ and the soluble salt of M 3+ in water without CO2 to obtain solution A, dissolve NaOH in water without CO2 to obtain solution B. Under the protection of N2 at room temperature, add solution A and solution B into a four-necked flask by the double-drop method and mix them. Then adjust the pH value to 6-10 with 0.1-5.0M NaOH solution to obtain a slurry. Crystallize the obtained slurry at 60-90°C for 12-72h, and wash it with water without CO2 until it is neutral. Take out the sample and dry it at 50-90°C for 20-48h to obtain the hydrotalcite precursor;

[0031] (2) Intercalation of dimehypo and polymer monomer into hydrotalcite:

[0032] Dissolve dimehypo and polymer monomer in deionized water without CO2, and then add the hydrotalcite precursor obtained in step (1) into this solution. Heat it to 50-70°C under the protection of N2 and react with stirring for 12-48h. Then wash it with water without CO2 until it is neutral, and dry it at 50-90°C for 20-48h to obtain dimehypo and polymer monomer intercalated hydrotalcite BS / D-LDHs;

[0033] (3) Polymerization reaction in hydrotalcite:

[0034] Prepare an aqueous ethanol solution of acrylate. Add the dimehypo and polymer monomer intercalated hydrotalcite obtained in step (2) into the aqueous ethanol solution of acrylate, then add potassium persulfate, soak for 2-4h, heat it to 70-80°C under the protection of N2 and react with stirring for 1-3h. Then raise the temperature to 85-90°C and react with stirring for 2-4h. Wash the product with water without CO2 until it is neutral, and dry it at 50-90°C for 20-48h to obtain the sustained-release insecticide.

[0035] When in use, bury the sustained-release insecticide in the soil or spray it on plants, and dimehypo will slowly diffuse out of the hydrotalcite, playing a long-term insecticidal role.

[0036] The beneficial effects of the present invention are as follows:

[0037] (1) The slow-release insecticide prepared by the present invention is a hydrotalcite containing bisultap and a polymer. A polymer of acrylate and styrene group is introduced into the interlayer of the hydrotalcite, and an acrylate polymer is introduced into the voids of the hydrotalcite particles. Since the polymer can significantly hinder the movement of bisultap within the hydrotalcite, a long-acting slow-release effect is achieved.

[0038] (2) In the present invention, bisultap and anions such as p-styrenesulfonate are first intercalated into the interlayer of the hydrotalcite, and then the hydrotalcite is fully soaked in an aqueous-ethanol solution of acrylate. First, the polymerization of acrylate in the voids of the hydrotalcite particles is initiated by potassium persulfate at a lower temperature, and then the temperature is raised to initiate the polymerization of p-styrenesulfonate / acrylate in the interlayer of the hydrotalcite, obtaining a hydrotalcite containing bisultap and a polymer. The difficulty of polymerization between the interlayer and particles of the hydrotalcite is different. The interlayer polymerization is more difficult and requires a higher temperature. The present invention adopts a gradient temperature rise polymerization method to control the degree of polymerization between the interlayer and particles, avoiding the problem of exfoliation of the hydrotalcite layer caused by excessive polymerization degree.

[0039] (3) The interlayer polymer in the present invention is composed of p-styrenesulfonate and acrylate. The benzene sulfonate groups on the branched chains are not only large in volume, but also the sulfonate groups can be firmly adsorbed on the layer board because they carry negative charges. Therefore, the hindrance effect on the slow-release agent is significant, especially for molecules with a relatively large volume such as bisultap. In addition, a polyacrylate chain is formed in the voids of the hydrotalcite particles, which can further extend the time for the molecule to be released from the hydrotalcite, achieving a long-acting slow-release effect. It is found that the degree of polymerization can be affected by changing polymerization conditions, monomer addition amount, etc., so as to regulate the slow-release rate and achieve a controllable slow-release effect. The greater the degree of polymerization of the polymer, the slower the slow-release rate of bisultap.

[0040] (4) From the perspective of the release of bisultap from the slow-release insecticide in an aqueous solution, each gram of the hydrotalcite containing bisultap and a polymer can release bisultap for a long time, and the release time lasts for more than 90 days. Bisultap in the hydrotalcite material containing bisultap and a polymer has a long-time slow-release effect. At the same time, the unique acid and alkali resistance of the hydrotalcite can be applied to most types of soil. Brief Description of the Drawings

[0041] Figure 1 is a schematic structural diagram of the slow-release insecticide prepared in Example 1.

[0042] Figure 2 is an X-ray powder diffraction pattern of the hydrotalcite containing bisultap and a polymer prepared in Example 1; in the figure: a is the hydrotalcite precursor, b is the hydrotalcite intercalated with bisultap and p-styrenesulfonate, and c is the hydrotalcite containing bisultap and a polymer.

[0043] Figure 3Schematic diagram of the interlayer structure before and after polymerization of the sustained-release insecticide prepared in Example 1.

[0044] Figure 4 Thermogravimetric analysis spectrum of the hydrotalcite containing bisultap and polymer prepared in Example 1.

[0045] Figure 5 Release curve of bisultap released from the hydrotalcite containing bisultap and polymer prepared in Example 1. Detailed implementation manners

[0046] The present invention will be further described below in conjunction with examples.

[0047] Example 1

[0048] (1) Weigh 53.8 g of Zn(NO3)2·6H2O and 33.9 g of Al(NO3)3·9H2O and dissolve them in 200 mL of CO2-free water to obtain solution A. Separately, dissolve 15.0 g of NaOH in 150 mL of CO2-free water to obtain solution B. Under the condition of full N2 protection, add solution A and solution B into a four-necked flask using the double-drop method, keep at room temperature, and stir strongly. After dropping, adjust the pH value to 7 with 0.1 mol / L NaOH solution. The obtained slurry is crystallized at 60 °C for 72 h, washed with CO2-free water until neutral; take out the sample and dry it at 50 °C for 48 h to obtain nitrate-intercalated zinc-aluminum hydrotalcite ZnAl-NO3-LDHs.

[0049] (2) Dissolve 2.0 g of sodium p-styrenesulfonate (C8H7NaO3S) solid and 5.0 g of bisultap (C5H 11 NO6S4Na2) in 150 mL of CO2-free deionized water, then transfer it into a four-necked flask, add 10 g of the hydrotalcite precursor ZnAl-NO3-LDHs, heat to 50 °C under N2 protection, and react for 48 h with stirring. Wash with CO2-free water until neutral, and dry at 50 °C for 48 h to obtain the hydrotalcite intercalated with bisultap anions and p-styrenesulfonate BS / VBS-LDHs.

[0050] (3) Add 5.0 g of methyl acrylate to 100 mL of a water-ethanol solution (the volume ratio of water to ethanol is 1:3) to obtain a water-ethanol solution of methyl acrylate. Add the water-ethanol solution of methyl acrylate into a four-necked flask, then add 10 g of the hydrotalcite intercalated with bisultap and p-styrenesulfonate BS / VBS-LDHs obtained in step (2), add 0.25 g of potassium persulfate, soak for 2 h, heat to 70 °C under N2 protection, react for 3 h with stirring, then raise the temperature to 85 °C and react for 4 h with stirring. The product is washed with CO2-free water until neutral, and after drying at 50 °C for 48 h, the hydrotalcite containing bisultap and polymer can be obtained, and its chemical formula is: [(Zn 2+ ) 0.67(Al 3 + ) 0.33 (OH)2] 0.33+ (BS 2- ) 0.12 (VBS - ) 0.09 (MA) 0.73 ·5H2O, the structural schematic diagram of the product is shown in Figure 1 .

[0051] The X-ray powder diffraction pattern of the product is shown in Figure 2 . It can be seen from Figure 2 that the d 003 layer spacing of bisultap and styrenesulfonate intercalated hydrotalcite is 1.85 nm, which is 0.96 nm larger than that of the intercalation precursor ZnAl-NO3-LDHs. This phenomenon of lamellar expansion indicates that bisultap and styrenesulfonic acid have successfully inserted into the LDHs interlayer. It can be known from the XRD structural parameters that bisultap anions and styrenesulfonate groups adopt a single-layer arrangement with the axis perpendicular to the lamellar in the hydrotalcite interlayer, and the a value of its unit cell parameter is similar to that of other hydrotalcites, indicating that the product has a complete layered structure. After polymerization, the d 003 layer spacing expands to 1.94 nm. This is because after the polymerization reaction occurs in the interlayer, the sulfonate groups are adsorbed on the positively charged hydrotalcite lamellar due to electrostatic attraction, and benzene is connected to the polymer chain. When the chain connecting adjacent benzene sulfonate groups is short, adjacent benzene sulfonate groups cannot freely adopt a single-layer arrangement with the axis perpendicular to the lamellar, but will show a staggered arrangement, and there is an intramolecular stress between the branched benzene sulfonate group and the polymer chain, causing the layer spacing to expand, as shown in Figure 3 .

[0052] After dissolving the lamellar of the product with acid, the molecular weight of the polymer was measured by the boiling point elevation method, which confirmed that the polymerization reaction occurred. Thermogravimetric analysis (air) was carried out on the hydrotalcite containing bisultap and polymer by a thermogravimetric / differential thermal comprehensive thermal analyzer, and the thermogravimetric analysis spectrum is shown in Figure 4 . It can be seen from Figure 4It can be seen that with the increase of temperature, the mass of hydrotalcite continuously decreases, and the weight loss process can be divided into three stages. The first stage (from room temperature to about 180 °C) is the loss of adsorbed water, bound water and other volatile components in the hydrotalcite; the second stage (180 °C to 345 °C) is the combustion and decomposition process of the polymer in the pores of the hydrotalcite in air. An obvious exothermic peak is observed in the DTA curve while there is weight loss; the third stage (345 °C to 490 °C) is the combustion and decomposition process of the benzene-containing polymer and dimehypo intercalated in the interlayer of the hydrotalcite in air. An obvious exothermic peak is also observed in the DTA curve while there is weight loss. The above results show that two obvious exothermic peaks appear corresponding to the combustion of the polymer in the pores and the combustion of the polymer in the interlayer. There are polymers both in the interlayer and pores of the hydrotalcite. The hydrotalcite layer can effectively protect the interlayer polymer and dimehypo, improve its high-temperature resistance ability, and the temperature of combustion and decomposition is significantly increased. The thermal decomposition temperature of the interlayer polymer and dimehypo is significantly higher than that of the polymer in the pores.

[0053] When 1 g of this hydrotalcite is immersed in 100 mL of distilled water, dimehypo will be continuously released, and the release is basically balanced after 90 days, and the total release amount is 0.1308 g.

[0054] Example 2

[0055] (1) Weigh 46.4 g of Mg(NO3)2﹒6H2O and 33.9 g of Al(NO3)3﹒9H2O and dissolve them in 200 mL of CO2-free water to obtain solution A. Separately, weigh 7.0 g of NaOH and dissolve it in 150 mL of CO2-free water to obtain solution B. Under the condition of full N2 protection, use the double-drop method to add solution A and solution B into a four-necked flask, keep at room temperature, and stir strongly. After dropping, adjust the pH value to 10 with 5 mol / L NaOH solution, and crystallize the obtained slurry at 90 °C for 12 h, and wash it with CO2-free water until neutral; take out the sample and dry it at 90 °C for 20 h to obtain nitrate-intercalated magnesium-aluminum hydrotalcite MgAl-NO3-LDHs.

[0056] (2) Dissolve 4.0 g of sodium p-styrenesulfonate (C8H7NaO3S) solid and 4.0 g of dimehypo (C5H 11 NO6S4Na2) in 150 mL of CO2-free deionized water, then transfer it into a four-necked flask, add another 10 g of hydrotalcite precursor MgAl-NO3-LDHs, heat to 70 °C under N2 protection, and react with stirring for 12 h. Wash it with CO2-free water until neutral, and dry it at 90 °C for 20 h to obtain dimehypo and p-styrenesulfonic acid intercalated hydrotalcite BS / VBS-LDHs.

[0057] (3) 4.0 g of methyl acrylate was added to 100 mL of a water-ethanol solution (volume ratio of water to ethanol is 1:2) to obtain a water-ethanol solution of methyl acrylate. The water-ethanol solution of methyl acrylate was added to a four-necked flask, and then 10 g of dimehypo and p-styrenesulfonate intercalated hydrotalcite BS / VBS-LDHs from step (2) were added, 0.50 g of potassium persulfate was added, and it was soaked for 4 h. Under N2 protection, it was heated to 80 °C and reacted with stirring for 1 h, then the temperature was raised to 90 °C and reacted with stirring for 2 h. The product was washed with CO2-free water until neutral, and dried at 90 °C for 20 h to obtain a hydrotalcite containing dimehypo and polymer, and its chemical formula is: [(Mg 2+ ) 0.67 (Al 3 + ) 0.33 (OH)2] 0.33+ (BS 2- ) 0.07 (VBS - ) 0.19 (MA) 0.65 ·3H2O.

[0058] It can be known from the X-ray powder diffraction of the product that the d 003 layer spacing of dimehypo and p-styrenesulfonate intercalated hydrotalcite is 1.86 nm, which is 0.97 nm larger than the layer spacing of the intercalation precursor MgAl-NO3-LDHs. This phenomenon of lamellar expansion indicates that dimehypo and p-styrenesulfonic acid have been successfully inserted into the LDHs interlayer. After polymerization, the d 003 layer spacing expands to 1.95 nm. This is because a polymerization reaction occurs between the layers, and an intramolecular stress is generated between the branched benzenesulfonate groups and the polymer chains, making the p-styrenesulfonate groups unable to freely adopt a single-layer arrangement perpendicular to the lamellar axis, resulting in an increase in the layer spacing.

[0059] When 1 g of this hydrotalcite was soaked in 100 mL of distilled water, dimehypo was continuously released, and the release was basically balanced after 135 days, and the total release amount was 0.1002 g.

[0060] Example 3

[0061] (1) Weigh 52.6 g of Ni(NO3)2﹒6H2O and 33.9 g of Al(NO3)3﹒9H2O and dissolve them in 200 mL of CO2-free water to obtain solution A. Separately, weigh 10.0 g of NaOH and dissolve it in 150 mL of CO2-free water to obtain solution B. Under the condition of full N2 protection, add solution A and solution B into a four-necked flask using the double-drop method, keep at room temperature, and stir vigorously. After dropping, adjust the pH value to 7 with 3.0 mol / L NaOH solution. The obtained slurry is crystallized at 80 °C for 30 h, and washed with CO2-free water until neutral; take out the sample and dry it at 50 °C for 48 h to obtain nitrate-intercalated nickel-aluminum hydrotalcite NiAl-NO3-LDHs.

[0062] (2) Dissolve 3.0 g of sodium p-styrenesulfonate (C8H7NaO3S) solid and 5.0 g of dimehypo (C5H 11 NO6S4Na2) in 150 mL of CO2-free deionized water, then transfer it into a four-necked flask, and add 10 g of the hydrotalcite precursor NiAl-NO3-LDHs. Heat to 60 °C under N2 protection and react for 36 h with stirring. Wash with CO2-free water until neutral and dry at 50 °C for 48 h to obtain dimehypo and p-styrenesulfonic acid intercalated hydrotalcite BS / VBS-LDHs.

[0063] (3) Add 6.0 g of methyl acrylate to 100 mL of a water-ethanol solution (volume ratio of water to ethanol is 1:3) to obtain a water-ethanol solution of methyl acrylate. Add the water-ethanol solution of methyl acrylate into a four-necked flask, then add 10 g of the dimehypo and p-styrenesulfonate intercalated hydrotalcite BS / VBS-LDHs from step (2), add 0.25 g of potassium persulfate, soak for 4 h, heat to 75 °C under N2 protection, react for 2 h with stirring, then raise the temperature to 88 °C and react for 3 h with stirring. Wash the product with CO2-free water until neutral, and dry at 70 °C for 30 h to obtain a hydrotalcite containing dimehypo and polymer, and its chemical formula is: [(Ni 2+ ) 0.67 (Al 3 + ) 0.33 (OH)2] 0.33+ (BS 2- ) 0.10 (VBS - ) 0.13 (MA) 0.82 ·4H2O.

[0064] It can be known from the X-ray powder diffraction of the product that the d 003 layer spacing of the dimehypo and p-styrenesulfonate intercalated hydrotalcite is 1.85 nm, which is 0.96 nm larger than that of the intercalation precursor NiAl-NO3-LDHs. After polymerization, d 003The layer spacing is expanded to 1.95 nm.

[0065] When 1 g of this hydrotalcite is immersed in 100 mL of distilled water, bisultap will be continuously released. The release basically reaches equilibrium after 113 days, and the total release amount is 0.1118 g.

[0066] Example 4

[0067] (1) Weigh 49.2 g of ZnCl2 and 43.5 g of AlCl3·6H2O and dissolve them in 200 mL of CO2-free water to obtain solution A. Separately, dissolve 20.0 g of NaOH in 150 mL of CO2-free water to obtain solution B. Under the condition of full N2 protection, use the double-drop method to add solution A and solution B into a four-necked flask, keep the room temperature, and stir strongly. After dropping, adjust the pH value to 6 with 0.5 mol / L NaOH solution. The obtained slurry is crystallized at 70 °C for 24 h, and washed with CO2-free water until neutral; take out the sample and dry it at 70 °C for 24 h to obtain chloride ion-intercalated zinc-aluminum hydrotalcite ZnAl-Cl-LDHs.

[0068] (2) Dissolve 2.0 g of sodium p-styrenesulfonate (C8H7NaO3S) solid and 3.5 g of bisultap (C5H 11 NO6S4Na2) in 150 mL of CO2-free deionized water and then transfer it into a four-necked flask. Then add 10 g of hydrotalcite precursor ZnAl-Cl-LDHs, heat to 70 °C under N2 protection, and react for 36 h with stirring. Wash with CO2-free water until neutral, and dry at 70 °C for 20 h to obtain bisultap and p-styrenesulfonate anion-intercalated hydrotalcite BS / VBS-LDHs.

[0069] (3) Add 5.0 g of methyl acrylate to 100 mL of a water-ethanol solution (the volume ratio of water to ethanol is 1:2) to obtain a water-ethanol solution of methyl acrylate. Add the water-ethanol solution of methyl acrylate into a four-necked flask, and then add 10 g of bisultap and p-styrenesulfonate anion-intercalated hydrotalcite BS / VBS-LDHs obtained in step (2), add 0.25 g of potassium persulfate, soak for 3 h, heat to 70 °C under N2 protection, react for 3 h with stirring, then raise the temperature to 90 °C, and react for 2 h with stirring. The product is washed with CO2-free water until neutral, and dried at 90 °C for 20 h to obtain a hydrotalcite containing bisultap and polymer, and its chemical formula is: [(Zn 2+ ) 0.67 (Al 3 + ) 0.33 (OH)2] 0.33+ (BS 2- ) 0.09 (VBS - ) 0.15 (MA) 0.71 ·4H2O.

[0070] The X-ray powder diffraction of the product showed that the d 003 The interlayer spacing is 1.85nm, which is 0.94nm larger than that of the intercalation precursor ZnAl-Cl-LDHs. 003 The interlayer spacing is expanded to 1.95nm.

[0071] When 1 g of the hydrotalcite is immersed in 100 mL of distilled water, dimethoate will be continuously released. After 112 days, the release is basically balanced, and the total release amount is 0.0929 g.

[0072] Example 5

[0073] (1) 79.2 g of Zn(NO₃)₂﹒6H₂O and 33.9 g of Al(NO₃)₃﹒9H₂O were dissolved in 200 mL of CO₂-free water to obtain solution A. 15.0 g of NaOH was dissolved in 150 mL of CO₂-free water to obtain solution B. Under nitrogen protection throughout, solutions A and B were added to a four-necked flask using the double-drop method. The mixture was maintained at room temperature and stirred vigorously. After the addition was complete, the pH was adjusted to 7 with 1.0 mol / L NaOH solution. The resulting slurry was crystallized at 60°C for 48 h and washed with CO₂-free water until neutral. The sample was removed and dried at 70°C for 24 h to obtain chloride-intercalated zinc-aluminum hydrotalcite (ZnAl-NO₃-LDHs).

[0074] (2) 2.0 g of sodium p-styrenesulfonate (C8H7NaO3S) solid and 4.0 g of dimehypo (C5H 11 Dissolve NO6S4Na2 in 150 mL of deionized water free of CO2 and transfer to a four-necked flask. Add 10 g of the hydrotalcite precursor ZnAl-NO3-LDHs. Heat to 70°C under nitrogen and stir for 36 hours. Wash with CO2-free water until neutral and dry at 70°C for 20 hours to obtain the dimehypo- and p-styrenesulfonate-intercalated hydrotalcite BS / VBS-LDHs.

[0075] (3) 5.0 g of ethyl acrylate was added to 100 mL of water-ethanol solution (the volume ratio of water to ethanol was 1:2) to obtain a water-ethanol solution of ethyl acrylate. The water-ethanol solution of ethyl acrylate was added to a four-necked flask, and then 10 g of the dimethoate and p-styrenesulfonate intercalated hydrotalcite BS / VBS-LDHs from step (2) were added. 0.25 g of potassium persulfate was added, and the mixture was soaked for 3 h. The mixture was heated to 70 ° C under N2 protection, stirred for 3 h, and then heated to 85 ° C, stirred for 3.8 h. The product was washed with CO2-free water until neutral, and dried at 70 ° C for 24 h to obtain a hydrotalcite containing dimethoate and a polymer. Its chemical formula is: [(Zn 2+ ) 0.75 (Al3+ ) 0.25 (OH)2] 0.25+ (BS 2- ) 0.07 (VBS - ) 0.11 (EA) 0.65 ·4H2O。

[0076] The product was analyzed by X-ray powder diffraction. It was found that the d-spacing of the intercalated hydrotalcite with bisultap and p-styrenesulfonate was 003 1.85 nm, which was 0.96 nm larger than that of the precursor ZnAl-NO3-LDHs before intercalation. After polymerization, the d-spacing 003 expanded to 1.95 nm.

[0077] When 1 g of this hydrotalcite was immersed in 100 mL of distilled water, bisultap was continuously released. After 106 days, the release reached equilibrium, and the total release amount was 0.0762 g.

[0078] Example 6

[0079] (1) Weigh 53.8 g of Zn(NO3)2﹒6H2O and 33.9 g of Al(NO3)3﹒9H2O and dissolve them in 200 mL of CO2-free water to obtain solution A. Separately, dissolve 15.0 g of NaOH in 150 mL of CO2-free water to obtain solution B. Under the condition of full N2 protection, add solution A and solution B to a four-necked flask using the double-drop method, keep the room temperature, and stir strongly. After dropping, adjust the pH value to 7 with 0.1 mol / L NaOH solution. The obtained slurry was crystallized at 60 °C for 72 h, washed with CO2-free water until neutral, and the sample was taken out and dried at 50 °C for 48 h to obtain nitrate-intercalated zinc-aluminum hydrotalcite ZnAl-NO3-LDHs.

[0080] (2) Dissolve 2.0 g of sodium p-vinylbenzoate (C9H7O2Na) solid and 5.0 g of bisultap (C5H 11 NO6S4Na2) in 150 mL of CO2-free deionized water, transfer it to a four-necked flask, then add 10 g of the hydrotalcite precursor ZnAl-NO3-LDHs, heat to 50 °C under N2 protection, and react with stirring for 48 h. Wash with CO2-free water until neutral and dry at 50 °C for 48 h to obtain the intercalated hydrotalcite with bisultap and p-vinylbenzoate BS / VBA-LDHs.

[0081] (3) Add 5.0 g of ethyl acrylate to 100 mL of a water-ethanol solution (the volume ratio of water to ethanol is 1:2) to obtain a water-ethanol solution of ethyl acrylate. Add the water-ethanol solution of ethyl acrylate to a four-necked flask, and then add 10 g of bisultap and p-vinylbenzoate intercalated hydrotalcite BS / VBA-LDHs from step (2). Add 0.25 g of potassium persulfate, soak for 3 h, heat to 70 °C under N2 protection, react for 3 h with stirring, then raise the temperature to 85 °C, and react for 3.5 h with stirring. Wash the product with CO2-free water until neutral, and dry at 70 °C for 24 h to obtain a hydrotalcite containing bisultap and polymer, and its chemical formula is: [(Zn 2+ ) 0.67 (Al 3+ ) 0.33 (OH)2] 0.33+ (BS 2- ) 0.125 (VBA - ) 0.08 (EA) 0.67 ·5H2O。

[0082] It can be known from the X-ray powder diffraction of the product that the d 003 layer spacing of bisultap and p-vinylbenzoate intercalated hydrotalcite is 1.85 nm, which is 0.96 nm larger than that of the intercalated precursor ZnAl-NO3-LDHs. This phenomenon of lamellar expansion indicates that bisultap and p-vinylbenzoate have been successfully inserted into the LDHs interlayer. After polymerization, the d 003 layer spacing expands to 1.94 nm.

[0083] Soak 1 g of this hydrotalcite in 100 mL of distilled water, and bisultap will be continuously released. After 120 days, the release is basically balanced, and the total release amount is 0.1308 g.

[0084] Example 7

[0085] (1) Weigh 53.8 g of Zn(NO3)2﹒6H2O and 33.9 g of Al(NO3)3﹒9H2O and dissolve them in 200 mL of CO2-free water to obtain solution A. Another 15.0 g of NaOH is dissolved in 150 mL of CO2-free water to obtain solution B. Under the condition of full N2 protection, add solution A and solution B to a four-necked flask by the double-drop method, keep at room temperature, and stir strongly. After dropping, adjust the pH value to 7 with 0.1 mol / L NaOH solution, crystallize the obtained slurry at 60 °C for 72 h, and wash it with CO2-free water until neutral; take out the sample and dry it at 50 °C for 48 h to obtain nitrate intercalated zinc-aluminum hydrotalcite ZnAl-NO3-LDHs.

[0086] (2) Dissolve 2.0 g of sodium p-vinylphenylacetate (C 10(Solid of H9O2Na) and 5.0 g of dimehypo (C5H 11 NO6S4Na2) were dissolved in 150 mL of CO2-free deionized water and transferred into a four-necked flask. Then 10 g of hydrotalcite precursor ZnAl-NO3-LDHs was added. Under N2 protection, it was heated to 50 °C and reacted with stirring for 48 h. It was washed with CO2-free water until neutral and dried at 50 °C for 48 h to obtain the intercalated hydrotalcite of dimehypo and 4-vinylbenzeneacetate BS / VBAA-LDHs.

[0087] (3) 5.0 g of methyl acrylate was added to 100 mL of a water-ethanol solution (volume ratio of water to ethanol was 1:2) to obtain a water-ethanol solution of methyl acrylate. The water-ethanol solution of methyl acrylate was added to a four-necked flask, and then 10 g of the intercalated hydrotalcite of dimehypo and 4-vinylbenzeneacetate BS / VBAA-LDHs obtained in step (2) was added. 0.25 g of potassium persulfate was added, and it was soaked for 3 h. Under N2 protection, it was heated to 70 °C and reacted with stirring for 3 h, then the temperature was raised to 90 °C and reacted with stirring for 2 h. The product was washed with CO2-free water until neutral and dried at 90 °C for 20 h to obtain a hydrotalcite containing dimehypo and polymer, and its chemical formula was: [(Zn 2+ ) 0.67 (Al 3+ ) 0.33 (OH)2] 0.33+ (BS 2- ) 0.125 (VBAA-) 0.08 (MA) 0.70 ·5H2O.

[0088] It can be known from X-ray powder diffraction of the product that the d 003 layer spacing of the intercalated hydrotalcite of dimehypo and 4-vinylbenzeneacetate was 1.85 nm, which was 0.96 nm larger than that of the intercalation precursor ZnAl-NO3-LDHs. This phenomenon of lamellar expansion indicated that dimehypo and 4-vinylbenzeneacetate were successfully intercalated into the LDHs interlayer. After polymerization, the d 003 layer spacing expanded to 1.94 nm.

[0089] When 1 g of this hydrotalcite was soaked in 100 mL of distilled water, dimehypo would be continuously released, and the release was basically balanced after 104 days, and the total release amount was 0.1372 g.

[0090] Example 8

[0091] (1) The same as step (1) of Example 1.

[0092] (2) 4.0 g of sodium p-styrenesulfonate (C8H7NaO3S) solid and 5.0 g of dimehypo (C5H 11Dissolve NO6S4Na2 in 150 mL of deionized water free of CO2 and transfer to a four-necked flask. Add 10 g of the hydrotalcite precursor ZnAl-NO3-LDHs. Heat to 50°C under nitrogen and stir for 48 hours. Wash with deionized water until neutral and dry at 50°C for 48 hours to obtain the insecticidal dianion and p-styrenesulfonate intercalated hydrotalcite BS / VBS-LDHs.

[0093] (3) Same as step (3) of Example 1, the chemical formula is: [(Zn 2+ ) 0.67 (Al 3+ ) 0.33 (OH)2] 0.33+ (BS 2- ) 0.08 (VBS - ) 0.17 (MA) 0.71 5H2O.

[0094] The X-ray powder diffraction of the product showed that the d 003 The interlayer spacing is 1.85nm, which is 0.96nm larger than that of the intercalation precursor ZnAl-NO3-LDHs. 003 The interlayer spacing is expanded to 1.94nm.

[0095] When 1 g of the hydrotalcite is immersed in 100 mL of distilled water, dimehypo will be continuously released. After 120 days, the release is basically balanced, and the total release amount is 0.1032 g.

[0096] Example 9

[0097] (1) Same as step (1) in Example 1.

[0098] (2) Same as step (2) in Example 1.

[0099] (3) 6.0 g of methyl acrylate was added to 100 mL of water-ethanol solution (the volume ratio of water to ethanol was 1:3) to obtain a water-ethanol solution of methyl acrylate. The water-ethanol solution of methyl acrylate was added to a four-necked flask, and then 10 g of the dimethoate and p-styrenesulfonate intercalated hydrotalcite BS / VBS-LDHs from step (2) were added. 0.25 g of potassium persulfate was added, and the mixture was soaked for 2 h. The mixture was heated to 70 ° C under N2 protection, stirred for 3 h, and then heated to 85 ° C, stirred for 4 h. The product was washed with CO2-free water until neutral, and dried at 50 ° C for 48 h to obtain a hydrotalcite containing dimethoate and a polymer. Its chemical formula is: [(Zn 2+ ) 0.67 (Al 3 + ) 0.33(OH)2] 0.33+ (BS 2- ) 0.12 (VBS - ) 0.09 (MA) 0.81 ·5H2O。

[0100] The product was analyzed by X-ray powder diffraction, and the d-spacing of the intercalated hydrotalcite of bisultap and p-styrenesulfonate was 003 1.85 nm, which was 0.96 nm larger than that of the precursor ZnAl-NO3-LDHs before intercalation. After polymerization, the d-spacing 003 expanded to 1.94 nm.

[0101] When 1 g of this hydrotalcite was immersed in 100 mL of distilled water, bisultap was continuously released, and the release basically reached equilibrium after 120 days, with a total release amount of 0.1248 g.

[0102] Comparative Example 1

[0103] (1) Prepare nitrate-intercalated zinc-aluminum hydrotalcite ZnAl-NO3-LDHs according to step (1) of Example 1.

[0104] (2) Dissolve 5.0 g of bisultap (C5H 11 NO6S4Na2) in 150 mL of CO2-free deionized water, transfer it to a four-necked flask, add 10 g of the hydrotalcite precursor ZnAl-NO3-LDHs, heat to 50 °C under N2 protection, and react with stirring for 48 h. Wash with CO2-free water until neutral, and dry at 50 °C for 48 h to obtain bisultap-intercalated hydrotalcite BS-LDHs.

[0105] When 1 g of the bisultap-intercalated hydrotalcite prepared in Comparative Example 1 was immersed in 100 mL of distilled water, the release basically reached equilibrium after 21 days. Without the barrier of the polymer in Comparative Example 1, the sustained-release rate of bisultap from the hydrotalcite was still relatively fast.

[0106] Comparative Example 2

[0107] Prepare bisultap and p-styrenesulfonate intercalated hydrotalcite BS / VBS-LDHs according to steps (1) and (2) of Example 1.

[0108] When 1 g of the bisultap and p-styrenesulfonate intercalated hydrotalcite prepared in Comparative Example 2 was immersed in 100 mL of distilled water, the release basically reached equilibrium after 36 days. Since p-styrene sulfonic acid did not polymerize in Comparative Example 2, its hindering effect on bisultap was relatively low, and the sustained-release rate of bisultap from the hydrotalcite was still relatively fast.

[0109] Comparative Example 3

[0110] (1) The same as step (1) of Example 1.

[0111] (2) The same as step (2) of Example 1.

[0112] (3) 5.0 g of methyl acrylate was added to 100 mL of a water-ethanol solution (volume ratio of water to ethanol was 1:3) to obtain a water-ethanol solution of methyl acrylate. The water-ethanol solution of methyl acrylate was added to a four-necked flask, and then 10 g of bisultap and styrenesulfonate intercalated hydrotalcite BS / VBS-LDHs from step (2) were added. It was soaked for 2 h and washed 5 times with a large amount of CO₂-free water. Then 100 mL of a water-ethanol solution (volume ratio of water to ethanol was 1:3) and 0.25 g of potassium persulfate were added. Under N₂ protection, it was heated to 70 °C and reacted with stirring for 3 h. Then the temperature was raised to 85 °C and reacted with stirring for 4 h. The product was washed with CO₂-free water until neutral and dried at 50 °C for 48 h to obtain bisultap and polymer intercalated hydrotalcite.

[0113] 1 g of bisultap and polymer intercalated hydrotalcite prepared in Comparative Example 3 was soaked in 100 mL of distilled water, and the release was basically balanced after 53 days. In Comparative Example 3, it was washed 5 times with a large amount of CO₂-free water before polymerization to wash out the methyl acrylate in the pores of the hydrotalcite. During the polymerization reaction, polymers were only formed between the layers of the hydrotalcite, and there was no polymer in the pores, resulting in a relatively small overall hindrance effect on bisultap in the hydrotalcite, and a relatively fast sustained-release rate of bisultap from the hydrotalcite.

[0114] Comparative Example 4

[0115] (1) The same as step (1) of Example 1.

[0116] (2) The same as step (2) of Example 1.

[0117] (3) 5.0 g of methyl acrylate was added to 100 mL of a water-ethanol solution (volume ratio of water to ethanol was 1:3) to obtain a water-ethanol solution of methyl acrylate. The water-ethanol solution of methyl acrylate was added to a four-necked flask, and then 10 g of bisultap and styrenesulfonate intercalated hydrotalcite BS / VBS-LDHs from step (2) were added. 0.25 g of potassium persulfate was added, soaked for 2 h, heated to 85 °C under N₂ protection, and reacted with stirring for 8 h. The product was washed with CO₂-free water until neutral and dried at 50 °C for 48 h to obtain a hydrotalcite containing bisultap and polymer. However, through X-ray powder diffraction, it was found that part of the hydrotalcite had been exfoliated.

[0118] 1 g of this hydrotalcite was soaked in 100 mL of distilled water, and the release was basically balanced after 18 days.

Claims

1. A preparation method of a sustained-release insecticide, characterized in that It includes the following steps: (1) Preparation of hydrotalcite precursor; (2) Preparation of dimehypo and polymer monomer intercalated hydrotalcite: Dissolve dimehypo and polymer monomer in deionized water without CO2 to obtain a solution, then add the hydrotalcite precursor obtained in step (1) to this solution, react under heating and stirring under N2 protection, wash, and dry to obtain dimehypo and polymer monomer intercalated hydrotalcite; (3) Polymerization reaction in hydrotalcite: Prepare an aqueous-ethanol solution of acrylate, add the dimehypo and polymer monomer intercalated hydrotalcite obtained in step (2) to the aqueous-ethanol solution of acrylate, then add potassium persulfate, soak, heat to 70 - 80 °C under N2 protection, react under stirring for 1 - 3 h, then raise the temperature to 85 - 90 °C, react under stirring for 2 - 4 h, wash the product, and dry to obtain a slow-release insecticide; The preparation method of the hydrotalcite precursor described in step (1) is to dissolve the soluble salt of M 2+ and the soluble salt of M 3+ in water without CO2 to obtain solution A, and dissolve NaOH in water without CO2 to obtain solution B; under the protection of N2 at room temperature, mix solution A and solution B, adjust the pH value to obtain a slurry; Slurry crystallization, washing, and drying to obtain a hydrotalcite precursor; The described M 2+ is Mg 2+ , Ni 2+ or Zn 2+ , one of them. M 3+ is Al 3+ , and the soluble salt of M 2+ is the hydrochloride salt of M 2+ or the nitrate salt of M 2+ . The soluble salt of M 3+ is the hydrochloride salt of M 3+ or the nitrate salt of M 3+ . The types of the soluble salt of M 2+ and the soluble salt of M 3+ in solution A are the same, and the molar ratio of M 2+ to M 3+ is 2 - 3; The polymer monomer described in step (2) is one of sodium p-styrenesulfonate, sodium p-vinylbenzoate, or sodium p-vinylphenylacetate; The acrylate described in step (3) is methyl acrylate or ethyl acrylate.

2. The preparation method of the sustained-release insecticide according to claim 1, characterized in that The molar concentration of solution B is 1.0 - 5.0 M, the pH value is adjusted to 6 - 10 with a 0.1 - 5.0 M NaOH solution, the crystallization temperature is 60 - 90 °C, the crystallization time is 12 - 72 h, the drying temperature is 50 - 90 °C, and the drying time is 20 - 48 h.

3. The preparation method of the sustained-release insecticide according to claim 1, characterized in that The mass ratio of dimehypo, polymer monomer, and hydrotalcite precursor described in step (2) is 3.5 - 5:2 - 4:

10.

4. The preparation method of the sustained-release insecticide according to claim 1, wherein The heating temperature in step (2) is 50 - 70 °C, the reaction time is 12 - 48 h; the drying temperature is 50 - 90 °C, and the drying time is 20 - 48 h.

5. The preparation method of the sustained-release insecticide according to claim 1, characterized in that The volume ratio of water to ethanol described in step (3) is 1:2 - 3, and the concentration of acrylate in the aqueous-ethanol solution of acrylate is 40 - 60 g / L.

6. The preparation method of the sustained-release insecticide according to claim 1, characterized in that The mass ratio of acrylate, dimehypo, polymer monomer intercalated hydrotalcite, and potassium persulfate described in step (3) is 4 - 6:10:0.25 - 0.

5.

7. The preparation method of the sustained-release insecticide according to claim 1, characterized in that The soaking time in step (3) is 2 - 4 h; the drying temperature is 50 - 90 °C, and the drying time is 20 - 48 h.

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