Pyrithiobac-methyl ionic liquid as well as preparation method and application thereof

Abstract

The invention discloses pyrithiobac-methyl ionic liquid and a preparation method and application thereof.The pyrithiobac-methyl ionic liquid is obtained by taking pyrithiobac-methyl as anions and combining the pyrithiobac-methyl with structure-modified quaternary ammonium cations, and after pyrithiobac-methyl is combined with cations with different carbon chain lengths, the pyrithiobac-methyl ionic liquid has high surface activity and thermal stability and can be used for preparing the pyrithiobac-methyl ionic liquid. Compared with a conventional pyrithiobac-methyl agent, the weeding efficiency and biological selectivity of the agent can be remarkably improved, the same weeding effect can be achieved in a targeted mode with a lower dosage, and therefore the purpose of environmental protection is achieved; the pyrithiobac-methyl ionic liquid microsphere is applied to preparation of the pyrithiobac-methyl ionic liquid microsphere, and a good pesticide effect can be achieved for a long time at a low pesticide concentration, so that a better weeding effect is achieved on the premise that side effects on the environment are reduced, and the pyrithiobac-methyl ionic liquid microsphere is greener and more environmentally friendly and has a great application prospect.

Description

Technical Field

[0001] The invention relates to a pyrithione ionic liquid and also relates to a preparation method and application of the ionic liquid. Background Art

[0002] Cotton is an important economic crop that is widely planted around the world. It is a necessity for human life and plays an important role in the global economy. However, weed control in cotton fields is one of the common problems. Due to the nutritional competition between field weeds and crops, the total cotton yield is greatly reduced, so weed control has become a focus of attention. In modern agricultural production, sulfadiazine has become a powerful tool for controlling weeds in cotton fields with its unique acetolactate synthase inhibition mechanism. It can effectively target most broad-leaved weeds and some grass weeds through stem and leaf treatment before or after seedlings. Although the effect is significant, sulfadiazine at high doses also shows a certain contact toxicity to cotton itself, causing damage to cotton and thus affecting cotton yield and quality.

[0003] The existing technology mixes the highly efficient flupyralid herbicide with pyrifos to improve the broad-spectrum weed control and herbicidal activity. However, although the improved method may improve the weed control effect, high-dose use may still cause contact phytotoxicity to crops such as cotton, and different ratios may also affect crop growth and safety. This may be due to the chemical properties of the agent itself or the sensitivity of the crop to the agent. It may also increase the potential pollution risk to the soil, water sources and other environments, and have an adverse impact on the ecosystem. At the same time, the production of pyrifos is restricted by many factors such as raw material supply, production technology and market demand, resulting in fluctuations in production costs. The mixing of the two herbicides increases production costs, leading to rising product prices, affecting farmers' acceptance and market promotion.

[0004] Ionic liquids are a class of compounds composed of anions and cations, with unique properties such as low vapor pressure, designable structure, and adjustable physical properties. Herbicidal ionic liquids, as a class of functionalized ionic liquids, are usually composed of structurally modified herbicide anions and cations. Generally, anions have herbicidal activity, and cations play a role in improving the physical and chemical properties of the compound. For example, Cao Yongsong's research group (Herbicide Ionic Liquid-A New Form of High-Efficiency and Environmentally Friendly Application of Fomesulfuron, Abstracts of the 12th National Weed Science Conference, 2015. Taiyuan) proposed that by matching cations with different functions, the solubility, surface activity, thermal stability and weed control effect of the herbicide can be specifically adjusted, thereby improving the thermal stability and surface activity of the herbicide and reducing its volatility. Chinese patent CN 110003270 B discloses a glyphosate dicationic ionic liquid compound and its preparation method and application. By introducing different types of cations, its physical and chemical properties are improved, its lipid solubility is enhanced, its plant penetration and absorption and conduction efficiency are improved, its weed control activity is enhanced, and its weed control spectrum is broadened. However, changing traditional pesticides into ionic liquids requires the introduction or replacement of certain groups to form compounds with ionic properties. This change in chemical structure may not always maintain or improve the original herbicidal effect, and its herbicidal effect is unpredictable. At the same time, the microtoxicity of the above-mentioned ionic liquids still poses potential hazards to the environment and human body, and more effective and less toxic herbicides are still urgently needed to be developed. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a pyrithione-butyl ionic liquid with high activity and a long weed control period, and also to provide a method for preparing the above ionic liquid and its application in herbicides after being prepared into pyrithione-butyl ionic liquid microspheres.

[0006] Technical solution: The present invention discloses a pyrimthiosulfuron ionic liquid, wherein the ionic liquid is obtained by combining pyrimthiosulfuron as an anion with a structurally modified quaternary ammonium cation through an acid-base neutralization reaction, wherein the anion is The quaternary ammonium cation is Among them, R1, R2, R3, and R4 are alkyl groups containing 1 to 18 carbon atoms.

[0007] Wherein, the quaternary ammonium cation is N,N,N-(triethyl)-N-dodecyl ammonium, N,N,N-(triethyl)-N-tetradecyl ammonium, N,N,N-(triethyl)-N-hexadecyl ammonium or N,N,N-(triethyl)-N-octadecyl ammonium.

[0008] Wherein, the pyrimthiosulfate ionic liquid is N,N,N-(triethyl)-N-dodecyl ammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylsulfur)benzoic acid) salt, N,N,N-(triethyl)-N-tetradecyl ammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylsulfur)benzoic acid) salt, N,N,N-(triethyl)-N-hexadecyl ammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylsulfur)benzoic acid) salt or N,N,N-(triethyl)-N-octadecyl ammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylsulfur)benzoic acid) salt.

[0009] The method for preparing the above-mentioned pyrithione ionic liquid comprises the following steps:

[0010] (1) Preparation of brominated ionic liquid ammonium salt: triethylamine, monobrominated alkane and solvent are mixed, heated under reflux reaction, and then rotary evaporated and dried to obtain brominated ionic liquid ammonium salt;

[0011] (2) Preparation of pyrimidinesulfuron ionic liquid: The bromide ionic liquid ammonium salt obtained in the previous step is dissolved in water and then passed through an activated anion exchange resin to perform an ion exchange reaction to obtain an aqueous solution of ionic liquid ammonium hydroxide salt, which is then mixed with 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio)benzoic acid to perform an acid-base neutralization reaction and dried to obtain a pyrimidinesulfuron ionic liquid.

[0012] The molar ratio of the ammonium hydroxide salt or organic amine to 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio)benzoic acid is 1:1.0-1.4, the reaction temperature is 20-40° C., and the reaction time is 12-24 hours.

[0013] Wherein, the organic amine is triethylamine; the ammonium hydroxide salt is N,N,N-(triethyl)-N-dodecyl ammonium hydroxide, N,N,N-(triethyl)-N-tetradecyl ammonium hydroxide, N,N,N-(triethyl)-N-hexadecyl ammonium hydroxide, and N,N,N-(triethyl)-N-octadecyl ammonium hydroxide.

[0014] The preparation of the ammonium hydroxide salt comprises the following steps: mixing triethylamine, monobromoalkane and a solvent, heating and refluxing, and obtaining an ammonium bromide salt by rotary evaporation and drying; dissolving the ammonium bromide salt in water, and then performing ion exchange through an activated anion exchange resin to obtain an aqueous solution of the ammonium hydroxide salt.

[0015] The monobrominated alkane is any one of 1-bromododecane, 1-bromotetradecane, 1-bromohexadecane and 1-bromooctadecane; the molar ratio of triethylamine to monobromoalkane is 1.4-2.2:1; the solvent used is one or more of distilled water, methanol, acetonitrile and acetone; the temperature of the heating reflux reaction is 65-95° C., and the reaction time is 48-72 hours; the prepared ammonium bromide salt is any one of N,N,N-(triethyl)-N-dodecylammonium bromide, N,N,N-(triethyl)-N-tetradecylammonium bromide, N,N,N-(triethyl)-N-hexadecylammonium bromide and N,N,N-(triethyl)-N-octadecylammonium bromide.

[0016] The above-mentioned pyrithione ionic liquid can also be used in the field of plant protection.

[0017] The application is to prepare pyrithiobac-butyl ionic liquid microspheres from pyrithiobac-butyl ionic liquid and apply them to herbicides.

[0018] The preparation method of the pyrithiobac-butyl ionic liquid microspheres is as follows: the pyrithiobac-butyl ionic liquid is ultrasonically dispersed in a sodium alginate solution, and then injected and dripped into a calcium chloride solution under high-speed stirring, and then the microspheres are obtained after cross-linking, filtering and washing.

[0019] Among them, the mass ratio of pyrithione ionic liquid, sodium alginate and chitosan in the pyrithione ionic liquid microspheres is 0.2-0.5:1.5-2.0:2, and the volume ratio of distilled water, 1% acetic acid aqueous solution, dichloromethane, Tween-80, 4% CaCl2 solution and 25% glutaraldehyde solution is 200:150-225:3:3:160-220:0.5.

[0020] Principle of the invention: The herbicidal activity of the pyrimidinesulfuron ionic liquid of the present invention is improved through structural modification. After combining pyrimidinesulfuron with cations of different carbon chain lengths, special physical and chemical properties and herbicidal effects are obtained. While playing a role in volume expansion and efficiency promotion, the long carbon chain cations also have a flocculation effect, that is, to a certain extent, the soil structure is improved, soil loss is reduced, and its water, soil and fertilizer retention capabilities are enhanced, thereby further achieving the effect of increasing production.

[0021] The specific principles are as follows: (1) Electrostatic interaction is the basis for the combination of anions and cations. The long-chain quaternary ammonium cations of the present invention carry a positive charge, while the herbicidal anions carry a negative charge. The strong electrostatic attraction generated causes them to combine tightly to form a stable complex. This combination not only enhances the interaction between herbicide molecules, but also enables the complex to adhere more tightly when it contacts the plant surface, reducing loss and waste; (2) The combined complex has excellent permeability. The long-chain quaternary ammonium cations, as surfactants, have the ability to reduce the surface tension of water, which allows the herbicide complex to more easily penetrate into the tiny gaps and cell walls of plant tissues. Once entering the plant body, the herbicidal anions can exert their herbicidal activity and interfere with the normal physiological functions of the plant; (3) This combination also enhances the stability of the herbicide. The presence of the long-chain quaternary ammonium cations provides a protective barrier for the herbicidal anions, reducing the possibility of them being affected by external environmental factors (such as light, temperature, humidity, etc.). This improvement in stability ensures The herbicide can maintain its original activity and effect during storage and use; (4) The combination of herbicidal anions and long-chain quaternary ammonium cations also expands the scope of action of the herbicide. Since the complex can adhere more tightly to the plant surface and penetrate deeper into the tissue layer, it can act more comprehensively on various parts of the plant body, including leaves, stems and roots. This comprehensive coverage and penetration enables the herbicide to kill or inhibit the growth of weeds more effectively; (5) This combination can further achieve a synergistic effect, accelerating plant death by destroying the plant cell membrane structure and metabolic function. The herbicide complex can penetrate the plant cell membrane and interfere with key metabolic processes such as protein synthesis and enzyme activity in the cell, thereby causing damage to the cell structure and function. This destructive effect will eventually lead to the death of the plant body, thereby achieving the purpose of weed control.

[0022] Further, the present invention uses sodium alginate microspheres as carriers to prepare pyrimthiosulfuron ionic liquid microspheres with the prepared pyrimthiosulfuron ionic liquid, which has the characteristics of prolonging drug efficacy, reducing toxic side effects, and improving drug stability, achieving the effect of stable and slow release of drugs, and utilizing the slow-release characteristics to fully improve the utilization efficiency of drugs. At the same time, the components of sodium alginate microspheres after decomposition in the soil can additionally play a certain role in soil regulation and crop protection, that is, promoting the activity of soil microbial communities, regulating soil acidity and alkalinity, and enhancing the ability of crops to resist adversity, achieving the purpose of volume increase, promoting efficiency and environmental friendliness. Converting herbicidal ionic liquids into microsphere form significantly improves the many advantages of herbicidal technology, not only realizing the continuous and slow release of drugs, prolonging the drug efficacy time, but also enhancing the targeting of drugs, and greatly reducing pesticide loss and environmental pollution. The microsphere structure effectively protects the stability of herbicidal ionic liquids, adapts to a variety of climate and soil conditions, and expands the scope of application.

[0023] Combined with modern agricultural technologies such as intelligent spraying systems, pyrifos-butyl ionic liquid microspheres effectively improve the accuracy and efficiency of weed control operations. In the long run, it can reduce farmers' drug costs, increase crop yields and quality, and make important contributions to agricultural sustainable development and environmental protection. Therefore, herbicide ionic liquid microsphere technology has extremely high application value and promotion prospects. Ionic liquids themselves usually have low toxicity. After being made into microspheres, they can further reduce potential harm to the environment and human body.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The pyrimidinesulfuron ionic liquid of the present invention has high surface activity and thermal stability, and can significantly improve the herbicidal efficacy and biological selectivity of the agent compared with conventional pyrimidinesulfuron agents, so as to achieve the same herbicidal effect with a lower dosage, thereby achieving the purpose of environmental protection; (2) The preparation method is simple and suitable for industrial large-scale production; (3) The pyrimidinesulfuron ionic liquid microspheres have high surface activity and good sustained-release effect, and can achieve good drug efficacy for a longer time with a lower pesticide concentration, thereby achieving a better herbicidal effect under the premise of reducing side effects on the environment, being more green and environmentally friendly, and having great application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 For [N 2,2,2,12 ][PTB] Statistical graph of growth inhibition rate in microsphere herbicidal activity test;

[0026] Figure 2 For [N 2,2,2,12 ][PTB] Statistical graph of fresh weight inhibition rate in microsphere herbicidal activity test;

[0027] Figure 3 For [N 2,2,2,14 ][PTB] Statistical graph of growth inhibition rate in microsphere herbicidal activity test;

[0028] Figure 4 For [N 2,2,2,14 ][PTB] Statistical graph of fresh weight inhibition rate in microsphere herbicidal activity test;

[0029] Figure 5 For [N 2,2,2,16 ][PTB] Statistical graph of growth inhibition rate in microsphere herbicidal activity test;

[0030] Figure 6 For [N 2,2,2,16 ][PTB] Statistical graph of fresh weight inhibition rate in microsphere herbicidal activity test;

[0031] Figure 7 For [N 2,2,2,18 ][PTB] Statistical graph of growth inhibition rate in microsphere herbicidal activity test;

[0032] Figure 8 For [N 2,2,2,18 ][PTB] Statistical graph of fresh weight inhibition rate in microsphere herbicidal activity test. DETAILED DESCRIPTION

[0033] The technical scheme of the present invention is further described below in conjunction with the examples. The test materials used in the examples can all be purchased through conventional channels.

[0034] Example 1

[0035] The pyrimidine sulfoxide ionic liquid of the present invention: N,N,N-(triethyl)-N-dodecyl ammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylsulfur)benzoic acid) salt ([N 2,2,2,12 ][PTB]), the preparation route is as follows:

[0036]

[0037] Preparation of bromide salt steps: In a 250mL round-bottom flask, add 0.045mol triethylamine, 0.03mol 1-bromododecane and 60mL acetonitrile in sequence. Heat and stir under reflux conditions, control the reaction temperature at 80°C, and continue the reaction for 60 hours. Remove the solvent by rotary evaporation and vacuum dry at 60°C for 48 hours. Obtain 8.72g of product, namely N,N,N-(triethyl)-N-dodecylammonium bromide ([N 2,2,2,12 ][Br]), the yield was 93.8%.

[0038] Ammonium hydroxide salt: weigh 0.015 mol [N 2,2,2,12 ][Br] was dissolved in 30 mL of distilled water and treated with anion exchange resin. The reaction progress was confirmed with pH test paper. When the test paper showed an alkaline color, the exchange solution was collected until the pH test paper showed that the solution was neutral. The collection was stopped. The resulting solution was N,N,N-(triethyl)-N-dodecylammonium hydroxide ([N 2,2,2,12 The collected solution was titrated with 0.02M standard hydrochloric acid solution to determine its concentration.

[0039] Pyrithione herbicidal ionic liquid: Weigh 0.017 mol of 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio)benzoic acid into a round-bottom flask containing ammonium hydroxide salt collection solution, and stir the mixture at room temperature for 24 hours. The solvent was removed by rotary evaporation, and vacuum dried at 60°C for 48 hours to obtain N,N,N-(triethyl)-N-dodecylammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio)benzoic acid) salt ([N 2,2,2,12 ][PTB]). The weight of the obtained product was 7.58 g, and the yield was 87.64%.

[0040] 1 H NMR(300MHz,Chloroform-d)δ7.54(dd,J=7.9,1.1Hz,1H),7.35–7.29(m,1H),7.11(t,J=7.9Hz,1H),5.69(s,1H),3.7 4(s,6H),3.51(q,J=7.2Hz,6H),3.26–3.10(m,2H),2.67(s,3H),1.68(s,2H),1.40–1.24(m,27H),0.92–0.86(m,3H).

[0041] The above-mentioned pyrithione ionic liquid [N 2,2,2,12 [PTB] was prepared into pyrithione ionic liquid microspheres:

[0042] Prescription: [N 2,2,2,12 [PTB] 300 mg, sodium alginate 2.0 g, chitosan 2.0 g, distilled water 200 ml, 1% acetic acid aqueous solution 200 mL, dichloromethane 3 ml, Tween-80 3 ml, 4% CaCl2 solution 200 ml, 25% glutaraldehyde solution 0.5 ml.

[0043] Sodium alginate and chitosan were dissolved in water and acetic acid solution respectively according to the prescription. 2,2,2,12 [PTB] was dissolved in dichloromethane, Tween-80 was added to improve its water solubility, and then mixed with sodium alginate solution to form an emulsion. The emulsion was dropped into a mixed solution of chitosan and calcium chloride to form microspheres, and glutaraldehyde solution was added to solidify, and then the obtained microspheres were washed and freeze-dried. After testing, the encapsulation efficiency of the obtained pyrithione ionic liquid microspheres was 74.5%, and the drug loading was 20.7%.

[0044] Example 2

[0045] The pyrimidine sulfoxide ionic liquid of the present invention: N,N,N-(triethyl)-N-tetradecyl ammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylsulfur)benzoic acid) salt ([N 2,2,2,14 ][PTB]), the preparation route is as follows:

[0046]

[0047] Ammonium bromide: In a 250 mL round-bottom flask, add 0.075 mol of triethylamine, 0.05 mol of 1-bromotetradecane and 60 mL of acetonitrile in sequence. Heat and stir under reflux conditions, and control the reaction temperature at 80 ° C for 60 hours. Remove the solvent by rotary evaporation and vacuum dry at 60 ° C for 48 hours. Finally, 15.98 g of product is obtained, namely N,N,N-(triethyl)-N-tetradecyl ammonium bromide ([N 2,2,2,14 ][Br]), the yield was 95.7%.

[0048] Ammonium hydroxide salt: weigh 0.015 mol [N 2,2,2,14 ][Br] was dissolved in 30 mL of distilled water and treated with anion exchange resin. The reaction progress was confirmed with pH test paper. When the test paper showed an alkaline color, the exchange solution was collected until the pH test paper showed that the solution was neutral. The collection was stopped. The resulting solution was N,N,N-(triethyl)-N-tetradecylammonium hydroxide ([N 2,2,2,14 The collected solution was titrated with a 0.02 M standard hydrochloric acid solution to determine its concentration.

[0049] Pyrithione herbicidal ionic liquid: Weigh 0.015 mol of 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio)benzoic acid and add it to a round-bottom flask containing the ionic liquid ammonium hydroxide salt collection solution, and stir at room temperature for 24 hours. Remove the solvent by rotary evaporation and vacuum dry at 60°C for 48 hours. Obtain N,N,N-(triethyl)-N-tetradecylammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio)benzoic acid) salt ([N 2,2,2,14 ][PTB]). The weight of the obtained product was 7.74 g, and the yield was 85.79%.

[0050] 1 H NMR(300MHz,Chloroform-d)δ7.54(dd,J=7.8,1.1Hz,1H),7.31(d,J=1.1Hz,1H),7.10(t,J=7.9Hz,1H),5.68(s,1H),3 .74(s,6H),3.52(q,J=6.6Hz,6H),3.28–3.13(m,2H),2.97(s,3H),1.68(s,2H),1.39–1.21(m,31H),0.95–0.84(m,3H).

[0051] The above-mentioned pyrithione ionic liquid [N 2,2,2,14 [PTB] was prepared into pyrithione ionic liquid microspheres:

[0052] Prescription: [N 2,2,2,14[PTB] 300 mg, sodium alginate 2.0 g, chitosan 2.0 g, distilled water 200 ml, 1% acetic acid aqueous solution 200 mL, dichloromethane 3 ml, Tween-80 3 ml, 4% CaCl2 solution 200 ml, 25% glutaraldehyde solution 0.5 ml.

[0053] Sodium alginate and chitosan were dissolved in water and acetic acid solution respectively according to the prescription. 2,2,2,14 [PTB] was dissolved in dichloromethane, Tween-80 was added to improve its water solubility, and then mixed with sodium alginate solution to form an emulsion. The emulsion was dropped into a mixed solution of chitosan and calcium chloride to form microspheres, and glutaraldehyde solution was added to solidify, and then the obtained microspheres were washed and freeze-dried. After testing, the encapsulation efficiency of the obtained pyrithione ionic liquid microspheres was 78.7% and the drug loading was 22.5%.

[0054] Example 3

[0055] The pyrimidine sulfoxide ionic liquid of the present invention: N,N,N-(triethyl)-N-hexadecyl ammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylsulfur)benzoic acid) salt ([N 2,2,2,16 ][PTB]), the preparation route is as follows:

[0056]

[0057] Ammonium bromide: In a 250 mL round-bottom flask, add 0.045 mol of triethylamine, 0.03 mol of 1-bromohexadecane and 60 mL of acetonitrile in sequence. Heat and stir under reflux conditions, and control the reaction temperature at 80 ° C. Continue the reaction for 60 hours. Remove the solvent by rotary evaporation, and vacuum dry at 60 ° C for 48 hours to obtain 9.93 g of product, namely N, N, N- (triethyl) -N- hexadecyl ammonium bromide ([N 2,2,2,16 ][Br]), the yield was 92.5%.

[0058] Ammonium hydroxide salt: weigh 0.009 mol [N 2,2,2,16 ][Br] was dissolved in 30 mL of distilled water. It was treated with anion exchange resin. The reaction progress was confirmed with pH test paper. When the test paper showed an alkaline color, the exchange solution was collected until the pH test paper showed that the solution was neutral. The collected solution was N,N,N-(triethyl)-N-hexadecyl ammonium hydroxide ([N 2,2,2,16 The collected solution was titrated with a 0.02 M standard hydrochloric acid solution to determine its concentration.

[0059] Pyrithione herbicidal ionic liquid: Weigh 0.01 mol of 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylsulfur)benzoic acid and add it to a round-bottom flask containing the ionic liquid ammonium hydroxide salt collection solution, and stir at room temperature for 24 hours. The solvent is removed by rotary evaporation, and vacuum dried at 60°C for 48 hours to finally obtain N,N,N-(triethyl)-N-hexadecylammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylsulfur)benzoic acid) salt ([N 2,2,2,16 ][PTB]). The weight of the obtained product was 4.92 g, and the yield was 87.35%.

[0060] 1 H NMR(300MHz,Chloroform-d)δ7.54(dd,J=7.9,1.1Hz,1H),7.35–7.29(m,1H),7.09(t,J=7.9Hz,1H),5.68(s,1H),3.74 (s,6H),3.54(q,J=7.1Hz,6H),3.20(d,J=16.8Hz,2H),2.77(s,3H)1.69(s,2H),1.41–1.23(m,35H),0.95–0.84(m,3H).

[0061] The above-mentioned pyrithione ionic liquid [N 2,2,2,16 [PTB] was prepared into pyrithione ionic liquid microspheres:

[0062] Prescription: [N 2,2,2,16 [PTB] 300 mg, sodium alginate 2.0 g, chitosan 2.0 g, distilled water 200 ml, 1% acetic acid aqueous solution 200 mL, dichloromethane 3 ml, Tween-80 3 ml, 4% CaCl2 solution 200 ml, 25% glutaraldehyde solution 0.5 ml.

[0063] Sodium alginate and chitosan were dissolved in water and acetic acid solution respectively according to the prescription. 2,2,2,16 [PTB] was dissolved in dichloromethane, Tween-80 was added to improve its water solubility, and then mixed with sodium alginate solution to form an emulsion. The emulsion was dropped into a mixed solution of chitosan and calcium chloride to form microspheres, and glutaraldehyde solution was added to solidify, and then the obtained microspheres were washed and freeze-dried. After testing, the encapsulation efficiency of the obtained pyrithione ionic liquid microspheres was 80.1%, and the drug loading was 23.1%.

[0064] Example 4

[0065] The pyrimidine sulfoxide ionic liquid of the present invention: N,N,N-(triethyl)-N-octadecyl ammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylsulfur) salt ([N 2,2,2,18][PTB]), the preparation route is as follows:

[0066]

[0067] Ammonium bromide: In a 250 mL round-bottom flask, add 0.075 mol of triethylamine, 0.05 mol of 1-bromooctadecane and 60 mL of acetonitrile. Heat and stir under reflux conditions, and control the reaction temperature at 80 ° C for 60 hours. Remove the solvent by rotary evaporation, and vacuum dry at 60 ° C for 48 hours to obtain 17.15 g of product, namely N, N, N- (triethyl) -N-octadecyl ammonium bromide ([N 2,2,2,18 ][Br]), the yield was 89.81%.

[0068] Ammonium hydroxide salt: weigh 0.009 mol [N 2,2,2,18 ][Br] was dissolved in 30 mL of distilled water. It was treated with anion exchange resin. The reaction progress was confirmed with pH test paper. When the test paper showed an alkaline color, the exchange solution was collected until the pH test paper showed that the solution was neutral. The resulting solution was N,N,N-(triethyl)-N-octadecylammonium hydroxide ([N 2,2,2,18 The collected solution was titrated with a 0.02 M standard hydrochloric acid solution to determine its concentration.

[0069] Pyrithione herbicidal ionic liquid: Weigh 0.01 mol of 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio)benzoic acid and add it to a round-bottom flask containing the ionic liquid ammonium hydroxide salt collection solution, and stir at room temperature for 24 hours. The solvent is removed by rotary evaporation, and vacuum drying is performed at 60°C for 48 hours to obtain N,N,N-(triethyl)-N-octadecylammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio)benzoic acid) salt ([N 2,2,2,18 ][PTB]). The weight of the obtained product was 5.28 g, and the yield was 90.38%.

[0070] 1 H NMR(300MHz,Chloroform-d)δ7.54(dd,J=7.8,1.1Hz,1H),7.35–7.29(m,1H),7.11(t,J=7.9Hz,1H),5.68(s,1H ),3.73(s,6H),3.54(q,J=7.2Hz,6H),3.21(t,J=8.5Hz,2H),2.87(s,3H)1.49–1.14(m,39H),0.95–0.84(m,3H).

[0071] The above-mentioned pyrithione ionic liquid [N 2,2,2,18[PTB] was prepared into pyrithione ionic liquid microspheres:

[0072] Prescription: [N 2,2,2,18 [PTB] 300 mg, sodium alginate 2.0 g, chitosan 2.0 g, distilled water 200 ml, 1% acetic acid aqueous solution 200 mL, dichloromethane 3 ml, Tween-80 3 ml, 4% CaCl2 solution 200 ml, 25% glutaraldehyde solution 0.5 ml.

[0073] Sodium alginate and chitosan were dissolved in water and acetic acid solution respectively according to the prescription. 2,2,2,18 [PTB] was dissolved in dichloromethane, Tween-80 was added to improve its water solubility, and then mixed with sodium alginate solution to form an emulsion. The emulsion was dropped into a mixed solution of chitosan and calcium chloride to form microspheres, and glutaraldehyde solution was added to solidify, and then the obtained microspheres were washed and freeze-dried. After testing, the encapsulation efficiency of the obtained pyrithione ionic liquid microspheres was 72.8%, and the drug loading was 18.3%.

[0074] The performance tests were conducted on the pyrithiobac-butyl ionic liquid and pyrithiobac-butyl ionic liquid microspheres prepared in Examples 1 to 4:

[0075] 1. [N 2,2,2,12 [PTB] Herbicidal activity test

[0076] The grass plant barnyard grass (Echinochloa crusgalli (L.) Beauv) was used as the herbicidal activity test object. Nutrition soil was placed in a seedling box to occupy 2 / 3 of the volume. The barnyard grass seeds were activated with distilled water and soaked for 4 hours. Then, they were evenly spread in the seedling box and covered with a layer of nutrition soil. A series of different qualities of [N 2,2,2,12 ][PTB] microspheres, the control group was commercially available pyrithione herbicide (PTB) microspheres, and the blank group seedling box was added with the same mass of blank microspheres. The plants were cultured at room temperature of 25±2℃ for 20 days, and the average aboveground height and average fresh weight of the plants were calculated. The formula for calculating the plant growth inhibition rate was growth inhibition rate = (average height of blank group plants - average height of test plants) / average height of blank plants; the formula for calculating the fresh weight inhibition rate was fresh weight inhibition rate = (average fresh weight of blank group plants - average fresh weight of test plants) / average fresh weight of blank plants.

[0077] After converting the mass of the microspheres into an equivalent concentration of pyrithione ionic liquid, the results of the herbicidal activity test with commercial herbicides are as follows:

[0078] Table 1, [N 2,2,2,12 [PTB] herbicidal activity test results

[0079]

[0080] As shown in Table 1 and Figures 1-2 As shown, at a concentration of 15-35g / mu, [N 2,2,2,12 The growth inhibition rate and fresh weight inhibition rate of the ][PTB] microspheres are higher than those of the commercially available pyrifos-butyl herbicide, indicating that the pyrifos-butyl ionic liquid microspheres prepared by the present application can effectively remove barnyard grass in the field.

[0081] 2. [N 2,2,2,14 [PTB] Herbicidal activity test

[0082] The grass plant barnyard grass (Echinochloa crusgalli (L.) Beauv) was used as the herbicidal activity test object. Nutrition soil was placed in a seedling box to occupy 2 / 3 of the volume. The barnyard grass seeds were activated with distilled water and soaked for 4 hours. Then, they were evenly spread in the seedling box and covered with a layer of nutrition soil. A series of different qualities of [N 2,2,2,14 ][PTB] microspheres, the control group was commercially available pyrithiobacillus (PTB) microspheres, and the blank group was added with the same mass of blank microspheres in the seedling box. The plants were cultured at room temperature of 25±2℃ for 20 days, and the average aboveground height and average fresh weight of the plants were calculated.

[0083] After converting the mass of the microspheres into an equivalent concentration of pyrithione ionic liquid, the results of the herbicidal activity test with commercial herbicides are as follows:

[0084] Table 2, [N 2,2,2,14 [PTB] herbicidal activity test results

[0085]

[0086]

[0087] As shown in Table 2 and Figures 3-4 As shown, at a concentration of 15-35g / mu, [N 2,2,2,14 The growth inhibition rate and fresh weight inhibition rate of the ][PTB] microspheres are higher than those of the commercially available pyrifos-butyl herbicide, indicating that the pyrifos-butyl ionic liquid microspheres prepared by the present application can effectively remove barnyard grass in the field.

[0088] 3. [N 2,2,2,16 [PTB] Herbicidal activity test

[0089] The grass plant barnyard grass (Echinochloa crusgalli (L.) Beauv) was used as the herbicidal activity test object. Nutrition soil was placed in a seedling box to occupy 2 / 3 of the volume. The barnyard grass seeds were activated with distilled water and soaked for 4 hours. Then, they were evenly spread in the seedling box and covered with a layer of nutrition soil. A series of different qualities of [N 2,2,2,16][PTB] microspheres, the control group was commercially available pyrithiobacillus (PTB) microspheres, and the blank group was added with the same mass of blank microspheres in the seedling box. The plants were cultured at room temperature of 25±2℃ for 20 days, and the average aboveground height and average fresh weight of the plants were calculated.

[0090] After converting the mass of the microspheres into an equivalent concentration of pyrithione ionic liquid, the results of the herbicidal activity test with commercial herbicides are as follows:

[0091] Table 3, [N 2,2,2,16 [PTB] herbicidal activity test results

[0092]

[0093] As shown in Table 3 and Figures 5-6 As shown, at a concentration of 15-35g / mu, [N 2,2,2,16 The growth inhibition rate and fresh weight inhibition rate of the ][PTB] microspheres are higher than those of the commercially available pyrifos-butyl herbicide, and the experimental group can achieve a higher growth inhibition rate when using a smaller dosage, indicating that the pyrifos-butyl ionic liquid microspheres prepared by the present application can effectively remove barnyard grass in the field.

[0094] 4. [N 2,2,2,18 [PTB] Herbicidal activity test

[0095] The grass plant barnyard grass (Echinochloa crusgalli (L.) Beauv) was used as the herbicidal activity test object. Nutrition soil was placed in a seedling box to occupy 2 / 3 of the volume. The barnyard grass seeds were activated with distilled water and soaked for 4 hours. Then, they were evenly spread in the seedling box and covered with a layer of nutrition soil. A series of different qualities of [N 2,2,2,18 ][PTB] microspheres, the control group was commercially available pyrithiobacillus (PTB) microspheres, and the blank group was added with the same mass of blank microspheres in the seedling box. The plants were cultured at room temperature of 25±2℃ for 20 days, and the average aboveground height and average fresh weight of the plants were calculated.

[0096] After converting the mass of the microspheres into an equivalent concentration of pyrithione ionic liquid, the results of the herbicidal activity test with commercial herbicides are as follows:

[0097] Table 4, [N 2,2,2,18 [PTB] herbicidal activity test results

[0098]

[0099] As shown in Table 4 and Figures 7-8 As shown, at a concentration of 15-35g / mu, [N 2,2,2,18The growth inhibition rate and fresh weight inhibition rate of the ][PTB] microspheres are higher than those of the commercially available pyrifos-butyl herbicide, and the experimental group can achieve a higher growth inhibition rate when using a smaller dosage, indicating that the pyrifos-butyl ionic liquid microspheres prepared by the present application can effectively remove barnyard grass in the field.

[0100] 5. Solubility test

[0101] Referring to the method in Vogel's Textbook of Practical Organic Chemistry, the solubility of herbicidal ionic liquids in 9 solvents was determined. The 9 solvents were arranged according to Snyder polarity, namely: water 9.0, methanol 6.6, DMSO 6.5, acetonitrile 6.5, acetone 5.4, isopropanol 4.3, ethyl acetate 4.3, chloroform 4.1, and n-hexane 0.0.

[0102] Weigh 0.1g of herbicidal ionic liquid respectively, place it in a centrifuge tube, add a certain volume of the above solvent, and shake. Evaluate the solubility of the herbicidal ionic liquid based on the volume of solvent added and the dissolution condition of the sample. If 0.1g of the sample is completely dissolved in 1mL of solvent, it is "soluble" and expressed as "+". If 0.1g of the sample is completely dissolved in 3mL of solvent, it is "partially soluble" and expressed as "±". If 0.1g of the sample cannot be completely dissolved in 3mL of solvent, it is "insoluble" and expressed as "-".

[0103] Table 5. Solubility test results

[0104]

[0105]

[0106] It can be seen from the test statistical results that, except for n-hexane, the solubility of the pyrifos-butyl ionic liquid in solvents of other different polarities is enhanced compared with pyrifos-butyl acid.

[0107] 6. Thermal stability test

[0108] Using a thermogravimetric analyzer, 5-10 mg of the sample was weighed and heated at a heating rate of 10°C / min in the range of 35-400°C to determine the decomposition temperature of the four ionic liquids.

[0109] Table 6. Thermal stability test results

[0110] HIL Initial decomposition temperature (℃) <![CDATA[[N 2,2,2,12 ][PTB]]]> 192.4 <![CDATA[[N 2,2,2,14 ][PTB]]]> 193.7 <![CDATA[[N 2,2,2,16 ][PTB]]]> 195.2 <![CDATA[[N 2,2,2,18 ][PTB]]]> 197.4

[0111] From the above statistical results, it can be seen that the initial decomposition temperatures of the four ionic liquids are all greater than 190°C, indicating that the ionic liquids have high thermal stability and are not easy to decompose.

[0112] Therefore, the pyrithiobac-butyl ionic liquid of the present invention improves its herbicidal activity through structural modification, and after pyrithiobac-butyl is combined with cations of different carbon chain lengths, it has a flocculation effect while playing a volume-enhancing and efficiency-promoting role, and can improve soil structure, reduce soil loss, and enhance its water, soil and fertilizer retention capabilities, thereby further achieving an increase in production. The pyrithiobac-butyl ionic liquid microspheres are prepared using sodium alginate microspheres as carriers, which improve stability, adapt to a variety of climate and soil conditions, expand the scope of application, and have extremely high application value and promotion prospects.

Claims

1. A pyrithione ionic liquid, characterized in that: The ionic liquid is obtained by combining pyrithiobacillus as an anion with a structurally modified quaternary ammonium cation through an acid-base neutralization reaction. The anion is The quaternary ammonium cation is Among them, R1, R2, R3, and R4 are alkyl groups containing 1 to 18 carbon atoms.

2. The pyrithione ionic liquid according to claim 1, characterized in that The quaternary ammonium cation is N,N,N-(triethyl)-N-dodecyl ammonium, N,N,N-(triethyl)-N-tetradecyl ammonium, N,N,N-(triethyl)-N-hexadecyl ammonium or N,N,N-(triethyl)-N-octadecyl ammonium.

3. The pyrimidinesulfuron ionic liquid according to claim 1, characterized in that The pyrimthiosulfate ionic liquid is N,N,N-(triethyl)-N-dodecyl ammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylsulfur)benzoic acid) salt, N,N,N-(triethyl)-N-tetradecyl ammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylsulfur)benzoic acid) salt, N,N,N-(triethyl)-N-hexadecyl ammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylsulfur)benzoic acid) salt or N,N,N-(triethyl)-N-octadecyl ammonium-(2-chloro-6-(4,6-dimethoxypyrimidin-2-ylsulfur)benzoic acid) salt.

4. A method for preparing the pyrithiobac-butyl ionic liquid according to claim 1, characterized in that: The method comprises the following steps: (1) Preparation of brominated ionic liquid ammonium salt: triethylamine, monobrominated alkane and solvent are mixed, heated under reflux reaction, and then rotary evaporated and dried to obtain brominated ionic liquid ammonium salt; (2) Preparation of pyrimidinesulfuron ionic liquid: The bromide ionic liquid ammonium salt obtained in the previous step is dissolved in water and then passed through an activated anion exchange resin to perform an ion exchange reaction to obtain an aqueous solution of ionic liquid ammonium hydroxide salt, which is then mixed with 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio)benzoic acid to perform an acid-base neutralization reaction and dried to obtain a pyrimidinesulfuron ionic liquid.

5. The method according to claim 4, characterized in that: The molar ratio of the ammonium hydroxide salt or organic amine to 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio)benzoic acid is 1:1.0-1.4, the reaction temperature is 20-40° C., and the reaction time is 12-24 hours.

6. The method according to claim 4, characterized in that: The organic amine is triethylamine; the ammonium hydroxide salt is N,N,N-(triethyl)-N-dodecyl ammonium hydroxide, N,N,N-(triethyl)-N-tetradecyl ammonium hydroxide, N,N,N-(triethyl)-N-hexadecyl ammonium hydroxide, and N,N,N-(triethyl)-N-octadecyl ammonium hydroxide.

7. The method according to claim 4, characterized in that: The preparation of the ammonium hydroxide salt comprises the following steps: mixing triethylamine, monobromoalkane and a solvent, heating and refluxing, and obtaining an ammonium bromide salt by rotary evaporation and drying; dissolving the ammonium bromide salt in water, and then performing ion exchange through an activated anion exchange resin to obtain an aqueous solution of the ammonium hydroxide salt.

8. Use of the pyrithione-butyl ionic liquid according to claim 1 in the field of plant protection.

9. The use according to claim 8, characterized in that: The application is that the pyrithiobac-butyl ionic liquid microspheres prepared from the pyrithiobac-butyl ionic liquid are applied to herbicides.

10. The use according to claim 8, characterized in that: The preparation method of the pyrithiobac-butyl ionic liquid microspheres is as follows: the pyrithiobac-butyl ionic liquid is ultrasonically dispersed in a sodium alginate solution, and then injected and dripped into a calcium chloride solution under high-speed stirring, and then the microspheres are obtained after cross-linking, filtering and washing.

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