Quinoline carboxylic acid-based ionic liquid W / O / W multiple emulsion and its preparation and application

Abstract

The present invention discloses a kind of quinoline carboxylic acid ionic liquid W / O / W multiple emulsion and its preparation and application, belonging to the technical field of plant protection. In the present invention, dichloroquinoline carboxylic acid is used as the anion and jointly composes a functionalized ionic liquid with a structurally modified quaternary ammonium cation. The quinoline carboxylic acid ionic liquid can be prepared by an ion exchange reaction, an acid-base neutralization reaction or by extraction, and this kind of ionic liquid has high thermal stability. After preparing a W / O / W multiple emulsion with this ionic liquid as the active ingredient and emulsifier, the drug content can be controlled according to the drug release requirements; when this ionic liquid is applied to field weeding activities, compared with the application of conventional dichloroquinoline carboxylic acid agents, it can significantly improve the weeding activity of the agent, and thus can reduce the dosage of pesticides under the same weeding effect, having the effect of environmental protection.

Description

Technical Field

[0001] The present invention relates to the technical field of plant protection, and particularly relates to a kind of quinoline carboxylic acid-based ionic liquid W / O / W multiple emulsion and its preparation and application. Background Art

[0002] Rice is an important food crop globally, feeding more than 50% of the world's population. One of the problems in rice cultivation is that field weeds compete with crops for nutrients, thereby greatly reducing the yield of rice. Among them, the most difficult weed to remove is barnyard grass. In modern agricultural production, quinclorac is a highly effective selective herbicide for controlling barnyard grass in paddy fields. It has outstanding effects on barnyard grass at the 4-7 leaf stage, with strong selectivity, a wide range of application periods, and one application can control barnyard grass throughout the growth period of rice. In addition, quinclorac can effectively control weeds such as monochoria vaginalis and water dropwort, but has poor control effects on sedge weeds. Quinclorac can be absorbed by germinated seeds, roots, and leaves, and has the characteristics of a hormone-type herbicide, with similar action symptoms to auxin-like substances and is harmless to rice. Traditional herbicides containing quinoline carboxylic acid generally have extremely poor water solubility and are usually wettable powder and suspension concentrate formulations, with low effective utilization rates. During the use process in agricultural production, high doses and repeated spraying of herbicides will accumulate a large amount of residual pesticides and organic solvents in paddy fields, leading to environmental problems such as excessive pesticide residues and groundwater pollution. Conducting research on the synergistic effect of quinclorac is particularly important for controlling the dosage of pesticides and reducing environmental hazards.

[0003] Ionic liquids refer to a class of compounds composed of anions and cations with a melting point below 100°C. Essentially, they are a class of low-melting salts with unique properties such as low vapor pressure, adjustable structure, and adjustable physical properties, and have been widely used in the fields of green solvents, catalysis, and electrochemistry. In recent years, technicians in this field have also focused on applying ionic liquids to the research of drugs and agricultural chemicals and have achieved corresponding results.

[0004] Herbicidal ionic liquids are a type of functional ionic liquids, usually composed of two parts: a herbicide anion and a structurally modified cation. The anion plays the role of herbicidal efficacy, and the cation is the functional part, which plays the role of improving physical and chemical properties. For example, the research group of Cao Yongsong (A new and efficient and environmentally friendly application form of herbicidal ionic liquid - fomesafen, Proceedings of the 12th National Weed Science Conference, 2015, Taiyuan) found that by pairing different functionalized cations, the properties such as the solubility, surface activity, thermal stability, and herbicidal activity of herbicides can be selectively adjusted, which can improve the thermal stability and surface activity of herbicides and reduce their volatility. Chinese Patent CN 110003270 B discloses a glyphosate double-cationic ionic liquid compound, its preparation method and application, in which different types of cations are introduced into the glyphosate parent structure to form a double-cationic liquid compound, playing the regulatory role of different cation functional groups and different carbon chain lengths, regulating its physical and chemical properties, enhancing liposolubility, improving the ability of glyphosate to penetrate the plant cuticle, promoting its absorption and conduction in the plant body, improving its herbicidal activity and expanding the herbicidal spectrum.

[0005] However, in the prior art, there has been no disclosure of herbicidal ionic liquids composed of quinclorac as an anion. The effects of different cation functional groups and different carbon chain lengths on the properties of quinclorac are different. After pairing quinclorac as an anion with different cations, the physical and chemical properties and herbicidal activity of the obtained herbicidal ionic liquids are unpredictable. Therefore, it is necessary to conduct targeted research on quinoline carboxylic acid ionic liquids, and it is expected that the herbicidal activity of quinclorac can be effectively improved through reasonable modification. Summary of the Invention

[0006] The purpose of the present invention is to solve the problems existing in the prior art, and provide a class of W / O / W multiple emulsions of quinoline carboxylic acid ionic liquids and their preparation and application. By transforming the quinclorac structure into an ionic liquid form, the herbicidal activity of quinclorac is improved.

[0007] The technical solution disclosed by the present invention is: A preparation method of a class of W / O / W multiple emulsions of quinoline carboxylic acid ionic liquids, comprising the following steps:

[0008] 1) Preparation of bromoionic liquid ammonium salt ([N 2,2,2,n [Br]): Triethylamine, monobromoalkane and a solvent are mixed, heated under reflux for reaction, and after rotary evaporation and drying, the bromoionic liquid ammonium salt is prepared;

[0009] 2) Preparation of quinoline carboxylic acid ionic liquid ([N 2,2,2,n [Quin]):

[0010] The bromoionic liquid ammonium salt obtained in the previous step ([N 2,2,2,n[Br]) is dissolved in water and undergoes an ion exchange reaction through an activated anion exchange resin to obtain an aqueous solution of the ammonium salt of the ionic liquid ammonium hydroxide ([N 2,2,2,n [OH]). The aqueous solution is then mixed with 3,7-dichloroquinoline-8-carboxylic acid to carry out an acid-base neutralization reaction, followed by drying to obtain a quinoline carboxylic acid-based ionic liquid ([N 2,2,2,n [Quin]);

[0011] Or

[0012] After mixing 3,7-dichloroquinoline-8-carboxylic acid with a basic substance to form a salt solution, the brominated ionic liquid ammonium salt ([N 2,2,2,n [Br]) obtained in the previous step is placed in a separatory funnel, extracted with an organic solvent, the organic phase is taken, rotary evaporated, and dried to obtain a quinoline carboxylic acid-based ionic liquid ([N 2,2,2,n [Quin]);

[0013] 3) Preparation of W / O type primary emulsion:

[0014] The oil phase containing the quinoline carboxylic acid-based ionic liquid ([N 2,2,2,n [Quin]) and the internal aqueous phase are heated to the same temperature, and the internal aqueous phase is added to the oil phase containing the ionic liquid under stirring to obtain a W / O type primary emulsion;

[0015] 4) Preparation of W / O / W type multiple emulsion:

[0016] The external aqueous phase containing the complex emulsifier is heated, and the W / O type primary emulsion obtained in the previous step is added to the external aqueous phase to obtain a W / O / W type multiple emulsion.

[0017] Furthermore, in step 1), the monobromoalkane is any one of 1-bromododecane, 1-bromotetradecane, 1-bromohexadecane, and 1-bromooctadecane; the molar ratio of triethylamine to the monobromoalkane is 1.2 - 2:1; the solvent used is one or more of distilled water, methanol, acetonitrile, and acetone, preferably acetonitrile; the temperature of the heating reflux reaction is 60 - 90 °C, and the reaction time is 48 - 72 hours.

[0018] Furthermore, the brominated ionic liquid ammonium salt ([N 2,2,2,n [Br]) prepared in step 1) is any one of N,N,N-(triethyl)-N-dodecylammonium bromide ([N 2,2,2,12 [Br]), N,N,N-(triethyl)-N-tetradecylammonium bromide ([N 2,2,2,14 [Br]), N,N,N-(triethyl)-N-hexadecylammonium bromide ([N 2,2,2,16 [Br]), and N,N,N-(triethyl)-N-octadecylammonium bromide ([N 2,2,2,18 [Br]).

[0019] Further, in step 2), when preparing the quinoline carboxylic acid ionic liquid ([N 2,2,2,n [Quin]) by using an acid-base neutralization reaction, the molar ratio of the ammonium hydroxide salt of the ionic liquid ([N 2,2,2,n [OH]) to 3,7-dichloroquinoline-8-carboxylic acid is 1:1 - 1.2, the reaction temperature is 25 - 45 °C, and the reaction time is 12 - 24 hours; the basic substance is one or more of potassium carbonate, sodium bicarbonate, sodium hydroxide, and potassium hydroxide.

[0020] Further, in step 2), when preparing the ammonium hydroxide salt of the ionic liquid ([N 2,2,2,n [OH]) by using an ion exchange reaction, the concentration of the aqueous solution of the bromide salt of the ionic liquid ([N 2,2,2,n [Br]) is 0.6 - 1 mol / L; the ammonium hydroxide salt of the ionic liquid ([N 2,2,2,n [OH]) in step 2) is one of N,N,N-(triethyl)-N-dodecylammonium hydroxide salt ([N 2,2,2,12 [OH]), N,N,N-(triethyl)-N-tetradecylammonium hydroxide salt ([N 2,2,2,14 [OH]), N,N,N-(triethyl)-N-hexadecylammonium hydroxide salt ([N 2,2,2,16 [OH]), and N,N,N-(triethyl)-N-octadecylammonium hydroxide salt ([N 2,2,2,18 [OH]).

[0021] Further, the oil phase in step 3) is one or more of camellia oil, liquid paraffin, and glycerol; the complex emulsifier in step 4) is one or more of gum arabic, gelatin, Span 80, Tween 80, Poloxamer 188, and apricot gum; the W / O / W type multiple emulsion prepared in step 4) is composed of a quinoline carboxylic acid ionic liquid, an oil phase, an emulsifier, and water, and the mass fractions of the quinoline carboxylic acid ionic liquid, the oil phase, and water are 10 - 15%, 20 - 25%, and 50 - 60% respectively.

[0022] In the W / O / W multiple emulsion of the quinoline carboxylic acid ionic liquid prepared by the above method, the structural formula of the quinoline carboxylic acid ionic liquid is as shown in (I):

[0023]

[0024] In the formula, the cation is a quaternary ammonium cation, where R1, R2, R3, and R4 are alkyl groups containing 1 - 18 carbon atoms.

[0025] Further, the quaternary ammonium cation is selected from any one of N,N,N-(triethyl)-N-dodecylammonium, N,N,N-(triethyl)-N-tetradecylammonium, N,N,N-(triethyl)-N-hexadecylammonium, and N,N,N-(triethyl)-N-octadecylammonium.

[0026] Further, the quinolinecarboxylic acid-based ionic liquid is N,N,N-(triethyl)-N-dodecylammonium-(3,7-dichloroquinoline-8-carboxylate) ([N 2,2,2,12 [Quin]), N,N,N-(triethyl)-N-tetradecylammonium-(3,7-dichloroquinoline-8-carboxylate) ([N 2,2,2,14 [Quin]), N,N,N-(triethyl)-N-hexadecylammonium-(3,7-dichloroquinoline-8-carboxylate) ([N 2,2,2,16 [Quin]), or N,N,N-(triethyl)-N-octadecylammonium-(3,7-dichloroquinoline-8-carboxylate) ([N 2,2,2,18 [Quin]).

[0027] The above-mentioned W / O / W multiple emulsion of quinolinecarboxylic acid-based ionic liquid can be applied in the field of plant protection. Compared with the commercially available quinclorac herbicide, this W / O / W multiple emulsion of quinolinecarboxylic acid-based ionic liquid can improve the herbicidal activity and reduce the dosage of pesticides under the same herbicidal effect.

[0028] The beneficial effects of the present invention are as follows:

[0029] 1. In this application, quinclorac is used as the anion and combined with a structurally modified quaternary ammonium cation to form a functionalized ionic liquid. The quaternary ammonium cation is N,N,N-(triethyl)-N-dodecylammonium, N,N,N-(triethyl)-N-tetradecylammonium, N,N,N-(triethyl)-N-hexadecylammonium, or N,N,N-(triethyl)-N-octadecylammonium. This type of ionic liquid has good thermal stability. After preparing a W / O / W multiple emulsion with this ionic liquid as the active ingredient and emulsifier, the drug content can be controlled according to the drug release requirements;

[0030] 2. After transforming the structure of quinclorac into an ionic liquid form, compared with the conventional quinclorac preparation, the herbicidal activity of quinclorac can be significantly improved. Furthermore, the dosage of pesticides can be reduced under the same herbicidal effect, playing a role in environmental protection;

[0031] 3. After transforming the structure of quinclorac into an ionic liquid form, the ionic liquid has high surface activity and can replace the emulsifier used in the preparation of the primary emulsion in the traditional W / O / W multiple emulsion, thus achieving the purpose of optimizing the formulation. Description of the Drawings

[0032] Figure 1 For [N 2,2,2,12 Statistical graphs of growth inhibition rate (top) and fresh weight inhibition rate (bottom) in the herbicidal activity test of Quin W / O / W type multiple emulsion;

[0033] Figure 2 For [N 2,2,2,14 Statistical graphs of growth inhibition rate (top) and fresh weight inhibition rate (bottom) in the herbicidal activity test of Quin W / O / W type multiple emulsion;

[0034] Figure 3 For [N 2,2,2,16 Statistical graphs of growth inhibition rate (top) and fresh weight inhibition rate (bottom) in the herbicidal activity test of Quin W / O / W type multiple emulsion;

[0035] Figure 4 For [N 2,2,2,18 ][Quin]Statistical graph of growth inhibition rate (top) and fresh weight inhibition rate (bottom) in the herbicidal activity test of W / O / W type multiple emulsion. DETAILED DESCRIPTION

[0036] The following examples further illustrate the present invention, but should not be construed as limiting the present invention. Without departing from the essence of the present invention, modifications and substitutions made to the methods, steps or conditions of the present invention are within the scope of the present invention.

[0037] Example 1

[0038] N,N,N-(Triethyl)-N-dodecyl ammonium-(3,7-dichloroquinoline-8-carboxylate) salt ([N 2,2,2,12 The preparation route of ][Quin]) is as follows:

[0039]

[0040] Preparation of bromide salt: 0.045 mol of triethylamine, 0.03 mol of 1-bromododecane, and 60 mL of acetonitrile were added to a 250 mL round-bottom flask equipped with a reflux condenser and a magnetic rod, and the mixture was heated and stirred under reflux at 80°C for 60 hours. The solvent was removed by rotary evaporation and vacuum dried at 60°C for 48 hours to obtain 9.96 g of the product, N,N,N-(triethyl)-N-dodecylammonium bromide ([N 2,2,2,12 ][Br]) yield 94.7%.

[0041] Ammonium hydroxide salt: weigh 0.024 mol [N 2,2,2,12[Br]Dissolve it in 30 mL of distilled water, pass it through an anion exchange resin, start collecting the exchanged solution after the pH test paper turns alkaline, and stop collecting until the pH test paper turns neutral. Titrate the collected solution with a 0.02 M standard hydrochloric acid solution to determine its concentration. At this time, the collected solution is an aqueous solution of N,N,N-(triethyl)-N-dodecylammonium hydroxide ([N 2,2,2,12 [OH]).

[0042] Quinoline carboxylic acid herbicidal ionic liquid: Weigh 0.014 mol of 3,7-dichloroquinoline-8-carboxylic acid and add it to a round-bottom flask containing the collected solution of the ionic liquid ammonium hydroxide salt. Add a magnetic stirrer and stir at room temperature for 24 hours. Rotate and evaporate to remove the solvent, and dry it under vacuum at 60 °C for 48 hours to obtain N,N,N-(triethyl)-N-dodecylammonium-(3,7-dichloroquinoline-8-carboxylate) salt ([N 2,2,2,12 [Quin]). A total of 6.38 g of the product is obtained, and the yield is 88.92%.

[0043] 1H NMR (300 MHz, Chloroform-d) δ 8.76 (d, J = 2.5 Hz, 1H), 8.03 (d, J = 2.5 Hz, 1H), 7.48 (s, 2H), 3.64 (q, J = 7.3 Hz, 6H), 3.38–3.09 (m, 2H), 1.72 (s, 2H), 1.55–1.16 (m, 27H), 0.99–0.77 (m, 3H).

[0044] Ionic liquid W / O / W multiple emulsion:

[0045] Prescription:

[0046] W / O primary emulsion: [N 2,2,2,12 [Quin] 5.0 g, liquid paraffin 8.8 g, soybean oil 2.2 g, water 11.2 g.

[0047] W / O / W multiple emulsion: Poloxamer188 0.6 g, Span80 1.15 g, Tween80 1.00 g, water 26 g.

[0048] According to the prescription, heat the oil phase soybean oil (containing [N 2,2,2,12 [Quin]) and the internal aqueous phase in a water bath to 80 °C, and slowly add the internal aqueous phase to the oil phase containing the ionic liquid at the same temperature under magnetic stirring to obtain a W / O primary emulsion by magnetic stirring.

[0049] Heat the external aqueous phase containing the complex emulsifier (Span80 - Tween80 / Poloxamer188) to 80 °C. While stirring, slowly add the uncooled W / O primary emulsion to the external aqueous phase, stirring continuously during the addition. A W / O / W double emulsion is obtained through magnetic stirring, and finally, the double emulsion is obtained by emulsification with a homogenizer.

[0050] Example 2

[0051] The preparation route of N,N,N-(triethyl)-N-tetradecylammonium-(3,7-dichloroquinoline-8-carboxylate) ([N 2,2,2,14 [Quin]) is as follows:

[0052]

[0053] Bromo salt: Add 0.075 mol of triethylamine, 0.05 mol of 1-bromotetradecane, and 60 mL of acetonitrile to a 250 mL round-bottom flask equipped with a reflux condenser and a magnetic stirrer. Heat and stir under reflux, control the temperature at 80 °C, and react for 60 hours. Rotate and evaporate to remove the solvent, and dry under vacuum at 60 °C for 48 hours to obtain 18.17 g of the product, N,N,N-(triethyl)-N-tetradecylammonium bromide ([N 2,2,2,14 [Br]), with a yield of 96%.

[0054] Ammonium hydroxide salt: Weigh 0.03 mol of [N 2,2,2,14 [Br] and dissolve it in 30 mL of distilled water. Pass it through an anion exchange resin. Start collecting the exchange solution after the pH test paper turns alkaline, and stop collecting until the pH test paper turns neutral. Titrate the collected solution with a 0.02 M standard hydrochloric acid solution to determine the concentration. At this time, the collected solution is an aqueous solution of N,N,N-(triethyl)-N-tetradecylammonium hydroxide ([N 2,2,2,14 [OH]).

[0055] Quinoline carboxylic acid herbicidal ionic liquid: Weigh 0.026 mol of 3,7-dichloroquinoline-8-carboxylic acid and add it to a round-bottom flask containing the collected solution of the ionic liquid ammonium hydroxide salt. Add a magnetic stirrer and stir at room temperature for 24 hours. Rotate and evaporate to remove the solvent, and dry under vacuum at 60 °C for 48 hours to obtain N,N,N-(triethyl)-N-tetradecyl-(3,7-dichloroquinoline-8-carboxylate) ([N 2,2,2,14 [Quin]), with a product of 13.86 g and a yield of 98.62%.

[0056] 1H NMR (300 MHz, Chloroform-d) δ 8.76 (d, J = 2.5 Hz, 1H), 8.03 (d, J = 2.5 Hz, 1H), 7.48 (s, 2H), 3.62 (q, J = 7.2 Hz, 6H), 3.37–3.14 (m, 2H), 1.72 (s, 2H), 1.59–1.01 (m, 31H), 0.99–0.70 (m, 3H).

[0057] Ionic liquid W / O / W multiple emulsion:

[0058] Prescription:

[0059] W / O primary emulsion: [N 2,2,2,14 [Quin] 5.0 g, liquid paraffin 8.8 g, soybean oil 2.2 g, water 11.2 g.

[0060] W / O / W multiple emulsion: Poloxamer188 0.6 g, Span80 1.15 g, Tween80 1.00 g, water 26 g.

[0061] According to the prescription, the oil phase soybean oil (containing [N 2,2,2,14 [Quin]) and the inner aqueous phase were respectively placed in a water bath and heated to 80 °C. Under magnetic stirring, the inner aqueous phase was slowly added to the oil phase containing ionic liquid at the same temperature. After magnetic stirring, a W / O primary emulsion was obtained.

[0062] The outer aqueous phase containing the complex emulsifier (Span80 - Tween80 / Poloxamer188) was heated to 80 °C. Under stirring, the uncooled W / O primary emulsion was slowly added to the outer aqueous phase while stirring. After magnetic stirring, a W / O / W multiple emulsion was prepared, and finally emulsified by a homogenizer.

[0063] Example 3:

[0064] The preparation route of N,N,N-(triethyl)-N-hexadecylammonium-(3,7-dichloroquinoline-8-carboxylate) ([N 2,2,2,16 [Quin]) is as follows:

[0065]

[0066] Bromide salt: 0.045 mol of triethylamine, 0.03 mol of 1-bromohexadecane, and 60 mL of acetonitrile were successively added to a 250 mL round-bottom flask equipped with a reflux condenser and a magnetic stirrer. The mixture was heated and stirred under reflux, controlling the temperature at 80 °C for 65 hours. The solvent was removed by rotary evaporation and vacuum dried at 60 °C for 48 hours to obtain 11.34 g of the product, N,N,N-(triethyl)-N-hexadecylammonium bromide ([N 2,2,2,16[Br] The yield is 93%.

[0067] Ammonium hydroxide salt: Weigh 0.023 mol of [N 2,2,2,16 [Br] and dissolve it in 30 mL of distilled water. Pass it through an ion exchange column containing hydroxide ions. Start collecting the exchanged solution after the pH test paper turns alkaline, and stop collecting until the pH test paper turns neutral. Titrate the obtained collected solution with a 0.02 M standard hydrochloric acid solution to determine the concentration. At this time, the collected solution is an aqueous solution of N,N,N-(triethyl)-N-hexadecylammonium hydroxide ([N 2,2,2,16 [OH]).

[0068] Quinoline carboxylic acid herbicidal ionic liquid: Weigh 0.012 mol of 3,7-dichloroquinoline-8-carboxylic acid and add it to a round-bottom flask containing the ammonium hydroxide salt collected solution. Add a magnetic stir bar and stir at room temperature for 24 hours. Rotate and evaporate to remove the solvent, and dry it under vacuum at 60 °C for 48 hours to obtain N,N,N-(triethyl)-hexadecyl-(3,7-dichloroquinoline-8-carboxylate) ([N 2,2,2,16 [Quin]). The product is 6.13 g, and the yield is 89.84%.

[0069] 1H NMR (300 MHz, Chloroform-d) δ 8.76 (d, J = 2.4 Hz, 1H), 8.03 (d, J = 2.4 Hz, 1H), 7.48 (s, 2H), 3.60 (q, J = 7.2 Hz, 6H), 3.39–3.14 (m, 2H), 1.69 (s, 2H), 1.48–1.16 (m, 35H), 1.01–0.74 (m, 3H).

[0070] Ionic liquid W / O / W multiple emulsion:

[0071] Prescription:

[0072] W / O primary emulsion: [N 2,2,2,16 [Quin] 5.0 g, liquid paraffin 8.8 g, soybean oil 2.2 g, water 11.2 g.

[0073] W / O / W multiple emulsion: Poloxamer188 0.6 g, Span80 1.15 g, Tween80 1.00 g, water 26 g.

[0074] According to the prescription, heat the oil phase soybean oil (containing [N 2,2,2,16 [Quin]) and the inner aqueous phase in a water bath to 80 °C. Slowly add the inner aqueous phase to the oil phase containing the ionic liquid at the same temperature under magnetic stirring to obtain a W / O primary emulsion through magnetic stirring.

[0075] Heat the external aqueous phase containing the complex emulsifier (Span80 - Tween80 / Poloxamer188) to 80 °C. While stirring, slowly add the uncooled W / O type primary emulsion to the external aqueous phase, stirring continuously during the addition. After magnetic stirring, a W / O / W type multiple emulsion is obtained, and finally it can be emulsified by a homogenizer.

[0076] Example 4:

[0077] N,N,N-(triethyl)-N-octadecylammonium-(3,7-dichloroquinoline-8-carboxylate) salt ([N 2,2,2,18 [Quin]

[0078] and the synthesis route is as follows:

[0079]

[0080] Bromo salt: Add 0.075 mol of triethylamine, 0.05 mol of 1-bromooctadecane, and 60 mL of acetonitrile to a 250 mL round-bottom flask equipped with a reflux condenser and a magnetic stir bar. Heat and stir under reflux, control the temperature at 80 °C, react for 65 hours, rotary evaporate to remove the solvent, and vacuum dry at 60 °C for 48 hours to obtain 19.56 g of the product, N,N,N-(triethyl)-N-octadecylammonium bromide ([N 2,2,2,18 [Br]) with a yield of 90%.

[0081] Quinoline carboxylic acid herbicidal ionic liquid: Weigh 0.015 mol of [N 2,2,2,18 [Br] and dissolve it in 50 mL of distilled water to make a constant volume to obtain a solution of N,N,N-(triethyl)-N-octadecylammonium bromide ([N 222 C 18 [Br]). Weigh 0.015 mol of 3,7-dichloroquinoline-8-carboxylic acid and 0.015 mol of KOH in 30 mL of distilled water to obtain a solution of potassium quinoline carboxylate; add 0.01 mol of N,N,N-(triethyl)-N-octadecylammonium bromide ([N 2,2,2,18 [Br]) solution, 21.9 mL of potassium quinoline carboxylate solution, and 40 mL of dichloromethane to a 250 mL separatory funnel for extraction. After taking the organic phase, add another 40 mL of dichloromethane for extraction, and repeat the extraction twice. After combining the obtained organic phases, add 10 mL of distilled water for washing, take the organic phase and rotary evaporate to remove the solvent, and vacuum dry at 50 °C for 48 hours to obtain 6.0 g of the product N,N,N-(triethyl)-N-octadecylammonium-(3,7-dichloroquinoline-8-carboxylate) salt ([N 2,2,2,18 [Quin]) with a yield of 92%.

[0082] 1H NMR (300 MHz, Chloroform-d) δ 8.75 (d, J = 2.4 Hz, 1H), 8.02 (d, J = 2.5 Hz, 1H), 7.47 (s, 2H), 3.58 (q, J = 7.2 Hz, 6H), 3.29–3.12 (m, 2H), 1.68 (s, 2H), 1.51–1.10 (m, 39H), 1.02–0.77 (m, 3H).

[0083] Prescription:

[0084] W / O type primary emulsion: [N 2,2,2,18 [Quin] 5.0 g, liquid paraffin 8.8 g, soybean oil 2.2 g, water 11.2 g.

[0085] W / O / W type multiple emulsion: Poloxamer188 0.6 g, Span80 1.15 g, Tween80 1.00 g, water 26 g.

[0086] According to the prescription, add the oil phase soybean oil (containing [N 2,2,2,18 [Quin]) and the internal aqueous phase to a water bath and heat to 80 °C. Slowly add the internal aqueous phase to the oil phase containing ionic liquid at the same temperature under magnetic stirring to obtain the W / O type primary emulsion through magnetic stirring.

[0087] Heat the external aqueous phase containing the double emulsifier (Span80 - Tween80 / Poloxamer188) to 80 °C. Slowly add the uncooled W / O type primary emulsion to the external aqueous phase under stirring, stirring while adding, and obtain the W / O / W type multiple emulsion through magnetic stirring. Finally, emulsify it with a homogenizer.

[0088] Performance test:

[0089] 1. [N 2,2,2,12 [Quin] herbicidal activity experiment

[0090] Use the gramineous plant Echinochloa crusgalli (L.) Beauv as the object for herbicidal activity test. Take Echinochloa crusgalli seeds, soak and activate them with distilled water for 4 hours. Use a seedling box (0.5×0.25, 0.125 m 2 ) to cultivate Echinochloa crusgalli seeds. Put 2 cm thick ceramsite sand in the seedling box, scatter the Echinochloa crusgalli seeds and then cover them with another layer of ceramsite sand, and add a series of concentrations of [N 2,2,2,12[Quin]W / O / W multiple emulsion. The control group was the commercially available quinclorac herbicide (Quin) at the same concentration, and the same volume of distilled water was added to the ceramsite sand in the blank group. Cultivate at room temperature of 25±2°C for 20 days, calculate the average above-ground height and average fresh weight of the plants. The calculation formula for the plant growth inhibition rate is: growth inhibition rate = (average height of plants in the blank group - average height of test plants) / average height of plants in the blank group; the calculation formula for the fresh weight inhibition rate is: fresh weight inhibition rate = (average fresh weight of plants in the blank group - average fresh weight of test plants) / average fresh weight of plants in the blank group. The test results of the herbicidal activity of the commercially available herbicide and the W / O / W multiple emulsion are as follows:

[0091]

[0092] Combined Figure 1 It can be seen that at a concentration of 15 - 35 g / acre, 2,2,2,12 [Quin] the growth inhibition rate and fresh weight inhibition rate of the W / O / W multiple emulsion are both higher than those of the commercially available quinclorac herbicide, indicating that the quinoline carboxylic acid ionic liquid multiple emulsion prepared by this application can effectively remove barnyard grass in the field.

[0093] 2. 2,2,2,14 [Quin] Herbicidal activity experiment

[0094] Use the gramineous plant barnyard grass (Echinochloa crusgalli (L.) Beauv) as the test object for herbicidal activity. Soak the barnyard grass seeds in distilled water for 4 hours for activation, and use a seedling raising box (0.5×0.25, 0.125 m 2 ) to cultivate barnyard grass seeds. Put 2 cm thick ceramsite sand in the seedling raising box, sprinkle barnyard grass seeds and then cover with another layer of ceramsite sand, and add a series of concentrations of 2,2,2,14 [Quin] W / O / W multiple emulsion. The control group was the commercially available quinclorac herbicide at the same concentration, and the same volume of distilled water was added to the ceramsite sand in the blank group. Cultivate at room temperature of 25±2°C for 20 days, calculate the average above-ground height and average fresh weight of the plants, and count the plant growth inhibition rate and fresh weight inhibition rate. The test results of the herbicidal activity of the commercially available herbicide and the W / O / W multiple emulsion are as follows:

[0095]

[0096] Combined Figure 2 It can be seen that at a concentration of 15 - 35 g / acre, 2,2,2,14 [Quin] the growth inhibition rate and fresh weight inhibition rate of the W / O / W multiple emulsion are both higher than those of the commercially available quinclorac herbicide, indicating that the quinoline carboxylic acid ionic liquid multiple emulsion prepared by this application can effectively remove barnyard grass in the field.

[0097] 3. 2,2,2,16[[Quin]]Weeding Activity Experiment

[0098] The grass Echinochloa crusgalli (L.) Beauv was used as the test object for weeding activity. The seeds of Echinochloa crusgalli were soaked in distilled water for 4 hours for activation, and a seedling box (0.5×0.25, 0.125 m 2 ) was used to cultivate the seeds of Echinochloa crusgalli. The seedling box was filled with 2 cm thick ceramsite sand. After spreading the seeds of Echinochloa crusgalli, another layer of ceramsite sand was covered, and a series of concentrations of [N 2,2,2,16 [[Quin]]W / O / W multiple emulsion was added. The control group was the commercially available quinclorac herbicide with the same concentration, and the blank group was added with the same volume of distilled water to the ceramsite sand. It was cultured at room temperature of 25±2 °C for 20 days. The average above-ground height and average fresh weight of the plants were calculated, and the plant growth inhibition rate and fresh weight inhibition rate were statistically analyzed. The weeding activity test results of the commercially available herbicide and the W / O / W multiple emulsion are as follows:

[0099]

[0100] Combined Figure 3 It can be seen that at the concentration of 15 - 35 g / mu, the growth inhibition rate and fresh weight inhibition rate of the [N 2,2,2,16 [[Quin]]W / O / W multiple emulsion are both higher than those of the commercially available quinclorac herbicide, and in the case of less dosage in the experimental group, the growth inhibition rate higher than that of the control group can be achieved, indicating that the quinoline carboxylic acid ionic liquid multiple emulsion prepared by this application can effectively remove Echinochloa crusgalli in the field.

[0101] 4. [[N 2,2,2,18 [[Quin]]Weeding Activity Experiment

[0102] The grass Echinochloa crusgalli (L.) Beauv was used as the test object for weeding activity. The seeds of Echinochloa crusgalli were soaked in distilled water for 4 hours for activation, and a seedling box (0.5×0.25, 0.125 m 2 ) was used to cultivate the seeds of Echinochloa crusgalli. The seedling box was filled with 2 cm thick ceramsite sand. After spreading the seeds of Echinochloa crusgalli, another layer of ceramsite sand was covered, and a series of concentrations of [N 2,2,2,18 [[Quin]]W / O / W multiple emulsion was added. The control group was the commercially available quinclorac herbicide with the same concentration, and the blank group was added with the same volume of distilled water to the ceramsite sand. It was cultured at room temperature of 25±2 °C for 20 days. The average above-ground height and average fresh weight of the plants were calculated, and the plant growth inhibition rate and fresh weight inhibition rate were statistically analyzed. The weeding activity test results of the commercially available herbicide and the W / O / W multiple emulsion are as follows:

[0103]

[0104]

[0105] Combined with Figure 4 it can be seen that at a concentration of 15 - 35 g / acre, [N 2,2,2,18 [Quin] W / O / W multiple emulsion has a higher growth inhibition rate and fresh weight inhibition rate than the commercially available quinclorac herbicide. Moreover, in the experimental group, even with a smaller dosage, a growth inhibition rate higher than that of the control group can be achieved, indicating that the quinolinic acid-based ionic liquid multiple emulsion prepared by this application can effectively remove barnyard grass in the field.

[0106] 5. Solubility Test

[0107] Referring to the method in Vogel’s Textbook of Practical Organic Chemistry, the solubility of the herbicidal ionic liquid in 9 solvents was determined. The 9 solvents were sorted according to Snyder polarity and were: 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, n-hexane 0.0.

[0108] Weigh 0.1 g of the herbicidal ionic liquid respectively and place it in a centrifuge tube, then add a certain volume of the above solvents and shake. According to the volume of the added solvent and the dissolution status of the sample, the solubility of the herbicidal ionic liquid was evaluated. If 0.1 g of the sample is completely dissolved in 1 mL of the solvent, it is "soluble" and denoted as "+", if 0.1 g of the sample is completely dissolved in 3 mL of the solvent, it is "partially soluble" and denoted as "±", if 0.1 g of the sample cannot be completely dissolved in 3 mL of the solvent, it is "insoluble" and denoted as "-".

[0109]

[0110] It can be seen from the test statistical results that except for n-hexane, the solubility of the quinolinic acid-based ionic liquid is enhanced compared with quinclorac in the solvents with different polarities.

[0111] 6. Thermal Stability Test

[0112] Using a thermogravimetric analyzer, weigh 5 - 10 mg of the sample and heat it 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. The results are as follows:

[0113] HIL Initial decomposition temperature (°C) <![CDATA[[N 2,2,2,12 [Quin]]]> 189.4 <![CDATA[[N 2,2,2,14 [Quin]]]> 190.9 <![CDATA[[N 2,2,2,16 [Quin]]]> 212.2 <![CDATA[[N 2,2,2,18 [Quin]]]> 232.9

[0114] It can be known from the above statistical results that the initial decomposition temperature of the four ionic liquids is greater than 185 °C, indicating that the ionic liquids have high thermal stability and are not easily decomposed.

[0115] The basic principles, main features and advantages of the present invention have been shown and described above. However, the above are only specific embodiments of the present invention, and the technical features of the present invention are not limited thereto. Any other embodiments obtained by those skilled in the art without departing from the technical solution of the present invention should be covered within the patent scope of the present invention.

Claims

1. Preparation method of quinoline carboxylic acid ionic liquid W / O / W multiple emulsion, characterized in that, It includes the following steps: 1) Preparation of bromoionic liquid ammonium salt: Triethylamine, monobromoalkane and a solvent are mixed, heated under reflux for reaction, and after rotary evaporation and drying, bromoionic liquid ammonium salt is prepared; 2) Preparation of quinoline carboxylic acid ionic liquid: The bromoionic liquid ammonium salt obtained in the previous step is dissolved in water and then passed through an activated anion exchange resin for ion exchange reaction. After obtaining an aqueous solution of ionic liquid ammonium hydroxide, it is mixed with 3,7-dichloroquinoline-8-carboxylic acid for acid-base neutralization reaction, and after drying, quinoline carboxylic acid ionic liquid is obtained; Or After mixing 3,7-dichloroquinoline-8-carboxylic acid with an alkaline substance to form a salt solution, it is placed in a separatory funnel with the bromoionic liquid ammonium salt obtained in the previous step, extracted with an organic solvent, the organic phase is taken, rotary evaporated and dried to obtain quinoline carboxylic acid ionic liquid; 3) Preparation of W / O type primary emulsion: The oil phase containing quinoline carboxylic acid ionic liquid and the internal aqueous phase are heated to the same temperature, and under stirring, the internal aqueous phase is added to the oil phase containing the ionic liquid to obtain a W / O type primary emulsion; 4) Preparation of W / O / W type multiple emulsion: The external aqueous phase containing a complex emulsifier is heated, and the W / O type primary emulsion obtained in the previous step is added to the external aqueous phase to obtain a W / O / W type multiple emulsion; In step 1), the monobromoalkane is any one of 1-bromododecane, 1-bromotetradecane, 1-bromohexadecane, 1-bromooctadecane; the molar ratio of triethylamine to monobromoalkane is 1.2-2:1; the solvent used is one or more of distilled water, methanol, acetonitrile, acetone; the temperature of the heating reflux reaction is 60-90 °C, and the reaction time is 48-72 hours.

2. The preparation method of the quinoline carboxylic acid-based ionic liquid W / O / W multiple emulsion according to claim 1, characterized in that, The bromoionic liquid ammonium salt prepared in step 1) 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, N,N,N-(triethyl)-N-octadecylammonium bromide.

3. The preparation method of the quinoline carboxylic acid ionic liquid W / O / W multiple emulsion according to claim 1, characterized in that, In step 2), when preparing quinoline carboxylic acid ionic liquid by acid-base neutralization reaction, the molar ratio of ionic liquid ammonium hydroxide to 3,7-dichloroquinoline-8-carboxylic acid is 1:1-1.2, the reaction temperature is 25-45 °C, and the reaction time is 12-24 hours; the alkaline substance is one or more of potassium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide.

4. The preparation method of the quinoline carboxylic acid ionic liquid W / O / W multiple emulsion according to claim 1, characterized in that, In step 2), when preparing ionic liquid ammonium hydroxide by ion exchange reaction, the concentration of the bromoionic liquid ammonium salt aqueous solution is 0.6-1 mol / L; the ionic liquid ammonium hydroxide in step 2) is any one of N,N,N-(triethyl)-N-dodecylammonium hydroxide, N,N,N-(triethyl)-N-tetradecylammonium hydroxide, N,N,N-(triethyl)-N-hexadecylammonium hydroxide, N,N,N-(triethyl)-N-octadecylammonium hydroxide.

5. The preparation method of the quinoline carboxylic acid ionic liquid W / O / W multiple emulsion according to claim 1, characterized in that, The oil phase described in step 3) is one or more of camellia oil, liquid paraffin, and glycerol; the emulsifiers used in step 4) are one or more of gum arabic, gelatin, span 80, tween 80, poloxamer 188, and apricot gum; the W / O / W double emulsion prepared in step 4) is composed of a quinoline carboxylic acid ionic liquid, an oil phase, an emulsifier, and water, and the mass fractions of the quinoline carboxylic acid ionic liquid, the oil phase, and water are 10-15%, 20-25%, and 50-60% respectively.

6. Quinoline carboxylic acid-based ionic liquid W / O / W multiple emulsion, characterized in that, It is prepared by the preparation method of the quinoline carboxylic acid ionic liquid W / O / W double emulsion according to any one of claims 1-5, and the structural formula of the quinoline carboxylic acid ionic liquid is shown in (I): In the formula, the cation is a quaternary ammonium cation, wherein R1, R2, R3, and R4 are alkyl groups containing 1-18 carbons.

7. The quinoline carboxylic acid-based ionic liquid W / O / W multiple emulsion according to claim 6, characterized in that, The quaternary ammonium cation is selected from any one of N,N,N-(triethyl)-N-dodecylammonium, N,N,N-(triethyl)-N-tetradecylammonium, N,N,N-(triethyl)-N-hexadecylammonium, and N,N,N-(triethyl)-N-octadecylammonium.

8. The preparation method of the quinoline carboxylic acid-based ionic liquid W / O / W multiple emulsion according to claim 1, characterized in that, The quinoline carboxylic acid ionic liquid is N,N,N-(triethyl)-N-dodecylammonium-(3,7-dichloroquinoline-8-carboxylate), N,N,N-(triethyl)-N-tetradecylammonium-(3,7-dichloroquinoline-8-carboxylate), N,N,N-(triethyl)-N-hexadecylammonium-(3,7-dichloroquinoline-8-carboxylate), or N,N,N-(triethyl)-N-octadecylammonium-(3,7-dichloroquinoline-8-carboxylate).

9. Use of the quinoline carboxylic acid-based ionic liquid W / O / W multiple emulsion according to claim 7 in the field of plant protection, characterized in that, This quinoline carboxylic acid ionic liquid W / O / W double emulsion can improve the herbicidal activity compared with the commercially available dichloroquinoline carboxylic acid herbicide, and reduce the dosage of pesticides under the same herbicidal effect.

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