2-chloro-4-nitrophenol soluble liquid, its preparation method and application

Abstract

The application provides a 2-chloro-4-nitrophenol soluble liquid agent, which comprises the following raw materials in percentage by mass: 2-chloro-4-nitrophenol 10-20%, solvent 70-90%, emulsifier 1-15%, and cosolvent 2-10%. Based on the same inventive concept, the application further provides a preparation method of the 2-chloro-4-nitrophenol soluble liquid agent. Based on the same inventive concept, the application further provides an application of the 2-chloro-4-nitrophenol soluble liquid agent, and the weeds applied include: amaranthus retroflexus, gypsophila oldhamii, chenopodium album, erigeron bonariensis, brome, and littleseed canarygrass. The soluble liquid agent has the advantages of easy processing, easy dilution, safe and convenient use, good biological effect and the like, and the prevention effect is significantly better than that of a commercial herbicide 10% glufosinate ammonium water agent.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of plant protection, and particularly relates to a 2-chloro-4-nitrophenol soluble liquid agent and a preparation method and application thereof. BACKGROUND

[0002] The structure of 2-chloro-4-nitrophenol is as follows:

[0003]

[0004] Chinese name: 2-chloro-4-nitrophenol, English name: 2-Chloro-4-nitrophenol (referred to as "2C4NP" in the application), CAS number: 619-08-9, molecular formula: C6H4ClNO3, molecular weight: 173.55 g / mol. Light yellow needle-like crystals, soluble in diethyl ether, ethanol, chloroform, slightly soluble in water. Based on the weed control effect of 2C4NP found by the inventors, as well as the low toxicity risk and environmental pollution risk, 2C4NP has great potential for herbicide development.

[0005] At present, there is no 2C4NP preparation. Based on the analysis of the physical and chemical properties of 2C4NP, the inventors tried to process 2C4NP into a solid preparation, but 2C4NP has certain irritation to the respiratory tract and eyes when processed into a solid preparation. 2C4NP is slightly soluble in water, and cannot be processed into an aqueous agent. Even if it is processed into a suspension agent, a large amount of emulsifier needs to be added, and the product form and use state are both suspensions. When processed into an emulsion, although the product form is a solution, its use form is still a milky suspension, which has poor dispersibility and poor efficacy.

[0006] The difficulty in preparing the 2C4NP preparation lies in finding an ideal solvent that can have high solubility of 2C4NP, and still maintain good solubility when diluted with water. However, in reality, it is almost impossible to find a solvent that can achieve the above ideal product state. Therefore, the mutual solubility of water and the solvent will affect the solubility of 2C4NP in the solvent. If a cosolvent is introduced, it may change the form of 2C4NP, thereby reducing the activity.

[0007] Therefore, the prior art needs to be solved. SUMMARY

[0008] The present application aims at the deficiencies of the prior art, and provides a 2-chloro-4-nitrophenol soluble liquid agent, a preparation method and application thereof. The 2-chloro-4-nitrophenol used in the present application is a compound with strong herbicidal activity screened from 34 eugenol structural derivatives by the inventor, and the inventor has applied for a patent with the patent application number 202211319640.X and the patent name of a herbicide and application of 2-chloro-4-nitrophenol as an active ingredient of the herbicide. The present application provides a 2-chloro-4-nitrophenol soluble liquid agent (hereinafter referred to as "SL" for short), which is a uniform and transparent liquid preparation. After dilution with water, a true solution is formed, the drug is dispersed in the medium in the form of molecules or ions, the dispersion degree is high, and the drug effect is good. The soluble liquid agent provided by the present application mainly consists of three basic components of the effective component 2-chloro-4-nitrophenol, the polar organic solvent miscible with water and the adjuvant, and has the advantages of easy processing, easy dilution, safe and convenient use and good biological effect.

[0009] The technical scheme of the present application is as follows:

[0010] A 2-chloro-4-nitrophenol soluble liquid agent, by mass percentage, comprises the following raw materials: 2-chloro-4-nitrophenol 10-20%, solvent 70-90%, emulsifier 1-15%, and cosolvent 2-10%. Preferably, a 2-chloro-4-nitrophenol soluble liquid agent, by mass percentage, comprises the following raw materials: 2-chloro-4-nitrophenol 10-20%, solvent 70-90%, emulsifier 3-15%, and cosolvent 5%. More preferably, a 2-chloro-4-nitrophenol soluble liquid agent, by mass percentage, comprises the following raw materials: 2-chloro-4-nitrophenol 12%, solvent 80%, emulsifier 3%, and cosolvent 5%. Under the above conditions, the 2C4NP decomposition rate is 2.9% after storage at 54±2℃ for 14d, which is less than 5%, and the heat storage stability is good.

[0011] The 2-chloro-4-nitrophenol soluble liquid agent as described above, wherein the solvent is any one of N-methylpyrrolidone, N,N-dimethylformamide, dimethyl sulfoxide, methanol, and ethanol. Preferably, the solvent is any one of N-methylpyrrolidone, N,N-dimethylformamide, and methanol, and more preferably, the solvent is N-methylpyrrolidone, under which conditions, the solubility is good and the low-temperature stability is good.

[0012] The 2-chloro-4-nitrophenol soluble liquid formulation described above, wherein the emulsifier is any one of HEL-40, BY-125, MOA-15, agricultural emulsion 500, agricultural emulsion 600-1, Tween 80, MOA-5, MOA-7, EL-30, O-10, and PEG-600. Preferably, the emulsifier is any one of HEL-40, BY-125, agricultural emulsion 600-1, MOA-7, EL-30, and PEG-600. Under these conditions, the formulation is uniform and transparent, and exhibits good low-temperature stability. More preferably, the emulsifier is MOA-7. Under these conditions, after the introduction of triethylamine into the formulation, it is clearer and more uniformly stable compared to other emulsifiers.

[0013] In the 2-chloro-4-nitrophenol soluble liquid formulation described above, the co-solvent is any one of triethylamine, methanol, glacial acetic acid, phenol, and DMSO. Preferably, the co-solvent is triethylamine. Under this condition, the co-solvent improves the solubility of 2C4NP, thereby reducing the influence of 2C4NP on the solubility of the emulsifier in the solvent, and does not affect the original activity of 2C4NP.

[0014] Based on the same inventive concept, this invention provides a method for preparing the 2-chloro-4-nitrophenol soluble liquid as described above, comprising the following steps: (1) weighing an emulsifier; (2) adding a solvent to the emulsifier until the emulsifier dissolves automatically; (3) adding a co-solvent to the solution in step (2) until it dissolves automatically; (4) adding the active ingredient 2-chloro-4-nitrophenol, sonicating, and dissolving completely to obtain the 2-chloro-4-nitrophenol soluble liquid. Preferably, the sonication conditions are: 25 kHz sonication for 30-50 seconds. No foam is generated throughout the above preparation process, and no standing time is required. pH is not required and no adjustment is necessary.

[0015] Based on the same inventive concept, this invention also provides the application of 2-chloro-4-nitrophenol soluble liquid in herbicides, applicable to weeds including: amaranth, wild peach grass, lambsquarters, annual elm, brome, and tuft of grass.

[0016] The beneficial effects of this invention are:

[0017] 1. The present invention provides a 2-chloro-4-nitrophenol soluble liquid preparation. By screening suitable solvents, especially suitable co-solvents, it can achieve both high solubility for the active ingredient and good solubility when diluted with water. This allows the active ingredient 2C4NP to be in molecular or ionic form during use, with high dispersibility and good efficacy. In addition, the solvent can effectively shield its irritant properties, ensuring the safety of the preparation.

[0018] 2. The 2-chloro-4-nitrophenol soluble liquid provided by this invention uses triethylamine as a cosolvent, which has a much higher solubilizing effect than methanol, phenol, glacial acetic acid and DMSO, which are commonly used cosolvents in liquid preparations. This not only improves the solubility of the active ingredient, but also reduces the amount of emulsifier used, without affecting the activity of the active ingredient.

[0019] 3. The soluble liquid containing 12% 2-chloro-4-nitrophenol provided by this invention was tested in pots and fields. The results showed that its efficacy was significantly better than that of the commercial herbicide 10% glufosinate aqueous solution.

[0020] 4. The 2-chloro-4-nitrophenol soluble liquid provided by this invention has good herbicidal activity against a variety of weeds such as amaranth, wild peach grass, lambsquarters, annual elm, wild oats, and tufts of grass.

[0021] 5. The preparation method of the 2-chloro-4-nitrophenol soluble liquid provided by the present invention is easy to process, and the prepared soluble liquid is easy to dilute and safe and convenient to use. Attached Figure Description

[0022] Figure 1 The effect of triethylamine on the embryo elongation of reverse-branch amaranth (5 mg / L) is shown in the figure.

[0023] Figure 2 The chromatogram of 2C4NP high-performance liquid chromatography;

[0024] Figure 3 The standard curve is 2C4NP;

[0025] Figure 4 The control efficacy of 12% 2C4NP SL and 10% glufosinate AS on potted amaranth vine 1 day after application (500 mg / L);

[0026] Figure 5 The control efficacy of 12% 2C4NP SL and 10% glufosinate AS on potted Erigeron annuus 'Atropurpurea' 1 day after application (500 mg / L);

[0027] Figure 6 The control effect of 12% 2C4NP SL and 10% glufosinate AS on potted bromegrass 1 day after application (500 mg / L);

[0028] Figure 7 The control efficacy of 12% 2C4NP SL and 10% glufosinate AS on potted lambsquarters 1 day after application (500 mg / L);

[0029] Figure 8 The control efficacy of 12% 2C4NP SL and 10% glufosinate AS on potted *Prunus cerasifera* var. *mongolica* 1 day after application (500 mg / L);

[0030] Figure 9 The control efficacy of 12% 2C4NP SL and 10% glufosinate AS on potted Erigeron tigrinum var. mongolicum 1 day after application (500 mg / L);

[0031] Figure 10 The field control efficacy of 12% 2C4NP SL and 10% glufosinate AS against lambsquarters 1 day after application (1000 mg / L). Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0034] Example 1 Solvent Screening

[0035] The selection of solvents must take into account factors such as the solubility of the active ingredient and the environmental friendliness of the solvent. The solvents selected for preparing soluble liquids must not only have good solubility for the active ingredient in the formulation, but also good compatibility with other components of the formulation, without layering, precipitation, crystallization at low temperatures, or adverse chemical reactions with the original drug.

[0036] Add 0.3g of 2C4NP and 0.5mL of solvent to a test tube sequentially, shake at room temperature, and observe the dissolution. If it does not dissolve completely, continue adding 0.5mL of solvent to the test tube and observe the dissolution as before. If it still does not dissolve completely after adding 3mL of solvent, discard that solvent and select another solvent for further screening. If 2C4NP dissolves completely in the solvent, place it in a 0℃ refrigerator to test its low-temperature stability. After 12 hours, observe whether there is layering or precipitation. If there is no layering or precipitation, it is considered qualified. Finally, determine whether the solvent is qualified based on its solubility and cold storage stability.

[0037] The solubility of 2C4NP in eight different solvents was determined, and the results are shown in Table 1. 2C4NP showed the best solubility in four polar solvents: N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and methanol, but poor solubility in other solvents. DMSO was discarded because it freezes at low temperatures. According to HG / T 4576-2013, the use of DMF and methanol is restricted in China; therefore, NMP, with its better solubility, was chosen to reduce the use of these solvents.

[0038] Table 1. Solubility of 2C4NP in different solvents

[0039]

[0040]

[0041] Note: The more "+" signs, the better the solubility.

[0042] Example 2: Emulsifier Screening

[0043] 1. Initial screening of emulsifiers

[0044] Add 15% (0.45g) of emulsifier monomer and 10% (0.3g) of 2C4NP to the selected NMP, and make up to 3g of NMP to prepare the formulation. Observe the solubility and examine the formulation's appearance transparency, low-temperature stability (0±2℃, 24h), dilution stability (200-fold dilution), and water bath stability (32±2℃, 1h) to select the emulsifier.

[0045] The preliminary screening results of emulsifiers are shown in Table 2. BY-125, Agricultural Emulsion 600-1, MOA-7, EL-30, HEL-40, and PEG-600 were relatively good, but still did not fully meet the quality standards, and all of them had trace amounts of oily droplets precipitated.

[0046] Table 2. Initial screening results of emulsifiers

[0047]

[0048]

[0049] Note: "-" indicates that this experiment was not performed.

[0050] 2. Evaluation of the effect of triethylamine as a cosolvent on emulsifiers

[0051] The emulsifiers obtained from the initial screening did not fully meet the quality requirements. Therefore, the co-solvent triethylamine was introduced, and the formulation was adjusted to: 10% 2C4NP (0.3g), 15% emulsifier (0.45g), 5% triethylamine (0.15g), and NMP to make up to 3g (by mass percentage). After the introduction of triethylamine, the six emulsifier monomers that were relatively good but not completely substandard in the initial screening could all make the formulated products meet the standards, as shown in Table 3.

[0052] Table 3. Effects of triethylamine on the performance of soluble liquid formulations prepared with six emulsifiers.

[0053]

[0054] 3. Effect of the cosolvent triethylamine on the activity of 2C4NP

[0055] Using seeds of Amaranthus retroflexus as the test subject, the study determined whether the addition of triethylamine to the formulation affected the 2C4NP activity.

[0056] Select plump seeds of *Amaranthus retroflexus* and place them in a petri dish. Add water to two-thirds of the seed volume and incubate in a 40℃ dark incubator for approximately 12 hours. Remove the dish and maintain humidity by adding water. Select 10 seeds of uniform size and with evenly emerging white kernels for testing. Weigh 10 mg of 2C4NP, dissolve it in 200 μL of NMP, and then dilute it to a concentration of 5 mg / L with 0.1% Tween 80 aqueous solution. A blank control group without 2C4NP was also included. Add 2 mL of the drug solution to each petri dish, with each dish constituting a replicate, and each treatment repeated three times. Cover the petri dishes with a damp towel for humidity control and incubate in the dark at 28℃ for 3 days. Measure the embryo length and calculate the growth inhibition rate. Growth inhibition rate (%) = [Control embryo length - Treatment embryo length] / Control embryo length × 100%.

[0057] Depend on Figure 1 As can be seen from left to right, the treatment groups are: control group without 2C4NP: 100 μL NMP; treatment group with 2C4NP but without triethylamine: 5 mg 2C4NP + 100 μL NMP; control group without 2C4NP but with triethylamine: 93 μL NMP + 7 μL triethylamine; and treatment group with both 2C4NP and triethylamine: 5 mg 2C4NP + 93 μL NMP + 7 μL triethylamine.

[0058] Each of the above treatment groups was diluted with 100 mL of 0.1% Tween 80 aqueous solution, and then 1 mL of the diluted solution was added to 9 mL of 0.1% Tween 80 aqueous solution to prepare a concentration of 5 mg / L.

[0059] Using *Amaranthus retroflexus* as the tested weed, the introduction of triethylamine at a concentration of 5 mg / L did not affect the original activity of the 2C4NP. The inhibition rates with and without triethylamine were 51.8% and 53.1%, respectively (p = 0.713, > 0.05), indicating no significant difference. Therefore, 5% by mass of triethylamine was added to the formulation as a co-solvent.

[0060] 4. Emulsifier re-screening

[0061] With the introduction of triethylamine, six emulsifier monomers are available. To select the optimal emulsifier, the formulation was adjusted, reducing the emulsifier content and increasing the 2C4NP content. The formulation is as follows: by mass percentage, 20% 2C4NP (0.6g), 3% emulsifier (0.09g), 5% triethylamine (0.15g), and NMP to make up to 3g. Based on the initial screening method for emulsifiers, the optimal emulsifier for the preparation of soluble liquids was finally determined.

[0062] After introducing 5% triethylamine into the formulation, the 2C4NP content was increased from 10% to 20%, and the emulsifier content was decreased from 10% to 3%. Six emulsifiers were then screened, and the results are shown in Table 4. From the four quality indicators of the formulation, it can be seen that MOA-7 is better than the other emulsifiers, with only a trace amount of oily droplets precipitating in the diluted solution. Therefore, MOA-7 was chosen as the emulsifier for the formulation of 2C4NP soluble liquids.

[0063] Table 4. Results of the secondary screening of emulsifiers

[0064]

[0065] Example 3: Determination of the content of emulsifier MOA-7

[0066] Five test tubes were prepared, each containing 20% ​​(w / w) 2C4NP (0.6 g) and 5% (w / w) triethylamine (0.15 g). 0.09, 0.18, 0.27, 0.36, and 0.45 g of emulsifier were added to the test tubes, respectively. NMP was then added to make up to 3 g, resulting in formulations containing 3%, 6%, 9%, 12%, and 15% emulsifier by mass. The emulsifier content was determined by evaluating the formulations according to the initial screening criteria for emulsifiers.

[0067] Five MOA-7 mass percentage contents were set, and the following SL formulation was prepared: MOA-7, 20% 2C4NP, 5% triethylamine, and NMP to make up to 3g. The quality test results are shown in Table 5. When the 2C4NP content was 20%, the appearance of both the formulation and the diluent deteriorated with increasing MOA-7 emulsifier content, indicating that a high 20% 2C4NP content led to a decrease in solubility. However, under this condition, the formulation containing 3% MOA-7 had relatively good quality, with only trace precipitation. Therefore, the MOA-7 content in the 2C4NP SL was determined to be 3%.

[0068] Table 5. Effect of MOA-7 emulsifier content on the quality of 2C4NP SL

[0069]

[0070] Example 4: Determination of the content of the active ingredient 2C4NP

[0071] Take 5 test tubes and add 0.09 g of MOA-7 (3% by mass) and 0.15 g of triethylamine (5% by mass) obtained from screening to the test tubes. Add 0.3, 0.36, 0.42, 0.48, 0.54 and 0.6 g of 2C4NP respectively, and make up to 3 g with NMP to prepare formulations with 10%, 12%, 14%, 16%, 18% and 20% 2C4NP by mass. Evaluate the solubility of 2C4NP in the solvent and select the optimal 2C4NP content.

[0072] Based on MOA-7 with a mass percentage of 3%, five different 2C4NP mass percentage contents were set to examine the SL (Supplementary Liquid) quality. Table 6 shows that when the 2C4NP content was between 14% and 20%, a small amount of precipitation appeared in the formulation; when the content was between 16% and 20%, oily droplets precipitated in the diluent; and the content was between 10% and 12%, meeting the standard. Considering cost and efficacy, the 2C4NP content was determined to be 12%.

[0073] Table 6. Effect of 2C4NP content on SL performance

[0074]

[0075]

[0076] Example 5: Establishment of a method for the analysis of 2C4NP soluble liquid (SL) content.

[0077] 1. 2C4NP content analysis method

[0078] The content of 2C4NP standard was determined by HPLC. The HPLC column was a Shimadzu C-18 (4.65 × 250 mm); the column temperature was 30℃; and the flow rate was 1 mL / min. -1 The injection volume was 10 μL; the mobile phase was methanol: 0.1% formic acid water (volume fraction 70:30); and the detection wavelength was 321 nm. Under these conditions, the retention time of 2C4NP was 6.441 min.

[0079] The 2C4NP standard was tested according to the above method, and the liquid chromatogram is shown below. Figure 2 The retention time of 2C4NP was 6.441 min.

[0080] 2. Establishment of the 2C4NP standard curve

[0081] Accurately weigh 5 mg of 2C4NP standard, dissolve it in 10 mL of chromatographically pure methanol to prepare a 500 mg / L stock solution, and then serially dilute it to prepare standard solutions with concentrations of 5, 10, 20, 40, 80, and 160 mg / L. Determine the concentration of each standard solution using HPLC according to the aforementioned content analysis method. Perform linear regression with 2C4NP mass concentration (mg / L) on the x-axis and peak area on the y-axis to obtain the regression equation and correlation coefficient.

[0082] Curve fitting was performed between the concentration of the standard and its corresponding chromatographic peak area. The results are shown in [Figure Number]. Figure 3 The fitted equation is y = 35074x - 8802, corresponding to a correlation coefficient (R²). 2 The value of 0.9999 indicates that 2C4NP exhibits good linearity in the concentration range of 5-160 mg / L, which meets the requirements for quantitative analysis in this experiment.

[0083] 3. Precision determination of HPLC analysis method

[0084] Accurately weigh 0.1 g of 12% 2C4NP sample, dilute to 40 mg / L with chromatographic methanol, and perform 5 parallel determinations of the 2C4NP content in the sample. Calculate the standard deviation and coefficient of variation of the content. The coefficient of variation should be less than 10%.

[0085] Standard deviation (SD) = (Predicted value - Measured value) / Predicted value × 100%

[0086] Coefficient of variation (CV) = (Standard deviation / Mean) × 100%

[0087] Five parallel determinations were performed on a 12% 2C4NP soluble liquid sample, and the results are shown in Table 7. The standard deviation of the 2C4NP content was 0.4330, and the coefficient of variation was 1.03, indicating that the selected method has high repeatability and good precision.

[0088] Table 7 Precision of HPLC method for the content of 12% 2C4NP SL

[0089]

[0090] 4. Accuracy determination of HPLC analytical method

[0091] Spike recovery: Accurately weigh 0.1 g of 12% (2C4NP)SL (containing 0.012 g of the test sample), dilute it to 40 mg / L with chromatographic methanol, add 40, 60, and 80 mg / L of standards (the spiked amount is generally 0.5-2.0 times the content of the analyte), and determine the spike recovery under chromatographic conditions. Each group is repeated 3 times, and the unspecified test sample is also measured simultaneously. According to the Chinese Pharmacopoeia (2020), the spike recovery should be between 80-120%.

[0092] Spiked recovery rate = (Spiked sample value - Sample value) / Spiked amount × 100%

[0093] In a 12% 2C4NP soluble liquid sample, a certain amount of standard was added to prepare three samples with known content. The results are shown in Table 8. With the addition of 40, 60 and 80 mg / L of standard, the recovery rate of 2C4NP was between 94.90% and 103.34%, 94.19% and 104.19% and 97.91% and 101.69%, respectively, all within the range of 80% to 120%, indicating that this method is accurate and reliable.

[0094] Table 8. Recovery rates of 12% 2C4NP SL content in HPLC analysis

[0095]

[0096] Example 6: Quality Inspection of 12% 2C4NP SL

[0097] 1. Appearance of the formulation

[0098] The formulation is required to be a homogeneous, stable, and transparent liquid.

[0099] 2. Thermal storage stability test

[0100] Refer to GB / T 19136-2003. Inject 10 mL of the sample into a 20 mL ampoule using a syringe, seal the ampoule with a high-temperature flame (to prevent solvent evaporation), and place it in a water bath at 54±2℃. After 14 days, remove the ampoule and test the content of the active ingredient within 24 hours. The thermal decomposition rate should be less than 5%.

[0101] Thermal decomposition rate = (Content before heat storage - Content after heat storage) / Content before heat storage × 100%

[0102] 3. Cold storage stability test

[0103] Refer to GB / T 19137-2003. Place the sample at 0±2℃ for 7 days. After 7 days, take it out and let it stand at room temperature (20℃) for 3 hours. The sample is qualified if it is uniform without precipitation or layering, or if there is a small amount of precipitation at first but it disappears on its own after returning to room temperature.

[0104] 4. Stability test of diluent

[0105] Refer to GB 28141-2011. Weigh 0.5g of the sample and place it in a 150mL Erlenmeyer flask. Add 99.5g of standard hard water to dilute it. Place the flask in a constant temperature water bath at 30±2℃ and let it stand for 1 hour. The solution is qualified if it is clear and uniform and there is no precipitate.

[0106] For the preparation of hard water, refer to GB / T 1603-2001. Weigh 0.304 g of anhydrous calcium chloride and 0.139 g of magnesium chloride hexahydrate into a 1000 mL volumetric flask, and dilute to the mark with distilled water.

[0107] The performance indicators of 12% 2C4NP SL were tested according to the above requirements, and all met the relevant national quality standards. After storage at 54±2℃ for 14 days, the decomposition rate of 2C4NP was 2.9%, less than 5%, indicating thermal stability. The test results for other quality indicators are shown in Table 9.

[0108] Table 9 Performance Indicators of 12% 2C4NP SL

[0109]

[0110] Through screening and evaluation of solvents, emulsifiers, cosolvents, and the content of 2C4NP, the 12% 2C4NP SL formulation was finally determined, as shown in Table 10. By mass percentage, it consists of 12% 2C4NP2, 80% NMP, 3% MOA-7, and 5% triethylamine.

[0111] The preparation steps are as follows: (1) Weigh the emulsifier MOA-7; (2) Add the solvent NMP to MOA-7, and MOA-7 will dissolve automatically; (3) Add the co-solvent triethylamine to the above solution, and it will dissolve automatically; (4) Add the active ingredient 2C4NP, and sonicate at 25K Hz for 50s until completely dissolved. No foam is generated during the entire preparation process, and no standing time is required. There are no pH requirements, and no adjustment is needed.

[0112] Table 10 Composition of 12% 2C4NP SL

[0113]

[0114] Example 7: Evaluation of the efficacy of 12% 2C4NP SL in controlling weeds

[0115] 1. Pot experiment

[0116] Potted amaranth, wild peach grass, lambsquarters, annual elm, wild oats, and small tufts of grass were used as test weeds. 10% glufosinate AS was used as the control, and water was used as the blank control. Foliar spraying was performed using a spray bottle to evaluate the weed control effect of 12% 2C4NP SL. In this example, glufosinate AS was purchased from Shandong Binnong Technology Co., Ltd.

[0117] 12% 2C4NP SL and 10% glufosinate AS were each prepared into 500 mg / L solutions with water and sprayed evenly onto weed plants. One day after application, the toxic symptoms were observed, and the control efficacy on the fresh weight of the above-ground parts of the weeds was calculated. One day after applying 2C4NP SL, most plant leaves rapidly lost water and withered, while the leaves of plants treated with glufosinate showed almost no change within one day. Figures 4-9 As shown.

[0118] Table 11 shows the control efficacy of 2C4NP SL and glufosinate AS on the aboveground parts of weeds 1 day after application. 12% 2C4NP SL showed the best inhibition of fresh weight of the aboveground parts of *Prunus cerasifera*, with a control efficacy of 69.7%, while 10% glufosinate AS only showed a control efficacy of 26.0%, a significant difference. Whether considering toxic symptoms or the control effect on aboveground fresh weight, 12% 2C4NP SL was significantly superior to glufosinate AS in controlling all six tested weeds.

[0119] Table 11. Efficacy evaluation of 12% 2C4NP SL and 10% glufosinate AS

[0120]

[0121] Note: * indicates that there is a significant difference in the t-test between the two herbicides in controlling the same weed (p<0.05).

[0122] 2. Field trials

[0123] To more objectively evaluate the herbicidal effect of 12% 2C4NP SL, a field efficacy test was conducted on the weed *Chenopodium album*. 10% glufosinate-ammonium AS was used as a control, with a water control also included. Both 12% 2C4NP SL and 10% glufosinate-ammonium AS were diluted to 1000 mg / L with water and sprayed using a Qingfeng brand 3WD-20 backpack electric sprayer (single nozzle, 1.2 mm nozzle diameter) at a working pressure of 0.2-0.4 MPa and a flow rate of 0.5 L / min, ensuring the solution was evenly applied to the leaves of *Chenopodium album*. One day after spraying, the toxic response of the weeds to the herbicides was observed, and the control efficacy was calculated based on the fresh weight of the above-ground portion of the weeds, comparing the differences in control efficacy between the two methods.

[0124] One day after spraying 1000 mg / L 12% 2C4NP SL and 10% glufosinate AS, the control effect on lambsquarters in the field was shown in the figure. Figure 10 Most lambsquarters leaves rapidly lost water, wilted, and curled within 1 day of application of 2C4NP, while the leaves of weeds treated with glufosinate showed almost no significant changes within 1 day. Further comparison with a water treatment control showed that 12% 2C4NP SL achieved a control efficacy of 51.9% ± 5.4% on the aboveground fresh weight of lambsquarters. Both in terms of weed toxicity symptoms and control efficacy on aboveground fresh weight, 2C4NP SL was significantly superior to 10% glufosinate AS.

[0125] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A 2-chloro-4-nitrophenol soluble liquid, characterized in that, The product comprises, by weight percentage, the following raw materials: 10-20% 2-chloro-4-nitrophenol, 70-90% solvent, 1-15% emulsifier, and 2-10% co-solvent; wherein the co-solvent is triethylamine; the solvent is N-methylpyrrolidone; and the emulsifier is any one of HEL-40, BY-125, agricultural emulsion 600-1, MOA-7, EL-30, and PEG-600.

2. The 2-chloro-4-nitrophenol soluble liquid according to claim 1, characterized in that, By mass percentage, it includes the following raw materials: 10-20% 2-chloro-4-nitrophenol, 70-90% solvent, 3-15% emulsifier, and 5% cosolvent.

3. A method for preparing the 2-chloro-4-nitrophenol soluble liquid as described in claim 1, characterized in that, Includes the following steps: (1) Weigh the emulsifier; (2) Add solvent to the emulsifier until the emulsifier dissolves automatically; (3) Add cosolvent to the solution in step (2) and it dissolves automatically; (4) Add the active ingredient 2-chloro-4-nitrophenol, sonicate, and dissolve completely to obtain 2-chloro-4-nitrophenol soluble liquid.

4. The method for preparing the 2-chloro-4-nitrophenol soluble liquid according to claim 3, characterized in that, The ultrasound conditions are: 25 kHz ultrasound for 30–50 s.

5. The application of a 2-chloro-4-nitrophenol soluble liquid according to any one of claims 1 to 2, or a 2-chloro-4-nitrophenol soluble liquid prepared by the preparation method according to any one of claims 3 to 4, in herbicides, characterized in that, The weeds used include: Amaranthus retroflexus, Prunus cerasifera var. chinensis, Lamb's quarters, Erigeron annuus, Bromus esculenta, and Erigeron simonii.

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