Sulfentrazone crystal form, preparation method and application thereof

Abstract

The application discloses a method for purifying 2',4'-dichloro-5'-(4-difluoromethyl-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl)methyl sulfonaniline (i.e. a crystal form of mesosulfuron) and a new crystal form obtained by the method; the method for purifying mesosulfuron crystal form of the application adopts an ester organic solvent to treat a product wet material obtained by the prior art, then the obtained product is subjected to stage heating and cooling operation, and the target crystal form is obtained by crystallization. The crystal form obtained by the application has low toluene residue, high purity, simple process, low cost and is particularly suitable for subsequent preparation processing.

Description

Technical Field

[0001] This invention belongs to the field of pesticide technology, specifically relating to a metsulfuron-methyl crystal form, preparation method and application. Background Technology

[0002] Methionyl sulfonamide (common English name: Sulfentrazone, CAS No. 122836-35-5) generally refers to methyl sulfonyl methyl sulfonamide or sulfonyl sulfadiazine, a triazoline herbicide developed by FMC Corporation in the United States. It belongs to the protoporphyrinogen oxidase inhibitor class and works by inducing the accumulation of protoporphyrin, thereby enhancing cell membrane lipid peroxidation, inhibiting plant photosynthesis, and causing rapid leaf drying and death. Methionyl sulfonamide can be used to control annual broadleaf weeds, some grass weeds, and sedges on crops such as soybeans, sugarcane, and tobacco. It is characterized by high efficiency, low toxicity, and broad spectrum. Its structural formula is as follows:

[0003]

[0004] US Patent 4818275 (publication date 1989-04-14) discloses N-[2,4-dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]phenyl]methanesulfonamide as a herbicide and its preparation method. In US Patent 4818275, the corresponding aryl amine is first reacted with methanesulfonyl chloride and excess triethylamine in dichloromethane, and then the resulting di(methanesulfonyl)amine intermediate is treated with sodium hydroxide to prepare the N-[2,4-dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]phenyl]methanesulfonamide; US Patent 5990315 discloses the direct sulfonation reaction of aryl amines with methanesulfonyl chloride catalyzed by soluble salts such as quaternary ammonium salts and quaternary phosphate salts; US Patent 7169952 reports the direct sulfonation reaction catalyzed by high-boiling-point amides such as DMF and tertiary amines, which solves the problem of direct sulfonation reaction by using inexpensive catalysts.

[0005] The existing synthesis process of mesotrione mainly follows the method in US7169952. However, the resulting product often inevitably suffers from solvent encapsulation, and the product purity does not meet the requirements. The residual mass fraction of toluene in the finished product is about 4-5%. This part of toluene not only affects the stability of mesotrione crystals, but also affects the stability and effectiveness of the formulation when it is formulated as mesotrione or compounded with other products. As a result, its biological effect as a herbicide is also greatly reduced.

[0006] Currently, most purification methods for mesotrione involve multiple recrystallizations using organic solvents. For example, methods according to CN109071463B or CN110099568B involve using polar protic solvents (C1-4 alcohols, water, or combinations thereof), heating the slurry containing mesotrione and organic solvents, and removing toluene through azeotropic distillation, followed by precipitation of mesotrione. Industrially, this purification method is complex, energy-intensive, and generates volatile gases that cause severe environmental pollution. Furthermore, there are incalculable losses during solvent recovery and product loss. The final product still contains some residual new solvent, affecting product stability and biological efficacy, resulting in high overall economic costs. Summary of the Invention

[0007] The main objective of this invention is to overcome the shortcomings of the prior art and provide a purification method for crude mesotrione suitable for industrial production, as well as the product obtained by the method.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for purifying mesotrione is provided, the method comprising the step of treating crude mesotrione with an ester-based organic solvent.

[0010] Furthermore, the present invention provides a method for purifying mesotrione, the method comprising:

[0011] (1) Mix the crude mesotrione product with an ester organic solvent, and then perform a pulping operation on the resulting mixture;

[0012] (2) After filtration, wet material is obtained. The wet material is dried to obtain purified mesotriamine product.

[0013] Furthermore, the present invention provides a method for purifying mesotrione, wherein the ester organic solvent is selected from alkyl esters of alkyl acids or alkyl carbonates, more preferably, the ester organic solvent is selected from one or more of methyl formate, ethyl formate, ethyl benzoate, methyl methacrylate, malonic acid ester, n-butyl acetate, methyl acetate, ethyl acetate, isobutyl acetate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, and ethylene carbonate.

[0014] Furthermore, the present invention provides a purification method for sulfadiazine, wherein the temperature of the pulping operation in step (1) is 10-30℃, preferably 10℃-30℃, the mass ratio of crude sulfadiazine to ester solvent is 1:1.0-5.0, preferably 1:1.5-2.5, and most preferably 1:2, the pulping operation time is not less than 1.5h, preferably 1.5-6h, and the stirring rate is 300-500r / min.

[0015] Furthermore, the present invention provides a purification method for mesotrione, wherein a staged heating method is used, preferably setting 2-5 stages from 30-90°C for thorough drying.

[0016] Furthermore, the present invention provides a purification method for mesotrione, wherein the method employs a staged heating approach, maintaining the temperature at 20-40°C for 30-90 min, at 40-60°C for 30-90 min, at 60-80°C for 30-90 min, and at 80-100°C for 30-90 min, to thoroughly dry the product and obtain mesotrione, which is then cooled to room temperature.

[0017] Furthermore, the present invention provides a method for purifying mesotrione, the method further comprising the step of applying the ester organic solvent.

[0018] Furthermore, the present invention provides a metolachlor crystal form, preferably prepared by the above method.

[0019] Furthermore, the present invention provides a metolachlor crystal form, which exhibits the following reflections as 2θ±0.2 degrees in an X-ray powder diffraction pattern recorded using Cu-Kα radiation at 25°C: 10.1493±0.2, 12.5321±0.2, 16.0380±0.2, 17.2356±0.2, 18.4007±0.2, 20.5405±0.2, 21.5974±0.2, 24.0798±0.2, 24.8666±0.2, 25.2625±0.2, 26.6192±0.2.

[0020] Furthermore, the present invention provides a metolachlor crystal form, which exhibits the following reflections as 2θ±0.2 degrees in an X-ray powder diffraction pattern recorded using Cu-Kα radiation at 25°C: 6.2437±0.2, 10.1493±0.2, 12.5321±0.2, 16.0380±0.2, 17.2356±0.2, 17.6402±0.2, 18.4007±0.2, 20.5405±0.2, 21.5974±0.2, 22.4979±0.2, 24.0798±0.2, 24.8666±0.2, 25.2625±0.2, 26.6192±0.2, 26.8073±0.2, 28.6997±0.2.

[0021] Furthermore, the present invention provides a metolachlor crystal form, which exhibits the following reflections as 2θ±0.2 degrees in an X-ray powder diffraction pattern recorded using Cu-Kα radiation at 25°C: 6.2437±0.2, 10.1493±0.2, 12.5321±0.2, 16.0380±0.2, 16.3504±0.2, 17.2356±0.2, 17.6402±0.2, 18.4007±0.2, 18.8647±0.2, 19. 2014, 20.5405±0.2, 21.5974±0.2, 22.4979±0.2, 23.3795±0.2, 23.5854, 24.0798±0.2, 24.8666±0.2, 25.2625±0.2, 26.6192±0.2, 26.8073±0.2, 28.6997±0.2, 30.8731±0.2, 31.1933±0.2, 33.8306±0.2, 37.1592±0.2.

[0022] Furthermore, the present invention provides a metolachlor crystal form, wherein the metolachlor crystal form exhibits the data shown in the table below in the X-ray powder diffraction pattern recorded using Cu-Kα radiation at 25°C, wherein the 2θ value has an error of ±0.2:

[0023]

[0024]

[0025]

[0026] Furthermore, the present invention provides a metolachlor crystal form, wherein the X-ray powder diffraction pattern of the metolachlor crystal form recorded using Cu-Kα radiation at 25°C has [specific characteristics]. Figure 1 The X-ray powder diffraction pattern shown.

[0027] Furthermore, the present invention provides a metolachlor crystal form, wherein the metolachlor crystal form has Figure 2 The FTIR spectrum shown is shown.

[0028] Furthermore, the present invention provides a composition comprising the above-mentioned metolachlor crystal form, wherein the preferred formulation of the composition is selected from suspension concentrate (SC) or water-dispersible granules (WG).

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The present invention performs purification under normal temperature and pressure conditions, which is simple and has low equipment requirements;

[0031] 2. The method of the present invention has low overall energy consumption, the purified mother liquor can be reused multiple times, produces less waste, and has low production cost;

[0032] 3. The present invention adopts a pulping operation and a staged heating method. The product obtained is subjected to a staged heating step and then cooled to room temperature to achieve crystal transformation and obtain a new crystal form of metolachlor.

[0033] 4. The residual toluene in the new crystal form of mesotriamine prepared by this invention is less than 0.1 wt%, the ester content is less than 0.1 wt%, and the crystal form of mesotriamine is stable after purification. Attached Figure Description

[0034] Figure 1 : Flow chart of the purification process of mesotrione in this invention.

[0035] Figure 2 X-ray powder diffraction pattern of mesotrione crystal form obtained in Example 1 of this invention.

[0036] Figure 3 The FTIR spectrum of the metolachlor crystal form obtained in Example 1 of this invention.

[0037] Figure 4 The DSC thermal stability test spectrum of the metolachlor crystal form obtained in Example 1 of this invention. Detailed Implementation

[0038] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0039] Example 1

[0040] 1.1 Mixing: Add 100g of wet metolachlor and 200g of methyl formate to a flask and mix thoroughly at room temperature. After mixing, continue stirring at room temperature at a speed of 300 rpm for 1.5 hours.

[0041] 1.2 Vacuum Filtration: The vacuum filtration flask is cooled using an ice bath to reduce solvent evaporation. After filtration, the mother liquor is retained for later reuse. 1.3 After filtration, the wet material is heated in stages: maintained at 20-40℃ for 30 min, 40-60℃ for 30 min, 60-80℃ for 30 min, and 80-100℃ for 30 min to thoroughly dry it, obtaining mesotrione. It is then cooled to room temperature; toluene 0.06%, methyl formate 0.02%, purity 98.9%, yield 82.4%.

[0042] Example 2

[0043] 2.1 Mixing: The methyl formate mother liquor obtained in step 1.1 of Example 1 was added to a flask, and new methyl formate was added to bring the total volume to 200g. 100g of wet metolachlor was added, and the mixture was stirred evenly at room temperature. After mixing, stirring was continued at room temperature at a speed of 400r / min for 2 hours.

[0044] 2.2 Vacuum Filtration: The vacuum filtration flask is cooled with an ice bath to reduce solvent evaporation. After vacuum filtration, the mother liquor is retained for later reuse.

[0045] 2.3 After filtration, the wet material was dried in stages: maintained at 20-40℃ for 40 min, 40-60℃ for 40 min, 60-80℃ for 40 min, and 80-100℃ for 40 min to obtain mesotrione. The material was then cooled to room temperature. The final product consisted of 0.05% toluene and 0.02% methyl formate, with a purity of 98.7% and a yield of 85.2%.

[0046] Example 3

[0047] 3.1 Mixing: The methyl formate mother liquor obtained in step 2.1 of Example 2 was added to a flask, and new methyl formate was added to bring the total volume to 200g. 100g of wet metolachlor was added, and the mixture was stirred evenly at room temperature. After mixing, stirring was continued at room temperature at a speed of 500r / min for 2.5 hours for pulping.

[0048] 3.2 Vacuum Filtration: The vacuum filtration flask is cooled using an ice bath to reduce solvent evaporation. After filtration, the mother liquor is retained for later reuse. 3.3 After filtration, the wet material is heated in stages: maintained at 20-40℃ for 50 min, 40-60℃ for 50 min, 60-80℃ for 50 min, and 80-100℃ for 50 min to thoroughly dry it and obtain mesotrione. It is then cooled to room temperature; toluene 0.06%, methyl formate 0.03%, purity 98.6%, yield 88.4%.

[0049] Example 4

[0050] 4.1 Mixing: Add 100g of wet metolachlor and 200g of ethyl acetate to a flask and mix thoroughly at room temperature. After mixing, continue stirring at room temperature at a speed of 400 rpm for 3 hours.

[0051] 4.2 Vacuum Filtration: The vacuum filtration flask is cooled using an ice bath to reduce solvent evaporation. After filtration, the mother liquor is retained for later reuse. 4.3 After filtration, the wet material is heated in stages: maintained at 20-40℃ for 60 min, 40-60℃ for 60 min, 60-80℃ for 60 min, and 80-100℃ for 60 min to thoroughly dry it and obtain mesotrione. It is then cooled to room temperature; toluene 0.04%, ethyl acetate 0.01%, purity 98.7%, yield 85.6%.

[0052] Example 5

[0053] 5.1 Mixing: The ethyl acetate mother liquor obtained in step 4.1 of Example 4 was added to the flask, and fresh ethyl acetate was added to bring the volume to 200g. 100g of wet metolachlor was added, and the mixture was stirred evenly at room temperature. After mixing, stirring was continued at room temperature at a speed of 400r / min for 4 hours.

[0054] 5.2 Vacuum Filtration: The vacuum filtration flask is cooled using an ice bath to reduce solvent evaporation. After filtration, the mother liquor is retained for later reuse. 5.3 After filtration, the wet material is heated in stages: maintained at 20-40℃ for 70 min, 40-60℃ for 70 min, 60-80℃ for 70 min, and 80-100℃ for 70 min to thoroughly dry it and obtain mesotrione. It is then cooled to room temperature; toluene 0.05%, ethyl acetate 0.01%, purity 98.6%, yield 88.8%.

[0055] Example 6

[0056] 6.1 Mixing: The ethyl acetate mother liquor obtained in step 5.1 of Example 5 was added to the flask, and fresh ethyl acetate was added to bring the volume to 200g. 100g of wet metolachlor was added, and the mixture was stirred evenly at room temperature. After mixing, stirring was continued at room temperature at a speed of 400r / min for 5 hours.

[0057] 6.2 Vacuum Filtration: The vacuum filtration flask is cooled using an ice bath to reduce solvent evaporation. After filtration, the mother liquor is retained for later reuse. 6.3 After filtration, the wet material is heated in stages: maintained at 20-40℃ for 80 min, 40-60℃ for 80 min, 60-80℃ for 80 min, and 80-100℃ for 80 min to thoroughly dry it and obtain mesotrione. It is then cooled to room temperature; toluene 0.04%, ethyl acetate 0.02%, purity 98.4%, yield 90.2%.

[0058] Example 7

[0059] 7.1 Mixing: Add 100g of wet metolachlor and 200g of ethyl formate to a flask and mix thoroughly at room temperature. After mixing, continue stirring at room temperature at a speed of 400 rpm for 6 hours.

[0060] 7.2 Vacuum Filtration: The vacuum filtration flask is cooled using an ice bath to reduce solvent evaporation. After filtration, the mother liquor is retained for later reuse. 7.3 After filtration, the wet material is heated in stages: maintained at 20-40℃ for 90 min, 40-60℃ for 90 min, 60-80℃ for 90 min, and 80-100℃ for 90 min to thoroughly dry it and obtain mesotrione. It is then cooled to room temperature; toluene 0.04%, ethyl formate 0.02%, purity 98.1%, yield 79.6%.

[0061] Test Example 1:

[0062] The mesotrione sample (i.e., mesotrione-1) prepared in Example 1 was subjected to XRD detection. Referring to the relevant content in Chapter 0451 of the Chinese Pharmacopoeia, the specific instruments and detection parameters are as follows:

[0063] Experimental Instruments: EMPYREAN X-ray diffractometer from Panaco GmbH, Netherlands. Experimental Method: Powder X-ray diffraction analysis of mesotrione-1 was performed using this diffractometer at 45 kV and 35 mA, collecting X-ray diffraction signals from 0° to 60°2θ.

[0064] Test Example 2:

[0065] Experimental Instruments: Bruker ALPHA II mid-infrared spectrometer. Experimental Method: 1.5g of the mesotrione sample prepared in Example 1 and approximately 150mg of potassium bromide sample were ground into a homogeneous powder in a mortar. The sample powder was placed in a tablet press mold, and a tablet was prepared using the tablet press. The tablet was then placed in the sample cell for measurement. The scanning wavenumber was 600cm⁻¹. -1 Up to 4000cm -1 .

[0066] The above operating parameters are typical. Depending on the characteristics of different instruments, the given operating parameters can be adjusted appropriately to obtain the best results.

[0067] Test Example 3:

[0068] The mesotrione sample prepared in Example 1 was subjected to DSC experiment;

[0069] DSC experimental method:

[0070] Refer to GB / T 22232-2008

[0071] Experimental apparatus: METTLER TOLEDO DSC

[0072] Test crucible: HP Gold Plated 25ul, withstands 15MPa pressure

[0073] Experimental conditions: temperature range of 25-500℃, heating rate of 4℃ / min;

[0074] The above operating parameters are typical. The given operating parameters can be adjusted appropriately according to the characteristics of different instruments in order to obtain the best results.

[0075] Test Example 4

[0076] Gas chromatography method: Detection of toluene / esters:

[0077] Experimental instruments: Agilent 7820A gas chromatograph system; Instrument temperature (°C): Column temperature: 40°C for 8 min, then increase to 280°C at 50°C / min and hold for 3 min; Vaporization chamber: 280°C; Detector: 280°C; Carrier gas (N2): 1.5 mL / min;

[0078] Hydrogen: 30 mL / min; Air: 300 mL / min; Weigh 0.05 g (accurate to 0.0001 g) of toluene / ester standard, place it in a 25 mL bottle, dissolve it with DMF, dilute to volume, and shake well. Weigh 1 g (accurate to 0.0001 g) of sample, place it in a 25 mL bottle, and use a 5 mL pipette to transfer the DMF solution and shake well.

[0079] Under the above operating conditions, after the instrument stabilizes: continuously inject several injections of standard solution until the peak area ratio of two adjacent injections is less than 1%.

[0080] Liquid chromatography detection: Laboratory instrument: Agilent Infinity II liquid chromatography system

[0081] Detection of mesotrione-1:

[0082] Mobile phase: Acetonitrile:water = 4:6, pH adjusted to 3.0 with phosphoric acid, filtered through a membrane and degassed; Flow rate: 1.0 mL / min; Column temperature: room temperature (temperature difference should not exceed 2℃); Detection wavelength: 230 mm; Injection volume: 2 μL; Weigh 0.05 g (accurate to 0.0001 g) of mesotrione standard, place it in a 50 mL volumetric flask, dissolve and dilute to the mark with acetonitrile, and mix well. Weigh 0.05 g (accurate to 0.0001 g) of mesotrione-1 sample, place it in a 50 mL volumetric flask, dissolve and dilute to the mark with acetonitrile, and mix well. Under the above operating conditions, after the instrument stabilizes, inject several injections of the standard solution continuously until the H60 peak area of ​​two adjacent injections is less than 1%.

[0083] The above operating parameters are typical. The given operating parameters can be adjusted appropriately according to the characteristics of different instruments in order to obtain the best results.

[0084] Application Example 1: Formulation Validation of Mesulfuron-1SC

[0085] The preparation method of the suspension containing mesotrione-1 (i.e., the mesotrione-1 prepared using the method of Example 1) includes the following steps:

[0086] 1. Mix water, dispersant, and defoamer evenly using high-speed shearing;

[0087] 2. Add the active ingredient mesotrione-1 and other herbicide products to step 1, and then mill the mixture using a sand mill until the particle size is below 5 μm.

[0088] 3. Add the thickener to the antifreeze and mix well. Then add the mixture to the liquid obtained from the above 2-stage milling process. Mix the mixture evenly by high-speed shearing to obtain the suspension product.

[0089] The specific formulation process is as follows:

[0090] Formulation 1: 15% Methionamide Suspension Concentrate

[0091] The composition includes 77.4% water, 3.0% dispersant (polyoxyethylene-polyoxypropylene ether block copolymer), 1.0% sodium methylnaphthalenesulfonate formaldehyde condensate, and defoamer C. 8-10 0.5% fatty alcohol is mixed evenly under high-speed shearing, then 13.9% mesotrione and 1.1% other herbicides are added. The mixture is then sand-milled until the product particle size is below 3μm. The mixture is then mixed evenly with 0.075% magnesium aluminum silicate, 0.025% polyvinylpyrrolidone, 1.5% glycerol and 1.5% ethylene glycol as antifreeze, and then added to the sand-milled liquid. The mixture is then mixed evenly under high-speed shearing to obtain 15% mesotrione suspension.

[0092] Formulation 2 30% Mesulfuron-methyl suspension

[0093] The composition includes 62.4% water, 3.0% dispersant (polyoxyethylene-polyoxypropylene ether block copolymer), 1.0% sodium methylnaphthalenesulfonate formaldehyde condensate, and defoamer C. 8-10 0.5% fatty alcohol is mixed evenly under high-speed shearing, then 27.3% mesotrione and 2.7% other herbicides are added. The mixture is then sand-milled until the product particle size is below 3μm. The mixture is then mixed evenly with 0.075% magnesium aluminum silicate, 0.025% polyvinylpyrrolidone, 1.5% glycerol and 1.5% ethylene glycol as antifreeze, and then added to the sand-milled liquid. The mixture is then mixed evenly under high-speed shearing to obtain 30% mesotrione suspension.

[0094] Formulation 3 45% Mesulfuron-methyl suspension

[0095] The composition includes 47.4% water, 3.0% dispersant (polyoxyethylene-polyoxypropylene ether block copolymer), 1.0% sodium methylnaphthalenesulfonate formaldehyde condensate, and defoamer C. 8-10 0.5% fatty alcohol is mixed evenly under high-speed shearing, then 39.8% mesotrione and 5.2% other herbicides are added. The mixture is then sand-milled until the product particle size is below 3μm. The mixture is then mixed evenly with 0.075% magnesium aluminum silicate, 0.025% polyvinylpyrrolidone, 1.5% glycerol and 1.5% ethylene glycol as antifreeze, and then added to the sand-milled liquid. The mixture is then mixed evenly under high-speed shearing to obtain 45% mesotrione suspension.

[0096] Formulation 4: 60% Mesulfuron-methyl suspension concentrate

[0097] The composition includes 33.9% water, 3.0% dispersant (polyoxyethylene-polyoxypropylene ether block copolymer), 1.0% sodium methylnaphthalenesulfonate formaldehyde condensate, and defoamer C. 8-10 0.5% fatty alcohol is mixed evenly under high-speed shearing, then 52.1% mesotrione and 7.9% other herbicides are added. The mixture is then sand-milled until the product particle size is below 3μm. The mixture is then mixed evenly with 0.075% magnesium aluminum silicate, 0.025% polyvinylpyrrolidone, 1.5% glycerol and 1.5% ethylene glycol as antifreeze, and then added to the sand-milled liquid. The mixture is then mixed evenly under high-speed shearing to obtain 60% mesotrione suspension.

[0098] Mesotrione was prepared according to the method in US Patent US7169952, and then the mesotrione-1 prepared in Example 4 of this patent method was used to prepare formulations 5-8 in the same manner; in addition, other adjuvants and raw materials were the same.

[0099]

[0100] The data in the table above show the quality differences of SC formulations prepared from metolachlor raw materials using different methods. This may be because the raw materials obtained by this method have lower toluene residues and improved stability during storage.

[0101] Application Example 2: Formulation Validation of Mesotrione-1WG The preparation method of water-dispersible granules of mesotrione-1 (i.e., mesotrione prepared by the method in Example 1 of this application) includes the following steps:

[0102] 1. Mix metolachlor-1, other selected herbicides, dispersants, wetting agents, disintegrants, and inert fillers evenly, and then perform ultra-fine airflow pulverization to obtain a fine powder of 680-840 mesh for later use;

[0103] 2. Add water to the obtained fine powder and knead it. Then, extrude the kneaded material to granulate it and dry it at 30-70℃ to obtain water-dispersible granules. The specific formulation process is as follows:

[0104] Formulation 9 20% Mesulfuron-methyl water-dispersible granules

[0105] Add 10% of mesotrione, 10% of other selected herbicides, 4% sodium naphthol sulfonate formaldehyde condensate, 4% sodium alkylphenol sulfonate, 1% sodium fatty alcohol polyoxyethylene ether sulfate, 1% sodium sulfate, 1% calcium chloride, and organic bentonite to a total of 100% to a mixer and mix thoroughly. Then, pulverize the mixture to 20-40 μm using an air jet mill, mix it thoroughly again, add water and knead it, extrude and granulate it, and dry it at 30-70℃ to obtain mesotrione water-dispersible granules.

[0106] Formulation 10 40% Mesulfuron-methyl water-dispersible granules

[0107] Add 20% metsulfuron-methyl, 20% of other selected herbicides, 4% sodium naphthol sulfonate formaldehyde condensate, 4% sodium alkylphenol sulfonate, 1% sodium fatty alcohol polyoxyethylene ether sulfate, 1% sodium sulfate, 1% calcium chloride, and organic bentonite to a total of 100% to a mixer and mix thoroughly. Then, pulverize the mixture to 20-40 μm using an air jet mill, mix it thoroughly again, add water and knead, extrude and granulate, and dry at 30-70℃ to obtain metsulfuron-methyl water-dispersible granules.

[0108] Formulation 11 60% Methionamide Water Dispersible Granules

[0109] Add 30% metsulfuron, 30% of other selected herbicides, 4% sodium naphthol sulfonate formaldehyde condensate, 4% sodium alkylphenol sulfonate, 1% sodium fatty alcohol polyoxyethylene ether sulfate, 1% sodium sulfate, 1% calcium chloride, and organic bentonite to a total of 100% to a mixer and mix thoroughly. Then, pulverize the mixture to 20-40 μm using an air jet mill, mix it thoroughly again, add water and knead, extrude and granulate, and dry at 30-70℃ to obtain metsulfuron water-dispersible granules.

[0110] Formulation 12 80% Methionamide Water Dispersible Granules

[0111] Add 40% metsulfuron-methyl, 40% of other selected herbicides, 4% sodium naphthol sulfonate formaldehyde condensate, 4% sodium alkylphenol sulfonate, 1% sodium fatty alcohol polyoxyethylene ether sulfate, 1% sodium sulfate, 1% calcium chloride, and organic bentonite to a total of 100% to a mixer and mix thoroughly. Then, pulverize the mixture to 20-40 μm using an air jet mill, mix it thoroughly again, add water and knead it, extrude and granulate it, and dry it at 30-70℃ to obtain metsulfuron-methyl water-dispersible granules.

[0112] Mesotrione was prepared according to the method in US Patent US7169952, and then the mesotrione-1 prepared in Example 4 of this patent method was used to prepare formulations 13-16 in the same manner; in addition, other adjuvants and raw materials were the same.

[0113]

[0114] The above data indicate the quality differences in WG formulations prepared from metolachlor raw materials using different methods. This difference may be due to the fact that the raw materials obtained by this method have lower toluene residues and improved stability during storage.

[0115] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for purifying mesotrione, characterized in that... The method includes the following steps: (1) Mix the crude mesotrione product with an ester organic solvent and pulp it; (2) After filtration at room temperature, wet material is obtained. The wet material is dried to obtain purified mesotrione product; The ester organic solvent is selected from one or more of methyl formate, ethyl formate, and ethyl acetate; The pulping operation in step (1) is performed at a temperature of 10-30°C, the mass ratio of crude mesotrione to ester solvent is 1:1.5~2.5, and the pulping operation takes no less than 1.5 hours.

2. The purification method of mesotrione according to claim 1, characterized in that... The mass ratio of crude mesotrione to ester solvent is 1:2, and the pulping operation takes 1.5-6 hours.

3. The purification method of mesotrione according to claim 1, characterized in that... The mass ratio of crude mesotrione to ester solvent is 1:2, and the pulping operation takes 1.5-6 hours.

4. The purification method of mesotrione according to claim 3, characterized in that... The drying process in step (2) involves a staged heating method, with 2-5 stages set from 30-90℃ for thorough drying, followed by cooling to room temperature.

5. The purification method of mesotrione according to claim 1, characterized in that... The method further includes the step of applying the ester-based organic solvent.

6. A crystalline form of mesotrione, characterized in that... The metsulfuron-methyl crystal form is prepared using the method according to any one of claims 1-5; and using Cu The following reflections of Kα radiation, recorded as 2θ±0.2 degrees, are observed in the X-ray powder diffraction pattern at 25 °C: 6.2437±0.2, 10.1493±0.2, 12.5321±0.2, 16.0380±0.2, 17.2356±0.2, 17.6402±0.2, 18.4007±0.2, 20.5405±0.2, 21.5974±0.2, 22.4979±0.2, 24.0798±0.2, 24.8666±0.2, 25.2625±0.2, 26.6192±0.2, 26.8073±0.2, 28.6997±0.

2.

7. A crystalline form of mesotrione, characterized in that... The metsulfuron-methyl crystal form is prepared using the method according to any one of claims 1-5; and using Cu The Kα radiation, as reflected in the X-ray powder diffraction pattern recorded at 25 °C, exhibits the following reflections at 2θ ± 0.2 degrees: 6.2437 ± 0.2, 10.1493 ± 0.2, 12.5321 ± 0.2, 16.0380 ± 0.2, 16.3504 ± 0.2, 17.2356 ± 0.2, 17.6402 ± 0.2, 18.4007 ± 0.2, 18.8647 ± 0.2, 19.2014, 20.5405 ± 0.

2. , 21.5974±0.2, 22.4979±0.2, 23.3795±0.2, 23.5854, 24.0798±0.2, 24.8666±0.2, 25.2625±0.2, 26.6192±0.2, 26.8073±0.2, 28.6997±0.2, 30.8731±0.2, 31.1933±0.2, 33.8306±0.2, 37.1592±0.

2.

8. A crystalline form of mesotrione, characterized in that... The metolachlor crystal form is used in Cu The X-ray powder diffraction pattern recorded by Kα radiation at 25°C is shown in Figure 2.

9. A crystalline form of mesotrione, characterized in that... The metolachlor crystal form has the X-ray powder diffraction pattern shown in Figure 2 and the FTIR spectrum shown in Figure 3.

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