Crystal form of clomazone, process for its preparation and use thereof

Abstract

The application discloses a crystal form of chlorthiamid, a preparation method of the crystal form and application of the crystal form. The application obtains a crystal form of chlorthiamid by recrystallizing amorphous chlorthiamid, and the crystal form is called a solid form A of chlorthiamid. The application analyzes the crystal by various analysis methods and prepares a stable agricultural chemical preparation by using the solid form A of chlorthiamid. The preparation method of the solid form A of chlorthiamid provided by the application has high recovery rate, is simple and convenient, and can be enlarged. Meanwhile, the crystal form of the solid form A of chlorthiamid has high stability when being prepared into a preparation, and has a good application prospect.

Description

Technical Field

[0001] This invention relates to a crystal form of bensulfuron, its preparation method and its uses, belonging to the field of agricultural herbicides technology. Background Technology

[0002] Benzoate is a diphenyl ether herbicide belonging to the benzoate family and is an inhibitor of protoporphyrin oxidase. Pre-emergence application controls broadleaf and grassy weeds in sunflower, potato, and winter wheat fields. It is also highly effective against grasses such as barnyardgrass and purslane in pea and carrot seedling fields. Due to its relatively high efficiency, low toxicity, and low residue, it holds an important position in the pesticide industry and is widely used.

[0003] Benzoate and methods for preparing this compound are known. It is also known that this compound has weed-controlling properties. A cost-effective industrial synthesis method for benzoate technical grade involves nitrifying 1,2,3-trichlorobenzene to obtain 2,3,4-trichloronitrobenzene; then reacting 2,3,4-trichloronitrobenzene with ammonia to give the ammonolysis product 2,3-dichloro-6-nitroaniline; finally, reacting 2,3-dichloro-6-nitroaniline with phenol or sodium phenolate to undergo etherification, yielding benzoate. Reference: For example, patent US4394159, with reaction conditions of 2,3-dichloro-6-nitroaniline and phenol or sodium phenolate, yielding 74%, and the synthetic route is as follows:

[0004]

[0005] Based on currently available literature on bensulfuron, no reports have been found regarding its crystal structure or related data. It is well-known in the pesticide field that different crystal forms of the active ingredient result in different efficacy and effects, and may also lead to variations in the performance of economically important formulations. Furthermore, bensulfuron prepared by this known method exists in an amorphous form. Similarly, bensulfuron prepared by this known method, such as… Figure 1 As shown, a resolvable X-ray powder diffraction pattern could not be obtained.

[0006] Furthermore, amorphous bensulfuron exhibits relatively poor storage stability, particularly showing aggregation issues after prolonged storage, making it unsuitable for formulation into compositions or formulations. Economically important formulations include granules, encapsulated granules, tablets, water-dispersible granules, water-dispersible tablets, and water-dispersible powders, as well as formulations where certain important active compounds exist in a dispersed form, such as suspensions. Formulations are economically relevant and require good storage stability. Therefore, there is a need to develop a new solid form of bensulfuron that offers storage stability. Summary of the Invention

[0007] The purpose of this invention is to address the technical problem that existing amorphous forms of bensulfuron are unstable during storage and tend to aggregate after storage, making them unsuitable for preparation into compositions or formulations. This invention provides a crystal form of bensulfuron, its preparation method, and its uses.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a crystal form of bensulfuron, denoted as bensulfuron solid form A, which exhibits, in any combination, the following reflections as 2θ ± 0.20 degrees in an X-ray powder diffraction (X-RPD) pattern recorded using Cu-Ka radiation at 25°C:

[0010] 2θ = 9.94 ± 0.20 (1)

[0011] 2θ = 10.98 ± 0.20 (2)

[0012] 2θ = 14.72 ± 0.20 (3)

[0013] 2θ = 15.08 ± 0.20 (4)

[0014] 2θ = 15.48 ± 0.20 (5)

[0015] 2θ = 19.26 ± 0.20 (6)

[0016] 2θ = 20.82 ± 0.20 (7)

[0017] 2θ = 22.74 ± 0.20 (8)

[0018] 2θ = 24.20 ± 0.20 (9)

[0019] 2θ = 25.04 ± 0.20 (10)

[0020] 2θ = 27.28 ± 0.20 (11)

[0021] 2θ = 28.20 ± 0.20 (12).

[0022] Preferably, it exhibits values ​​of 3503, 3390, 1621, 1591, 1568, 1551, 1485, 1462, 1421, 1357, 1243, 1112, and 754 cm. -1 One or more wavenumbers (cm) -1 Infrared (IR) spectra with characteristic functional group vibration peaks at (±0.2%).

[0023] And / or, it exhibits a differential scanning calorimetry (DSC) curve with an endothermic melting peak at 82.5 °C. Preferably, it has a melting enthalpy of 72 J / g.

[0024] Preferably, it is through substantially as Figure 2 The X-ray powder diffraction pattern shown is used to characterize and / or by substantially as Figure 3 The IR spectra shown are used to characterize and / or by substantially as Figure 4 The DSC thermogram shown is used to characterize it.

[0025] This bensulfuron solid form A exhibits significantly improved storage stability, substantially reducing the long-term storage stability issues encountered with currently commercially available bensulfuron formulations, particularly the long-term storage stability issues of SC formulations. Furthermore, it has been found that this bensulfuron solid form A demonstrates high stability in formulation preparation compared to amorphous bensulfuron prepared according to the disclosure of patent US4394159. Moreover, due to its excellent thermodynamic stability, this bensulfuron solid form A does not transform into other forms even during prolonged storage, making it suitable for economically relevant applications and providing the desired long shelf life for formulations.

[0026] Methods for preparing amorphous bensulfuron are well known in the art. Amorphous bensulfuron is commercially manufactured and available. A particularly suitable method for preparing amorphous bensulfuron is described in patent US4394159.

[0027] A second aspect of the present invention provides a method for preparing the benzyl ether solid form A described in the first aspect of the present invention, comprising the following steps:

[0028] Step 1: Dissolve bensulfuron in a solvent, wherein the bensulfuron is amorphous bensulfuron;

[0029] Step 2: Precipitate the dissolved bensulfuron into bensulfuron solid form A;

[0030] Step 3: Separate the precipitated bensulfuron solid form A.

[0031] Preferably, the solvent in step 1 is selected from any one of the following solvents: methanol, ethanol, ethyl acetate, toluene, xylene, chlorobenzene or any combination thereof, or toluene and n-hexane, toluene and cyclohexane, ethyl acetate and n-hexane, dichloromethane and n-hexane, THF and water, DMF and water, and mixtures of methanol and water, and mixtures of ethanol and water.

[0032] Preferably, the solvent is selected from at least one of methanol and ethanol.

[0033] Preferably, in step 1, benzyl ether is dissolved in a solvent by heating.

[0034] Preferably, benzyl ether is dissolved in the solvent in step 1 by heating from room temperature to or below the reflux temperature of the solvent.

[0035] Preferably, the heating temperature is 60–90°C.

[0036] Preferably, the solution prepared in step 1 is then cooled to a temperature of approximately 0°C to 15°C to crystallize from the solvent to obtain the desired crystal form. Alternatively, with or without a vacuum and by cooling to below the reflux temperature of the solvent or solvent mixture, the homogeneous solution can be concentrated by removing solvent to a certain amount, thereby crystallizing bensulfuron-methyl solid form A.

[0037] Preferably, bensulfuron solid form A can also be produced by adding seed crystals of the desired crystal form (which can promote or accelerate crystallization) to the solution prepared in step 1 during crystallization. The amount of seed crystals added to the solution is typically 0.001% to 5% by weight, more preferably 0.005% to 1.0% by weight, based on the weight of the solution formed by dissolving bensulfuron in the solvent in step 1. Optionally, the seed crystals are added to the concentrated solution at a temperature below the boiling point of the corresponding solvent or solvent mixture.

[0038] Preferably, the precipitated bensulfuron solid form A obtained in step 2 is separated from the solution using common solid component separation techniques (e.g., filtration, centrifugation, or decantation). The separated solid is then washed once or multiple times with a solvent. Preferably, the solvent used in the washing stage can be the same as the solvent used for dissolution in step 1 as described above. Depending on the solubility of the crystals, washing is typically performed using the appropriate solvent between room temperature and 0°C to minimize the loss of crystalline material in the corresponding washing solvent.

[0039] Preferably, benzyl ether solid form A is prepared by dissolution and recrystallization.

[0040] Preferably, step 2, precipitating the dissolved bensulfuron into bensulfuron solid form A, specifically includes: concentrating the solution and / or by cooling and / or by adding a solvent that reduces solubility and / or by adding seed crystals of the bensulfuron solid form A.

[0041] Preferably, in step 2, the dissolved bensulfuron is precipitated into bensulfuron solid form A by gradient cooling, and finally cooled to 0°C to 15°C to precipitate crystals.

[0042] In a third aspect, the present invention provides a bensulfuron solid form A, which is obtained by the method described in the second aspect of the present invention and has a content of at least 97% bensulfuron solid form A by weight.

[0043] A fourth aspect of the present invention provides a composition comprising benzyl ether solid form A as described in the first or third aspect of the present invention and at least one adjuvant selected from one or more of the following: surfactants, diluents, dispersants, wetting agents, antioxidants, defoamers, antifreeze agents, and thickeners.

[0044] Preferably, the composition is in the form of: suspending agent (SC), soluble agent (SL), dispersible liquid (DC), emulsifiable concentrate (EC), emulsion seed dressing agent, granules (GR), suspension emulsion (SE), oil-based suspension (OD), soluble granules (SG), microparticles (MG), or water-dispersible granules (WG).

[0045] Preferably, the composition is in the form of a suspension (SC).

[0046] Preferably, the composition comprises less than 80% by weight of the bensulfuron solid form A.

[0047] Preferably, the composition comprises 60% by weight of the bensulfuron solid form A.

[0048] The use of bensulfuron as a herbicide is well known in the art and is used on a commercial scale. This bensulfuron solid form A is also active in controlling harmful weeds. Therefore, techniques known in the art for the formulation and application of amorphous bensulfuron (e.g., disclosed in the prior art literature described above) can also be applied in a similar manner to the bensulfuron solid form A of the present invention.

[0049] Therefore, the present invention provides a herbicide composition comprising bensulfuron in solid form A as defined above.

[0050] In this invention, bensulfuron solid form A is present at a concentration sufficient to achieve the desired dosage when applied to the plant or its location, preferably at a concentration of about 1% to about 80% by weight of the total mixture. Formulations are prepared, for example, by incorporating water, solvent, and carrier into bensulfuron solid form A, and, if suitable, using emulsifiers and / or dispersants and / or other adjuvants.

[0051] These formulations are prepared by mixing bensulfuron solid form A with at least one adjuvant (e.g., surfactant, diluent, wetting agent, dispersant, thickener, antifreeze, defoamer, antioxidant, and any necessary adjuvants and other formulation components).

[0052] Surfactants can be ionic or nonionic emulsifiers, dispersants, or wetting agents. Examples of surfactants that can be used include, but are not limited to, salts of polyacrylic acid, lignin sulfonates, salts of benzenesulfonic acid or naphthalenesulfonic acid, condensates of ethylene oxide with fatty alcohols or fatty acids or fatty amines, substituted phenols (especially alkylphenols), sulfosuccinate salts, taurine derivatives (especially alkyltaurine), or phosphate esters of polyethoxylated phenols or alcohols. Preferred surfactants are selected from lignin sulfonates (such as calcium lignin sulfonate).

[0053] Diluents include, but are not limited to, water, N,N-dimethylamide, ethylene glycol, polypropylene glycol, propylene carbonate, diesters, paraffin wax, alkylbenzenes, alkylnaphthalenes, glycerin, olive oil, castor oil, linseed oil, sesame oil, corn oil, peanut oil, cottonseed oil, soybean oil, rapeseed oil, and coconut oil, ketones (such as cyclohexanone, 2-heptanone, and 4-hydroxy-4-methyl-2-pentanone), acetates (such as hexyl acetate, heptyl acetate, and octyl acetate), water, and alcohols (such as methanol, cyclohexanol, decanol, benzyl alcohol, and tetrahydrofurfuryl alcohol), salts such as alkali metal phosphates (e.g., sodium dihydrogen phosphate), alkaline earth metal phosphates, sulfates of sodium, potassium, magnesium, and zinc, sodium chloride, potassium chloride, sodium acetate, sodium carbonate, and sugars and sugar derivatives such as sorbitol, lactose, sucrose, and mannitol, clay, synthetic silica and diatomaceous earth, calcium silicate, titanium dioxide, aluminum oxide, calcium oxide, and zinc oxide, and mixtures thereof.

[0054] Wetting agents include, but are not limited to: phosphate esters, acetylenic glycol, ethoxylated silicone, sodium lauryl sulfate, chelating agents, soap powder, detergent LS (sodium p-methoxy fatty amide benzenesulfonate), alkyl-substituted naphthalene sulfonates, and polyalkylene glycol ethers. Preferred wetting agents are selected from polyalkylene glycol ethers, sodium lauryl sulfate, and soap powder.

[0055] Dispersants include, but are not limited to: polycarboxylates, alkylphenol polyoxyethylene ether formaldehyde condensate sulfates, calcium alkylbenzene sulfonate salts, alkylphenol polyoxyethylene ethers, fatty amine polyoxyethylene ethers, fatty acid polyoxyethylene esters and glycerol fatty acid polyoxyethylene ethers, sodium, calcium and ammonium salts of lignin sulfonate, and naphthalene sulfonate-formaldehyde condensates. Preferred dispersants are selected from lignin sulfonates (such as calcium lignin sulfonate) and calcium alkylbenzene sulfonate salts.

[0056] Thickeners include, but are not limited to, guar gum, pectin, casein, carrageenan, xanthan gum, alginate, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and carboxymethylcellulose. Synthetic thickeners include derivatives of the aforementioned categories, as well as polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, various polyethers, copolymers thereof, polyacrylic acid, and their salts. Preferred thickeners are xanthan gum and polyvinyl alcohol.

[0057] Suitable antifreeze agents are liquid polyols, such as ethylene glycol, propylene glycol, or glycerin. The amount of antifreeze is typically from about 1% to about 20% by weight, particularly from about 5% to 10% by weight, based on the total weight of the composition.

[0058] Defoamers encompass all substances commonly used for this purpose in agricultural chemical compositions. Suitable defoamers are known in the art and are commercially available. Preferred defoamers are mixtures of polydimethylsiloxane, perfluoroalkylphosphonic acids, and polyether-modified silicones.

[0059] Antioxidants include all substances known in the art that are commonly used for this purpose in agrochemical compositions. Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are preferred.

[0060] pH adjusters include all substances known in the art that are commonly used for this purpose in agricultural chemical compositions. Citric acid and tartaric acid are preferred.

[0061] Other formulation components can also be used in this invention, such as preservatives and penetrants. Herbicides can also be added to the composition containing bensulfuron-methyl solid form A according to this invention. Suitable combinations of herbicides, such as the addition of appropriate amounts of one or more herbicide components, may result in better combined weed control effects. These components are known to those skilled in the art.

[0062] A fifth aspect of the invention provides the use of the solid form A of bensulfuron as described in the first or third aspect of the invention, or the composition as described in the fourth aspect of the invention, in the preparation of herbicides.

[0063] The herbicide can be used to control harmful weeds, which are selected from grass weeds and broadleaf weeds.

[0064] Preferably, the harmful weeds are selected from Alopecurus aequalis, Alopecurus aequalis, Cercis chinensis, Sesamum indicum, Forget-me-not, Chickweed, Ivy, Veronica persica, Sophora flavescens, and Viola yedoensis.

[0065] Preferably, the herbicide is used to control harmful weeds in ornamental plants, fruit trees, vegetables, legumes, and cereal crops.

[0066] Preferably, the herbicide is used to control harmful weeds in winter wheat, potatoes, sunflowers, sugar beets, sugarcane, carrots, corn, and soybeans.

[0067] Furthermore, the present invention also provides a method for controlling weeds, comprising applying an effective amount of the aforementioned bensulfuron solid form A or the aforementioned composition to the plant, plant parts, or the environment surrounding the plant. Therefore, this provides a method for controlling weeds on a plant, plant parts, and / or its surrounding environment, comprising applying an effective amount of the bensulfuron solid form A or the composition to the roots of the plant, plant parts, or the environment surrounding the plant.

[0068] As used herein, the term “about” when used in conjunction with a numerical quantity or range means slightly greater than or slightly less than the numerical quantity or range, and deviating from the endpoints of the numerical quantity or range by ±10%.

[0069] Treatment of plants and plant parts with the compositions or formulations of the present invention is carried out directly or by conventional treatment methods that allow the compositions or formulations to act on their surrounding environment, habitat, or storage space. Examples of such conventional treatment methods include impregnation, spraying, vaporization, atomization, broadcasting, brushing, mixing (such as soil treatment), etc.

[0070] The term "room temperature" as used in this article refers to a temperature range of approximately 20°C to 25°C.

[0071] Generally, crystalline materials can be identified, for example, by the presence of diffraction peaks when subjected to X-ray irradiation and / or by the appearance of an endothermic melting peak curve with characteristic apex under differential scanning calorimetry (DSC). Unless otherwise stated, all percentages in this invention are given in weight percent.

[0072] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0073] 1. This invention provides a new crystal form of bensulfuron, referred to as "solid form A", and provides X-ray powder diffraction pattern, IR infrared spectrum, differential scanning calorimetry (DSC) data, enthalpy of fusion, etc. of bensulfuron solid form A;

[0074] 2. This bensulfuron solid form A can significantly reduce the long-term storage stability problems of current bensulfuron formulations, especially bensulfuron SC formulations; this bensulfuron solid form A exhibits high stability when formulated; furthermore, due to its good thermodynamic stability, this bensulfuron solid form A will not transform into other forms even during long-term storage, which is sufficient for economically relevant applications and can provide the long shelf life expected by the formulation.

[0075] 3. This invention provides a method for preparing bensulfuron-methyl solid form A. The method has a simple preparation process, is easy to operate, has a high recovery rate, a high comprehensive utilization rate of raw materials, and a high content. Attached Figure Description

[0076] Figure 1 This is an X-ray powder diffraction pattern of amorphous bensulfuron.

[0077] Figure 2 This is the X-ray powder diffraction pattern (X-RPD) of bensulfuron solid form A.

[0078] Figure 3 The infrared (IR) spectrum of bensulfuron solid form A is shown.

[0079] Figure 4 This is a differential scanning calorimetry (DSC) thermogram of bensulfuron solid form A. Detailed Implementation

[0080] To make the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0081] In the following embodiments of the present invention, all X-ray diffraction patterns were measured using a powder diffractometer at 25°C with the following acquisition parameters:

[0082] θ-compensated slit and graphite monochromator Copper (Ka) radiation, 40kV, 40mA Step size: 0.02 degrees 2-θ Counting time: 1.0 second Maximum peak intensity: 9285 counts / second Scan range: 3-70 degrees 2-θ

[0083] Example 1: Preparation of amorphous bensulfuron

[0084] Amorphous bensulfuron was prepared according to the disclosure of patent US4394159, wherein the method for preparing bensulfuron from purified 2,3-dichloro-6-nitroaniline in Example 22 (b-ii) was appropriately modified. Several synthetic methods for preparing bensulfuron exist in the prior art, and therefore it can be manufactured on a commercial scale using one of the reported methods or purchased in bulk by various manufacturing industries. Bensulfuron can be conveniently prepared using purified 2,3-dichloro-6-nitroaniline and phenol through one of the procedures reported in patent US4394159.

[0085] In a reaction flask, 15.5 g of purified 2,3-dichloro-6-nitroaniline, 75 mL of dimethyl sulfoxide, and 7.8 g of phenol were added sequentially. The mixture was stirred slowly at room temperature. Then, 11.5 g of potassium carbonate was added, and the temperature was raised to 50 °C. The mixture was stirred and reacted for 8 hours. After the reaction was complete, the mixture was acidified with 10 g of glacial acetic acid. The product was precipitated with 400 g of ice water, filtered, and dried. 19.5 g of a yellow solid was obtained, with a yield of 98%. The melting point of this benzyl ether is 80.5 °C.

[0086] like Figure 1 As shown, the X-ray powder diffraction pattern of the obtained bensulfuron product showed no significant signal, indicating that the bensulfuron product prepared according to the disclosure of patent US4394159 is amorphous.

[0087] Example 2: Preparation of bensulfuron solid form A

[0088] 15 g of the amorphous sample of bensulfuron prepared in Example 1 was placed in a three-necked round-bottom flask along with 150 mL of methanol, and the resulting slurry was heated to 65 °C to obtain a homogeneous solution. The homogeneous solution was stirred at 65 °C for 1 hour, and insoluble particles (if present) were filtered off. The resulting solution was slowly and uniformly cooled to 55 ± 2 °C over 2 hours and held at that temperature for 0.5 hours; then slowly and uniformly cooled to 40 ± 2 °C over 2 hours and held at that temperature for 0.5 hours; then slowly cooled to 5 ± 2 °C over 2 hours. Fine crystals were formed, and the resulting heterogeneous mixture was stirred at 5 ± 2 °C for 0.5 hours. The slurry was then filtered and washed with 10 mL of cold methanol. The filtered crystals were dried at 60 °C. The purity of the obtained crystalline product was >97%, the mass of the crystalline product was 14.0 g, and the yield of the crystalline product was 93%.

[0089] The crystals obtained by X-RPD, IR spectroscopy, and DSC analysis are as follows: Figure 2 , Figure 3 and Figure 4 The solid form of bensulfuron shown is A. The IR spectrum of this solid form of bensulfuron is... Figure 2 The IR spectrum of bensulfuron solid form A is given in [reference]. It appears at approximately 3503, 3390, 1621, 1591, 1568, 1551, 1485, 1462, 1421, 1357, 1243, 1112, and 754 cm⁻¹. -1 Characteristic vibrational peaks of functional groups at one or more wavenumbers.

[0090] The DSC thermogram of bensulfuron solid form A shows the following Figure 4 The figure shows the endothermic melting peak at 82.4 °C and the enthalpy of fusion of 72 J / g.

[0091] The X-ray powder diffraction pattern of the crystal shows the following Figure 2 The reflections are shown, and the values ​​are summarized in List 1 below:

[0092] Table 1. X-ray powder diffraction pattern of bensulfuron solid form A.

[0093]

[0094]

[0095] Example 3: Preparation of bensulfuron solid form A

[0096] 15 g of the amorphous sample of bensulfuron prepared in Example 1 was placed in a three-necked round-bottom flask along with 300 mL of ethanol, and the resulting slurry was heated to 78 °C to obtain a homogeneous solution. The homogeneous solution was stirred at 78 °C for 1 hour, and insoluble particles (if present) were filtered off. The resulting solution was slowly and uniformly cooled to 25 ± 2 °C over 2 hours, and the resulting homogeneous mixture was poured into an open glass container and placed in a ventilated sample cabinet to evaporate the solvent at room temperature; fine crystals formed, and the resulting heterogeneous mixture was stirred at 10 ± 2 °C for 0.5 hours. The slurry was then filtered and washed with 10 mL of cold ethanol. The filtered crystals were dried at 60 °C. The purity of the obtained crystalline product was >97%, the mass of the crystalline product was 13.2 g, and the yield of the crystalline product was 88%.

[0097] Example 4: Preparation of amorphous bensulfuron suspension (SC)

[0098] Mix all the components listed in Table 2 evenly and grind the resulting mixture with a grinder to obtain a suspending agent.

[0099] Table 2 Components of Amorphous Benzoyl Suspension (SC)

[0100]

[0101]

[0102] Example 5: Preparation of bensulfuron solid form A suspension (SC)

[0103] Mix all the components listed in Table 3 evenly and grind the resulting mixture with a grinder to obtain a suspending agent.

[0104] Table 3. Components of Benzoflubenzuron Solid Form A Suspension (SC)

[0105]

[0106] Example 6: Comparison of storage stability

[0107] The samples prepared in Examples 4 and 5 were stored in a heated oven at 54°C under the same atmosphere for 1 month, 3 months, and 6 months, respectively. The procedure followed was in accordance with CIPAC MT 46.3. The concentration of bensulfuron was measured by high performance liquid chromatography (HPLC) at the end of each storage period. By observing the aggregates, the original concentration of bensulfuron in each formulation was 60%. The results are listed in Table 4.

[0108] Table 4 Comparison of storage stability data for bensulfuron SC samples

[0109]

[0110] In Table 4 above, "+" indicates a small number of clusters; "+++" indicates a large number of clusters; and "-" indicates no clusters.

[0111] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make several improvements and additions without departing from the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A crystal form of bensulfuron, denoted as bensulfuron solid form A, characterized in that, In X-ray powder diffraction patterns (X-RPD) recorded using Cu-Ka radiation at 25 °C, the following reflections, in any combination, are observed as 2θ ± 0.20 degrees: 2θ = 9.94 ± 0.20 (1) 2θ = 10.98 ± 0.20 (2) 2θ = 14.72 ± 0.20 (3) 2θ = 15.08 ± 0.20 (4) 2θ = 15.48 ± 0.20 (5) 2θ = 19.26 ± 0.20 (6) 2θ = 20.82 ± 0.20 (7) 2θ = 22.74 ± 0.20 (8) 2θ = 24.20 ± 0.20 (9) 2θ = 25.04 ± 0.20 (10) 2θ = 27.28 ± 0.20 (11) 2θ = 28.20 ± 0.20 (12); It exhibits one or more wavenumbers (cm) among 3503, 3390, 1621, 1591, 1568, 1551, 1485, 1462, 1421, 1357, 1243, 1112, and 754 cm⁻¹. -1 Infrared (IR) spectra with characteristic functional group vibration peaks at (±0.2%). And its differential scanning calorimetry (DSC) curve shows an endothermic melting peak at 82.5℃.

2. A method for preparing bensulfuron-methyl solid form A as described in claim 1, characterized in that, Includes the following steps: Step 1: Dissolve bensulfuron in a solvent, wherein the bensulfuron is amorphous bensulfuron; Step 2: Precipitate the dissolved bensulfuron into bensulfuron solid form A; Step 3: Separate the precipitated bensulfuron solid form A; The solvent in step 1 is selected from at least one of methanol and ethanol; Step 2, precipitating the dissolved bensulfuron into bensulfuron solid form A, specifically includes: concentrating the solution and / or cooling and / or adding a solvent that reduces solubility; Step 2 is performed by cooling to 0°C to 15°C.

3. The method as described in claim 2, characterized in that, The dissolution is achieved by heating.

4. A solid form of bensulfuron-methyl, characterized in that, It is obtained by the method as described in claim 3, and has a content of at least 97% by weight of bensulfuron solid form A.

5. A composition, characterized in that, It comprises benzyl ether solid form A as described in any one of claims 1 and 4 and at least one adjuvant selected from one or more of the following: surfactants, diluents, dispersants, wetting agents, antioxidants, defoamers, antifreeze agents, and thickeners.

6. The composition according to claim 5, characterized in that, The composition comprises less than 80% by weight of the bensulfuron solid form A.

7. The use of the solid form A of bensulfuron as described in any one of claims 1 and 4, or the composition of claim 5, in the preparation of herbicides.

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