Crystal form of aclonifen, and preparation method therefor and use thereof

Abstract

The present invention discloses a crystal form of aclonifen, and a preparation method therefor and the use thereof. In the present invention, a crystal form of aclonifen is obtained by recrystallizing amorphous aclonifen, and is referred as solid form A of aclonifen. In the present invention, the crystal is analyzed by means of various analytical methods, and solid form A of aclonifen is used to prepare a stable agrochemical formulation. The preparation method for solid form A of aclonifen provided by the present invention has a high recovery rate, is simple and convenient, and can be scaled up. Moreover, the crystal form, i.e., solid form A of aclonifen, is highly stable when used for formulation of a preparation, and thus has good application prospects.

Description

Crystal form of aclonital, preparation method and use thereof Technical Field

[0001] The invention relates to a crystal form of aclonifen, a preparation method and application thereof, and belongs to the technical field of agricultural herbicides. Background Art

[0002] Afenoxyfop, a diphenyl ether herbicide, is a protoporphyrin oxidase inhibitor. When applied pre-emergence, it controls broadleaf weeds and grass weeds in sunflower, potato, and winter wheat fields. It also has excellent control effects on alopecuroides and windweed in seedling fields of peas and carrots. Due to its relatively high efficacy, low toxicity, and low residue, it holds a significant position in the pesticide industry and is widely used.

[0003] Afenobine and the method for preparing the compound are both known. It is also known that the compound has the effect of controlling weeds. Afenobine technical, based on a cost-effective industrial synthesis method, is to use 1,2,3-trichlorobenzene as a raw material to nitrate to obtain 2,3,4-trichloronitrobenzene; then react 2,3,4-trichloronitrobenzene with ammonia to obtain an ammonolysis product 2,3-dichloro-6-nitroaniline; then react 2,3-dichloro-6-nitroaniline with phenol or sodium phenolate, so that the two undergo an etherification reaction to obtain afenobine. References: For example, in patent US4394159, the reaction conditions are the reaction of 2,3-dichloro-6-nitroaniline with phenol or sodium phenolate, with a yield of 74%. The synthesis route is as follows:

[0004] [Corrected 10.07.2024 in accordance with Rule 91] A review of publicly available literature on aclonifen revealed no reports of its crystalline structure or related data. It is well known in the pesticide field that different crystalline forms of pesticide technicals can have varying efficacy and effects, and that the properties of economically important formulations can also vary. Furthermore, it was discovered that aclonifen prepared by this known method exists in an amorphous state. Similarly, as shown in Figure 1, no resolvable X-ray powder diffraction pattern was obtained for aclonifen prepared by this known method.

[0005] Furthermore, amorphous azofenoxam has relatively poor storage stability, particularly aggregation after prolonged storage, making it unsuitable for preparation into compositions or formulations. Such economically important formulations include, for example, granules, encapsulated granules, tablets, water-dispersible granules, water-dispersible tablets, and water-dispersible powders. Certain formulations, such as suspension concentrates, contain important active ingredients in a dispersed form. Formulations are economically relevant and should exhibit good storage stability. Therefore, there is a need to develop a new solid form of azofenoxam that exhibits storage stability.

[0006] Summary of the Invention

[0007] The purpose of the present invention is to solve the technical problems that the existing amorphous form of aclonifen is unstable during storage, aggregates after storage, and is not suitable for preparation into a composition or preparation. The present invention provides a crystalline form of aclonifen, a preparation method thereof, and uses thereof.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

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

[0010] Preferably, it exhibits peaks at 3503, 3390, 1621, 1591, 1568, 1551, 1485, 1462, 1421, 1357, 1243, 1112, and 754 cm -1 One or more wave numbers (cm -1 , ±0.2%) with characteristic functional group vibration peaks in infrared (IR) spectrum.

[0011] and / or, it exhibits a differential scanning calorimetry (DSC) curve having an endothermic melting peak at 82.5° C. Preferably, it has a melting enthalpy of 72 J / g.

[0012] Preferably, it is characterised by an X-ray powder diffraction pattern substantially as shown in FIG2 , and / or by an IR spectrum substantially as shown in FIG3 , and / or by a DSC thermogram substantially as shown in FIG4 .

[0013] This aclonifen solid form A exhibits significantly improved storage stability, significantly alleviating the long-term storage stability issues currently encountered with commercially available aclonifen formulations, particularly those of SC formulations. Furthermore, it has been found that compared to amorphous aclonifen prepared according to the disclosure of US Patent No. 4,394,159, this aclonifen solid form A exhibits high stability when formulated into a formulation. Furthermore, due to its excellent thermodynamic stability, this aclonifen solid form A does not transform into other forms even after prolonged storage, making it suitable for economically relevant applications and providing the desired long shelf life of the formulation.

[0014] Methods for preparing amorphous azofenib are well known in the art. Amorphous azofenib is manufactured and available on a commercial scale. A particularly suitable method for preparing amorphous azofenib is described in US Pat. No. 4,394,159.

[0015] The second aspect of the present invention provides a method for preparing the solid form A of aclonifen according to the first aspect of the present invention, comprising the following steps:

[0016] Step 1: dissolving aclonifen in a solvent, wherein the aclonifen is amorphous aclonifen;

[0017] Step 2: precipitating the dissolved aclonifen-butyl into aclonifen-butyl solid form A;

[0018] Step 3: Isolation of the precipitated solid aclonifen Form A.

[0019] 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 a mixture of toluene and n-hexane, toluene and cyclohexane, ethyl acetate and n-hexane, dichloromethane and n-hexane, THF and water, DMF and water, and a mixture of methanol and water, and a mixture of ethanol and water.

[0020] Preferably, the solvent is selected from at least one of methanol and ethanol.

[0021] Preferably, in step 1, aclonifen-butyl is dissolved in the solvent by heating.

[0022] Preferably, aclonifen is dissolved in the solvent in step 1 by heating from room temperature to the reflux temperature of the solvent or below.

[0023] Preferably, the heating temperature is 60-90°C.

[0024] Preferably, the solution prepared in step 1 is then cooled to a temperature of about 0° C. to 15° C. to crystallize the desired crystalline form from the solvent. Aclonifen-butyl solid Form A can also be crystallized by concentrating the homogeneous solution by removing the solvent to a certain amount with or without the application of vacuum and cooling to below the reflux temperature of the solvent or solvent mixture.

[0025] Preferably, aclonifen solid form A can also be produced by adding seed crystals of the desired crystalline 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 generally 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 aclonifen 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.

[0026] Preferably, the precipitated aclonifen solid form A obtained in step 2 is separated from the solution by a commonly used solid component separation technique (e.g., filtration, centrifugation, or decantation). The separated solid is then washed one or more times with a solvent. Preferably, the solvent used in the washing stage can be the solvent used for the dissolution in step 1 of the preparation described above. Depending on the solubility of the crystals, washing is generally performed using a corresponding solvent at a temperature between room temperature and 0°C to minimize the loss of the crystalline material in the corresponding washing solvent.

[0027] Preferably, the solid form A of aclonifen is prepared by dissolution and recrystallization.

[0028] Preferably, the step 2 of precipitating the dissolved aclonifen into aclonifen solid form A specifically comprises: concentrating the solution and / or cooling and / or adding a solvent that reduces the solubility and / or adding seed crystals of the aclonifen solid form A.

[0029] Preferably, in step 2, the dissolved aclonifen is precipitated into aclonifen solid form A by gradient cooling, and finally cooled to 0°C to 15°C to precipitate crystals.

[0030] The third aspect of the present invention provides aclonifen solid form A, which is obtained by the method described in the second aspect of the present invention and has a content of aclonifen solid form A of at least 97% by weight.

[0031] The fourth aspect of the present invention provides a composition comprising the solid form A of fennivolum according to the first or third aspect of the present invention and at least one adjuvant, wherein the adjuvant is selected from one or more of the following: a surfactant, a diluent, a dispersant, a wetting agent, an antioxidant, a defoaming agent, an antifreeze agent, and a thickener.

[0032] Preferably, the composition is in the form of a suspension concentrate (SC), a soluble concentrate (SL), a dispersible concentrate (DC), an emulsifiable concentrate (EC), an emulsion seed dressing, granules (GR), a suspoemulsion (SE), an oil-based suspension concentrate (OD), a soluble granule (SG), a microgranule (MG) or a water-dispersible granule (WG).

[0033] Preferably, the composition is in the form of a suspension concentrate (SC).

[0034] Preferably, the composition comprises the aclonifen solid form A in an amount of less than 80% by weight.

[0035] Preferably, the composition comprises the aclonifen solid form A in an amount of 60% by weight.

[0036] The use of aclonifen as a herbicide is well known in the art and is used on a commercial scale. The solid form A of aclonifen is also active in controlling noxious weeds. Therefore, techniques known in the art for the preparation and application of amorphous aclonifen (e.g., as disclosed in the prior art documents described above) can also be applied in a similar manner to the solid form A of the present invention.

[0037] The present invention therefore provides a herbicidal composition comprising aclonifen in solid form A as defined above.

[0038] In the present invention, aclonifen solid form A can be present in a concentration sufficient to achieve the desired dosage when applied to plants or their loci, desirably at a concentration of about 1% to about 80% by weight of the total mixture. A formulation can be prepared, for example, by incorporating aclonifen solid form A into water, a solvent, and a carrier, and, if appropriate, using an emulsifier and / or dispersant and / or other adjuvants.

[0039] These formulations are prepared by mixing aclonifen solid form A with at least one auxiliary agent (e.g., a surfactant, a diluent, a wetting agent, a dispersant, a thickener, an antifreeze agent, an antifoaming agent, an antioxidant, and any necessary adjuvants and other formulation ingredients).

[0040] The surfactant can be an ionic or nonionic emulsifier, dispersant or wetting agent. Examples that can be used include, but are not limited to, salts of polyacrylic acid, lignin sulfonates, salts of benzenesulfonic acid or naphthalenesulfonic acid, condensation products of ethylene oxide with fatty alcohols, fatty acids or fatty amines, substituted phenols (especially alkylphenols), sulfosuccinates, taurine derivatives (especially alkyltaurine), or phosphate esters of polyethoxylated phenols or alcohols. Preferred surfactants are selected from lignin sulfonates (such as calcium lignin sulfonate).

[0041] Diluents include, but are not limited to, water, N,N-dimethylformamide, ethylene glycol, polypropylene glycol, propylene carbonate, dibasic esters, paraffin waxes, 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, as well as sugars and sugar derivatives such as sorbitol, lactose, sucrose and mannitol, clays, synthetic silica and diatomaceous earth, calcium silicate, titanium dioxide, aluminum oxide, calcium oxide and zinc oxide and mixtures thereof.

[0042] Wetting agents include, but are not limited to, phosphate esters, acetylenic glycols, ethoxylated silicones, sodium lauryl sulfate, pulverizing powder, soapnut powder, detergent LS (sodium p-methoxy fatty amide benzene sulfonate), alkyl-substituted naphthalene sulfonates, and polyalkylene glycol ethers. Preferred wetting agents are selected from polyalkylene glycol ethers, sodium lauryl sulfate, and soapnut powder.

[0043] Dispersants include, but are not limited to, polycarboxylates, alkylphenol polyoxyethylene ether formaldehyde condensate sulfates, alkylbenzenesulfonic acid calcium salts, alkylphenol polyoxyethylene ethers, fatty amine polyoxyethylene ethers, fatty acid polyoxyethylene esters, and glycerol fatty acid polyoxyethylene ethers, sodium, calcium, and ammonium salts of ligninsulfonic acid, and naphthalenesulfonate-formaldehyde condensates. Preferred dispersants are selected from ligninsulfonates (e.g., calcium ligninsulfonate) and alkylbenzenesulfonic acid calcium salts.

[0044] Thickeners include but are not limited to guar gum, pectin, casein, carrageenan, xanthan gum, alginate, methylcellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and carboxymethyl cellulose. Synthetic thickeners include derivatives of the above categories, and also polyvinyl alcohol, polyacrylamide, polyvinyl pyrrolidone, various polyethers, their copolymers together with polyacrylic acid and their salts. Preferred thickeners are selected from xanthan gum, polyvinyl alcohol.

[0045] Suitable antifreeze agents are liquid polyols such as ethylene glycol, propylene glycol or glycerol. The amount of antifreeze agent is generally about 1% to about 20% by weight, in particular about 5% to 10% by weight, based on the total weight of the composition.

[0046] Defoamers include all substances that can usually be used for this purpose in agrochemical compositions. Suitable defoamers are known in the art and are commercially available. Preferred defoamers are polydimethylsiloxane, mixtures of perfluoroalkylphosphonic acids, and polyether-modified silicones.

[0047] Antioxidants include all substances known in the art that can usually be used for this purpose in agrochemical compositions, preferably butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT).

[0048] The pH adjuster includes all substances known in the art that can be generally used for this purpose in agrochemical compositions, preferably citric acid and tartaric acid.

[0049] Other formulation ingredients may also be used in the present invention, such as preservatives and penetrants. Herbicides may also be added to the composition containing the aclonifen Solid Form A according to the present invention. Suitable herbicide combinations, such as the addition of appropriate amounts of one or more herbicide components, may result in improved compound herbicidal efficacy. These components are known to those skilled in the art.

[0050] The fifth aspect of the present invention provides use of the solid form A of aclonifen according to the first or third aspect of the present invention, or the composition according to the fourth aspect of the present invention, in the preparation of a herbicide.

[0051] The herbicide can be used to control harmful weeds selected from grass weeds and broadleaf weeds.

[0052] Preferably, the harmful weeds are selected from the group consisting of Alopecurus serrata, Alopecurus serrata, Clavermus ovata, Sesame truncatum, Forget-me-not, Chickweed, Ivy, Veronica officinalis, Watercress and Viola odorata.

[0053] Preferably, the herbicide is used to control harmful weeds in ornamental plants, fruit trees, vegetables, legumes, and cereal crops.

[0054] Preferably, the herbicide is used to control harmful weeds in winter wheat, potato, sunflower, sugar beet, sugar cane, carrot, corn, and soybean.

[0055] The present invention also provides a method for controlling weeds, comprising applying a herbicidally effective amount of the aforementioned solid form A of aclonifen or the aforementioned composition to a plant, a plant part, or the surrounding environment of the plant. Thus, a method for controlling weeds in a plant, a plant part, and / or the surrounding environment thereof is provided, comprising applying an effective amount of the solid form A of aclonifen or the composition to the roots of the plant, the plant part, or the surrounding environment of the plant.

[0056] As used herein, the term "about" when used in conjunction with a numerical amount or range means slightly more or less than the numerical amount or range, with a deviation of ±10% from the endpoints of the numerical amount or range.

[0057] The treatment of plants and plant parts with the compositions or formulations of the present invention is carried out directly or by allowing the compositions or formulations to act on their surroundings, habitats or storage spaces using conventional treatment methods. Examples of such conventional treatment methods include dipping, spraying, vaporizing, atomizing, broadcasting, brushing, mixing (e.g., soil treatment), and the like.

[0058] The term "room temperature" as used herein refers to a temperature range of about 20°C to 25°C.

[0059] Generally speaking, crystalline materials can be identified by, for example, producing diffraction peaks when subjected to X-ray radiation and / or exhibiting an endothermic melting peak curve with a characteristic peak under differential scanning calorimetry (DSC). Unless otherwise indicated, all percentages herein are given in weight %.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] 1. The present invention provides for the first time a new crystalline form of aclonifen, referred to as "Solid Form A", and provides the X-ray powder diffraction pattern, IR infrared spectrum, differential scanning calorimetry (DSC) data, melting enthalpy, etc. of the solid form A of aclonifen;

[0062] 2. The aclonifen solid form A can significantly reduce the long-term storage stability issues of current aclonifen formulations, especially aclonifen SC formulations. The aclonifen solid form A exhibits high stability when formulated into formulations. Furthermore, due to its excellent thermodynamic stability, the aclonifen solid form A does not transform into other forms even during long-term storage, making it suitable for economically relevant applications and providing the desired long shelf life for formulations.

[0063] 3. The present invention provides a method for preparing solid form A of fennivolum, which has a simple preparation process, easy operation, high recovery rate, high comprehensive utilization rate of raw materials, and high content. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] FIG1 is an X-ray powder diffraction pattern of amorphous benifufen-butyl.

[0065] FIG2 is an X-ray powder diffraction pattern (X-RPD) of solid form A of aclonifen.

[0066] FIG3 is an infrared (IR) spectrum of solid form A of aclonifen.

[0067] FIG4 is a differential scanning calorimetry (DSC) thermogram of solid form A of aclonifen. DETAILED DESCRIPTION

[0068] To make the present invention more clearly understood, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0069] In the following examples of the present invention, all X-ray diffraction patterns were measured using a powder diffractometer at 25° C. and under the following acquisition parameters:

[0070] Example 1: Preparation of amorphous benitofen

[0071] Amorphous aclonifen was prepared according to the disclosure of US Patent No. 4,394,159, with appropriate modifications to the method for preparing aclonifen from purified 2,3-dichloro-6-nitroaniline in Example 22(b-ii). Several synthetic methods for preparing aclonifen have been reported in the prior art, and thus, it can be manufactured on a commercial scale using one of the reported methods or purchased in bulk by various manufacturing industries. Aclonifen can be conveniently prepared using one of the procedures reported in US Patent No. 4,394,159 using purified 2,3-dichloro-6-nitroaniline and phenol.

[0072] To 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 with slow stirring. At room temperature, 11.5 g of potassium carbonate was added, and the temperature was raised to 50°C with stirring. The reaction was complete after 8 hours. The mixture was acidified with 10 g of glacial acetic acid, and the product was precipitated with 400 g of ice water, filtered, and dried. The resulting yellow solid was 19.5 g, with a yield of 98%. The melting point of aclonifen-butyl was 80.5°C.

[0073] As shown in FIG1 , the X-ray powder diffraction pattern of the obtained aclonifen product has no significant signals, which indicates that the aclonifen product prepared according to the disclosure of US Pat. No. 4,394,159 is amorphous.

[0074] Example 2: Preparation of aclonifen-butyl Solid Form A

[0075] 15 grams of the amorphous sample of fenthion prepared in Example 1 was placed in a three-necked round-bottom flask together with 150 milliliters of methanol, and the resulting slurry was heated to 65°C to obtain a homogeneous solution. After stirring the homogeneous solution at 65°C for 1 hour, insoluble particles (if any) were filtered out. The resulting solution was slowly and uniformly cooled to 55±2°C within 2 hours and kept warm for 0.5 hours; then slowly and uniformly cooled to 40±2°C within 2 hours and kept warm for 0.5 hours; then slowly cooled to 5±2°C within 2 hours. Fine crystals were formed, and the resulting heterogeneous mixture was stirred at 5±2°C for 0.5 hours. Then, the slurry was filtered and washed with 10 mL of cold methanol. The filtered crystals were dried at 60°C. The purity of the resulting crystalline product was >97%, the mass of the crystalline product was 14.0 grams, and the yield of the crystalline product was 93%.

[0076] The obtained crystals were analyzed by X-RPD, IR spectroscopy, and DSC, which were found to be aclonifen solid form A as shown in Figures 2, 3, and 4. The IR spectrum of the aclonifen solid form A is shown in Figure 2. The IR spectrum of the aclonifen solid form A exhibited peaks at approximately 3503, 3390, 1621, 1591, 1568, 1551, 1485, 1462, 1421, 1357, 1243, 1112, and 754 cm -1 Characteristic vibration peaks of functional groups at one or more wavenumbers in .

[0077] The DSC thermogram of aclonifen solid Form A exhibited an endothermic melting peak at 82.4° C. and a melting enthalpy of 72 J / g as shown in FIG4 .

[0078] The X-ray powder diffraction pattern of the crystals exhibited the reflections shown in FIG2 , and the values ​​are summarized in the following Table 1:

[0079] Table 1 X-ray powder diffraction pattern reflections of aclonifen solid form A

[0080] Example 3: Preparation of aclonifen solid form A

[0081] 15 grams of the amorphous sample of fenthion prepared in Example 1 was placed in a three-necked round-bottom flask together with 300 milliliters of ethanol, and the resulting slurry was heated to 78°C to obtain a homogeneous solution. After stirring the homogeneous solution at 78°C for 1 hour, insoluble particles (if any) were filtered out. 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 were formed, and the resulting heterogeneous mixture was stirred at 10±2°C for 0.5 hours. Then, the slurry was filtered and washed with 10 mL of cold ethanol. The filtered crystals were dried at 60°C. The purity of the resulting crystalline product was >97%, the mass of the crystalline product was 13.2 grams, and the yield of the crystalline product was 88%.

[0082] Example 4: Preparation of amorphous fenpropimorph suspension concentrate (SC)

[0083] All the components listed in Table 2 were uniformly mixed, and the resulting mixture was ground with a grinder to obtain a suspension.

[0084] Table 2 Components of amorphous benzonitr suspension concentrate (SC)

[0085] Example 5: Preparation of aclonifen solid form A suspension concentrate (SC)

[0086] All the components listed in Table 3 were uniformly mixed, and the resulting mixture was ground with a grinder to obtain a suspension.

[0087] Table 3 Aclonital solid form A suspension concentrate (SC) components

[0088] Example 6: Comparison of storage stability

[0089] The samples prepared in Examples 4 and 5 were stored in a heated oven at 54°C with the same atmosphere for 1 month, 3 months, and 6 months. The procedure followed was in accordance with CIPAC MT 46.3. The concentration of aclonifen was measured by high performance liquid chromatography (HPLC) at the end of each storage period. Aggregation was measured by observation, and the original concentration of aclonifen in each formulation was 60%. The results are listed in Table 4.

[0090] Table 4 Comparative data of storage stability of aclonital SC samples

[0091] In the above Table 4, "+" indicates a small amount of aggregation; "+++" indicates a large amount of aggregation; and "-" indicates no aggregation.

[0092] The above embodiments are only 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 ordinary technicians in this technical field can make several improvements and supplements without departing from the present invention, and these improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A crystalline form of aclonifen, designated as aclonifen solid form A, characterized in that: The following reflections are present in any combination as 2θ±0.20 degrees in the X-ray powder diffraction pattern (X-RPD) recorded at 25°C using Cu—K a radiation: 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).

2. The solid form A of aclonifen according to claim 1, wherein It appears at 3503, 3390, 1621, 1591, 1568, 1551, 1485, 1462, 1421, 1357, 1243, 1112 and 754 cm -1 One or more wave numbers (cm -1 , ±0.2%) with characteristic functional group vibration peaks in infrared (IR) spectrum. and / or, it exhibits a differential scanning calorimetry (DSC) curve having an endothermic melting peak at 82.5°C.

3. A method for preparing the solid form A of aclonifen according to claim 1 or 2, characterized in that: The following steps are involved: Step 1: dissolving aclonifen in a solvent, wherein the aclonifen is amorphous aclonifen; Step 2: precipitating the dissolved aclonifen-butyl into aclonifen-butyl solid form A; Step 3: Isolation of the precipitated solid aclonifen Form A.

4. The method according to claim 3, wherein The solvent in step 1 is selected from at least one of methanol and ethanol, and the dissolution is performed by heating.

5. The method according to claim 3, wherein The step 2 of precipitating the dissolved aclonifen to form aclonifen solid form A specifically comprises: concentrating the solution and / or cooling and / or adding a solvent that reduces the solubility and / or adding seed crystals of the aclonifen solid form A.

6. The method according to claim 3, wherein The step 2 is performed by cooling the mixture to 0°C to 15°C.

7. A solid form A of aclonifen, characterized in that: It is obtained by the process as claimed in claim 3 and has a content of aclonifen solid form A of at least 97% by weight.

8. A composition, characterized in that The invention comprises the solid form A of aclonifen according to any one of claims 1, 2 and 7 and at least one auxiliary agent, wherein the auxiliary agent is selected from one or more of the following: a surfactant, a diluent, a dispersant, a wetting agent, an antioxidant, a defoaming agent, an antifreeze agent, and a thickener.

9. The composition according to claim 8, wherein The composition comprises the aclonifen solid form A in an amount of less than 80% by weight.

10. Use of the solid form A of aclonifen according to any one of claims 1, 2 and 7, or the composition according to claim 8 in the preparation of a herbicide.

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