L-glufosinate ammonium salt in crystalline form and preparation method thereof

Abstract

The present disclosure relates to novel crystalline forms of L-glufosinate ammonium salts and processes for preparing the novel crystalline forms of L-glufosinate ammonium salts. The present disclosure also provides compositions comprising the forms and methods for controlling undesirable plant growth using the compositions.

Description

[0001] This application is a divisional application of the invention patent application with the application date of July 30, 2021, application number 202180050299.X, and invention title "Crystalline Form of L-Glyphosate Ammonium Salt and Its Preparation Method". Technical Field

[0002] The present invention relates to novel solid forms of L-glyphosate ammonium salt and its preparation method. The present invention also provides compositions comprising said forms and methods for using said compositions to control unwanted plant growth. Background Art

[0003] DL-Homoalanine-4-yl(methyl)phosphinic acid (glyphosate) and salts are amino acid derivatives with herbicidal activity. The L-form of the amino acid derivative is active. In order to use the pure active ingredient, several methods have been developed for the preparation of L-homoalanine-4-yl(methyl)phosphinic acid (L-glyphosate), especially the ammonium salt.

[0004] Many synthetic methods end with the acid addition salt of L-glyphosate, and it is necessary to produce the corresponding free acid (L-glyphosate) or ammonium salt therefrom. Due to its high solubility in water, the salt is commercially preferred.

[0005] US4226941 discloses the preparation of L-glyphosate or salt by enzymatic preparation.

[0006] US5869668 and CN111072718A disclose the preparation of L-glyphosate or salt, which is resolved by using a chiral base to precipitate one of the diastereomeric salts, followed by a separation process.

[0007] US7795464 discloses the preparation of L-glyphosate by an asymmetric synthesis reaction.

[0008] CN105541906A discloses a two-step method for preparing L-glyphosate ammonium salt starting from L-glyphosate hydrochloride using an aqueous alcohol solvent system and ammonia.

[0009] In most cases, an addition salt of L-glyphosate is obtained at the end of the reaction, which needs to be converted into the ammonium salt or alkali metal salt of L-glyphosate. This can be done in two ways, by converting the acid addition salt into the free acid and then into the desired salt; or by converting the acid addition salt into the desired salt.

[0010] By following either of the methods described above, the separation process will require a post-treatment process that involves a complex procedure using an ion exchange column or treating the acid addition salt of L-glyphosate with hazardous chemicals such as ethylene oxide and propylene oxide. The preparation and purification of L-glyphosate ammonium salt usually require a multi-step process, which includes hydrolysis and crystallization procedures that affect the yield and purity of the product.

[0011] Therefore, there is a need to develop a novel solid form of ammonium L - glufosinate, and a method for preparing a high - purity ammonium L - glufosinate free of acid addition salts of L - glufosinate and / or L - glufosinate starting from an acid addition salt of L - glufosinate is required.

[0012] The inventors have surprisingly found that ammonium L - glufosinate with high purity and high yield can be prepared from an acid addition salt of L - glufosinate in a single step. The present disclosure also provides a crystalline form of ammonium L - glufosinate, which is beneficial for preparation and use in formulated products.

[0013] Object of the Invention

[0014] One object of the present invention is to provide a novel solid form of ammonium L - glufosinate.

[0015] Another object of the present invention is to provide a simple and convenient preparation of ammonium L - glufosinate.

[0016] Another object of the present invention is to provide a single - step method for preparing an ammonium salt of L - glufosinate.

[0017] Another object of the present invention is to provide a method for preparing ammonium L - glufosinate substantially free of acid addition salts of L - glufosinate and / or L - glufosinate and any other reaction by - products.

[0018] Another object of the present invention is to provide ammonium L - glufosinate in high purity and high yield. Summary of the Invention

[0019] In one aspect, the present disclosure provides a novel solid form of ammonium L - glufosinate.

[0020] In another aspect, the present disclosure provides a crystalline form of ammonium L - glufosinate, which is substantially free of acid addition salts of L - glufosinate and / or L - glufosinate and any other reaction by - products.

[0021] In another aspect, the present disclosure provides a method for preparing a compound represented by the following formula (I)

[0022]

[0023] The method comprises:

[0024] a) suspending an acid addition salt compound represented by the following formula (II) in which A - is an anion in a solvent to form a suspension;

[0025]

[0026] b) contacting the suspension with gaseous ammonia until the compound represented by formula (II) is completely dissolved to form a solution; and

[0027] c) precipitating the compound represented by formula (I)

[0028] In another aspect, the present disclosure provides a method for preparing a compound represented by formula (I), the method comprising:

[0029] a) suspending an acid addition salt compound represented by formula (II) in an alcohol solvent to form a suspension, the ratio of the compound represented by formula (II) to the alcohol being about 1:5 to about 1:15 by weight;

[0030] b) contacting the suspension with gaseous ammonia under non-aqueous conditions until the compound represented by formula (II) is completely dissolved to form a solution; and

[0031] c) subjecting the solution to conditions sufficient to precipitate the compound represented by formula (I).

[0032] In another aspect, the present disclosure provides L-glufosinate-ammonium having a volume average particle size distribution D50 of less than or equal to about 250 microns, specifically about 1 micron to about 200 microns, and most specifically about 10 microns to about 175 microns.

[0033] The present disclosure also provides the use of crystalline form I of L-glufosinate-ammonium for the preparation of other forms of L-glufosinate or other salts thereof.

[0034] The present disclosure also encompasses the use of crystalline form I of L-glufosinate-ammonium of the present disclosure for the preparation of agrochemical compositions and / or formulations.

[0035] In another aspect, the present disclosure provides an agrochemical composition comprising crystalline form I of L-glufosinate-ammonium according to the present disclosure.

[0036] In yet another embodiment, the agrochemical formulation of the present disclosure comprises crystalline form I of L-glufosinate-ammonium and at least one agrochemically acceptable additive / excipient.

[0037] The present disclosure includes a method for preparing an agrochemical formulation of the above L-glufosinate-ammonium, the agrochemical formulation comprising crystalline form I of L-glufosinate-ammonium and at least one agrochemically acceptable additive / excipient.

[0038] In another aspect, the present disclosure provides a method for controlling unwanted plant growth, the method comprising subjecting a plant or its locus to the action of crystalline form I of L-glufosinate-ammonium. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 : X-ray powder diffraction pattern of ammonium L-glufosinate in crystalline form I recorded using Cu-Kα radiation.

[0040] Figure 2 : Differential scanning calorimetry thermogram of ammonium L-glufosinate in crystalline form I.

[0041] Figure 3 : HPLC chromatogram of ammonium L-glufosinate prepared according to the present disclosure.

[0042] Figure 4 : Chiral HPLC chromatogram of ammonium L-glufosinate prepared according to the present disclosure.

[0043] Figure 5 : Particle size distribution of ammonium L-glufosinate. Detailed Description

[0044] In any of the aspects or embodiments described below, the phrase "comprising" may be replaced with the phrase "consisting of" or "consisting essentially of" or "substantially consisting of". Additionally, the terms "comprising", "having", "relating to", "containing", "characterized by" and their variants (e.g., "comprises", "has" and "relates to", "contains", etc.) and similar terms as used herein (including the claims) should be inclusive and / or open-ended and should have the same meaning as the word "comprising" and its variants (e.g., "comprising" and "including") and illustratively do not exclude additional, unrecited elements or method steps. As used herein, in this context, the expression "substantially free of" will be understood to mean that the crystalline form contains 20% or less, 10% or less, 5% or less, 2% or less, or 1% or less of any other form or salt of the subject compound, such as, for example, as measured by PXRD. As used herein, the term "about" refers to a measurable value, such as a parameter, amount, duration, etc., and is intended to include variations of + / −15% or less, specifically + / −10% or less, more specifically + / −5% or less, even more specifically + / −1% or less, and still more specifically + / −0.1% or less of the specifically recited value, provided that such variations are suitable for use in the disclosure described herein. Further, it should also be understood that the value itself to which the modifier "about" refers is specifically disclosed herein.

[0045] In one aspect, the present disclosure provides novel solid forms of ammonium L-glufosinate.

[0046] Regarding the present disclosure, the L-glufosinate ammonium salt is in a crystalline form, referred to herein as Form I. The terms "L-glufosinate ammonium salt", "L-glufosinate ammonium", and the crystalline form of the L-glufosinate ammonium salt, which are used interchangeably throughout the specification, refer to crystalline Form I.

[0047] Accordingly, the present disclosure provides the L-glufosinate ammonium salt in crystalline Form I.

[0048] The present disclosure provides the L-glufosinate ammonium salt in crystalline Form I, which consists of at least 80% by weight, specifically at least 90% by weight, of the L-glufosinate ammonium salt in Form I.

[0049] The L-glufosinate ammonium salt in crystalline Form I can be identified by X-ray powder diffraction based on its diffraction pattern.

[0050] Generally, the crystalline form of the L-glufosinate ammonium salt is characterized by an X-ray powder diffraction pattern substantially as Figure 1 depicted therein.

[0051] In one embodiment, the present disclosure provides the L-glufosinate ammonium salt in crystalline Form I, which shows at least three of the following reflections in an X-ray powder diffraction pattern using Cu-Kα radiation: reflections cited at 2θ (±0.2°) values of about 9.0, 11.6, 13.1, 14.1, 17.6, 18.2, 18.9, 19.5, 22.4, 23.4, 26.0, 31.1, 33.3, and 36.3.

[0052] In one embodiment, the present disclosure provides the L-glufosinate ammonium salt in crystalline Form I, which shows at least the following reflections in an X-ray powder diffraction pattern using Cu-Kα radiation: reflections cited at 2θ (±0.2°) values of about 9.0, 13.1, 14.1, and 18.9.

[0053] In one embodiment, the present invention provides the L-glufosinate ammonium salt in crystalline Form I, which shows at least one peak selected from 17.6, 18.2, 18.9, and 23.4 degrees 2θ ± 0.2 degrees 2θ in an X-ray powder diffraction pattern using Cu-Kα radiation.

[0054] In one embodiment, the present disclosure provides the L-glufosinate ammonium salt in crystalline Form I, which shows at least one of the values selected from the following cited at 2θ (±0.2°) in an X-ray powder diffraction pattern using Cu-Kα radiation: 17.6, 18.2, 18.9, and 23.4 degrees 2θ ± 0.2 degrees 2θ, having a relative intensity of at least 30% compared to the highest intensity peak at 18.9.

[0055] In one embodiment, the present disclosure provides the L-glufosinate ammonium salt in crystalline form I, which shows in an X-ray powder diffraction pattern using Cu-Kα radiation at least one of the values cited as 2θ (±0.2°) selected from the following: 17.6, 18.2, 18.9, and 23.4, having a relative intensity of at least 30% compared to the highest intensity peak at 18.9.

[0056] In another embodiment, the present disclosure provides the L-glufosinate ammonium salt in crystalline form I, which shows in an X-ray powder diffraction pattern using Cu-Kα radiation at least one of the values cited as 2θ (±0.2°) selected from the following: 17.6, 18.2, 18.9, and 23.4, having a relative intensity of at least 50% compared to the highest intensity peak at 18.9.

[0057] In one embodiment, the L-glufosinate ammonium salt in crystalline form I shows in an X-ray powder diffraction pattern using Cu-Kα radiation at least one of the values cited as 2θ (±0.2°) selected from the following: 17.6, 18.2, 18.9, and 23.4, having the % intensity of the peaks as described below:

[0058] Peak (2θ (±0.2°) Intensity (%) 17.6 88.3 18.2 80.6 18.9 100.0 23.5 54.3

[0059] In another embodiment, the L-glufosinate ammonium salt in crystalline form I shows in an X-ray powder diffraction pattern using Cu-Kα radiation at least one of the values cited as 2θ (±0.2°) selected from the following: 17.6, 18.2, 18.9, and 23.4, having the % intensity of the peaks as described below:

[0060] Peak (2θ (±0.2°) Intensity (%) 17.5 79.8 18.1 49.3 18.9 100.0 23.4 53.2

[0061] In another embodiment, the L-glufosinate ammonium salt in crystalline form I shows in an X-ray powder diffraction pattern using Cu-Kα radiation at least one of the values cited as 2θ (±0.2°) selected from the following: 17.6, 18.2, 18.9, and 23.4, having the % intensity of the peaks as described below:

[0062] Peak (2θ (±0.2°) Intensity (%) 17.6 79.1 18.2 53.0 19.0 100.0 23.5 54.6

[0063] In another embodiment, the L-glufosinate ammonium salt in crystalline form I shows in an X-ray powder diffraction pattern using Cu-Kα radiation at least one of the values cited as 2θ (±0.2°) selected from the following: 17.6, 18.2, 18.9, and 23.4, having the % intensity of the peaks as described below:

[0064]

[0065]

[0066] In another embodiment, the L-glufosinate ammonium salt of crystalline Form I shows in an X-ray powder diffraction pattern using Cu-Kα radiation at least one of the values cited as 2θ (±0.2°) selected from the following: 17.6, 18.2, 18.9, and 23.4, with the % intensity of the peaks as described below:

[0067] Peak (2θ (±0.2°) Intensity (%) 17.6 88.5 18.2 61.6 18.9 100.0 23.5 61.8

[0068] In one embodiment, the present disclosure provides the L-glufosinate ammonium salt of crystalline Form I, which shows at least six of the following reflections in an X-ray powder diffraction pattern using Cu-Kα radiation: reflections cited at 2θ (±0.2°) values of about 9.0, 11.6, 13.1, 14.1, 17.6, 18.2, 18.9, 19.5, 22.4, 23.4, 26.0, 31.1, 33.3, and 36.3.

[0069] In one embodiment, the present disclosure provides a crystalline form of the L-glufosinate ammonium salt, characterized by one or more of the following data:

[0070] An X-ray powder diffraction pattern having peaks at 2θ of 9.0, 11.6, 13.1, 14.1, 17.6, 18.2, 18.9, 19.5, 22.4, 23.4, 26.0, 31.1, 33.3, and 36.3 degrees 2θ ± 0.2 degrees 2θ;

[0071] An X-ray powder diffraction pattern having at least three peaks selected from the following: 9.0, 11.6, 13.1, 14.1, 17.6, 18.2, 18.9, 19.5, 22.4, 23.4, 26.0, 31.1, 33.3, and 36.3 degrees 2θ ± 0.2 degrees 2θ;

[0072] Substantially as Figure 1 The X-ray powder diffraction pattern shown;

[0073] A differential scanning calorimetry thermogram having at least two characteristic thermal events in the ranges of 65°C to 115°C, 185°C to 210°C, and 210°C to 235°C;

[0074] Substantially as Figure 2 The differential scanning calorimetry thermogram shown;

[0075] And combinations thereof.

[0076] In one aspect, the present disclosure provides the L-glufosinate ammonium salt of crystalline Form I, further characterized by the w / w ratio of L-glufosinate to ammonium.

[0077] According to one embodiment, the present invention provides a crystalline form of ammonium L - glufosinate, wherein the ratio of L - glufosinate to ammonium is in the range of 9.5 - 11:1.

[0078] The ammonium salt of crystalline Form I of L - glufosinate is further characterized in that the ratio of L - glufosinate to ammonium is equal to the theoretical ratio of 10.06:1.

[0079] In one embodiment, the present disclosure provides the ammonium salt of crystalline Form I of L - glufosinate, which contains L - glufosinate and ammonium in a w / w ratio in the range of 9.5 - 11:1.

[0080] In one embodiment, the present disclosure provides the ammonium salt of crystalline Form I of L - glufosinate, which contains L - glufosinate and ammonium in a w / w ratio in the range of 9.9 - 10.5:1.

[0081] In one embodiment, the present disclosure provides the ammonium salt of crystalline Form I of L - glufosinate, which shows at least three of the following reflections in an X - ray powder diffraction pattern using Cu - Kα radiation: reflections cited at 2θ (±0.2°) values of approximately 9.0, 11.6, 13.1, 14.1, 17.6, 18.2, 18.9, 19.5, 22.4, 23.4, 26.0, 31.1, 33.3 and 36.3, and contains L - glufosinate and ammonium in a w / w ratio in the range of 9.5 - 11:1.

[0082] In one embodiment, the present disclosure provides the ammonium salt of crystalline Form I of L - glufosinate, which shows at least one of the values selected from the following cited at 2θ (±0.2°): 17.6, 18.2, 18.9 and 23.4, having a relative intensity of at least 50% compared to the highest intensity peak, and contains L - glufosinate and ammonium in a w / w ratio in the range of 9.5 - 11:1.

[0083] In one embodiment, the present disclosure provides the ammonium salt of crystalline Form I of L - glufosinate, which shows at least one of the values cited at 2θ (±0.2°) of approximately 11.6, 17.6, 18.2, 23.4, 26.0 and 33.3 in an X - ray powder diffraction pattern using Cu - Kα radiation, and contains L - glufosinate and ammonium in a w / w ratio in the range of 9.5 - 11:1.

[0084] In one embodiment, the present disclosure provides the ammonium salt of crystalline Form I of L - glufosinate, which shows a differential scanning calorimetry (DSC) thermogram having at least two characteristic thermal events in the ranges of 65°C to 115°C, 185°C to 210°C and 210°C to 235°C.

[0085] In one embodiment, the characteristic thermal event is recorded as an endotherm.

[0086] In one embodiment, the present invention provides the L-glufosinate ammonium salt in crystalline form I, which shows differential scanning calorimetry (DSC) thermograms having at least two characteristic endotherms in the ranges of 65°C to 115°C, 185°C to 210°C, and 210°C to 235°C.

[0087] In one embodiment, the present disclosure provides the L-glufosinate ammonium salt in crystalline form I, which shows a DSC thermogram with reference to Figure 2 the DSC thermogram.

[0088] For the purposes of the present disclosure, the compound represented by formula (I) refers to L-glufosinate ammonium, the L-glufosinate ammonium salt, or the L-glufosinate ammonium salt in crystalline form I.

[0089] For the purposes of the present disclosure, the compound represented by formula (II) refers to the acid addition salts of L-glufosinate, which salts are formed with an acid selected from inorganic acids or organic acids, such as hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, etc.

[0090] In one embodiment, the present disclosure provides the L-glufosinate ammonium salt in crystalline form I, which is characterized by at least one of the following data:

[0091] An X-ray powder diffraction pattern showing at least three of the following reflections using Cu-Kα radiation: reflections cited at 2θ (±0.2°) values of about 9.0, 11.6, 13.1, 14.1, 17.6, 18.2, 18.9, 19.5, 22.4, 23.4, 26.0, 31.1, 33.3, and 36.3, and

[0092] A differential scanning calorimetry (DSC) thermogram having at least two characteristic thermal events in the ranges of 65°C to 115°C, 185°C to 210°C, and 210°C to 235°C.

[0093] In one embodiment, the present disclosure provides the L-glufosinate ammonium salt in crystalline form I, which is characterized by at least one of the following properties:

[0094] An X-ray powder diffraction pattern showing at least three of the following reflections using Cu-Kα radiation: reflections cited at 2θ (±0.2°) values of about 9.0, 11.6, 13.1, 14.1, 17.6, 18.2, 18.9, 19.5, 22.4, 23.4, 26.0, 31.1, 33.3, and 36.3, and containing L-glufosinate and ammonium in a ratio in the range of 9.5 - 11:1

[0095] or

[0096] A differential scanning calorimetry (DSC) thermogram having at least two characteristic thermal events in the ranges of 65 °C to 115 °C, 185 °C to 210 °C, and 210 °C to 235 °C.

[0097] In one embodiment, the present disclosure provides L - glufosinate ammonium salt in crystalline form I, which shows in an X - ray powder diffraction pattern using Cu - Kα radiation at least one of the values cited as 2θ (±0.2°) selected from: 17.6, 18.2, 18.9, and 23.4, having peaks with at least 50% intensity and containing L - glufosinate and ammonium in a w / w ratio in the range of 9.5 - 11:1, and exhibiting a differential scanning calorimetry (DSC) thermogram having at least two characteristic thermal events in the ranges of 65 °C to 115 °C, 185 °C to 210 °C, and 210 °C to 235 °C.

[0098] In one embodiment, the present disclosure provides L - glufosinate ammonium salt in crystalline form I, which shows at least one of the values cited as 2θ (±0.2°) of approximately 11.6, 17.6, 18.2, 23.4, 26.0, and 33.3 in an X - ray powder diffraction pattern using Cu - Kα radiation, and containing L - glufosinate and ammonium in a w / w ratio in the range of 9.5 - 11:1, and exhibiting a differential scanning calorimetry (DSC) thermogram having at least two characteristic thermal events in the ranges of 65 °C to 115 °C, 185 °C to 210 °C, and 210 °C to 235 °C.

[0099] In another aspect, the present disclosure provides a one - step conversion of an acid addition salt of L - glufosinate to the ammonium salt of L - glufosinate in high yield and purity.

[0100] In one aspect, the present disclosure provides a method for preparing a solid form of L - glufosinate ammonium salt.

[0101] In one embodiment, the present disclosure provides a method for preparing a crystalline form of L - glufosinate ammonium salt.

[0102] This method can produce a solid form of L - glufosinate ammonium salt in substantially pure form.

[0103] The term "substantially pure solid form of L - glufosinate ammonium salt" refers to a solid form having a purity greater than about 95 wt%, specifically greater than about 98 wt%. The substantially pure form of L - glufosinate ammonium salt is substantially free of the acid addition salt of L - glufosinate and / or L - glufosinate and any other reaction by - products.

[0104] Typically, purity can be measured by high - performance liquid chromatography (HPLC).

[0105] On the other hand, the present disclosure provides substantially pure crystalline forms of the ammonium salt of L-glufosinate.

[0106] In one embodiment, the present disclosure provides a method for preparing a compound represented by the following formula (I)

[0107]

[0108] The method comprises:

[0109] a) suspending an acid addition salt compound represented by the following formula (II) in which A - is an anion in an alcohol solvent to form a suspension;

[0110]

[0111] b) contacting the suspension with gaseous ammonia until the compound represented by formula (II) is completely dissolved to form a solution; and

[0112] c) subjecting the solution to conditions sufficient to precipitate the compound represented by formula (I).

[0113] The method according to the present disclosure is schematically represented as follows:

[0114]

[0115] wherein A - is an anion.

[0116] In one embodiment, the anion A - is selected from halide ions, phosphate, sulfate or acetate.

[0117] In one embodiment, the acid addition salt of the compound represented by the following formula (II) is formed with L-glufosinate and an acid selected from hydrochloric acid, sulfuric acid, phosphoric acid and acetic acid.

[0118] In one embodiment, the acid addition salt of L-glufosinate is L-glufosinate hydrochloride.

[0119] L-glufosinate hydrochloride can be prepared by methods known in the art.

[0120] In one embodiment, the present disclosure provides a method for preparing the ammonium salt of L-glufosinate, the method comprising:

[0121] a) suspending L-glufosinate hydrochloride in an alcohol solvent to form a suspension;

[0122] b) contacting the suspension with gaseous ammonia under non-aqueous conditions until L-glufosinate hydrochloride is completely dissolved to form a solution; and

[0123] c) Subject the solution to conditions sufficient to precipitate the ammonium salt of L - glufosinate.

[0124] In one embodiment, a method for preparing the ammonium salt of L - glufosinate comprises:

[0125] a) Contacting a suspension comprising the hydrochloride salt of L - glufosinate in an alcohol solvent with gaseous ammonia under non - aqueous conditions to form a solution, and

[0126] b) Subjecting the solution to conditions sufficient to obtain the ammonium salt of L - glufosinate.

[0127] The present disclosure further provides a method for preparing a compound represented by formula (I), the method comprising:

[0128] a) Suspending an acid addition salt compound represented by formula (II) in an alcohol solvent to form a suspension, the ratio of the compound represented by formula (II) to the alcohol being about 1:5 to about 1:15 by weight;

[0129] b) Contacting the suspension with gaseous ammonia under non - aqueous conditions until the compound represented by formula (II) is completely dissolved to form a solution; and

[0130] c) Subjecting the solution to conditions sufficient to precipitate the compound represented by formula (I).

[0131] In one embodiment, the present disclosure provides a method for preparing the ammonium salt of L - glufosinate, the method comprising:

[0132] a) Suspending the hydrochloride salt of L - glufosinate in an alcohol solvent to form a suspension, the ratio of the hydrochloride salt of L - glufosinate to the alcohol being about 1:5 to about 1:10 by weight;

[0133] b) Contacting the suspension with gaseous ammonia under non - aqueous conditions until the hydrochloride salt of L - glufosinate is completely dissolved to form a solution; and

[0134] c) Subjecting the solution to conditions sufficient to precipitate the ammonium salt of L - glufosinate.

[0135] In one embodiment, the method is carried out under non - aqueous conditions.

[0136] In one embodiment, the alcohol solvent is selected from, but not limited to, methanol, ethanol, propanol, isopropanol, ethylene glycol, glycerol, or mixtures thereof.

[0137] In one embodiment, the alcohol solvent is methanol.

[0138] In one embodiment, the ratio of the acid addition salt compound represented by formula (II) to the alcohol is about 1:5 to about 1:10 by weight.

[0139] In one embodiment, the ratio of the acid addition salt compound represented by formula (II) to the alcohol is about 1:5 to about 1:8 by weight.

[0140] In one embodiment, the ratio of L-glufosinate hydrochloride to the alcohol is about 1:5 to about 1:8 by weight.

[0141] In one embodiment, the alcohol solvent is selected from a mixture of an alcohol solvent and a ketone solvent such as acetone.

[0142] In one embodiment, step b) is carried out by contacting the suspension of step a) with gaseous ammonia until the L-glufosinate hydrochloride is completely dissolved.

[0143] In one embodiment, step b) is carried out by purging gaseous ammonia.

[0144] In one embodiment, the ratio of the acid addition salt compound represented by formula (II) to gaseous ammonia is about 1:1 to about 1:5.

[0145] In one embodiment, the ratio of the acid addition salt compound represented by formula (II) to gaseous ammonia is about 1:2 to about 1:5.

[0146] In one embodiment, the molar ratio of L-glufosinate hydrochloride to gaseous ammonia is about 1:2 to about 1:5.

[0147] In one embodiment, step b) provides a solution having a pH of 7 to 12.

[0148] In one embodiment, step b) provides a solution having a pH of 7.5 to 10.

[0149] In one embodiment, step c) is carried out at a temperature of 30 °C to 90 °C to allow the L-glufosinate ammonium salt to precipitate out.

[0150] In one embodiment, step c) is carried out at a temperature between 40 °C and 80 °C to allow the L-glufosinate ammonium salt to precipitate out.

[0151] In one embodiment, the L-glufosinate ammonium salt is filtered out.

[0152] In one embodiment, the impurities and by-products from the previous step and the ammonium chloride formed in the reaction are retained in the filtrate.

[0153] In one embodiment, the chemical purity of the L-glufosinate ammonium salt is at least 95% by weight.

[0154] In one embodiment, the chemical purity of the L-glufosinate ammonium salt is greater than 96% by weight.

[0155] In one embodiment, the chiral purity of ammonium L - glufosinate is the absolute purity.

[0156] In one embodiment, the L:D ratio of ammonium L - glufosinate is from about 95:5 to about 99.9:0.1.

[0157] In one embodiment, the L:D ratio of ammonium L - glufosinate is from about 96:4 to about 99:1.

[0158] The present disclosure also provides acid addition salts of L - glufosinate substantially free of L - glufosinate and / or ammonium L - glufosinate of L - glufosinate.

[0159] In one embodiment, the present disclosure provides ammonium L - glufosinate substantially free of acid addition salts of L - glufosinate.

[0160] In one embodiment, the present disclosure provides ammonium L - glufosinate substantially free of L - glufosinate hydrochloride.

[0161] In one embodiment, the present disclosure provides ammonium L - glufosinate containing less than 0.5 wt% of L - glufosinate hydrochloride.

[0162] In one embodiment, the present disclosure provides ammonium L - glufosinate substantially free of L - glufosinate.

[0163] In one embodiment, the present disclosure provides ammonium L - glufosinate containing less than 0.5 wt% of L - glufosinate.

[0164] The ammonium L - glufosinate prepared according to the present disclosure has a volume - average particle size distribution D50 of less than or equal to about 250 microns, specifically from about 1 micron to about 200 microns, and most specifically from about 10 microns to about 175 microns.

[0165] In one embodiment, the particles of ammonium L - glufosinate prepared according to the present disclosure have a D50 (the median of the volume distribution is defined as the diameter below which half of the population lies) of less than or equal to about 250 microns.

[0166] In one embodiment, the present disclosure provides a method for preparing crystalline form I of ammonium L - glufosinate, characterized by data selected from one or more of the following:

[0167] An X - ray powder diffraction pattern showing at least three of the following reflections using Cu - Kα radiation: reflections cited at 2θ (±0.2°) values of about 9.0, 11.6, 13.1, 14.1, 17.6, 18.2, 18.9, 19.5, 22.4, 23.4, 26.0, 31.1, 33.3, and 36.3;

[0168] The ammonium salt of L-glufosinate containing L-glufosinate and ammonium in a ratio in the range of 9.5 - 11:1;

[0169] A differential scanning calorimetry (DSC) thermogram having at least two characteristic thermal events in the ranges of 65°C to 115°C, 185°C to 210°C, and 210°C to 235°C;

[0170] The method comprises:

[0171] a) Suspending L-glufosinate hydrochloride in an alcohol solvent to form a suspension;

[0172] b) Contacting the suspension with gaseous ammonia under non-aqueous conditions until the L-glufosinate hydrochloride is completely dissolved to form a solution; and

[0173] c) Subjecting the solution to conditions sufficient to precipitate the ammonium salt of L-glufosinate in crystalline form I.

[0174] The present disclosure also provides the use of the crystalline form of the ammonium salt of L-glufosinate for the preparation of other forms of L-glufosinate or its salts.

[0175] The present disclosure also encompasses the use of the crystalline form of the ammonium salt of L-glufosinate of the present disclosure above for the preparation of agrochemical compositions and / or formulations.

[0176] The present disclosure includes a method for preparing an agrochemical formulation of the ammonium salt of L-glufosinate above, the agrochemical formulation comprising the crystalline form of the ammonium salt of L-glufosinate above and one or more agrochemically acceptable additives / excipients.

[0177] In one aspect, the present disclosure provides an agrochemical composition comprising the ammonium salt of L-glufosinate in crystalline form I.

[0178] Thus, in one embodiment, the present disclosure provides a herbicide composition comprising:

[0179] i) The ammonium salt of L-glufosinate in crystalline form I; and

[0180] ii) At least one agrochemically acceptable additive / excipient.

[0181] In one embodiment, the composition according to the present disclosure comprises the ammonium salt of L-glufosinate in crystalline form I in an amount of about 1% to about 99% by weight of the composition.

[0182] In one embodiment, the composition according to the present disclosure comprises the ammonium salt of L-glufosinate in crystalline form I having a volume average particle size distribution D50 of less than or equal to about 250 microns, specifically about 1 micron to about 200 microns, and most specifically about 10 microns to about 175 microns.

[0183] In one embodiment, the agrochemically acceptable excipients / additives can be selected from adjuvants or surfactants, including but not limited to wetting agents, emulsifying agents, dispersing agents, viscosity modifiers, defoaming agents, antifreeze agents, pH regulators, stabilizers, anticaking agents, biocides, etc.

[0184] The ammonium L - glufosinate composition according to the present disclosure may comprise additives such as surfactants, solvents, fertilizers, pH regulators, crystallization inhibitors, viscosity modifiers, suspending agents, droplet modifiers, pigments, antioxidants, foaming agents, light blockers, compatibilizers, defoaming agents, polyvalent chelating agents, neutralizing agents, corrosion inhibitors, dyes, flavoring agents, spreading agents, penetration aids, micronutrients, softeners, lubricants, adhesives, dispersing agents, thickeners, cryoprotectants, antimicrobials, and the like.

[0185] In one embodiment, the composition according to the present disclosure can be in the form of a soluble liquid concentrate, an emulsion concentrate, a microemulsion, a suspension concentrate, a water - dispersible powder or a granule.

[0186] In one embodiment, the composition according to the present disclosure can be in the form of a water - dispersible powder or a granule.

[0187] In one embodiment, the composition according to the present disclosure further comprises one or more other active ingredients.

[0188] In one embodiment, the active ingredients that can be present in the composition according to the present disclosure are selected from but not limited to herbicides, fungicides, insecticides, defoliants, desiccants, and plant growth regulators.

[0189] In one embodiment, the active ingredient that can be present in the composition according to the present disclosure is a herbicide.

[0190] The active substance can be a water-soluble or water-insoluble herbicide selected from: diphenyl ether herbicides such as oxyfluorfen, acifluorfen and its salts, lactofen and its salts, fomesafen and its salts; pyrimidyloxybenzoic acid analogue herbicides such as pyrithiobac sodium, bispyribac sodium; organophosphorus-based herbicides such as glyphosate and its salts, bilanafos and its salts, bialaphos and its salts; bipyridyl herbicides such as paraquat and diquat and their salts; aryloxyalkanoic acid herbicides such as 2,4-D and its salts and esters, MCPA, MCPB and their salts; aryloxyphenoxypropionic acid herbicides such as haloxyfop, isomers and esters, clodinafop-propargyl and its esters; pyridine herbicides such as picloram, tordon, aminopyralid and their salts; aromatic herbicides such as dicamba, 2,3,6-TBA, tricamba and their salts; pyridinecarboxylic acid herbicides such as picolinic acid; imidazolinones selected from imazamethabenz, imazamethapyr, imazapic, imazapic, imazapyr, imazaquin, imazethapyr; herbicides such as sulfonylurea herbicides such as flazasulfuron, rimsulfuron, bensulfuron-methyl, ethoxysulfuron, mesosulfuron-methyl, oxasulfuron, pyrazosulfuron-ethyl and its salts; cyclohexanedione oxime herbicides such as clethodim and its salts; chloroacetamide herbicides such as metolachlor and its salts and isomers; phenylphthalimide herbicides such as flumioxazin and its salts; mesotrione; dinitroaniline herbicides such as oryzalin, pendimethalin, profluralin, trifluralin and their salts; bicyclic dicarboxylic acid herbicides such as endothal and its salts; or mixtures of these herbicides.

[0191] In one embodiment,Suitable herbicides may be selected from: acetochlor, acifluorfen, oxyfluorfen, alachlor, ametryn, amidosulfuron, aminopyralid, aminotriazole, anilofos, asulam, atrazine, azafenidin, azimsulfuron, benazolin, benfluralin, bensulfuron-methyl, bentazone, bifenox, binalafos, bispyribac-sodium, bromacil, bromoxynil, butachlor, butroxidim, cafenstrole, carbetamide, carfentrazone-ethyl, chloridazon, chlorimuron-ethyl, chlorthiamid, chlorotoluron, chlorsulfuron, cinidon-ethyl, cyclosulfamuron, cycloate, desmedipham, dicamba, dichlobenil, diallyl dichloride, diclosulam, diflufenican, dimefuron, dimepiperate, dimethachlor, dimethenamid, diquat, diuron, EPTC, ethalfluralin, ethametsulfuron-methyl, ethofumesate, flazasulfuron, flucarbazone-sodium, flufenacet, flumioxazin, flumipropyn, flumetsulam, flupoxam, flupyrsulfuron-methyl-sodium, flurtamone, fomesafen, foramsulfuron, hexazinone, imazamethabenz-methyl, imazamox, imazapic, imazapyr, imazaquin, imazethapyr, imazosulfuron, iodosulfuron-methyl-sodium, ioxynil, isoproturon, isoxaben, isoxaflutole, lactofen, lenacil, linuron, mefenacet, mesosulfuron-methyl, mesotrione, metconazole, metobenzuron, metolachlor, S-metolachlor, penoxsulam, methoxydiuron, metribuzin, metsulfuron-methyl, molinate, MSMA, napropamide, nicosulfuron, norflurazon, oryzalin, paraquat, pendimethalin, phenmedipham, picloram, pretilachlor, propanil, propisochlor, prosulfuron, pyraflufen-ethyl, pyrazosulfuron-ethyl, pyrazolynate, pyrazosulfuron-ethyl, pyrithiobac-sodium, quinclorac, quinmerac, quinotrione, rimsulfuron, sethoxydim, simazine, sulcotrione, sulfentrazone, sulfosulfuron, tebuthiuron, thidiazimin, thifensulfuron-methyl, thiobencarb, tralkoxydim, triallate, tribenuron-methyl, triclopyr, trifloxysulfuron-sodium, trifluralin, triflusulfuron-methyl, triflusulfuron-sodium, and mixtures and combinations thereof.

[0192] In one embodiment, the compositions of the present disclosure can be used in glyphosate-tolerant crops.

[0193] The herbicidal compositions of the present disclosure can also be used in combination with glyphosate, dicamba, or 2,4-D in glyphosate-tolerant, dicamba-tolerant, or 2,4-D-tolerant crops.

[0194] In one embodiment, the compositions according to the present disclosure can be used in combination with herbicides that are selective for the crop to be treated and that complement the weed spectrum controlled by these compositions at the application rates used. When used in combination with other active ingredients, the L-glufosinate-ammonium salt claimed in the present invention can be formulated as a premix concentrate together with other active ingredients, tank-mixed with other active ingredients for spray application, or applied sequentially with other active ingredients in separate spray applications. Depending on local agricultural practices, the compositions can be diluted 1 to 2000 times in the insecticide spray mixture at the time of use and used in the insecticide spray application to control weeds in crop and non-crop environments.

[0195] In one embodiment, the present disclosure provides a method for controlling unwanted plant growth, comprising subjecting a plant or its locus to the action of a composition comprising:

[0196] i) L-glufosinate-ammonium salt in crystalline form I; and

[0197] ii) one or more agrochemically acceptable additives.

[0198] In one aspect, the present disclosure provides a method for controlling unwanted plant growth, the method comprising subjecting a plant or its locus to the action of L-glufosinate-ammonium salt in crystalline form I.

[0199] In one embodiment, the present disclosure provides a method for controlling unwanted plant growth, comprising subjecting a plant or its locus to the action of an agronomically effective amount of L-glufosinate-ammonium salt in crystalline form I.

[0200] In one embodiment, the agronomically effective amount comprises from about 10 grams to about 1500 grams per hectare of L-glufosinate-ammonium salt in crystalline form I.

[0201] In one embodiment, the agronomically effective amount comprises from about 100 grams to about 1000 grams per hectare of L-glufosinate-ammonium salt in crystalline form I.

[0202] In one embodiment, the temperature range during the application of the compositions according to the present invention can be critical and will vary based on the crop and geographical region.

[0203] Analysis Method

[0204] Powder X-Ray Diffraction (XRD) method:

[0205] X-ray powder diffraction pattern of L-glufosinate ammonium salt in crystalline form I

[0206] Recorded using Cu-Kα radiation. The detailed parameters are given below.

[0207] Instrument: Bruker make second-generation D2 Phaser powder X-ray diffractometer;

[0208] Operated at 30.0 kV, 10 mA;

[0209] Radiation: Cu Kα;

[0210] Mode: Reflection

[0211] Wavelength: 1.54060 Å,

[0212] Scanning range: 2 - 40 2θ,

[0213] Step size: 0.02°

[0214] Differential Scanning Calorimeter (DSC):

[0215] Differential scanning calorimetry thermogram of L-glufosinate ammonium salt in crystalline form I is recorded as follows:

[0216] Instrument: Differential Scanning Calorimeter Mettler Toledo DSC-3

[0217] Heating rate: 10 °C / min

[0218] Temperature range: 30 °C to 350 °C, under a N2 flow of 20 ml / min

[0219] Particle size:

[0220] Using a Malvern Mastersizer 2000 particle size analyzer with Hydro 2000SM(A) accessory, the particle size distribution of L-glufosinate ammonium salt is recorded using a 1% suspension of L-glufosinate ammonium salt in dry isopropanol.

[0221] The present invention is more specifically explained by the following examples. However, it should be understood that the scope of the present invention is not limited in any way by these examples. In some cases, some features of the disclosed embodiments may be employed without correspondingly using other features. Therefore, the claims should be interpreted broadly and in a manner consistent with the scope of the present invention. Those skilled in the art should understand that the present invention includes the following examples and can also be modified and changed within the technical scope of the present invention.

[0222] Examples :

[0223] Preparation of Crystalline Form of L-Glyphosate Ammonium Salt

[0224] Example 1: Preparation of L-Glyphosinate Ammonium Salt

[0225] At 30 °C, 366 g (1.35 moles) of L-glyphosate hydrochloride was suspended in 2820 g of methanol (1:7.7 w / w). The suspension was purged with dry ammonia gas (57.1 g, 3.36 moles) until the pH of the solution reached 7.9 to 8.5 and the L-glyphosate hydrochloride was completely dissolved. Then the reaction mass was heated and maintained at 65 °C to 70 °C until the L-glyphosate ammonium salt began to precipitate (4 hours to 6 hours). Then the reaction mass was cooled to 30 °C and allowed to stand for 1 hour to 2 hours to completely precipitate the product. The precipitated L-glyphosate ammonium salt was filtered and washed with 300 g of methanol to obtain 225 g of L-glyphosate ammonium salt. Yield: 78.4%; HPLC purity: 96.63%; L-glyphosate: 0.25%; L-glyphosate hydrochloride <0.05%, Figure 1 and Figure 2 . The ratio of L-glyphosate to ammonium (w / w) was 9.88:1.

[0226] Example 2: Preparation of L-Glyphosinate Ammonium Salt

[0227] At 30 °C, 530 g (1.95 moles) of L-glyphosate hydrochloride was suspended in 3700 g of methanol (1:7.0 w / w). The suspension was purged with dry ammonia gas (83 g, 4.87 moles) until the L-glyphosate hydrochloride was completely dissolved. Then the reaction mass was heated and maintained at 65 °C to 70 °C until the L-glyphosate ammonium salt began to precipitate (4 hours to 6 hours). Then the reaction mass was cooled to 30 °C and allowed to stand for 1 hour to 2 hours to completely precipitate the product. The precipitated L-glyphosate ammonium salt was filtered and washed with 400 g of methanol to obtain 342 g of L-glyphosate ammonium salt. Yield: 85%; HPLC purity: 96.47%, Figure 3 ; L-glyphosate: 0.19%; L-glyphosate hydrochloride <0.05%. The ratio of L-glyphosate to ammonium was 9.79:1.

[0228] The sample was tested again after a 360-day cycle, and the ratio of L-glufosinate to ammonium (w / w) was found to be 9.82:1.

[0229] Example 3: Preparation of L-Glyphosinate Ammonium Salt

[0230] 70 g (0.283 mol) of L-glufosinate hydrochloride was suspended in 490 g of methanol (1:7.0 w / w) at 30 °C. The suspension was purged with dry ammonia gas (12 g, 0.70 mol) until the L-glufosinate hydrochloride was completely dissolved. The reaction mass was heated and maintained at 70 °C to 75 °C until the L-glufosinate ammonium salt began to precipitate (4 h to 6 h). Then the reaction mass was cooled to 30 °C and allowed to stand for 1 h to 2 h to completely precipitate the product. The precipitated L-glufosinate ammonium salt was filtered and washed with 50 g of methanol to obtain 45 g of L-glufosinate ammonium salt. Yield: 80%; HPLC purity: 98.13%; enantiomeric purity: 97.05:2.95; Figure 4 。

[0231] Example 4: Preparation of L-Glyphosinate Ammonium Salt (Ratio of L-Glyphosinate Hydrochloride to Alcohol is 1:6)

[0232] 70 g (0.283 mol) of L-glufosinate hydrochloride was suspended in 420 g of methanol (1:6.0 w / w) at 30 °C. The suspension was purged with dry ammonia gas (12 g, 0.70 mol) until the pH of the solution reached 7.9 to 8.5 and the L-glufosinate hydrochloride was completely dissolved. Then the reaction mass was heated and maintained at 65 °C to 70 °C until the L-glufosinate ammonium salt began to precipitate (4 h to 6 h). Then the reaction mass was cooled to 30 °C and allowed to stand for 1 h to 2 h to completely precipitate the product. The precipitated L-glufosinate ammonium salt was filtered and washed with 42 g of methanol to obtain 48 g of L-glufosinate ammonium salt. Yield: 82.7%; HPLC purity: 96.5%.

[0233] Example 5: Preparation of L-Glyphosinate Ammonium Salt (Ratio of L-Glyphosinate Hydrochloride to Alcohol is 1:10)

[0234] 70 g (0.283 mol) of L-glufosinate hydrochloride was suspended in 700 g of methanol (1:10.0 w / w) at 30 °C. The suspension was purged with dry ammonia gas (12 g, 0.70 mol) until the pH of the solution reached 7.9 to 8.5 and the L-glufosinate hydrochloride was completely dissolved. Then the reaction mass was heated and maintained at 65 °C to 70 °C until the L-glufosinate ammonium salt began to precipitate (4 h to 6 h). Then the reaction mass was cooled to 30 °C and allowed to stand for 1 h to 2 h to completely precipitate the product. The precipitated L-glufosinate ammonium salt was filtered and washed with 70 g of methanol to obtain 40 g of L-glufosinate ammonium salt. Yield: 70.6%; HPLC purity: 98.9%.

[0235] Example 6: Preparation of L-Glyphosinate Ammonium Salt

[0236] At 30 °C, 350 g (1.29 moles) of L-glufosinate hydrochloride was suspended in 2700 g of methanol (1:7.7 w / w). The suspension was purged with dry ammonia gas (54.6 g, 3.19 moles) until the pH of the solution reached 7.9 to 8.5 and the L-glufosinate hydrochloride was completely dissolved. Then the reaction mass was heated and maintained at 65 °C to 70 °C until the L-glufosinate ammonium salt began to precipitate (4 hours to 6 hours). Then the reaction mass was cooled to 30 °C and allowed to stand for 1 hour to 2 hours to completely precipitate the product. The precipitated L-glufosinate ammonium salt was filtered and washed with 290 g of methanol to obtain 209 g of L-glufosinate ammonium salt. Yield: 80%; HPLC purity: 97.4%; L-glufosinate: 0.1%; L-glufosinate hydrochloride <0.05%, Figure 2 . The ratio of L-glufosinate to ammonium (w / w) was 9.90:1.

[0237] Example 7: Preparation of L-Glyphosinate Ammonium Salt

[0238] At 30 °C, 350 g (1.29 moles) of L-glufosinate hydrochloride was suspended in 2450 g of methanol (1:7 w / w). The suspension was purged with dry ammonia gas (68 g, 2.5 equivalents) until the pH of the solution reached 7.9 to 8.5 and the L-glufosinate hydrochloride was completely dissolved. Then the reaction mass was heated and maintained at 65 °C to 70 °C until the L-glufosinate ammonium salt began to precipitate (4 hours to 6 hours). Then the reaction mass was cooled to 30 °C and allowed to stand for 1 hour to 2 hours to completely precipitate the product. The precipitated L-glufosinate ammonium salt was filtered and washed with 290 g of methanol to obtain 262 g of L-glufosinate ammonium salt. Yield: 92.5%; Chiral ratio 98.7:1.3; The ratio of L-glufosinate to ammonium (w / w / ) was 9.60:1.

[0239] After testing the sample after a 50-day period, the ratio of L-glufosinate to ammonium (w / w) was found to be 9.61:1.

[0240] Formulations :

[0241] Example 8: A soluble liquid concentrate formulation containing crystalline form I of L-Glyphosinate Ammonium Salt prepared according to the present disclosure Liquid Concentrate Formulation :

[0242] Ingredients Amount (% w / w) L-Glyphosinate Ammonium Salt 13.5 Alkyl Glucamide 5 Sodium Lauryl Ether Sulfate 20 Glycol Ether (solvent) 3 Potassium Chloride 5 Water Appropriate amount Total 100

[0243] Example 9: A water-dispersible granule formulation containing crystalline form I of L-Glyphosinate Ammonium Salt is as follows :

[0244]

[0245]

[0246] Example 10: A water-dispersible granule formulation containing crystalline form I of L-Glyphosinate Ammonium Salt is as follows :

[0247] Ingredients Amount (% w / w) L-Glyphosinate Ammonium Salt 50 Alcohol Ethoxylate 6 Methyl Palmitate / Oleic Acid Methyl Ester 2.5 Potassium Chloride 5 Sodium Alkyl Sulfate 8 Hexamethylenetetramine 1 Ammonium Sulfate Appropriate amount Total 100

[0248] Example 11: A water-dispersible granule formulation containing crystalline form I of L-Glyphosinate Ammonium Salt is as follows :

[0249] Ingredients Amount (% w / w) L-Glyphosinate Ammonium Salt 26 Methyl Palmitate / Oleic Acid Methyl Ester Blend 2.5 Silica 3 Hexamethylenetetramine 1 Alcohol Ethoxylate 6 Sodium Alkyl Sulfate 8 Potassium Chloride 5 Ammonium Sulfate 48 Polydimethylsiloxane 0.5

[0250] Example 12: A water-dispersible granule formulation containing crystalline form I of L-Glyphosinate Ammonium Salt is as follows :

[0251] Ingredients Amount (% w / w) L-Glyphosinate Ammonium Salt 26 Methyl Palmitate / Oleic Acid Methyl Ester Blend 2.5 Magnesium Chloride 20 Silica 3 Hexamethylenetetramine 1 Alcohol Ethoxylate 6 Sodium Alkyl Sulfate 8 Potassium Chloride 5 Polydimethylsiloxane 0.5 Ammonium Sulfate 28 Total 100

[0252] Example 13: A water-dispersible granule formulation containing crystalline form I of L-Glyphosinate Ammonium Salt is given as follows 。

[0253] Ingredients Amount (% w / w) L-Glyphosinate Ammonium Salt 26 Magnesium Chloride 20 Silica 3 Hexamethylenetetramine 1 Phosphate Ester 8 Sodium Alkyl Sulfate 8 Potassium Chloride 5 Polydimethylsiloxane 0.5 Ammonium Sulfate 28.5

[0254] Example 14: A water-dispersible granule formulation containing racemic glyphosinate ammonium salt is as follows (comparative example)

[0255]

[0256]

[0257] Example 15: A water-dispersible granule formulation containing racemic glyphosinate ammonium salt is as follows (comparative example)

[0258] Ingredients Amount (% w / w) Glyphosinate Ammonium Salt 52.1 Silica 3 Magnesium Chloride 20 Hexamethylenetetramine 1 Phosphate Ester 8 Sodium Alkyl Sulfate 8 Potassium Chloride 5 Polydimethylsiloxane 0.5 Ammonium Sulfate 2.4

[0259] Field Trial Efficacy Data :

[0260] Field trials were conducted using a water-dispersible granule formulation containing the ammonium salt of L-glufosinate in crystalline form I prepared according to the present disclosure as a broad-spectrum herbicide. The composition was dispersed with water and optionally other tank mix adjuvants and applied at a water application rate of 300 - 600 l / ha to cropped and non-cropped land containing numerous broadleaf weeds, grasses, and sedges.

[0261] The inventors of the present disclosure conducted field trials using the samples prepared according to Example 11 (Sample 1), Example 12 (Sample 2), and Example 13 (Sample 3) at a dose of 250 g a.i. / hectare. After treatment with the said composition, chlorosis and subsequent weed necrosis were observed, demonstrating the biological efficacy of the new formulation. Observations at 4 days and 14 days after application are summarized in the table below. Comparative samples were prepared according to Example 14 (Sample 4) and Example 15 (Sample 5) and tested at a dose of 500 g a.i. / hectare. The details of the trials are given below.

[0262] Table 1 :

[0263]

[0264] Table 2: Weed Control % 4 days after application

[0265]

[0266] Table 3: Weed Control % 14 days after application

[0267]

[0268] It can be clearly seen from the above table that the compositions according to the present disclosure exhibit acceptable weed control against various persistent weeds. It is also noted that, compared to the racemic glufosinate ammonium composition, the compositions of the present invention perform at least equivalently, and in many cases exceed, the weed control measures at half the dose. Thus, it has been determined that the compositions of the present invention are highly effective and eliminate the inactive D-isomer of glufosinate, thereby making such compositions environmentally friendly and readily biodegradable.

Claims

1. A method for preparing a compound of formula (I), The method comprises: a) Suspend an acid addition salt compound of the following formula (II) in which A - is an anion in an alcohol solvent to form a suspension; b) contacting the suspension with gaseous ammonia until the compound of formula (II) is completely dissolved to form a solution; And c) subjecting the solution to conditions sufficient to precipitate the compound of formula (I).

2. A method for preparing a compound of formula (I), the method comprising: a) contacting a suspension comprising an acid addition salt compound of formula (II) in an alcohol solvent with gaseous ammonia under non-aqueous conditions to form a solution; And b) subjecting the solution to conditions sufficient to precipitate the compound of formula (I).

3. The method for preparing a compound of formula (I) according to claim 1, the method comprising: a) suspending an acid addition salt compound of formula (II) in an alcohol solvent to form the suspension, the ratio of the compound of formula (II) to the alcohol being about 1:5 to about 1:15 by weight; b) contacting the suspension with gaseous ammonia under non-aqueous conditions until the compound of formula (II) is completely dissolved to form the solution; And c) subjecting the solution to conditions sufficient to precipitate the compound of formula (I).

4. The method for preparing a compound of formula (I) according to claim 1, wherein the alcohol solvent is selected from methanol, ethanol, propanol, isopropanol, ethylene glycol, glycerol or a mixture thereof.

5. The method for preparing a compound of formula (I) according to claim 1, wherein the ratio of the acid addition salt compound of formula (II) to the alcohol is 1:5 to 1:15 by weight.

6. The method for preparing a compound of formula (I) according to claim 1, wherein the ratio of the acid addition salt compound of formula (II) to gaseous ammonia is 1:1 to 1:

5.

7. The method for preparing a compound of formula (I) according to claim 1, wherein the compound is the crystalline form of ammonium L-glufosinate.

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