Title - HERBICIDE COMPOSITION AND PREPARATION PROCESS AND METHOD

Abstract

This description describes mesotrione metal chelate polymorphs and a process for preparing the polymorphs. It also describes agrochemical formulations comprising these polymorphs.

Description

CLAIMS PRIORITY OF THE PATENT APPLICATION FILED IN INDIA ON JUNE 19, 2017 UNDER No. 201731021418 MESOTRIONE METAL CHELATE POLYMORPHS AND PROCESS PREPARATION TECHNICAL FIELD OF THE INVENTION The present invention relates to mesotrione metal chelate polymorphs. The invention provides polymorphic forms of mesotrione metal chelate and the process for preparing the polymorphs. The invention further provides agrochemical formulations comprising said polymorphs. SUMMARY The invention provides mesotrione copper chelate form I and mesotrione copper chelate form II. A process for preparing mesotrione copper chelate form I and mesotrione copper chelate form II is further described. II. Additionally, the present invention provides a process for preparing mesotrione metal chelate polymorphs and agrochemical formulations comprising said polymorphs. BACKGROUND OF THE INVENTION Cyclohexanedione compounds exhibit herbicidal activity. Mesotrione is a cyclohexane-1,3-dione herbicide developed for the selective control of a wide variety of weeds in corn. The term 'mesotrione' in this description means 2-(2-nitro-4'-methylsulfonylbenzoyl)-1,3-cyclohexanedione, which includes any enol or tautomeric form of the molecule. It further includes all tautomeric, racemic, and optical isomers derived from salts and various substituted mesotriones. It also includes all agriculturally acceptable salts derived from mesotrione. Mesotrione is a synthetic analogue of a naturally occurring herbicide derived from the bottlebrush plant (Callistemon citrines). Mesotrione acts as a phydroxyphenyl pyruvate dioxygenase inhibitor, which ultimately affects carotenoid biosynthesis. Its selectivity in corn stems from differential metabolism (to the 4-hydroxy derivative) and possibly slower foliar uptake. It is used for pre- and post-emergence control of broadleaf weeds such as Xanthium strumarium, Ambrosia trifida, Abutilon theophrasti, and Chenopodium, Amaranthus, and Polygonum spp., as well as some grassy weeds in corn. Mesotrione is rapidly taken up by weed species after foliar application and is distributed within plants by both acropetal and basipetal movement. Corn is tolerant to mesotrione due to selective metabolism within the crop plant. The slower uptake of mesotrione by susceptible weed species may also contribute to its usefulness as a selective herbicide for use in corn. It has been observed that water-based formulations with active ingredients that are insoluble or partially soluble in water, such as mesotrione, can suffer from a variety of problems, including chemical degradation, crystallization, agglomeration, thickening or gel formation, serum formation, sedimentation, precipitation, and the like. This problem is exacerbated when the active ingredient has the ability to exist in different crystalline or polymorphic forms. Mesotrione exhibits polymorphism. U.S. patents Nos. 8063253 and 8980796 describe different polymorphs of mesotrione and processes for preparing different polymorphs. U.S. Patent No. 8063253 describes mesotrione polymorph form I as a thermodynamically stable form and form II as the metastable form. The metastable form would gradually convert to the thermodynamically stable form I. Formulations containing these forms may exhibit stability issues during storage and during field application. U.S. Patent No. 8980796 describes the polymorph form 3 of mesotrione, which has improved physical and biological properties. U.S. Patent No. 5912207 describes that cyclohexanedione herbicide compounds, such as mesotrione, have the disadvantage of undergoing degradation in water and certain solvents. To overcome the problems associated with the degradation of mesotrione in aqueous formulations, as well as in certain solvents, metal chelates have been prepared. The interconversion of polymorphs, the drastic difference in their physical properties, and their unpredictable properties in water and other solvents make it difficult to formulate a mesotrione that has the desired physical and biological properties. The inventors' attempt to develop mesotrione chelate formulations in combination with other active ingredients led to stability problems and handling difficulties, such as sedimentation, thickening, and precipitation. These problems are due to the larger particle size of the mesotrione chelate. Additional effort is required to obtain the active ingredient with the necessary uniform particle size, and during these processes, morphological changes can occur in the particles, consequently causing problems in the formulations. Another common concern in the manufacture of agrochemical formulations is the product's toxicological profile. In some cases, products are unacceptable due to the potential for eye irritation during handling. This can lead to restrictive labeling of the formulation, limiting its suitability for its intended use. The indicative word used by the EPA for the marketed product comprising the combination of mesotrione and S-metolachlor (trade name: Camix) is a 'Warning'. Formulations with this classification may cause an undesirable degree of eye irritation due to the formulation. Therefore, it is a challenge to develop methods to improve existing mesotrione formulation products without the disadvantages of existing formulations. OBJECTS OF THE INVENTION An objective of the present invention is to provide mesotrione chelate polymorphs. Another objective of the present invention is to provide a process for preparing mesotrione chelate polymorphs. Another objective of the present invention is to provide stable herbicide formulations comprising mesotrione chelate polymorphs. Another additional objective of the present invention is to provide a stable herbicide formulation comprising mesotrione chelate polymorphs that have an improved toxicological profile. An objective of the present invention is to provide copper chelate polymorphs of mesotrione. BRIEF DESCRIPTION OF THE INVENTION The present invention provides mesotrione copper chelate form I. The present invention provides mesotrione copper chelate form II. The present invention further provides a process for preparing mesotrione metal chelate polymorphs. Additionally, the invention provides a herbicide formulation comprising mesotrione metal chelate polymorphs. Furthermore, the invention provides a herbicide formulation comprising mesotrione metal chelate polymorphs wherein the formulation causes less eye irritation. The invention further relates to a method for controlling unwanted weed species; the method comprises applying an effective amount of a composition comprising mesotrione metal chelate polymorphs to the weed or the place where it is located. DETAILED DESCRIPTION The inventors of the present invention surprisingly discovered that mesotrione chelate exists in different polymorphic forms. These crystalline forms exhibit distinct characteristics as classified by X-ray powder diffractograms and when considering other physical properties. It has also been discovered that, through suitable processes, two polymorphs of mesotrione metal chelate can be prepared that are suitable for manufacturing stable formulations. These new polymorphs, as well as the preparation processes, are described below. Unexpectedly, the inventors of the present invention discovered that different processes for preparing mesotrione metal chelate lead to different polymorphic forms of mesotrione metal chelate. Furthermore, the inventors of the present invention observed, surprisingly, that formulations comprising a polymorphic form of mesotrione metal chelate cause less eye irritation. The two innovative polymorphic forms of the present invention are named mesotrione copper chelate form I and mesotrione copper chelate form II. The invention also provides a process for preparing mesotrione metal chelate polymorphs. In addition, processes are provided for preparing mesotrione copper chelate form I and mesotrione copper chelate form II. Unexpectedly, the inventors of the present invention discovered that mesotrione copper chelate form I is suitable for preparing herbicidal compositions, especially liquid compositions. Accordingly, herbicidal compositions comprising mesotrione copper chelate form I or mesotrione copper chelate form II are provided. Accordingly, mesotrione copper chelate form I is provided. In one embodiment of the present invention, mesotrione copper chelate form I is provided exhibiting a characteristic X-ray powder diffraction pattern. In another embodiment, copper chelate of Mesotrione form I exhibiting a diffraction pattern of X-rays expressed in 20( + 0.2°) showing at least three of the following reflections: 9.1, 10.6, 11.8, 13.7, 15.9, 16.6, 18.3, 21.4, 22.1, 22.4, 24.1 and 27.7. In another embodiment of the present invention, mesotrione copper chelate form I is provided which exhibits an X-ray diffraction pattern expressed in 20(+0.2°) showing at least five of the following reflexes: 9.1, 10.6, 11.8, 13.7, 15.9, 16.6, 18.3, 21.4, 22.1, 22.4, 24.1 and 27.7. In another further embodiment of the present invention, mesotrione copper chelate form I is provided which exhibits an X-ray diffraction pattern expressed in 20(+0.2°) which shows all the following reflections: 9.1, 10.6, 11.8, 13.7, 15.9, 16.6, 18.3, 21.4, 22.1, 22.4, 24.1 and 27.7. In another embodiment, mesotrione copper chelate form I is provided, characterized by all of the following reflections and interplane spacings d as illustrated in the table below: Angle Spacing (20+0.2°) interplanes (d) A 9.1 9.7 10.6 8.4 11.8 7.5 13.7 6.5 15.9 5.6 16.6 5.3 18.3 4.8 21.4 4.2 22.1 4.0 22.4 4.0 24.1 27.7 3.7 3.2 Figure I provides a typical X-ray powder diffraction pattern of mesotrione copper chelate form I according to the present invention. Figure II provides a typical FT-IR spectrum of mesotrione copper chelate form I according to the present invention. During the study of polymorphic forms of mesotrione copper chelate, another polymorphic form, designated Form II, was discovered. Unlike Form I of mesotrione copper chelate, Form II was found to be suitable for manufacturing particularly robust formulations. The Form II of mesotrione copper chelate of the present invention can be identified using an X-ray powder diffractometric pattern. In one modality, mesotrione copper chelate form II is provided which exhibits an X-ray diffraction pattern expressed in 2Θ (±0.2°) showing at least 3 of the following reflections: 7,6, 9,1, 10,7, 11,8, 13,7, 15,4, 18.8, 21.0, 22.3, 23.8, 27.7, 28.7 and 29.5. In another modality, mesotrione copper chelate form II is provided which exhibits an X-ray diffraction pattern expressed in 2Θ (±0.2°) showing all of the following reflections: 7.6, 9.1, 10.7, 11.8, 13.7, 15.4, 18.8, 21.0, 22.3, 23.8, 27.7, 28.7 and 29.5. In one embodiment, mesotrione copper chelate form II is provided, characterized by the following reflections expressed as 29 values ​​and interplane spacings d as illustrated in the table below: Angle Spacing (2θ±0.2o) interplanes (d) A 7.6 11.5 9.1 9.6 10.7 8.3 11.8 7.4 13.7 6.4 15.4 5.8 18.8 4.8 21.0 4.2 22.3 4.0 23.8 3.7 27.7 3.2 28.7 3.1 29.5 3.0 Figure III provides a typical X-ray powder diffraction pattern of mesotrione copper chelate form II according to the present invention: Figure IV provides a typical FT-IR spectrum of mesotrione copper chelate form II according to the present invention. In one embodiment of the present invention, a process is provided for preparing a mesotrione metal chelate polymorph. In one embodiment, a process is provided for preparing a mesotrione metal chelate polymorph; the process comprises the following steps: a) prepare a mesotrione dispersion using a suitable base and water; b) precipitate the mesotrione metal chelate polymorph by adding a metal salt solution; and c) filtration and isolation of the mesotrione metal chelate polymorph. In one embodiment of the present invention, the base of step (a) is selected from alkali or alkaline earth metal hydroxides, carbonates, bicarbonates or an ammonium base. In another modality, the base of step (a) is selected from sodium hydroxide or ammonium hydroxide. In another embodiment, the metal ions that are useful for forming the metal chelate polymorphs of the present invention include transition metal ions such as Mn+2, Co+2, Cu+2, Zn+2, Fe+2, Ni+2 and Fe+3. In another embodiment, the metal salts that are suitable for forming the metal chelate polymorphs of the present invention include metal salts of Mn, Co, Cu, Zn, Fe, Ni, and Fe. In another additional modality, the metal ions of particular interest are selected from Zn+2, Fe+2 and Cu+2. In another embodiment, a process is provided for preparing mesotrione copper chelate form I; the process comprises the following steps: d) prepare a mesotrione dispersion using sodium hydroxide and water; e) precipitate the mesotrione metal chelate form I by adding a copper salt solution; and f) filtration and isolation of mesotrione copper chelate form I. In one modality, the pH of the dispersion of stage (a) varies from approximately 6 to approximately 10. In one modality, in step (b), the appropriate copper salt is selected from chlorides, sulfates, nitrates, carbonates, and phosphates. Mesotrione copper chelate form I is particularly advantageous for manufacturing liquid formulations. Specifically, it has been found to facilitate formulation manufacturing and handling, especially during storage, for extended shelf life. Furthermore, formulations containing mesotrione copper chelate form I have been shown to be advantageous during dilution and application. Physical characteristics such as bulk density and particle size demonstrate these advantages. Mesotrione copper chelate form I exhibits a characteristic bulk density. The bulk density of mesotrione copper chelate form I is approximately 0.51 to approximately 0.535 g / mL. Mesotrione copper chelate form I has a characteristic particle size. The mean diameter or mean value of the particle size distribution (D50 and D90) recorded for mesotrione copper chelate form I is provided in the table below. Samples (a) and (b) are prepared according to the process described in Example 1. No. Sample Name Series Mesotrione copper chelate form Ia Mesotrione copper chelate form Ib Particle size (pm) D(0.5) D(0.9) 7.94 13.02 7.62 13.22 The physical properties of mesotrione copper chelate form I listed above demonstrate the advantages of manufacturing and using herbicide formulations comprising mesotrione copper chelate form I. The inventors have observed that, due to its smaller particle size, mesotrione copper chelate form I is suitable for preparing liquid formulations, thus avoiding the repetitive and tedious grinding required to obtain the desired particle size. Furthermore, it has been observed, surprisingly, that when preparing solid formulations comprising mesotrione copper chelate form I, the arduous grinding process can be completely avoided. Additionally, it has been observed that by avoiding multiple grinding processes, the possibility of morphological changes in the mesotrione chelate is reduced, leading to a physically and chemically stable formulation. According to the present invention, a process is provided for preparing a copper chelate of mesotrione form II. In one embodiment, a process is provided for preparing mesotrione copper chelate form II; the process comprises the following steps: a) prepare a mesotrione dispersion using ammonium hydroxide and water; b) precipitate the mesotrione copper chelate form II by adding a copper salt solution; and c) filtration and isolation of mesotrione copper chelate form II. In one embodiment, the pH of the dispersion of stage (a) is approximately 6 to approximately 9. In one modality, in step (b), the appropriate copper salt is selected from chlorides, sulfates, nitrates, carbonates, and phosphates. Mesotrione copper chelate form II exhibits a characteristic bulk density. The bulk density of mesotrione copper chelate form II is approximately 0.61 to approximately 0.65 gm / ml. Mesotrione copper chelate form II has a characteristic particle size. The mean diameter or mean value of the particle size distribution (D50 and D90) recorded for mesotrione copper chelate form II is provided in the table below. Samples (a) and (b) are prepared according to the process described in Example 2. No. Particle size (pm) of Sample name, „ series D(0,5) D(0,9) Mesotrione Copper Chelate Form Il-a Mesotrione Copper Chelate Form Il-b 17.58 16.74 34.08 27.33 It can be concluded from the above data that the mesotrione copper chelate form II is suitable for manufacturing particularly robust formulations, where no grinding process may be required. Furthermore, the inventors observed that the use of the innovative mesotrione copper chelate form II in formulations helps prevent any unwanted changes in the nature of the mesotrione crystals, resulting in stable formulations. The invention also relates to formulations comprising mesotrione metal chelate polymorphs. In one embodiment, formulations comprising mesotrione copper chelate form I or mesotrione copper chelate form II are provided. In one embodiment, herbicide formulations comprising mesotrione copper chelate form I are provided. In another modality, herbicide formulations are provided comprising mesotrione copper chelate form I and additives useful for the formulation of plant protection agents. The present invention further provides a process for preparing herbicide formulations comprising mesotrione copper chelate polymorphs. In one embodiment, the present invention provides a process for preparing a herbicide formulation comprising a mesotrione copper chelate polymorph; the process comprises the steps of: a) prepare a mesotrione dispersion using a suitable base and water; b) add a metal salt solution to form a mesotrione metal chelate polymorph; c) add other agrochemical excipients if necessary; d) optionally add one or more additional active ingredients; and e) homogenize the mixture. In another embodiment, a process is provided for preparing a herbicide formulation comprising mesotrione copper chelate polymorph; the process comprises the following steps: f) prepare a mesotrione dispersion using a suitable base and water; g) add a copper salt solution to form mesotrione copper guellate form I; h) add other agrochemical excipients if necessary; i) optionally add one or more additional active ingredients; and j) homogenize the mixture. In another additional embodiment, a process is provided for preparing a herbicide formulation comprising mesotrione copper chelate form I; the process comprises the following steps: a) prepare a mesotrione dispersion using sodium hydroxide and water; b) precipitate the mesotrione copper chelate form I by adding a copper salt solution; c) filter the mesotrione copper chelate form I if necessary; d) add other agrochemical excipients if necessary; e) optionally add one or more additional active ingredients; and f) homogenize the mixture. In another embodiment, a process is provided for preparing a herbicide formulation comprising mesotrione copper chelate form I; the process comprises the following steps: a) prepare a mesotrione dispersion using sodium hydroxide and water; b) precipitate the mesotrione copper chelate form I by adding a copper salt solution; c) add other agrochemical excipients if necessary; d) optionally add one or more additional active ingredients; and e) homogenize the mixture. In another additional embodiment, a process is provided for preparing a herbicide formulation comprising mesotrione metal chelate form II; the process comprises the following steps: a) prepare a mesotrione dispersion using ammonium hydroxide and water; b) add a metal salt solution to form mesotrione metal chelate form II; c) add other agrochemical excipients if necessary; d) optionally add one or more additional active ingredients; and e) homogenize the mixture. In another additional embodiment, a process is provided for preparing a herbicide formulation comprising mesotrione copper chelate form II; the process comprises the following steps: a) prepare a mesotrione dispersion using ammonium hydroxide and water; b) add a copper salt solution to form mesotrione metal chelate form II; c) add other agrochemical excipients if necessary; d) optionally add one or more additional active ingredients; and e) homogenize the mixture. In another additional embodiment, a process is provided for preparing a herbicide formulation comprising mesotrione copper chelate form II; the process comprises the following steps: f) prepare a mesotrione dispersion using ammonium hydroxide and water; g) precipitate the mesotrione copper chelate form II by adding a copper salt solution; and h) filter the mesotrione copper chelate form II if necessary; i) add other agrochemical excipients if necessary; j) optionally add one or more additional active ingredients; and k) homogenize the mixture. The mesotrione copper chelate form I of the invention is of particular interest in mesotrione formulations in combination with one or more additional plant protection agents. In one embodiment, the copper chelate of mesotrione forms Part I of the invention is of particular interest in mesotrione formulations in combination with one or more additional plant protection agents, wherein the concentration of mesotrione ranges from approximately 0.01% to approximately 30% by weight of the composition. In one embodiment, the present invention provides herbicidal formulations comprising mesotrione copper chelate form I and a second active ingredient together with suitable additives. In another embodiment, the present invention provides herbicidal combinations comprising mesotrione copper chelate form I and a second active ingredient. The second active ingredient is, preferably, a herbicide. In one embodiment, the second herbicide that can be combined with the mesotrione copper chelate form I of the invention is selected from, but not limited to, isoxazolidinone herbicides, urea herbicides, triazine herbicides, hydroxybenzonitrile herbicides, organophosphorus herbicides, thiocarbamate herbicides, pyridazine herbicides, chloroacetanilide herbicides; benzothiazole herbicides; carbanilate herbicides, cyclohexene oxime herbicides; picolinic acid herbicides; pyridine herbicides; quinolinecarboxylic acid herbicides; chlorotriazine herbicides, aryloxyphenoxypropionic herbicides, oxadiazolone herbicides; phenylurea herbicides, sulfonaniide herbicides; triazolopyrimidine herbicides, amide herbicides, pyridazine herbicides, dinitroaniline herbicides, or combinations thereof. In a preferred embodiment, the second herbicide is selected from a triazine herbicide. With respect to the present invention, the term triazine refers to chemical compounds in the group of their equivalents, metabolites, salts, esters, isomers, and derivatives. Examples of triazine herbicides include chloroazine, cyanazine, cyprazine, eglinazine, ipazine, mesoprazine, procyanazine, proglinazine, propazine, sebutylazine, simazine, terbuthylazine, trietazine, dipropetrin, fucaojing, and trihydroxytriazine. Accordingly, a herbicide formulation is provided comprising mesotrione copper chelate form I and a triazine herbicide together with other suitable excipients. The composition comprises from approximately 0.01% to 30% by weight of mesotrione copper chelate form I and from approximately 1% to approximately 70% by weight of triazine herbicide. In another embodiment, the herbicide that may be present with the mesotrione copper chelate form I of the present invention is selected from organophosphorus herbicides. With respect to the present invention, the term organophosphorus refers to chemical compounds of the organophosphorus group, their equivalents, metabolites, salts, esters, isomers, and derivatives. Examples of organophosphorus herbicides include amiprofos-methyl, amiprofos, anilofos, bensulide, bilanafos, EBEP, phosamine, butamifos, clacifos, 2,4-DEP, DMPA, glufosinate, glufosinateP, glyphosate, piperofos, huangeaoling, and shuangjiaancaolin. In another preferred embodiment, the second herbicide is selected from a chloroacetanilide herbicide. With respect to the present invention, the term chloroacetanilide refers to chemical compounds of the chloroacetanilide group, their equivalents, metabolites, salts, esters, isomers, and derivatives. Examples of chloroacetanilide herbicides include acetochlor, alachlor, butachlor, butenachlor, delachlor, diethyl, dimetachlor, etahchlor, etaprochlor, metazachlor, metolachlor, S-metolachlor, pretylachlor, propachlor, propisochlor, prinachlor, terbuchlor, tenylchlor, and xylachlor. More specifically, the second herbicide is Smetolachlor. Accordingly, a herbicidal formulation is provided comprising mesotrione copper chelate form I and a chloroacetanilide herbicide together with other suitable excipients. The composition comprises from approximately 0.01% to 20% by weight of mesotrione copper chelate form I and from approximately 1% to approximately 70% by weight of chloroacetanilide herbicide. In another embodiment according to the present invention, a formulation is provided comprising mesotrione copper chelate form I, a chloroacetanilide herbicide, and a triazine herbicide, together with other suitable excipients. The composition comprises from approximately 0.01% to 20% by weight of mesotrione copper chelate form I, from approximately 1% to approximately 70% by weight of chloroacetanilide herbicide, and from approximately 1% to approximately 70% by weight of triazine herbicide. In another embodiment, the present invention provides a composition comprising mesotrione copper chelate form I and S-metolachlor. The inventors of the present invention observed that the composition comprising mesotrione copper chelate form I and S-metolachlor produced mild eye irritation. The formulations comprising mesotrione copper chelate form I of the present invention include both solid and liquid base formulations such as powders, granules, dry formulations, solutions, emulsions, suspoemulsions, suspensions, and microencapsulations in polymeric substances. Preferably, the mesotrione copper chelate forms I is suitable for liquid base formulations. In one embodiment of the present invention, the mesotrione copper chelate form I formulations further comprise a phytoprotectant. In one modality, the phytoprotectant is selected from the group consisting of quinoline derivatives; benoxacor; dichlormid; fenchlorazole ethyl; fenchlorim; flurazole; fluxofenim; furylazole; isoxadifen ethyl; mefenpyr; mefenpyr diethyl, oxabetrinil, ciometrinil, dimron, dimepiperate, cloquintocetmexyl, and cyprosulfamide. In one embodiment, a herbicide formulation comprising mesotrione copper chelate form II is provided. In another embodiment, a herbicide formulation comprising mesotrione copper chelate is provided. II and useful additives for the formulation of plant protection agents. The mesotrione copper chelate form II of the invention is of particular interest in mesotrione formulations in combination with one or more additional plant protection agents. In one embodiment, the mesotrione copper chelate form II of the invention is of particular interest in mesotrione formulations in combination with one or more additional plant protection agents, wherein the concentration of mesotrione ranges from approximately 0.01% to approximately 30% by weight of the composition. In a preferred embodiment, a herbicidal formulation is provided comprising mesotrione copper chelate form II and a triazine herbicide together with other suitable excipients. The composition comprises from approximately 0.01% to 30% by weight of mesotrione copper chelate form II and from approximately 1% to approximately 70% by weight of triazine herbicide. The formulations of the present invention further comprise conventional adjuvants suitable for agrochemical formulation and selected from solvents / carriers, surfactants, emulsifiers, dispersing agents, antifoaming agents, antifreeze agents, colorants, wetting agents, anticaking agents, structuring agents, biocides, viscosity modifiers, and binding agents. The composition of these adjuvants is not particularly limiting and can be determined by a skilled technician in accordance with conventional protocols. The present invention also relates to a method for controlling unwanted weed species; the method comprises applying an effective amount of a composition comprising mesotrione chelate polymorph to the weed or the place where it is located. In one embodiment, a method is provided for controlling unwanted weed species; the method comprises applying an effective amount of a composition comprising mesotrione copper chelate form I or form II to the weed or the location where it is found. In another embodiment, a method is provided for controlling unwanted weed species; the method comprises applying an effective amount of a composition comprising mesotrione copper chelate form I or form II together with one or more additional active ingredients to the weed or the place where it is located. The formulations of the present invention can be sold as a premixed composition or a kit of parts so that the individual components of the formulations can be mixed before spraying. Therefore, in one aspect, the present invention provides a case comprising mesotrione and a component comprising a suitable base and water. In one embodiment, instructions are given to mix the components of the kit before use. Therefore, in this embodiment, the kit of the The invention also includes an instruction manual. In another embodiment, the kit comprises mesotrione, a component comprising a suitable base and water, and a third component comprising at least one copesticide. The inventors of the present invention have succeeded in producing innovative polymorphs and in using them to produce advantageous, stable herbicide formulations. The following specific examples further illustrate the invention. Examples: Example 1: Process for preparing copper chelate of mesotrione from urine I: A mesotrione suspension was prepared by adding 522 g of mesotrione to 2 L of water. The pH of the suspension was raised to the range of 7–10 with a 20% sodium hydroxide solution. The mixture was stirred for one hour, followed by the addition of a 30% copper sulfate solution. The reaction mixture was stirred for 2–3 hours, and the pH of the mixture was observed to be within the range of 4.8-5.2. The resulting suspension of mesotrione copper chelate form I was filtered, washed with hot water and dried under vacuum (555 gm). A sample was analyzed by p-XRD and the spectra obtained are presented in Figure I. Example 2: Process for preparing mesotrione copper chelate form II: A mesotrione suspension was prepared by adding 345 g of mesotrione to 1.4 L of water. The pH of the suspension was raised to the range of 6–9 with ammonia solution. The mixture was stirred for one hour, followed by the addition of 20% copper sulfate solution. The reaction mixture was stirred for 2–3 hours, and the pH was observed to be in the range of 4.5–5.5. The resulting suspension of mesotrione copper chelate form II was filtered, washed with hot water, and vacuum dried (372 g / mL). A sample was analyzed by p-XRD, and the resulting spectra are shown in Figure III. Example 3: A mesotrione and S-metolachlor suspoemulsion formulation was prepared according to the present invention as follows: a) Preparation of suspension concentrate (SC) with mesotrione (35%) Ingredients Mesotrione copper chelate form I Propylene glycol Water DM (csp) Total % (w / w) 6.0 59.0 100 Procedure: The mesotrione copper chelate form I was mixed with the listed ingredients, the mixture was homogenized by stirring and subjected to wet grinding to achieve the required particle size. b) Preparation of oil-in-water (EW) emulsion with S-metolachlor (65%) Ingredients. S-metolachlor EO PO Block Copolymer DM Water (qsp) Total % (w / w) 66.67 2.65 30.68 100 Procedure: S-metolachlor was mixed with the listed ingredients and homogenized with sufficient stirring to form an oil-in-water emulsion. c) Preparation of suspoemulsion (SE) formulation of mesotrione + S-metolachlor % (w / w) Ingredients S-metolachlor EW 65 Mesotrione Copper Chelate SC Form I 35 Benoxacor EO Block Copolymer PO Propylene Glycol Water DM (csp) Total 58.5 10.86 2.0 8.0 3.0 15.59 100 Procedure: S-metolachlor EW was mixed with benoxacor, EO PO block copolymer, and water. Mesotrione chelate SC form I was then added and stirred. The mixture was further homogenized by stirring until uniform. The formulation was determined to be stable, and no sedimentation or thickening was observed during storage. Example 4: A suspoemulsion formulation of mesotrione, S-metolachlor, and atrazine was prepared according to the present a) Preparation of mesotrione suspension concentrate (SC) (35%): invention as follows: Ingredients Mesotrione Copper Chelate Form I EO Block Copolymer PO Water DM (csp) Total % (w / w) 35.0 6.0 59.0 100 Procedure: The mesotrione copper chelate form I was mixed with the listed ingredients and the mixture was homogenized by stirring. b) Preparation of oil-in-water emulsion (EW) with Smetolachlor (65%) Ingredients S-metolachlor EO block copolymer PO Water DM (csp) Total % (w / w) 66.67 2.65 30.68 100 Procedure: S-metolachlor was mixed with the listed ingredients and homogenized by stirring to form the oil-in-water emulsion. c) Preparation of atrazine suspension concentrate (SC) (58%): Ingredients Atrazine EO block copolymer PO % (w / w) 58.0 5.0 Procedure: Atrazine was mixed with the listed ingredients and homogenized by stirring to prepare a homogeneous suspension. d) Preparation of suspoemulsion (SE) formulation of Smetolachlor, mesotrione and atrazine DM Water (qsp) Total 37.0 100 Ingredients S-metolachlor EW 65 Mesotrione Copper Chelate Form I SC 35 SC of atrazine 58% Benoxacor EO PO Block Copolymer Propylene glycol DM Water (qsp) Total % (w / w) 45.23 8.40 18.97 2.0 9.0 3.0 13.40 100 Procedure: S-metolachlor EW was mixed with water, benoxacor, EO PO block copolymer, and propylene glycol, followed by the addition of mesotrione copper chelate form I SC and atrazine SC. Water was added, and the mixture was homogenized by stirring until a uniform suspension was obtained. The formulation was determined to be stable, and no sedimentation or precipitation was observed during storage. Example 5: A mesotrione and S-metolachlor suspoemulsion formulation was prepared according to the present invention as follows: a) Preparation of suspension concentrate (SC) with mesotrione (35%) Ingredients Mesotrione % (w / w) 35.0 Copper sulfate Sodium hydroxide 13.00 20.00 (20% bleach) EO PO block copolymer DM Water (qsp) Total 6.00 26.00 100 Procedure: Mesotrione was mixed with the listed ingredients and the mixture was homogenized by stirring to form mesotrione copper chelate SC form I which was further subjected to wet grinding to achieve the required particle size. b) Preparation of oil-in-water emulsion (EW) with Smetolachlor (65%) Ingredients S-metolachlor EO PO Block Copolymer DM Water (qsp) Total % (w / w) 66.67 2.65 30.68 100 Procedure: The S-metolachlor was mixed with the listed ingredients and homogenized with stirring to form the oil-in-water emulsion. (c) Preparation of suspoemulsion (SE) formulation of mesotrione + S-metolachlor Ingredients EW of S-metolachlor 65 SC chelate of % (w / w) 58.5 10.86 copper mesotrione form I 35 Benoxacor Block copolymer of EO PO Propylene glycol Water DM (csp) Total 2.0 10.0 3.0 15.64 100 Procedure: S-metolachlor EW was mixed with benoxacor, EO PO block copolymer, propylene glycol, and water. Then, mesotrione copper chelate form I SC was added and stirred. The mixture was further homogenized by stirring until uniform. The formulation was determined to be stable, and no sedimentation or thickening was observed during storage. Study of acute eye irritation: A composition comprising mesotrione copper chelate form I and S-metolachlor prepared according to the present invention (Example 3) was tested for eye irritation. This study was conducted to evaluate the acute eye irritation effect produced by the formulation. Study guidelines: The present study was conducted in accordance with the following standards: EPA, 1998: The United States Environmental Protection Agency (EPA), Health Effects Test Guidelines, OCSPP 870.2400, Acute Eye Irritation (EPA 712-C-98-195) (August 1998). OECD, 2012: The Organization for Economic Co-operation and Development (OECD), Guidelines for the Testing of Chemicals Chemicals), OECD 405, Acute Eye Irritation / Corrosion, adopted by the Council on 2 October 2012. In a study of acute eye irritation, three New Zealand white rabbits were administered a single ocular application of 0.1 ml of a formulation prepared according to the Yo Example 3 of the present invention involves applying the test element to the right eye of a rabbit, while the other eye was left untreated and served as a control. Initially, one rabbit was tested. Based on the results obtained 24 hours after application of the test element (TIA), the irritation response was confirmed by simultaneously testing two additional rabbits. Observations were made 1, 24, 48, and 72 hours after the TIA. The overall health condition was also verified. Individual scores of eye reactions after application Eye check Sex: Female rabbit number 123 Left Left Left application site Reaction Hour 72 Hour 48 Hour 72 1 24 48 1 24 72 1 24 48 Opacity: 0 0 0 0 0 0 0 0 0 0 0 0 Degree of density Iris 0 0 0 0 0 0 0 0 0 0 0 0 Conjunctiva 0 0 0 0 0 0 0 0 0 0 0 0 (Redness) Conjunctiva 0 0 0 0 0 0 0 0 0 0 0 0 (Chemosis) Treated eye Rabbit number 123 Law site Law Law application Reaction Time Time Time 1 24 48 72 1 24 48 72 1 24 48 72 Opacity: 0 0 0 0 0 0 0 0 0 0 0 0 Degree of density Iris 0 0 0 0 0 0 0 0 0 0 0 0 Conjunctiva 1 2 1 0 1 1 0 0 1 1 0 0 (Redness) Conjunctiva 1 1 0 0 1 0 0 0 1 0 0 0 (Chemosis) Individual observations of the cornea 24 h after application using fluorescein dye staining Control Eye Sex: Female Rabbit Eye Day Fluorescein Details of the number Control Observation response of corneal staining in the control eye 1 Left 1 Negative No damage to the corneal epithelium was observed 2 Negative No damage to the corneal epithelium was observed 3 Negative No damage to the corneal epithelium was observed 2 Left 1 Negative No damage to the corneal epithelium was observed 2 Negative No damage to the corneal epithelium was observed 3 Left 1 2 Negative Negative No corneal epithelium damage observed No corneal epithelium damage observed Treated eye Rabbit Eye Day Fluorescein Details of the Control No. Corneal staining observation response in the control eye 1 Right 1 Positive 25% corneal epithelium damage observed 2 Positive 10% corneal epithelium damage observed 3 Negative No corneal epithelium damage observed 2 Right 1 Positive 10% corneal epithelium damage observed 2 Negative No corneal epithelium damage observed 3 Right 1 Positive 10% corneal epithelium damage observed 2 Negative No corneal epithelium damage observed Based on the results of this study, the following are the classifications for the formulation under test: Globally Harmonized System of Classification and Labelling of Chemicals (GHS 2015) Chemicals): Not classified as an eye irritant EPA toxicity categories (December 2002): Category III. The present invention is explained more specifically by the examples provided above. However, it should be understood that the scope of the present invention is in no way limited to the examples. Anyone skilled in the art will appreciate that the present invention includes the examples provided and may also be modified and altered without departing from the novel lessons and advantages of the invention that are intended to be included within the scope of the invention. 1) Mesotrione copper chelate form I characterized in that it exhibits an X-ray diffraction pattern expressed in 20( + 0.2°) , which shows at least three of the following reflexes: 9.1, 10.6, 11.8, 13.7, 15.9, 16.6, 18.3, 21.4, 22.1, 22.4, 24.1 and 27.7.

Claims

1. A herbicidal composition characterized in that it consists of: a. a polymorph of a mesotrione copper chelate of form I exhibiting an X-ray diffraction pattern expressed in 2θ (± 0.2°), showing at least three of the following reflections: 9.1, 10.6, 11.8, 13.7, 15.9, 16.6, 18.3, 21.4, 22.1, 22.4, 24.1, and 27.7; b. S-metolachlor; optionally, a triazine herbicide; and at least one agrochemical excipient selected from solvents / carriers, surfactants, emulsifiers, dispersing agents, antifoaming agents, antifreeze agents, colorants, wetting agents, anticaking agents, structuring agents, viscosity modifiers, and binding agents. Three claims follow.