BRPI0702341B1 - soluble solid glufosinate for pesticide, process for obtaining it and process for controlling agricultural pests - Google Patents

Abstract

soluble solid glufosinate for pesticide, process for obtaining it and process of agricultural pest control. The present invention describes agricultural pesticides comprising dry and water soluble solid glufosinate as well as the process for their production. The product of the invention comprises glufosinate ammonium salt in high purity (95 to 100% purity) and low moisture content <1.0% w / w. The production process is based on the reaction in a solid / liquid / solid system between a solid ammonium salt and solid acid glufosinate dispersed in a non-aqueous liquid organic medium. The product of this reaction has adequate water solubility and can be used directly as a pesticide or as an ingredient in the preparation of glufosinate salt-containing compositions in various adjuvant combinations. The production process of the invention has, among others, the following advantages over known counterparts: it requires less investment for industrial facilities; Operating costs are lower, safety for operators is higher; The production process is environmentally improved, as the inputs used, besides being less toxic to the environment, are reusable and or recyclable. furthermore, the process of the invention does not entail the technical problem of heat formation, and the product of the invention comprises the high purity solid form glufosinate ammonium salt. As the product of the invention contains low water concentration, it substantially reduces the technical problems and costs involved in its transportation.

Description

Inventive Patent Descriptive Report Soluble Solid Glufosinate for Pesticides, Process for Obtaining and Pest Control Processes Field of the Invention The present invention relates to pesticides and processes for their production. More specifically, the present invention relates to a process for producing the glufosinate ammonium salt, at high purity (95 to 100% purity) and low moisture content (<1.0% w / w). The production process is based on the reaction in a solid / liquid / solid system between a solid ammonium salt and solid acid glufosinate dispersed in an organic medium. The thus obtained glufosinate ammonium salt is insoluble in the reaction medium and either low solubility in this medium, thus allowing its isolation as a solid with high purity and concentration. The product of this reaction has adequate water solubility and can be used directly as a crop protection product or as an ingredient in the preparation of glufosinate salt-containing compositions in various adjuvant combinations. Glufosinate ammonium salt is a well-known active ingredient for the production of herbicides used in various agricultural crops.

BACKGROUND OF THE INVENTION The patent literature on the subject is vast, indicating the relevance of the sector and the continuous pursuit of improvements and innovations. However, none of the documents found anticipate the objects of the present invention and do not even suggest it, even indirectly, as will be shown in more detail below.

Glufosinate (4-hydroxy (methyl) phosphinoyl] -DL-homoalanine or DL-homoalanin-4-yl (methyl) phosphinic acid) is known in the art as an effective herbicide. Glufosinate is an only weakly organic acid. water soluble, being typically marketed formulated and applied as a water soluble salt such as ammonium salt.

U.S. Patent 4,168,963 to Hoechst AG, entitled "Herbicidal Agents", was filed May 16, 1977. Said document describes herbicidal ingredients containing a general formula in which the glufosinate falls within. That document also reports that substances with such a structure have potential herbicidal action and can be applied in various forms, such as emulsifiable concentrations, wet powder, sprayable solutions etc., as well as pointing out desirable conditions for each use.

U.S. Patent 5,308,827 to Fumakilla Ltd. entitled "Herbicidal Foam Composition" was filed February 24, 1996. Said document discloses a herbicidal composition comprising, on the basis of the total weight of the composition, (a) a herbicide comprising glufosinate or a mixture thereof and other herbicides, (b) an anionic and / or non-anionic surfactant, (c) a solvent, (d) a foam controlling agent, (e) water as a diluent and (f) liquefied petroleum gas as a propellant. The pH of said composition is adjusted between 3-11. This document seeks to solve drawbacks around the use of herbicides in the solid, liquid (aqueous solutions, emulsions) and gas (aerosol) phases.

Hoechst AG U.S. Patent 5,491,125, entitled "Liquid herbicidal formulations of glufosinate", was filed December 1, 1992. This document points to the use of glufosinate in high temperature resistant liquid herbicides. , better herbicidal action when compared to other formulations, good resistance to rain (preventing the herbicide from being washed) and small addition of organic solvents.

Hoechst AG U.S. Patent 4,830,658, entitled "Herbicidal Compositions", was filed on October 30, 1986. Said document discloses herbicidal compositions containing as an effective herbicidal ingredient amounts of phosphinothrocin derived from a general formula. (where glufosinate can originate from) in combination with SIMAZIM. The weight ratio of phosphinitrocin and SIMAZIM is in the ratio of 1: 1.5 to 1: 4, exhibiting an increase in effective herbicidal capacity.

Ishihara Sangyo Kaisha U.S. Patent 5,391,539, entitled Herbicidal composition comprising glufosinate and a heterocyclic sulfonylurea herbicide, was filed December 3, 1986. That document discloses compositions comprising as active ingredients 1 - 1. {4,6-dimethoxypyrimidin-2-yl) -3- {3-trifluoromethyl-2-pyridylsulfonyl) urea and a homoalanin-4-yl (methyl) phosphinic acid ammonium salt (better known as ammonium glufosinate salt), obtaining a composition containing more effective herbicidal characteristics than those observed in these substances alone. [0009] U.S. Patent 4,692,541 to Hoechst AG entitled "Phosphorus-containing α-amino nitriles and a process for their preparation" was published in 1987. Said document discloses a process for the preparation of a compound of formula I: wherein R1 is (C1 -C6) alkyl which is unsubstituted, monosubstituted or polysubstituted by halogen or by alkoxycarbonyl, or is (C6 -C10) -aryl, (07 -C10) -alkyl, or (03 -C10) -cycloalkyl, -R2 is (C1 -C6) -alkyl which is unsubstituted, monosubstituted or polysubstituted. halogen, or is (C 6 -C 10) -aryl, (C 7 -C 10) -alkyl, or (C 3 -C 10) -cycloalkyl, -R 3 is hydrogen, (C 1 -C 6) alkyl or -phenalkyl, (C 1 -C 6) -acyl, (01 -C6) -alkoxycarbonyl, or (C6-010) -aryloxycarbonyl, and -n is zero or one which comprises the reaction of a compound of formula II: wherein R4 and R5 independently of one another are (C1-C6) -acyl, (C1-C6) alkoxycarbonyl, phenoxycarbonyl or naphthoxycarbonyl in the presence of alkali metal cyanides with amines of formula H2 H-R3.

U.S. Patent 5,420,329 to Hoechst AG entitled "Process for the Preparation of L-Phosphinothricin and Its Derivatives" was published in 1995. That document discloses a process for the enantioselective preparation of L-phosphinothricin or derivatives thereof: from the reaction of an L-vinylglycine derivative with a methanophosphonic acid monoester of the formula: in the presence of a catalytic amount of a free radical initiator selected from the group consisting of t-butyl perbenzoate, t-butyl perp iva lato, t-butyl perethylhexanoate, t-butyl perneodecanoate, or azobisisobutyronitrile and combinations thereof, at temperatures from 70 ° C to 115 ° C. Alternatively, the process may include conversion of the compound obtained in the first step by hydrolysis or aminolysis. , in a structurally different compound, optionally converted to its salt [0011] ICI Australia Operations Proprietary Limited EP 0321527 Water dispersible granules, was issued August 12, 1992. This document describes formulations of agricultural chemicals used, and more particularly to methods for preparing water dispersible granules containing such chemicals. The object of said document is a process for preparing water dispersible granules containing active agricultural agents such as herbicides and / or fungicides and / or insecticides. The process consists of mixing the active ingredient (s) with a surfactant in the presence of water to form an extrusable wet mass, which is then extruded and then rotated for at least 30s under rotation between 1 and 100 rpm to break up the extruded mass and form granules, optionally dried thereafter.

Brazilian patent application PI 0101302, filed by Sumitomo Chemical Company and entitled "Solid Pesticide Formulation", was published on February 13, 2002 and is pending examination. Such document describes a solid pesticide formulation comprising: (a) 0.1 to 75% by weight of an actively pesticidal agent; (b) 0.3 to 40% by weight of a dispersant; (c) 0.3 to 20% by weight of a wetting agent; (d) 0.1 to 30% by weight of a boron compound selected from the group of boron oxide, boric acid and borate; (e) 0.1 to 95% by weight of a water soluble carrier; and (f) 0.1 to 30% by weight of smectite.

Monsanto Company International Patent Application WO 9702742, entitled "Improved Formulations Having Enhanced Water Dissolution", was filed July 11, 1996. This document describes dry, water-soluble and particulate, pesticide-acceptable compositions. Said compositions consist of at least one pesticide and a silicone copolymer or a fluororganic compound (or a combination of both) as wetting agent. Such composition aims to obtain cylindrical pellets with a diameter of 1mm and an average length of 3mm, being completely dissolved or dispersed in at least half the time of the similar compositions.

Rhone-Poulenc Agrochimie US Patent 6,274,156, entitled "Agrochemical Compositions in the Form of Dispersible Granules", was filed June 1, 1999 and granted August 14, 2001. Such document describes a composition. homogeneous agrochemical formed by mixing two compositions in the form of water dispersible granules. The solid composition consists of a homogeneous mixture of: (1) at least one concentrated composition A in the form of dispersible granules containing active ingredient and without any effervescent agent having a cumulative pore volume of 0.17 to 0.35 ml / g an apparent density between 0.35 and 0.8 g / cm3; and (2) a concentrated composition B in the form of dispersible granules, containing an effervescent agent and not containing active ingredient, the effervescent agent containing: (a) an alkaline carbonate or hydrogen carbonate; and (b) an acid, wherein the acid / carbonate weight ratio is between 0.3 and 30, and the granules of composition B have a cumulative pore volume of 0.020 to 0.13 ml / g and an apparent density of 0, 8 to 1.5 g / cm3.

Nippon Soda Co. European Patent EP 0 853 883 entitled "Agricultural Chemical Composition with improved raindrop resistance" was filed June 6, 1997 and granted August 13, 2003. Such document describes a composition. herbicide with improved rainfall resistance consisting of 0.1-70 wt% of a pesticidal agent and 10-50 wt% sorbitan trioleate. Said composition may optionally also contain other solvents and may be in the form of wettable powder, concentrated suspension or water dispersible granules.

Patent application PI 9205234-7 (equivalent to US 5,324,708), filed by Alkaloida Vegyeszeti Gyar and entitled "New Non-Hygroscopic Mono-Ammonium Salts", was filed in 1992 and rejected in April 2000. said document discloses salts of glufosinate or glyphosate monoisopropylamine, as well as processes for obtaining them. Herbicide products and pest control method are claimed and there is no process claim. The processes for obtaining such salts are based on the reaction of the respective phosphinic or phosphonic acid in solid form in a reactor containing an organic polar solvent in which the respective acid and salt formed are only partially soluble with an alkaline soluble reagent. said organic polar solvent. Said alkaline reagent is monoisopropylamine, also known as M1 PA, the reaction being therefore a solid / liquid / liquid system. Among the many disadvantages of the products and processes disclosed in this document, the following stand out: the products obtained are Ml PA salts of glufosinate or glyphosate, whose salts dissolution in water is highly exothermic, making it difficult for the farmer to use and causing undesirable risks. at the time of handling; The use of MIPA in an industrial plant is highly hazardous because in addition to being very toxic (considered to be IDLH immediately dangerous to Life and Health) MIPA is also flammable; The reaction between MIPA and phosphinic or phosphonic acid is also exothermic, requiring sophisticated process control on an industrial scale and the related energy costs.

In summary, no prior art process has been found for obtaining glufosinate ammonium salt having as its inventive concept the reaction in a solid / liquid / solid system between a solid ammonium salt and solid acid glufosinate, dispersed in a non-aqueous liquid organic medium. This innovation provides insoluble glufosinate ammonium salt in the reaction medium, thus allowing its direct isolation as a solid with high purity and concentration, and does not use gaseous or liquid anhydrous ammonia as a source of ammonium cations. It should be noted that the equipment required for the process of the present invention is much simpler and less expensive compared to the equipment required for obtaining glufosinate ammonium salts from known processes. In addition, the drawbacks of handling anhydrous or liquid ammonia are known, both from a safety and environmental point of view, which requires additional investment to meet the requirements of safety and environmental standards. These and other disadvantages of processes and products known in the art are overcome by the process and product of the present invention.

SUMMARY OF THE INVENTION The present invention has as its object to provide an improved process of producing the glufosinate ammonium salt in solid form. The product obtained by this process is also an object of the present invention and is usable in various presentations, as well as in various formulations including combinations with other herbicides, insecticides, acaricides and or fungicides.

It is also an object of the present invention to provide a production process that requires less investment for industrial facilities, since the equipment and unitary operations used are simpler than known similar processes.

It is also an object of the present invention to provide a production process whose operating costs are lower as it uses cheaper and available inputs than those used in known similar industrial processes.

It is also another object of the present invention to provide a safer production process for operators as it uses less toxic and less hazardous inputs than those used in known similar industrial processes.

It is also yet another object of the present invention to provide an environmentally improved production process, as the inputs used, in addition to being less toxic to the environment, are reusable and or recyclable, in contrast to those used in known similar industrial processes.

In a preferred aspect of the invention, therefore, being yet another object of the present invention, the process conditions for obtaining the glufosinate ammonium salt do not entail the technical problem of heat formation, as occurs in known similar industrial processes. .

In another preferred aspect of the invention, and therefore still another object of the present invention, the product of the invention comprises the high purity solid form glufosinate ammonium salt, as opposed to the products of the present invention. In other preferred aspect of the invention, and therefore still another object of the present invention, the product of the invention contains low water concentration, substantially reducing the technical problems and costs involved in transporting it. when compared to products obtained by known similar industrial processes.

[0026] These and other objects of the invention will be immediately appreciated by those skilled in the art and companies having an interest in the segment, and will be described in sufficient detail for their reproduction in the following description.

BRIEF DESCRIPTION OF THE FIGURE Figure 1 shows a flowchart of one of the preferred embodiments of the process of the present invention for producing industrial scale glufosinate ammonium salt, wherein: a steel stirring tank (A) is indicated. stainless steel; a stirred stainless steel reactor (B) which also includes a dryer and filter; a capacitor (C); a recovery column (D); and material flow lines (1), (2), (3), (4), (5), (6), ¢ 7), (8), (9), (10) and ¢ 11) .

DETAILED DESCRIPTION OF THE INVENTION The inventor, in search of an alternative solution to the various technical problems cited, has developed a new and improved process for obtaining high purity and concentrated solid glufosinate ammonium salt as well as developing new and improved ones. The following is an improved process for obtaining the high purity dry solid glufosinate ammonium salt. The term solid and dry employed herein means the physical state in which the product is obtained. For purposes of the present invention all concentrations are indicated in% mass / mass (or% w / w) unless expressly stated otherwise. Glufosinate ammonium salt is obtained by reaction between acid glufosinate in wet or dry cake, preferably with insoluble ammonium salts and suspended in an organic reaction medium, under constant stirring and at room temperature (the reaction is not exothermic). ), with sufficient post-reaction time for the reaction to complete. The production process is based on the reaction in a solid / liquid / solid system between a solid ammonium salt and solid acid glufosinate, dispersed in a liquid organic medium.

The glufosinate ammonium salt thus obtained is insoluble in the reaction medium and or has low solubility in this organic medium, thus allowing its isolation as a solid with high purity and concentration. The product of this reaction, although insoluble in the reaction medium, has adequate water solubility and can be used directly as a pesticide or as an ingredient in the preparation of glufosinate salt-containing compositions in various adjuvant combinations. The product obtained (glufosinate ammonium salt) is then isolated and optionally dried by classical methods. The mother liquor can be recycled to the next batch without prior treatment, preferably for up to five cycles and then recovered by simple distillation.

Preferably, the ammonium salts used in this process are hydrogen ammonium carbonate and / or ammonium carbonate. The reaction medium preferably employs organic compounds used as solvents and having the required characteristics of very low solubility. of the final product in said reaction medium. Most suitable and preferably employed in the process of the invention are alcohols of up to four carbons, preferably ethanol, due to their low cost, low toxicity and high availability. The following examples illustrate, but do not limit, the embodiments of the present invention.

Example I

In a reactor equipped with a mechanical stirrer, 810.0 g of commercial ethyl alcohol (96%), 372.8 g of 95.5% solid acid glufosinate (2.00 moles) were charged. Immediately thereafter, 100.8g of ammonium carbonate (1.05 moles) was charged and the reaction mixture was kept at room temperature and stirred for approximately 30 minutes to complete the reaction. Said reaction can be simply described as: The contents of the reactor were then filtered and the product dried to constant weight. The mother liquor was recycled for the next batch. The yield was 370 g of glufosinate ammonium salt with <1.0% w / w humidity and> 95.5% purity.

Example II

In a reactor equipped with a mechanical stirrer, 810.0g of commercial ethyl alcohol (96%) and 416.4g of 85.5% acid glufosinate (2.00mol) were charged to a wet cake. Immediately thereafter, 100.8g of ammonium carbonate (1.05 moles) was charged and the reaction mixture was kept at room temperature for at least 30 minutes to complete the reaction. The reactor contents were then filtered and the product dried to constant weight. The mother liquor was recycled for the next batch. The yield was 368 g of glufosinate ammonium salt with <1.0% w / w humidity and> 95.5% purity.

Example III

The conditions of example I were repeated using 810.0g of 98% methyl alcohol now. The yield was 368 g of glufosinate ammonium salt with <1.0% w / w humidity and> 95.5% purity.

Example IV

The conditions of Example I were now repeated using 162.0g of ammonium hydrogen carbonate. The yield was 366 g of glufosinate ammonium salt with <1.0% w / w humidity and> 95.5% purity. The results were similar, but this one had a higher specific consumption due to its stoichiometric ratio.

Example V

The conditions of example III were repeated using 162.0g of ammonium hydrogen carbonate (2.05moles). The yield was 319 g of glufosinate ammonium salt with <1.0% w / w humidity and> 95.5% purity. The results were therefore similar in terms of yield and purity.

Example VI

The process of the present invention has also been evaluated on an industrial scale. Referring to Figure 1, it is shown that line (1) feeds the stirring tank (A) equipped with mechanical stirrer with commercial ethyl alcohol (96%), while line (2) feeds solid acid glufosinate. 95.5% to the same agitation tank (A), kept under agitation to obtain homogeneity. Then line (3) feeds the contents of the agitation tank (A) to reactor (B), which is also fed by line (4) with ammonium carbonate. The reaction mixture is then kept at room temperature and under stirring for approximately 30 minutes for the reaction to complete. The reaction conducted in reactor (B) can be simply described as: The contents of the reactor are then filtered, the residual liquor containing the alcohol being directly reused or optionally fed from the line (7) to a recovery column (D). . The final product, the solid glufosinate ammonium salt, is obtained in line (9) and, after drying to constant weight, has <1.0% w / w humidity and> 95.5% purity. The yield obtained in this preferred embodiment of the invention is above 98%. It is to be noted with reference to Figure 1 that the production unit is very simple and does not involve any utilities (steam, ice water etc.) and It is recommended to use only N2 to control the atmosphere inside the vessels, to ensure inert atmosphere according to Brazilian standards. The gases formed in reactor (B) may preferably be treated in a condenser (C). Solvent recovery for reuse is very simple in steamed installations.

The Glufosinate Ammonium Salt obtained by the process of the present invention is an active that can be used in various forms of presentation, as well as in various formulations, including combinations containing other herbicides, insecticides, acaricides and fungicides. It is understood that anyone skilled in the art of process development can propose process changes by combining alcohols and other solvents that offer the characteristics of this process, but this does not alter the principle of this invention.

Those skilled in the art will appreciate the knowledge presented herein and may reproduce the invention in the embodiments disclosed and in other embodiments within the scope of the appended claims.

Claims (5)

Process for obtaining a solid glufosinate ammonium salt comprising a reaction with the following steps: adding solid acid glufosinate in a liquid organic medium selected from the group consisting of: an organic solvent; an alcohol of up to four carbon atoms; other alcohol; or combinations thereof; adding to said medium a solid ammonium salt selected from the group comprising ammonium carbonate, ammonium hydrogen carbonate, or combinations thereof; and - homogenize to complete reaction, forming ammonium glufosinate which is insoluble in said organic medium and precipitates, being separated, Process according to Claim 1, characterized in that the solid ammonium salt is ammonium carbonate and / or the liquid organic medium is ethane. Process according to Claim 1 or 2, characterized in that, upon completion of said reaction, the reaction product is separated from the liquid organic medium and obtained as water-soluble solid ammonium glufosinate, of equal or greater purity. 95% w / w and / or humidity of 1% w / w or less, Process according to any one of claims 1-3, characterized in that it is conducted at room temperature and without significant heat formation. Process according to any one of claims 1-4, characterized in that said liquid organic medium is directly reused in another reaction batch or optionally recycled.