MXPA97009885A - Preparation of ammonium glifosate using aqueous ammonium hydroxide in a liquid-sol dereaccion system - Google Patents

Abstract

The present invention relates to a method for preparing a dry ammonium phytoactive composition N-phosphono-methylcylic capable of receiving a high load of one or two adjuvants characterized in that it comprises the step of: reacting aqueous ammonium hydroxide with N-phosphonomethylglycine in a conventional reactor system so that the moisture content of the reaction mass decreases constantly during the reaction

Description

PREPARATION OF AMMONIUM GLYPHOSATE USING HIDRQXIDQ OF AQUEOUS AMMONIUM IN A LIQUID-SOLID REACTION SYSTEM BACKGROUND OF THE INVENTION The present invention relates to a dry herbicidal composition, which is not agglomerated, and to a method for manufacturing said composition. More particularly, the present invention relates to an ammonium glyphosate herbicide and to an effective method for manufacturing solid ammonium glyphosate products which dissolves rapidly in water and which can be used to prepare solid and dry glycosate compositions containing adjuvants DESCRIPTION OF THE STATE OF THE ART The N-phosphonomethylglycine CHOOCCH, NH CH2 PO (0H) 2], which is commonly known as glyphosate acid or simply glyphosate, is widely known in the art as a highly effective herbicide. It is also known that glyphosate, an organic acid, has a relatively low solubility in water. Therefore, glyphosate is typically formylated as a water-soluble salt, particularly as the rnono-isopropylamine (IPA) salt to kill or control herbs or plants. Glyphosate is offered commercially in the form of its IPfi salt by Monsanto Company of St. Louis, Missouri (U.S.A.) ba or the trademark RoundupR. US Patent Nos. 3,799,758 and 4,405,531 issued to John E. Franz on March 26, 1974 and September 20, 1983 respectively, disclose various salts of glyphosate, methods for preparing glycosate salts, formulations of glycosate and application methods to kill and control herbs and plants. Other US patents disclosing glyphosate salts include U.S. Patent No. 4,315,765 issued to George B. Large on February 16, 1982, U.S. Patent No. 4,507,250 issued to Izak. Bakel on March 26, 1985, U.S. Patent No. 4,397,676 issued to Izal-Bakel on August 9, 1983, U.S. Patent No. 4,481 issued to Michael P. Prisbylla on November 6, 1984. and U.S. Patent No. 4,140,513 issued to Erhard 3. Prill on February 20, 1979. All of the patents mentioned are incorporated in their entirety to the present application by way of reference. The Roundup® brand herbicide is sold as a water-soluble liquid concentrate. However, efforts have recently been made in the relevant technical field to develop a formulation of water-soluble dry solid glyphosate that has an efficacy equivalent to that of Roundup *. The conventional reasons that motivate these efforts are those of economizing costs related to the packaging, shipping and storage of a solid formulation with respect to a liquid one. As can be appreciated, the aqueous concentrates include a significant amount of solvent that increases the volume and weight of the container containers and increases the costs related to the post-manufacture distribution of the product on the market. A less obvious benefit lies in the advantage of making dry glyphosate, soluble in water. Specifically, it is believed that granulated formulations offer superior handling characteristics (i.e., controlled losses) and 1. 0 are substantially lighter and less awkward to transport (and often to manipulate), making the product better suited to use in remote geographic locations. However, the manufacture of a granulated glyphosate formulation involves overcoming inherent disadvantages L5 related to higher production costs and comparative complexity of composing a solid product from a combination of liquid and solid reagents instead of manufacturing a product in solution with the same reagents. Various methods are known for making a The composition contains water-soluble solid glyphosate salt. For example, U.S. Patent No. 5,047,079 issued September 10, 1991 in the name of Djafar, discloses a method for preparing a phytotoxic composition comprising mixing an isopropylamino salt.

-K hydroscopic highly hygroscopic glyphosate acid with a fused surfactant to form a matrix, the surfactant being a solid at room temperatures. In U.S. Patent No. 5,070,197, issued December 3, 1991 to Chin, et al., There is disclosed an extrusion method in which a Bronsted acid, for example N-phosphonomethylglycine, is intimately mixed with hydroxyl hydroxide. Sodium in an extruder to produce a granular extrudate having a residual moisture content of no more than 10%. Another method that includes the production of a dry sodium glyphosate composition, but not including extrusion, is described in the PCT application of Publication No. UO 87/04595. In U.S. Patent No. 5,266,553, issued on November 30, 1993 to Champion et al., There is disclosed a method for preparing a bentazon salt or a herbicide containing a carboxylic acid functionality that includes repeated treatments of the salt with a neutralizing base selected from the group consisting of ammonia, an alkylamine, a hydroxyalkylamine, an alkali metal salt of an alkali metal and combinations thereof. In French Patent Publication No. 2,692,439 which was filed on May 19, 1993 and has been assigned to Productos Osa SACIFIA, a phytotoxic preparation comprising the monoammonium salt of N-phosphonomethylglycine in powder form is generally described. granules in combination with a wetting agent, surfactant and / or a powdery additive. As exemplified in the reference, the rnonoaronium salt is derived from reacting glyphosate acid with ammonium bicarbonate. U.S. Patent No. 5,324,708, issued June 28, 1994 to Moreno, et al., Discloses a composition and related methods for making and using a non-hygroscopic glyphosate ammonium salt such as rnono salt. isopropylammonium of N- (phosphono-methyl) -glycine and the mono-isopropylammonium salt of (3-amino-3-carboxypropyl) -rnetaphosphonic acid in dry powder form Csic]. In the publication of the PCT Application Nro UO 94/10844, published on May 26, 1994, a dry glyphosate composition is disclosed in which N-phosphonornetylglycine is mixed with, among others, a non-caustic, inorganic or organic basic material, such as diarrhonium phosphate or a basic guanidine salt such as guanidino acetate. In EPO Application Publication No. 0 394 211, published on October 24, 1990, an invention is disclosed comprising a dry pesticidal composition and related methods for using and producing them. More particularly, the invention relates to a greater solubility of the pesticidal composition that is achieved by adding an effective amount of an organosilicone block copolymer or a fluorocarbon wetting agent. In the EPO Patent Application Publication No. UO 90/072775 published on July 12, 1990, an invention is disclosed by means of which water-soluble granular glyphosate compositions are manufactured by means of the mixing steps, granulating, drying, spraying and extruding. In PCT Patent Application Publication No. URO 92/12637, which was published on August 6, 1992, an invention is disclosed that relates to dry water-soluble glyphosate that includes a composition comprising substantially unreacted glyphosate, an acidic acceptor such as sodium acetate and a liquid or solid surfactant. lf) All prior patents and publications are hereby incorporated by reference. In the related art, as described, it is appreciated that considerable efforts have been made towards the formulation of compositions and related methods for manufacture and use dry glyphosates. However, none of the aforementioned references discloses a practical method for producing a water-dispersible, water-dispersible, substantially non-hygroscopic, water-dispersible, ammonium glyphosate composition that is capable of absorbing and adsorbing a level. exceptionally high of adjuvants from N-phosphonomethylglycine and the relatively inexpensive aqueous ammonium hydroxide on an industrial scale and at an acceptable cost. Therefore, there is an unmet need for current technology whose solution is found in this invention, which meets these and other objectives.

BRIEF DESCRIPTION OF THE INVENTION The unresolved needs of current technology are met by the present invention which provides a dry ammonium glyphosate composition regulating plant growth and herbicide and a new method for producing the composition, with which the disadvantages related to the known dry compositions and the related methods that have been described are overcome by means of limitations hitherto unknown and undisclosed. According to the present invention glyphosate acid is loaded in, for example, a mixer, for example in a ribbon mixer where it is mixed and then, if necessary, partially pre-dried by recirculation through a grinding / drying system by hot air. While the acid is continuously recirculated, a cooled ammonium hydroxide solution is added, for example by spraying, at a certain critical rate, to react with the acid. After adding a specific amount of ammonium hydroxide, the reaction mass / reaction product, which is in powder form, is suitable for its final use as a herbicide or as a plant growth regulator. In addition, and perhaps in a more important aspect, the product of the reaction in powder form - because of its highly absorbent and adsorbent character, can be further formulated to absorb / adsorb an exceptionally high level of an adjuvant such as a wetting agent. , an anti-foaming agent and particularly a surfactant composition. Therefore, when formulated in this way, a highly desirable product loaded with coadjuvants is formed which is in all its aspects as good and effective as the comparable products obtained by the processes of the prior art which require more expensive raw materials. Optionally, the reaction product in powder form or the product loaded with adjuvants can be granulated to provide an herbicide and / or plant growth regulator of ammonium glyphosate that slides freely (ie, does not form lumps) soluble in water and substantially free of dust It is also possible to carry out other optional processes using the reaction product in powder form. For example, the powder can be further ground or dried before packaging. The significant advantages achieved by the present invention lie in its relative simplicity, its low comparative costs and in the fact that highly specialized equipment is not required for the practice of the invention. Therefore, when conventional mixing and milling / milling equipment is already in place, the present invention can be practiced effectively on a commercial scale to produce high amounts of the dried ammonium glyphosate product. BRIEF DESCRIPTION OF THE FIGURE Figure 1 is a schematic diagram illustrating the process for preparing dry ammonium glyphosate according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention relates to a novel method for reacting N-phosphonomethylglycine (glyphosate acid?) With ammonium hydroxide to produce ammonium glyphosate powder, a key raw material that can be used as it is or in a granular composition of dry glyphosate loaded with surfactant. Until now, a comparatively economical, efficient and practical method of producing dry ammonium glyphosate powder capable of being formulated to absorb / adsorb an exceptionally high level of a coadjuvant using aqueous ammonium hydroxide was not known. Instead, various less advantageous alternative methods have been developed by means of which ammonium glyphosate as well as alkali metal glyphosates such as sodium glyphosate have been converted to dry powder form. For example, has sodium glyphosate been produced by reacting glyphosate acid? with sodium acetate or by extrusion of the acid with sodium hydroxide as described in PCT Patent Application Publication No. UO 92/12637 and U.S. Patent No. 5,070,197 respectively. Hitherto, the granules and powders of sodium glyphosate have been used to produce satisfactory compositions of dry glyphosate. However, when compared to ammonium glyphosate salt compositions, the sodium salt is much more hygroscopic, which means that it is not so ID resistant to ambient humidity. Therefore, the sodium glyphosate salt is considered more difficult and expensive to process as a dry composition and, once formed as such, has a greater tendency to agglutinate with which undesirable "cakes" of the finished material are produced. L5 fidernás, due to the relative molecular weight of ammonia and sodium, the sodium glyphosate salt compositions have a lower concentration of active glyphosate than the equivalent glyphosate ammonium salt compositions. In addition, the cost per pound of the sodium cation is much more expensive than the cost of obtaining the ammonium cation. The comparative disadvantages of the sodium glyphosate compositions are, therefore, obvious. As noted above, some solid / solid reaction methods are known for making dry ammonium glyphosate. For example, it is believed that by reacting ammonium bicarbonate with glycoside acid, as described i 1 in French Publication No. 2,692,439 a dry ammonium glyphosate composition is obtained. The invention described herein, however, constitutes an advance in the art of making dry ammonium glyphosate even with respect to other known methods using ammonium bicarbonate. For example, in the practice of the present invention, which includes reacting liquid ammonium hydroxide with solid N-phos-fonomethylglycine, it has been observed that the cost per pound of obtaining the ammonium cation derived from ammonium bicarbonate is about ten. Twenty times more expensive than the cost per pound to obtain an equivalent amount of the same cation from ammonium hydroxide. In the large-scale production of ammonium glyphosate, this cost difference alone is a strong argument in favor of an effective method, such as that of the present invention, for producing a solid ammonium glyphosate using ammonium hydroxide as a source of the ammonium cation. As it is used in this documentation, the terms "solid" and / or "dry" refer to the physical state in which the formulation has a specific shape and volume and resists deformation. The solid may take the form of pellets, flakes, granules, powder or the like. Furthermore, it is understood that the solid formulation can be subsequently dissolved in a suitable diluent, generally and preferably water, and applied to the locus in which the regulation or eradication of the plants is desired either by spraying or by other conventional means. From a technical perspective, the simple mixing of N-phosphonornetylglycine in the commercially standard form of "wet cake" (ie, with a moisture content of about 6-20 percent by weight) with liquid ammonium hydroxide in stoichiometric amounts produces a viscous product, with a dough aspect, which is not compatible with conventional equipment for further processing. Said product has a physical character totally different from the product generated by the process of the present invention. Therefore, the strict monitoring of the process of the present invention and the shape and extent to which the reaction between the glycosate acid and the ammonium hydroxide are controlled according to the process, are critical to ensure the creation of a salt of water-soluble ammonium glyphosate (ie, not forming cake), which, in one important aspect, is capable of being further formulated to absorb / adsorb an exceptionally high level of adjuvants as surfactants. In accordance with the process of the present invention, the reagent mixture is dried and conditioned to maintain a suitable moisture content during the step of adding ammonium hydroxide so as to generate a fluidly flowing, easily manipulable powder. This not only allows conventional equipment to be used, but also produces a powder of ammonium glyphosate that can be used to manufacture dry glyphosate products highly loaded with adjuvants. The inventors have determined that the moisture content in the reaction mass during the addition of ammonium hydroxide to glyphosate acid is a critical aspect of the present invention. The amount of ammonium hydroxide that is required for the practice of the invention is equivalent to the amount that is required to achieve a neutralization of about 95-105% of the acid that can be determined by conventional analytical methods known to those of ordinary skill. of the technique, such as by pH measurement. According to the process of the present invention, the wet cake is charged in a conventional suitable mixer. A predetermined amount of sodium sulfite can be added to prevent the possible formation of nitrosamines. Although the addition of sodium sulfite is not necessary for the practice of the invention and does not affect the reaction between glyphosate acid and ammonium hydroxide, some governmental regulations require that nitrosamine levels in products of this nature be less than 1. ppm. Experience indicates that, when aggregated, the effective range of sodium sulfite that must be added to ensure against the presence of unacceptable levels of nitrosarnines is between 0.2 and 1.0 percent by weight of the dry and finished product. A pre-drying step, if necessary, is then carried out during which the wet cake and, if desired, the sodium sulfite are circulated continuously through a hot air and grinding system which is arranged in communication with the mixer. The drying air is maintained at a constant and high temperature of about 170 to 300 degrees Fahrenheit (76.7 to 148.9 ° C), preferably between 250 ° and 270 ° F (121.1 to 132.2 ° C) and the mixture is circulated in a continuous manner until the total moisture content is below about 6% by weight. To determine the existence of this condition, a sample of the mixture is recovered and tested. If the moisture content of the wet cake of raw material is already less than about 6% by weight, the pre-drying step is unnecessary. Next, the temperature of the air drying system is substantially reduced to a temperature of about 150 to 200 degrees Fahrenheit (65.5 to 93.3 ° C) as the mixture continues to circulate. A cooled solution of ammonium hydroxide is then added to the mixture, for example by spray application in the mixer, to form a reaction mass of ammonium glyphosate. A commercial ammonium hydroxide solution is used, preferably one containing approximately 29% by weight of ammonium. The solution is first cooled to approximately 40 to 50 degrees Fahrenheit (4.4 to 10 ° C) because it is known that liquid ammonium hydroxide is volatile and boiling at 86 degrees Fahrenheit (30 ° C). Therefore the loss of ammonium hydroxide is controlled and the possibility of atmospheric pollution is reduced by the evaporation of the solution. The form and speed at which ammonium hydroxide is introduced are very significant. Preferably, the solution is sprayed, by one or more nozzles in the mixer containing the wet cake and sodium sulfite, if any, using a coarse spray. The flow of the sprayed solution is run so that the moisture content of the reaction mass decreases from the initial concentration of about 6% by weight to about 2% by weight (ie, loss of weight upon drying or LOD) or less, during the period in which the ammonium hydroxide is added and the exothermic reaction occurs. Under the specified process conditions, the spray rate of ammonium hydroxide is designed to control the rate at which water is introduced with the ammonium hydroxide and a reaction product is formed between the glyphosate acid and the hydroxide. of ammonium. The object is to introduce the water at a lower speed than the speed at which the moisture is removed from the wet cake / sodium sulfite mixture by means of the drying circulation system.

Ib Other aggregate speeds were experienced but these did not yield the highly desirable product generated by the present invention. For example, when the ammonium hydroxide was introduced under the same process conditions but at a 40% higher speed, the ammonium glyphosate powder produced had less absorption and adsorption capacity, making it unsuitable for further processing as the charge with coadjuvants and particularly with surfactants. Addition rates greater than 40% have an immediate adverse effect on the physical characteristics of the reaction mass; the reaction mass becomes a doughy and very wet mass that is inadequate to complete the process. In addition, for example if the mixture of glyphosate and sodium sulfite is not previously dried to less than 6% by weight, the material of the mixer also becomes very wet and pasty, which makes it unsuitable for use to complete the process. It will be appreciated that the pre-drying step can be avoided or abbreviated such that the content of the mixture of glyphosate acid and sodium sulfite can be initially greater than approx. 6% weight. However, it is also known that the rate of addition of ammonium hydroxide under such circumstances would be so low that the process would be economically impracticable. As the process progresses, samples should be obtained periodically for the analysis and measurement of moisture content to ensure that the water removal rate of the reaction is greater than the rate at which the water is added. This can be determined in a simple way by observing the progressive reduction in the moisture content of the mixture. The process conditions described should be maintained until all of the ammonium hydroxide has been added. At this point, the ammonium glyphosate is in the form of a powder product that can be subjected to further processing. Said additional processing may include: the addition of sodium sulphite, grinding, drying, granulation and formulation with coadjuvants. The decision as to which additional process, if any, should be made, depends largely on the intended use of the product. Regardless of the selection of the additional process, however, sodium sulfite may optionally be added again. Along with that step, the reaction mass can be ground again to make it more suitable for further processing. If additional processing such as granulation or formulation with adjuvants is to be carried out immediately, it is not necessary that the product be further dried in this step. However, if the product should be shipped or stored for more than a few days, for example, then it should be further dried to less than 1% by weight of moisture at this time to prevent the formation of cakes. When it is desired to use the product without the addition of adjuvants as a herbicide or as a plant growth regulator, then it is desirable to granulate or agglomerate it, for example by panning or drying or other methods known in the art. If it is desirable to produce a product containing adjuvants such as surfactants, anti-foam agents, wetting agents and the like, they may be added by mixing in a suitable mixer and preferably by kneading, extruding and drying or by other methods well known to connoisseurs of the technique. The following example illustrates the production of the composition of the invention according to the process described herein. All percentages are based on weight, unless clearly indicated otherwise.

EXAMPLE 1 In an industrial-scale reactor system comprising a stainless steel ribbon mixer, a hot air drying system such as an air-swept mill with hot air and an adapted dust collector, all of which are communicated with each other by medium of suitable conduits, 2400 pounds (1089.6 kg) of "wet cake" of standard grade N-phosphonomethylglycine was charged with a moisture content of about 10% LOD in a ribbon blender, where they were mixed immediately. Once all the wet cake had been deposited in the ribbon blender, 4.8 pounds (2.18 kg) of solid sodium sulfite were charged to the mixer and combined with the wet cake with which they were intimately mixed . The combination of wet cake and sodium sulfite was then circulated within the mill system with hot air sweeping using an inlet air temperature of approximately 250 ° F (121.1 ° C) for one hour. A sample of the mixture was then recovered and analyzed to determine its moisture content / LOD. When the moisture content of the mixture had been reduced to approximately 6%, the material continued to be circulated through the drying system and the inlet air temperature was reduced to approximately 170 ° F (76.7 ° C). Maintaining the air temperature inside the system at approximately 170 ßF (76.7 ° C), a solution of ammonium hydroxide (29% NH3) previously cooled to a temperature between 40 and 50 ° F (4.4 ° C) was pumped. C) and 50 ° F (10 ° C) to the ribbon mixer and sprayed coarsely through five adjustable nozzles on the glyphosate acid to form a reaction mass. A total amount of 730 pounds (331.42 ° C) of liquid ammonium hydroxide was introduced by spraying. Was a flow rate not exceeding 3.5 pounds fixed? (1.59 kg) / minute for feeding the liquid ammonium hydroxide. During the approximately 3.5 hours that were needed to feed the entire ammonium hydroxide solution, various samples of the circulating mixture were obtained and analyzed to ensure that the feed flow of ammonium hydroxide established for the progressive reduction of the moisture content of the reaction mixture. Upon completion of the ammonium hydroxide addition, the reaction mass was a free-flowing powder product particularly suitable for its immediate, immediate, desirable processing. In the process that gave rise to the present Example 1 it was intended that the reaction mass be processed further below. In view of this, the reaction mass, at this point, was conditioned so as to ensure that no cakes were formed during storage. First, however, an additional and equal amount of sodium sulfite was charged to the mixer and mixed for approximately ten minutes to ensure even dispersion with the powdered reaction mass. This combination was then comminuted by passing the composition as a dry powder through an air sorting mill to reduce the discrete particles of the composition to a substantially small and uniform size. Although the air sorting mill is? 1 used because it was part of the equipment used for Example 1, this grinding process is not necessary for the practice of the invention. After grinding, the product was subjected to conventional bed drying to ensure that the resulting finished product had a moisture content of not more than 1.0% LOD. From raw materials consisting of 2400 pounds (1,089.6Kg) of glyphosate acid (ie "wet cake with approximately 10% moisture), a total of 9.6 pounds (4.3 kg) of sodium sulfite (optionally) and 730 pounds (331.4 kg) of liquid ammonium hydroxide, a theoretical product of 2394 pounds (1,083.9 kg) of powdered ammonium hydroxide with a residual moisture content of approximately 0.5% was obtained In addition to possessing highly desirable qualities, the product obtained in connection with the preceding example has been shown to have excellent storage and stability characteristics, in fact, if properly stored, such as in sealed polyethylene bags, the product has been tested Do not degrade or regrind after more than six months of actual storage As discussed in more detail above, the powder reaction product / mass produced in accordance with the present invention is adapted particularly well for its additional formulation by absorption / adsorption of high levels of adjuvants. In combination, the relative simplicity of the present invention, its ability to be practiced using conventional equipment and the comparatively reduced costs of the ammonium cation provided by ammonium hydroxide make the ability of the product / reaction mass of powder to absorb / adsorb high levels of adjuvants is very significant. Although the selection of a particular adjuvant or a combination of adjuvants can be easily performed by those of ordinary skill in the art without undue experimentation, Example 2 illustrates the exceptional absorption and adsorption capacity of the product / mass of powder reaction when it is loaded with a surfactant.

EXAMPLE 2 The powder reaction product / mass formed by the process described in Example 1 can be used to make a dry formulation of ammonium glyphosate containing a high level of surfactant of at least about 20% by weight. To manufacture said highly charged product, 16 kilograms of the product / reaction mass powder is mixed with 4 kilograms of a polyoxyethylene alkylamine surfactant and, 4 kilograms of water in a batch mixer such as a Fuji Paudal, for approximately 10 minutes with water at a temperature of approximately 80 ° C circulating in the jacket. The mass that is formed is then extruded, for example in a Fuji Paudal twin-screw extruder, equipped with screens with holes of 1 nm in diameter. The extrudate obtained consists of short, "tagliatelle" cylinders, which did not stick to each other and which dried easily, for example in a Fitz-Ai e fluid bed dryer, without forming undesirable lumps. To illustrate the importance of the process of the present invention with respect to the absorbent and adsorbent characteristics of the product / mass of the powder reaction, a product was made according to all the variables of the process of the invention but in which the speed of feed of the ammonium hydroxide solution was 40% higher, obtaining a product that turned out to be undesirably moist and sticky to the touch. In addition, the extrudate produced therefrom consisted of undesirably long cylinders in the form of "noodles" sticking together and forming large conglomerates. This extrudate was very difficult to fluidize in the milkfluid dryer and resulted in the formation of a large quantity of dry agglomerates which, to be reusable, would have to be ground and recycled through the extrusion process.

Claims (20)

NOVELTY OF THE INVENTION CLAIMS

1. Method for preparing a dry ammonium phytoactive composition N-phosphono-methylcylicine capable of receiving a high load of one or two adjuvants characterized in that it comprises the step of: reacting aqueous ammonium hydroxide with N-phosphonomethylglycine in a conventional reactor system in a manner such that the moisture content of the reaction mass decreases constantly during the reaction.

2. The method of clause 1, characterized in that it further comprises the step of drying said N-phosphonomethylglycine before reacting it with said ammonium hydroxide.

3. The method of clause 1, characterized in that said ammonium hydroxide and said N-phosphonomethylglycine are reacted in approximately equivalent molar amounts.

4. The method of clause 1, characterized in that the reaction is carried out in a conventional mixing equipment such as a ribbon mixer.

5. The method of clause 1, characterized in that the moisture content of said reaction mass is constantly decreased through the reaction by circulating said reaction mass through a mill swept with air or the like using air heated to a temperature that '.j? ranges from 150 ° F (65.5 ° C) to 300 ° F (148.9 ° C).

6. The method of clause 2, characterized in that said drying is achieved by circulating said N-phosphonomethylglycine through a mill system swept with air or the like, using air heated to a temperature ranging from 230 ° F (110 ° C) ) and 280 ° F (137.8 ° C).

7. The method of clause 1, characterized in that said ammonium hydroxide is any commercially available ammonia water solution.

8. The method of clause 1, characterized in that the moisture content of said N-phosphonomethylglycine is in the range of between 7% by weight and 20% by weight.

9. The method of clause 5, characterized in that the air is heated to a temperature ranging from 150 ° F (65.5 ° C) to 200 ° F (93.3 ° C).

10. The method of clause 1, characterized in that said moisture content of said reaction mass is less than 2% by weight at the end of said reaction.

11. The method of clause 2, characterized in that the molar ratio of ammonia to N-phosphonomethylglycine in said reaction mass ranges from 0.95: 1.0 to 1.05: 1.0.

12. The method of clause 2, characterized in that said reactor system comprises at least one conventional mixer and hot air dryer and in which said N-phosphonomethylcylic is dried by circulation through said reactor system which is heated to a temperature that ranges from 250 ° F (121.1 ° C) to 280 ° F (137.8 ° C) until its moisture content is reduced to approximately 6% by weight or less.

13. The method of clause 2, characterized in that said ammonium hydroxide solution is an aqueous solution containing 29% weight of ammonia cation.

14. Method of preparing a phytoactive ammonium glyphosate characterized in that it comprises; (a) charging to a suitable reactor system a first molar amount of wet cake of glyphosate acid with a moisture content of up to about 20% by weight; (b) introducing a second molar amount, equivalent to said first molar amount, of ammonium hydroxide to said reactor system containing said glyphosate acid; and (c) controlling the reaction that occurs between said glyphosate acid and said ammonium hydroxide in such a way that the moisture content in the reaction mass / product produced decreases correspondingly.

15. The method of clause 14 characterized in that it further comprises the step of pre-drying said glyphosate acid in order to reduce its moisture content between 5% by weight and 8% by weight before the introduction of said ammonium hydroxide.

16. The method of clause 15, characterized in that said pre-drying is achieved by circulating said glyphosate acid through a hot air dryer that is part of said reactor system. 7 7

17. The method of clause 16, characterized in that the temperature of the air within said hot air dryer ranges from 200 ° F (93.3 ° C) to about 300 ° F (148 ° C) during said pre-drying.

18. The method of clause 17, characterized in that said glyphosate acid continues to circulate through the hot air dryer of said reactor system during the passage in which said ammonium hydroxide is introduced and the temperature inside said dryer by hot air , before the introduction of said ammonium hydroxide, it is reduced to a value that ranges between 150 ° F (65.5 ° C) and 180 ° F (82.2 ° C) and it is maintained until the feeding of the ammonium hydroxide is complete. said ammonium hydroxide.

19. The method of clause 18, characterized in that said ammonium hydroxide is first cooled to a temperature ranging from 40 ° F (4.4 ° C) to 50 ° F (10 ° C) and then introduced into said reactor system and glyphosate acid is reacted with coarse spray.

20. The method of clause 19, characterized in that said reaction mass / product is a highly absorbent, adsorbent, free-sliding powder with a moisture content of approximately 2% by weight or less.