Treatment of m-(phosphomethyl)glycine |
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IPC classes for russian patent Treatment of m-(phosphomethyl)glycine (RU 2369611):
 Polymorphic modification of a ibandronate / 2368617
Invention relates to a new crystalline polymorphic modification of a monohydrate of mon-sodium salt of 3-(N-methyl-N-pentyl)amino-1-hydroxypropane-1,1-diphosphonic acid (ibandronate) of formula 1, used for controlling hypercalcemia.
Method of obtaining alkali metal salts of n-phosphonomethylglycine / 2364601
Claimed invention relates to method of obtaining alkali metal salts of N-phosphomethylglycine and can be applied in agriculture, for fight against weeds. Claimed method lies in the following: reaction of glyphosate and alkaline reagent interaction is carried out in solid phase in highly efficient mixer in conditions of crashing and in close contact of reaction components.
Method of obtaining ethylenediammonium bis(1-hydroxyethane-1,1-diphosphonato(2-))cuprate(+2), zincate(+2) and nickelate(+2) / 2352575
Invention relates to obtaining etyheleneammonium bis(1-hydroxyethane-1,1-diphosphonato(2-))cuprate (+2), etyheleneammonium bis(1-hydroxyethane-1,1-diphosphonato(2-)) zincate(+2) and etyheleneammonium bis(1-hydroxyethane-1,1-diphosphonato(2-)) nickelate(+2) and can be used for processing toxic wastes of obtaining metal coatings - waste electrolytes of galvanic copper, zinc and nickel plating, waste solutions of chemical nickel plating and copper plating. Products, obtained by said method, can be used for preparation of electrolytes, metal corrosion inhibitors, for obtaining various copper, zinc and nickel compounds, including catalysts of organic and inorganic substance synthesis. Claimed method includes using liquid industrial wastes, containing metal(+2), ethyleneammonium and/or anion of 1-hydroxyethane-1,1-diphosphonic acid as reagents. Target products are obtained by crystallisation from reaction water solution with separation of sediment from solution, process is carried out at temperature from (-5) to 105°C and atmospheric pressure. Method allows to obtain pure crystalline products with yield up to 98%, to reduce expenditures on environment protection.
 Chemical compounds, pharmaceutical cmposition, containing them, their application (versions) and method of binding erα and erβ -estrogen receptors / 2352555
Invention relates to novel compounds of formula (I), including its pharmaceutically acceptable salts, solvates, ethers and amides, possessing ability to bind ERα- and ERβ-estrogen receptors, to pharmaceutical composition based on them, to versions of applying claimed compounds in medication preparation and to method of binding ERα- and ERβ-estrogen receptors.
 Complexonate nitrylotri(methylenphosphonat)-2-phenyl-3-ethyl-8-oxychinolin sodium salts salt-deposition inhibitor / 2337915
Invention relates to novel chemical compounds as salt-deposition inhibitors and can be used in oil industry in oil extraction, in particular in system of sewage water utilising, as well as in systems of circulating water supply of industrial enterprises. Suggested is complexonate of nitrylotri(methylenephosphonato)-2-phenyl-3-ethyl-8-oxychinolin sodium salt of formula
 Long-chain alkylphosphonic acids as soft steel corrosion inhibitors and their production / 2337914
Invention relates to phosphoroorganic chemistry, namely, to method of obtaining long-chain alkylphosphonic acids, possessing anticorrosion activity, based on α-olefins of industrial fraction C16-C18 and C20-C26. Invention can be applied for protection of pipelines, reservoirs, construction metallic structures, equipment for extraction, transportation and processing oil and gas, in metal processing. Long-chain alkylphosphonic acids are obtained by interaction of α-olefins of industrial fraction C16-C18 and C20-C26 with O,O-dimethylphosphorous acid in molar ratio 1:(1.0-2.0) in presence of benzoyl peroxide in amount of 1.0-5.0% of weight of dimethylphosphorous acid at 110-150°C during 10-12 hours in absence of solvent with further hydrolysis of intermediate higher O,O-dimethyl(alkyl) phosphonates with hydrochloric acid with heating, obtaining target product which represents mixture of long-chain alkylphosphonic acids.
 Amorphous alendronate monosodium, methods of production, based pharmaceutical composition and method of inhibition of bone resobrtion / 2334751
Invention refers to method of production of amorphous alendronate monosodium and to solid pharmaceutical composition having property to invoke bone bulk expansion and containing therapeutically effective amount of amorphous alendronate monosodium, produced by stated method. Method of production of amorphous alendronate monosodium includes solvent removal from alendronate monosodium solution using spray drying.
 Acidic phosphorous containing complex forming reagent and method of obtaining it (versions) / 2331651
The invention pertains to an acidic phosphorous containing reagent, is used in the oil industry, heat energy, textile industry, production of mineral fertilizers and household chemistry, and to methods of obtaining the reagent. The reagent (conventional name "АФК-1") contains the following in given mass %: acetoxyethylidenediphosphonic acid 50.0-95.0 mass %, acetic acid - 29.5-0.5 mass %, the rest is acetic anhydride to 100. The quantitative composition of the indicated reagent is determined by the method of obtaining it and the ratios of the initial reagents. The method of obtaining the reagent involves adding acetic anhydride to a suspension of acetic and phosphorous acid at temperature of 60-90°C for a period of 1.5 hours. The reaction mixture is kept at 100-110°C for 1 hour and acidic impurities are distilled off to a controlled volume of distillate. Similar methods are developed based on phosphorous containing wastes from production of acid chlorides of higher fatty acids. The wastes are treated with water or a water solution of acetic acid with subsequent separation of the organic layer of fatty acids, after which the residue, containing phosphorous acid, is treated with phosphorous tri-chloride and acetic anhydride at 115-130°C, and acidic impurities are distilled off to the controlled distillate volume.
 Acidic phosphorous containing complex-forming reagent and method of obtaining it / 2331650
Invention pertains to the chemistry of phosphorous organic compounds, and specifically to an acidic phosphorous containing complex-forming reagent, which can be used in the oil industry, heat energy, textile industry, production of mineral fertilizers and household chemistry, and to the method of obtaining it. The acidic phosphorous containing complex-forming reagent (conventional name "АФК-2") contains the following in mass %: acetoxyethylidenediphosphonic acid - 50-95 mass %, acetic acid - 50-5 mass %. The method of obtaining the composition involves adding phosphorous tri-chloride, acetic acid and water simultaneously to glacial acetic acid in molar ratios equal to 1:(4.5-5.5):(1.93-1.95), at temperature of 35-45°C with subsequent keeping of the reaction mixture at 110-120°C for a period of 2 hours and controlled distillation of acidic impurities to the required distillate volume.
Method of obtaining inhibitor of precipitation of mineral salts / 2329270
Invention pertains to the method of obtaining an inhibitor of precipitation of mineral salts, The inhibitor is obtained by reaction of hexamethylenediamine and ammonium chloride with formaldehyde and phosphorous acid in a medium of diluted hydrochloric acid at high temperature with subsequent neutralisation of the obtained solution using sodium hydroxide to pH of 6.5±1.0. The process is carried out with molar ratio of hexamethylenediamine to ammonium chloride of 1:3-6.
 Phosphonate derivatives / 2258707
Invention relates to new biologically active phosphonate compounds. Invention describes phosphonate compound of the formula:
 Method for preparing n-phosphonomethylglycine and intermediate substance for its preparing / 2260010
Invention relates to the improved method for preparing N-phosphonomethylglycine. Method involves interaction of derivative of hexahydrotriazine of the formula (II):
Chloride removing in method for preparing phosphonomethyliminodiacetic acid / 2263116
Invention relates to a selective method for removing chloride as NaCl from waste in method for preparing N-phosphonomethyliminodiacetic acid. The waste flow is neutralized with NaOH to pH value about 7, water is evaporated from flow of neutralized waste under atmospheric or lower pressure at temperature from 40°C to 130°C until to precipitation of NaCl. The precipitate is filtered off at temperature from 35°C to 110°C to isolate NaCl from filtrate and NaCl is washed out with saturated saline solution. Invention provides effective removal of NaCl from waste in a method for manufacturing N-phoaphonomethyliminodiacetic acid.
 New acyclic nucleoside phosphonate derivatives, their salts and method for preparing these compounds / 2266294
Invention relates to acyclic nucleoside phosphonate derivatives of the formula (1):
 Method for preparing nickel (ii) bis-(1-hydroxyethane-1,1-diphosphonate (1-)) / 2271362
Method involves preparing nickel (II) bis-(1-hydroxyethane-1,1-diphosphonate (1-)) by addition 1-hydroxyethane-1,1-diphosphonic acid in the concentration 0.2-4.5 mole/l to an aqueous solution containing nickel (II) in the concentration 0.1-2.0 mole/l and organic solvent mixing with water followed by crystallization of the end substance from the solution. Method provides preparing the pure homogeneous end product with high yield, and utilization of depleted electrolyte in nickel plating representing a toxic waste in galvanic manufacture.
 Method for preparing n-phosphonomethylglycine / 2274641
Invention relates to a method for preparing N-phosphonomethylglycine. Invention describes a method for preparing N-phosphonomethylglycine from an aqueous mixture containing dissolved N-phosphonomethylglycine, ammonium halides, alkali or earth-alkali metal halides and, optionally, organic impurities. Method involves (a) using a mixture with pH value from 2 to 8; (b) separation of mixture is carried out on a selective nanofiltration membrane, and retentate enriched with N-phosphonomethylglycine and depleted with halides and permeate depleted with N-phosphonomethylglycine are obtained, and (c) N-phosphonomethylglycine is isolated from retentate. Method provides preparing N-phosphonomethylglycine in simultaneous separation of halide salts.
Method for preparing copper (ii) bis-(1-hydroxyethane-1,1-diphosphonate (1-)) from production waste / 2280647
Invention relates to technology of organic substances, in particular, to the improved method for preparing copper (II) bis-(1-hydroxyethane-1,1-diphosphonate (1-)). The final copper (II) bis-(1-hydroxyethane-1,1-diphosphonate (1-)) is prepared by crystallization from aqueous solution with concentrations of copper salt (II) from 0.5 to 2.0 mole/l and 1-hydroxyethane-1,1-diphosphonic acid with concentration from 2.0 to 6.0 mole/l prepared by using copper-containing waste in galvanic and electronic engineering manufacture, or by using a semi-finished product from production of 1-hydroxyethane-1,1-diphosphonic acid. Invention provides reducing cost in production of copper (I) bis-(1-hydroxyethane-1,1-diphosphonate (1-)) in combination with retaining purity, expanded raw base for preparing the end product and utilization of manufacture waste.
 Stimulator of growth agricultural root crop plants / 2283317
Invention describes bis-(diethylammonium)-dihydrogen-1-hydroxyethyl-1,1diphosphonate monohydrate of the formula (I)
 Method for preparing bis-(1-hydroxyethane-1,1-diphosphonate(1-)) zinc (ii) / 2287532
Invention relates to the improved method for preparing bis-(1-hydroxyethane-1,1-diphosphonate(1-)) zinc (II). Method involves interaction of zinc-containing reagent and 1-hydroxyethane-1,1-diphosphonic acid in a solvent medium, crystallization of the end product from solution, separation of deposit from solution and drying the deposit. Method involves using water-soluble zinc (II) salt with anion of strong acid as a zinc-containing reagent and preparing the solution with the concentration of zinc (II) salt from 0.2 to 2.2 mole/l and the concentration of 1-hydroxyethane-1,1-diphosphonic acid from 0.4 to 5.0 mole/l. The end product prepared by proposed method can be used in preparing phosphonate electrolytes for galvanic zinc-plating, for preparing zinc-phosphate inhibitors of steel corrosion, as trace supplement to vitamin preparations and fodders for animals, as a zinc microfertilizer in agriculture and for preparing other compounds of zinc (II). Invention provides enhancing purity and uniformity of the end product, increasing its yield, improved technological effectiveness of process, utilizing toxic waste in galvanic manufacturing.
Method for preparing crystalline nitrilotrimethylphosphonic acid disodium salt monohydrate / 2293087
Invention relates to technology for synthesis of crystalline nitrilotrimethylphosphonic acid sodium salts. For synthesis of nitrilotrimethylphosphonic acid disodium salt monohydrate the method involves preliminary synthesis of nitrilotrimethylphosphonic acid by interaction of phosphorus trichloride, formaldehyde and ammonia or its derivative followed by neutralization with sodium hydroxide in the content in the reaction mass 46-54 wt.-% of nitrilotrimethylphosphonic acid and 6.0-16.0 wt.-% of hydrogen chloride up to pH value 2.5-4.5, and isolation of the end compound by crystallization. The mass part of the main substance in synthesized product is 88-95%, the content of chloride ions is 1.2-2.0%, yield is 50-60% as measured for PCl3. Synthesized compound is recommended for using as chelate compounds as a component of detergents, anti-rheological additive in drilling solutions, plasticizing agents for building concretes, in wine-making industry, as inhibitors of salt depositions in heat and power engineering and others fields.
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FIELD: medicine. SUBSTANCE: material, containing glyphosate, is diluted or suspended in water in the presence of the base with production of composition, including glyphosate salt in water solution of the base then without preliminary concentration and filtration the produced composition is added into acid and precipitated neutralised glyphosate is separated. EFFECT: development of the method of glyphosate treatment. 10 cl, 1 ex
The present invention relates to the purification of N-(phosphonomethyl)glycine, commonly called glyphosate or PMG. The synthesis of glyphosate (PMG) can be performed by several known methods, including catalytic oxidation of N-(phosphonomethyl)iminodiacetic acid (PMIDA) and hydrolysis of triple complex ester of glyphosate. At the same time, different reactions leading to the PMG, and used raw materials produce different by-products and contaminants in the final PMG product, including glycine, iminodiethanol acid (IDA), N-formallist, N-(phosphonomethyl)iminodiethanol acid (PMIDA), (aminomethyl)phosphonic acid (AMPA), N-methyl-N-(phosphonomethyl)glycine (MePMG), N,N-bis(phosphonomethyl)amine (bPMNH or iminobis(methylenephosphonic acid)), N,N-bis(phosphonomethyl)glycine (bPMG or glitsin) and sodium chloride (NaCl). Annually sold more than 250,000 metric tons of glyphosate. Production costs, including raw material cost, time, energy costs, cleaning, organizing the elimination of waste and, of course, the release of the product are very important in the current competitive market. Thus, the existing market PMG requires the product offer of high purity in accordance with the desired economic requirements. U.S. patents 3799758 and 3956370 describe how to obtain glyphosate. is, however, not presented analysis of impurities and does not describe additional methods of cleaning. WO 2003000704 describes how the selection of N-(phosphonomethyl)glycine (PMG or glyphosate), including the regulation of the pH of the liquid containing N-(phosphonomethyl)glycine and impurities including sodium chloride /ammonium chloride, by concentrating on the membrane nanofilter under pressure and isolation of pure N-(phosphonomethyl)glycine from the concentrate by precipitation of HCl at a pH of 1.3. However, this method removes the halides and is a cumbersome and expensive process, due to the inclusion in the cleaning stage nanofiltration. Thus, there is an urgent need for an improved method of cleaning PMG, which takes into account the efficiency and economic requirements and provides enough clean PMG for commercial gain of large-scale production. The present invention is a method of purification of glyphosate (PMG), including: 1) dissolution or suspension of the material containing the PMG, in water in the presence of a base to obtain a composition comprising salt PG in an aqueous solution of the base, 2) bringing the composition into contact with the acid so that the salt PMG neutralized with getting besieged PMG and 3) isolation of the precipitated PMG. provided that the composition with stage 1) not concentrated and not filtered using membrane nanofilter. The decree of the config method substantially removes impurities, in particular glycine and glitsin, and results in PMG high purity, it remains economically viable for commercial production. In General, the present invention is directed to a method of purification of N-(phosphonomethyl)glycine or glyphosate (denoted here as PMG). PMG can be obtained in several different ways, as described in U.S. patent 3799758 and 3956370, which are included here as a reference. These methods include the esterification of glycine, followed by phosphonomethylglycine and hydrolysis, however, received glyphosate may include unacceptable concentration of glycine and glyphosine. It was found that the method according to the present invention is specifically reduces the number of glycine and glyphosine in such compositions economical from a commercial point of view so that the impurity concentration is reduced. Material PMG, which must be cleared, may be any material PMG, which contains impurities in unacceptable quantities. Usually the material PMG will contain glycine in an amount greater than 0.1 wt.% calculated on the total weight of the material PMG. Additional material PMG, which must be cleared, will typically contain glitsin in amounts greater than 0.2 wt.% calculated on the total weight of the material PMG. In the General case material PMG contains at least 90 wt.% order the PMG, preferably at least 93 wt.% calculated on the total weight of the material PMG. For cleaning material PMG his first dissolved or suspended in water and treated with a base or, alternatively, it can be dissolved or suspended directly in an aqueous solution of the base so that the PMG is partially or completely converted into a more soluble salt, to obtain the composition of salt PMG. This can be achieved by mixing the material PMG with water followed by addition of a base or mixing material PMG directly with an aqueous solution of the base. Usually the amount of salt PMG in the composition is a such that the composition is a saturated or nearly saturated. In particular, the composition of salt PMG may constitute suspension at ambient temperature, but forms a clear solution when heated to high temperatures. In some cases, part of the PMG may remain undissolved in the composition of salt PMG. Usually the number of PMG (represented as PMG salt or undissolved material PMG) will be from 10, preferably between 12 and most preferably from 15 to 30, preferably up to 28, and most preferably up to 25 wt.% calculated on the total weight of the composition PMG salt. The base used in the method according to the present invention, may predstavljati any basis, which will form a salt PMG, which is more soluble in water compared with the material PMG. Typical bases include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonia or ammonium hydroxide, etc. The amount of base needed to provide the desired concentration and to obtain a sufficient amount of salt PMG, is usually from 0.50, preferably from 0.65 and most preferably from 0.75 to 1.2, preferably to 1.1, and most preferably up to 1.0 molar equivalents of base based on the total amount of material PMG. Under one molar equivalent of base mean one mole of base to one mole of the material PMG for a monovalent base such as sodium hydroxide, or 0.5 mole of base to one mole of the material PMG for divalent bases, such as sodium carbonate. Composition PMG salt in aqueous solution base will typically have a pH from 1.7 to 3.5. To facilitate dissolution and formation of salts PMG solution can be heated so as to accelerate the dissolution process and a saturated or nearly saturated solution. Usually the solution is heated to a temperature of from 50 to 85°C. This method can also be carried out at such low temperatures, 15°C, while at lower temperatures dissolve the awn salts PMG is reduced. Composition PMG salt in an aqueous solution of base concentrate more, and do not pass through the membrane nanofilter. Unexpectedly, it was found that the method according to the present invention sufficiently removes impurities from the interest of the substance without the use of nanofiltration. After obtaining the desired composition PMG in aqueous solution base add acid to neutralize the salt PMG. You can use any acid which will lower the pH of the composition and lead to the neutralization of the salt PMG. Typical acids include any acid strong enough to complete protonation PMG salt such as hydrochloric acid, sulfuric acid or phosphoric acid. Hydrochloric acid and sulfuric acid are preferred because of their low cost and high solubility of their salts in water. The amount of acid used for neutralization, is a number, which is preferably fully neutralized salt PMG and to cause precipitation of the PMG. Usually the number of moles of acid is approximately equal to the number of previously used molar equivalents of the base. This amount will typically be in the range of from 0.5, preferably between 0.6 and most preferably from 0.7 to 1.3, preferably up to 1.2 and the most p is edocfile to 1.1 equivalents of acid per source used amount of material PMG. Normally, the amount of acid used in the method according to the present invention, is an amount which will lower the pH of the composition to a level of 0.3, preferably from 0.35 and most preferably from 0.38 to 1.6, preferably up to 1.5 and most preferably up to 1.4. The final pH depends on the temperature of neutralization, since higher temperatures will increase the number of PMG in solution and the degree of dissociation PMG acid will increase, thereby lowering the pH. Neutralization typically occurs at a temperature in the range from 20 to 90°C. the Acid is usually added slowly or dropwise with shaking or stirring in order to prevent excessive heating of the solution. the pH of the final solution will change as the temperature of the solution to reach room temperature or about 25°C. Final pH will typically be in the range from 0.9, preferably between 1 and most preferably from 1.05 to 2.9, preferably up to 1.4 and most preferably up to 1.25. End PMG product can be allocated in any way, and it usually isolated by centrifugation, belt filtration or filtration under vacuum, as is well known in the art. The product can also be optionally washed with an additional quantity of the water. The method according to the present invention also considers ways, including the stage of recycling, such as recycling of the filtrate. Purified PMG product typically contains less than 0.1 wt.% glycine, preferably less than 0.08 and most preferably less than 0.06 wt.% calculated on the total weight of purified PMG. Additionally purified PMG product typically contains less than 0.2 wt.% glyphosine, preferably less than about 0.15, more preferably less than 0.10 and most preferably less than 0.08 wt.% calculated on the total weight of purified PMG. Purified PMG product typically contains less than 0.1 wt.% MePMG, preferably less than 0.08 and most preferably less than 0.06 wt.% calculated on the total weight of purified PMG. Preferably purified PMG product comprises at least 95 wt.% technical PMG, more preferably at least 98 wt.%, even more preferably at least to 98.5 wt.% and most preferably at least 99 wt.% calculated on the total weight of purified PMG. The following example is presented to illustrate the present invention. The example is not intended to limit the scope of the present invention and should not be so interpreted. The number represented in parts by weight or percentages by weight, unless stated otherwise. Example DV is hottovy glass cylindrical vessel with a bottom outlet and the shirt was fitted top with an electric mixer, reverse water-fridge, a cell for placement of thermometer, pH probe and tube for addition of chemical reagents. To the vessel was added 200,00 g of glyphosate (96,5% according to the analysis 0.11% glycine, 0,19% MePGM and 1.00% glyphosine) and 800,5 g of deionized water. The mixture was stirred at 245 rpm when using the slant of a four-level glass stirrer. After 15 minutes the observed pH was 1,96 when the internal temperature of 24°C and started adding 89,96 g of sodium hydroxide solution of (0.95 molar equivalents of a 50 wt.% aqueous solution). The base was added for one hour by using a peristaltic pump. At the end of the addition the pH was 3.57 and the solution looked like almost transparent and colorless, although present in the solution a small amount of nerastvorimogo of glyphosate gave the solution a slight turbidity. The mixture was heated up to 80°C for 45 minutes. At 85°C. the solution became clear and colorless and the observed pH was 3,11. Was added for 45 minutes, concentrated hydrochloric acid (109,2 g of 37.5% HCl, of 0.95 molar equivalents). the pH decreased to 0.67, and formed a slurry of white solids. Continued cooling and as soon as the internal temperature reached 30°C, set the bath temperature at 25°C and the suspension was stirred for an additional 30 the minutes. After 30 minutes of absorption observed pH amounted to $ 1.66 when the internal temperature is 28°C. was Added via pipette concentrated hydrochloric acid to the observed pH of 1.40 (needed 3,44 g of 37.5% hydrochloric acid to 0.03 molar equivalent). Then the suspension was left to mix and interact within two hours at a bath temperature of 25°C. Solid glyphosate was isolated by vacuum filtration using 350 ml Buchner funnel of rough glass, located on 2 liters vacuum flask. The precipitate on the filter was washed with deionized water in the amount of ½ of the volume of the precipitate on the filter, leaving to dry under vacuum using water-jet pump, then leaving it overnight in a chemical fume hood. The filter cake was placed in a vacuum oven to dry overnight at room temperature, was transferred to a 600 ml glass vessel, and then the drying process is completed overnight in a vacuum oven. This has led to 179,42 g of product with a yield of 89.7%. The analysis of the sample showed that it contains a >99.9% of PMG according to the analysis of 0.04% glycine, 0.04% of MePMG and 0.06% glyphosine. 1. The method of purification of glyphosate (PMG), including: 2. The method according to claim 1, wherein the amount of base is from 0.5 to 1.2 molar equivalents based on the number of moles of material PMG. 3. The method according to claim 1, wherein the amount of acid used for neutralization is from 0.5 to 1.3 molar equivalents based on the number of moles of material PMG. 4. The method according to claim 1, wherein the base is a hydroxide of sodium. 5. The method according to claim 1, wherein the acid is a hydrochloric acid. 6. The method according to claim 1, wherein the purified product PMG contains less than 0.1 wt.% glycine calculated on the total weight of the pure product PMG. 7. The method according to claim 1, wherein the purified product PMG contains less than 0.1 wt.% MePMG calculated on the total weight of the pure product PMG. 8. The method according to claim 1, wherein the purified product PMG contains less than 0.2 wt.% glyphosine of the total mass of the pure product PMG. 9. The method according to claim 1, in which the product stage 2) has a pH of from 0.9 to 2.9. 10. The method according to claim 1, in which the product stage 2) has a pH of from 0.9 to 1.25.
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