KR820001201B1 - Process for the preparation of n-phosphono methylglycine sesquisodium salt - Google Patents

Abstract

Title compd. (I) wherein the molar ratio of sodium cation to acid substantially 1.5-1 was prepd. by reaction of N-phosphonomethylglycine(II) and base donating 1.25-1.75 mol Na per I. I(5.6 kg/ha postemergence) completely controlled lambsquater, smartweed, quackgrass and barnyardgrass 4 week after application. Application of I(0.8 kg/ha) produced a Pol% of 14.89 in sugarcane relative to 8.11 in untreated controls.

Description

Method for preparing sesquisodium salt of N-phosphonomethylglycine

The present invention relates to a process for preparing sesqui sodium salt of N-phosphonomethylglycine (aka: glyphosate) of the following structural formula (I).

Since this compound is considered to have amphoteric ions in the solid state, it can be represented by the following structural formula.

Glyphosate is described in US Pat. No. 3,799,758 as a herbicide and in US Pat. No. 3,853,530 for use as a plant growth regulator, including sugar cane treatment. Each of these patents falls within the scope of the invention, and among these, alkali metal salts of glyphosate and mono-, di- and trisodium salts and the like are particularly mentioned.

The sesquisodium salt of glyphosate was found to be a new and unique compound having the agricultural uses described above. In addition, it has been found that sodium sesquiglyphosate has such desirable properties present in the sodium salts mentioned in the patent or other desirable properties not shown in the prior art.

The sesquisodium salt of glyphosate is prepared by partial neutralization of the acid with a suitable base. Of course the molar ratio of glyphosate anion to substantial sodium cation for this salt is 1.5 to 1. Effective bases used for neutralization are sodium carbonate, sodium bicarbonate, sodium hydroxide, sodium sulfite, sodium bisulfite, sodium sulfide, sodium formate, sodium acet silicate and the like. Donor sources of sodium cations can be selected from a wide variety of bases of organic and inorganic acids. The use of sodium hydroxide is preferred because it is easy to purchase and can easily recover the desired sesqui salt product after neutralization.

As described in US Pat. No. 3,799,758, column 13, columns 5 to 8, the alkali metal salts of glyphosate are highly soluble in water. Agriculturally effective active ingredients are often prepared and marketed in the form of liquid formulations, and the most economical and convenient diluent is water, so water soluble properties are preferred. Such high water solubility is a characteristic seen in the mono-, di- and trisodium salts mentioned in the prior art.

In many other cases, agriculturally effective active ingredients are prepared and marketed as solid preparations. This makes it possible to spread the preparation as a powder or powder and in another aspect it can be added to the solid concentrate in the paper before the desired amount of liquid diluent is used. A significant advantage of these desiccants is to reduce the size and shipping weight of the container.

Because of such high water solubility, the mono-, di- and trisodium salts of glyphosate are not readily available in dry crystalline form. Glassy amorphous solids can be obtained by vacuum dehydration of concentrated aqueous salt solutions but are very hygroscopic and readily moistened cakes when exposed to air.

Low temperature crystallization at about 0 ° C. or lower can give these salts in crystalline form. However, as described below, this method is uneconomical as it takes at least several days.

This problem was found to be solved by using sodium sesquiglyphosate, which is water soluble but readily crystallizes from concentrated aqueous solutions. For example, neutralizing 33.86 g of 99.6% glyphosate at 25 ° C. with 12.3 g of 98% sodium hydroxide in 21.5 g of water gives crystals of a very viscous slurry which is spread out on a glass plate and dried. The crystalline seski salt product after dehydration in the oven shows the presence of hydrated water. The degree of hydration was measured prior to drying, the product being in the form of the tetrahydrate and the hydrated product decomposed at about 235 ° C while the anhydrous product Silver melting point is <300 degreeC.

Many addition neutralizations are further performed using at least 1.5 moles or less sodium cations per mole of glyphosate anion. Some of these operations use 99.6% glyphosate while others use 95.3% glyphosate. At each operation, the crystal product is collected and dried at 70 ° C. until its content is reached.

Titrate with facial sodium hydroxide to determine the composition of the salt product.

(The sesqui + yl or sesqui +, which depends on the ratio of the reactants at or above stoichiometric 1.5: 1)

All operations were carried out using 0.1 mole of glyphosate, sodium hydroxide at about 30% solution (7.92 meq / g) for operations 1-10 and about 45% solution (10.87 meq / g) for operations 11-14. use. The total weight of the reactants in water is kept constant at 39.2 g. The yield was crystallized in 60% concentrated reaction mixture and calculated for oven dried product at 70 ° C. and the results of this operation are shown in the table below.

Sodium Sesquiglyphosate Manufacturer

It can be seen from this data that a significant percentage of sodium sesquiglyphosate is obtained by using about 1.25-1.75 moles of sodium cations per mole of glyphosate. As expected, it is preferable to use sodium cations per mole of glyphosate within the range of 1.45 to 1.55 moles because mixtures with mono- or di-salts obtained outside this range entail some difficulty in separation. By further limiting this range, the yield of sesqui salts can be maximized and the product recovery can be simplified.

The following examples illustrate a process for producing sodium sesquiglyphosate by neutralizing an acid with sodium cations introduced through various sources.

Example 1

16.93 g (0.1 mol) of 99.6% glyphosate is slowly added while cooling to 7.95 g (0.075 mol) of anhydrous sodium carbonate solution in 18.73 g of water. Addition rate is measured as the generation intensity of carbon dioxide. After all additions, the reaction mixture is heated to 70 ° C. to remove residual carbon dioxide.

The reaction mixture is initially cooled to room temperature and then cooled in an ice bath to get maximum crystallization.

The crystalline mass is crushed, separated by filtration and air dried to yield 9.99 g of product.

The above product is further dried overnight at 70 ° C. resulting in a weight loss of 1.34 g. This reduction represents a theoretical value of 98% of the tetrahydrate and the remaining hydrated water is removed by air drying. As a result of titration with anhydrous product-expressing sodium hydroxide, it contained 99.63% of sodium sesquiglyphosate and 0.37% of monosodium salt.

Example 2

16.93 g (0.1 mol) of 99.6% glyphosate is added to a solution of 9.5 g (0.075 mol) of anhydrous sodium sulfite in 17.58 g of water. The reaction mixture is heated to the boiling point to remove most of the sulfur dioxide. The removal of sulfur dioxide is completed by evaporation by adding distilled water twice in 100 ml from the reaction mixture in a steam bath, and a dry residue is obtained when evaporation is completed. Drying the residue overnight at 70 ° C. yields 20.65 g of crystalline product.

Titration with facial sodium hydroxide contained 99.51% sodium sesquiglyphosate and 0.49% monosodium salt.

Example 3

16.93 g (0.1 mol) of 99.6% glyphosate is added to a solution of 18.0 g (0.075 mol) of sodium sulfite nonahydrate in 50 g of water. The addition is carried out slowly to control the bubbles that occur due to the rapid generation of hydrogen sulfide. After the addition, the reaction mixture was transferred to an evaporating dish, and 100 ml of distilled water was added twice in a steam bath and evaporated.

The nearly dried product is ground with a spatula and air dried in a constant temperature / humidity chamber (23 ° C./50% relative humidity) to yield 23.68 g of the product in hydrated form. Drying overnight at 70 ° C. yielded 20.15 g and the weight loss was equal to 97.9% of the tetrahydrate theory. Titration with the expression sodium hydroxide contained 99.74% sodium sesquiglyphosate and 0.26% disodium salt.

Example 4

13.93 g (0.1 mol) of 99.6% glyphosate is added to a solution of anhydrous sodium acetate (0.15 mol) in 19.08 g of water. Heating the reaction mixture to the boiling point gives a strong odor of acetic acid. The above mixture is transferred to an evaporating dish and evaporated by adding 100 ml of distilled water three times in a steam bath to further remove acetic acid. 20.55 g of anhydrous product is obtained by grinding the nearly dried meal obtained by continued removal of water and drying overnight to remove the hydrated water of the water. Titration with the expression sodium hydroxide contained 99.35% sodium sesquiglyphosate and 0.65% disodium salt.

Example 5

16.93 g (0.1 mol) of 99.6% glyphosate and 24.0 g sodium silicate solution (0.15 molar equivalent of sodium cation) in 150 ml water are slowly added. The partially gelled solution is transferred to an evaporating dish and heated in a steam bath to remove water to obtain 30.52 g of granule residue.

This residue is extracted three times with 200 ml of hot water. The water extract is evaporated in a steam bath to almost dryness and heated at 70 ° C. overnight to yield 20.86 g of anhydrous product. Titration with facial sodium hydroxide contained 99.88% sodium sesquiglyphosate and 0.12% monosodium salt.

To demonstrate that the sodium sesquiglyphosate of the present invention is physically specific and different from monosodium and disodium salts, crystals of each salt were prepared and subjected to X-ray crystallographic investigation. Crystals of sesqui salts are usually obtained in the form of fine needles or prisms, but large crystals are preferred. One way to obtain large crystals is to slowly evaporate the sesqui salt solution in a Petri dish covered with filter paper.

Microcrystalline mass is obtained with several large crystals attached around the mass. Alternatively, a lump slightly smaller than the saturated solution of SesquiYoung is placed in a flask covered with filter paper. After a few days, it is slowly dehydrated to form slightly larger crystals. Together with the crystals in the petri dish, these large large crystals are provided for X-ray irradiation.

To prepare monosalt crystals, a solution of 4.10 g of 98% sodium hydroxide in 19.0 g of water was slowly added to 16.93 g of 99.6% glyphosate with ice bath cooling to maintain the temperature at 25 to 30 ° C. If the obtained 50% salt bath is left in a -7 degreeC freezer for several days, 10.3 g (air dry) cubic crystal will precipitate. No weight loss occurred for 4 hours at 70 ° C. The crystals become relatively large (3 mm or more) and decompose at 185 ° C in a sealed tube when placed in a thermal bath. These crystals are provided for X-ray irradiation.

To prepare the di-salt crystals, a solution of 8.20 g of 98% sodium hydroxide in 14.4 g of water is slowly added to 16.93 g of 99.6% glyphosate. The 60% saline solution is left in a freezer at -7 ° C and after several hours the seed crystals are added.

The crystalline material used as crystal nuclei is obtained by leaving a few drops of the already prepared di-sodium salt for a long time. About one week after the addition of the nuclei, the solution becomes a solid mass of crystals. 3.5 g of this mass is slurried with 1.5 g of water and the crystals are washed with ice water and filtered. The crystals turn into a dry, molten mass when placed in a 70 ° C. oven. The remainder of the first crystalline mass is slurried with 15.5 g of water, filtered and washed with ice water. The obtained crystals are dried in a Buchner funnel to obtain a glassy prism having a melting point of 43 to 45 ° C. These crystals dehydrate overnight and apparently become chalky. The preparation was repeated and the crystals washed with ice water were placed in a wet bottle and served for X-ray irradiation.

The decision data obtained in this study are summarized in the table below and the numbers in parentheses are the measured standard deviation, not the most significant.

Cell units of the above-described mono-salts present in the monohydrate form were measured to contain 4 glyphosate molecules, tetrasodium cations, and 4 water molecules. The cell unit of the above-described dichloride present in the hydrate form contains 2 glyphosate molecules, tetrasodium cations and 18 water molecules. The cell unit of the above-mentioned sesqui salt present in tetrahydrate form contains tetraglyphosate molecules, hexasodium cations, and octahydric molecules.

It is evident from the results of X-ray crystal structure analysis that the sesqui salt compound is specific and not a physical mixture of monosodium and disodium salts. As mentioned above, the glyphosate exhibits a zwitterion, such that the monosodium salt corresponds to the loss of the carboxylate hydrogen atom, which corresponds to the additional loss of hydrogen attached to the phosphate oxygen atom. The sesqui salts correspond to a pair of glyphosate molecules (containing three sodium cations), where the carboxylate hydrogen atoms are lost in each glyphosate molecule and the phosphate hydrogen atoms are lost in one glyphosate molecule.

Example A

It should be noted that a suitable application ratio in demonstrating the modulating effect of the present invention's sequinate salt on sugar cane can be varied from about 0.112 kg / ha to about 5.6 kg / ha. In many parts of the world, sugar cane grows from about 9 to about 30 months before harvesting, depending on the region, so it is necessary to consider both maturity and age of sorghum in determining the ratio. In that case application is generally carried out about 2 to 12 weeks before the planned harvest date and is preferably used at 3 to 10 weeks before harvest.

Testing of individual sugar cane stems treated with the compounds of the present invention is conducted 4 to 5 weeks before harvest.

Homeless rice, preferably 13 to 23 months old, is used in the test to avoid sampling errors. At least 5 stems of sorghum are used for each compound used and the total value obtained is obtained by averaging the values of each stem.

Untreated sugar cane stems of the same age are treated similarly to form a control sample. Comparing the treated sorghum and the values obtained from the control sample is a convenient way to measure the modulating effects of these compounds.

The analysis was performed by the method reported in the literature [T. Tanimoto, Hawaiian planter's Record 57, pp 133-150 (1964). Data represent juice purity and pol percentage in sorghum. A polarization measurement of pole percent is equal to the percentage of sucrose when a substance rotates to the polarization side in solution. The sorghum side is an effective method for measuring the sucrose content of sugarcane juice and is well known to those of ordinary skill in the art.

In order to convert the Paul whites into a corresponding change in the amount of sugar obtained, it is first necessary to know the average normal yield of sugar in the test area. The tests here were conducted in areas where about 225-245 metric tons of sorghum was harvested per hectare and about 22.5 metric tons of sugar were obtained from the amount of sorghum. An increase of 0.1 pole percent sorghum, with an average normal yield of 22.5 metric tons per hectare, translates to a hectare of sugar increase of about 225 kg.

About 38 mg of sesqui salt (acid equivalent) is dissolved in about 0.3 ml of water. A small amount (about 0.1% of the final volume) of the solution is usually added with a nonionic surfactant (ethoxylated nonylphenol containing 9.5 moles of ethylene oxide per mole of nonylphenyl). This solution is subjected to the rotator of each stem to be tested except for the control stem. During treatment, each stem is marked with the number 13 between nodes as a reference point. After 4 or 5 weeks of treatment (WAT) plants are harvested and the portions from the base point of each stem of the treated or untreated group to the end of the stem are collected and analyzed as described.

The result is as follows.

Example B

In the same area, tests were conducted on small crops of sugarcane and application was made using manual sprayers.

The formulation contains 74.5% sesqui salt of the present invention, 2% conventional anionic surfactant system (complex salt of benzoic acid and sodium dioctyl silfosuccinate), 9.5% dodecanethiol / urea complex salt and 14% urea.

The latter two components act to inhibit corrosion of the metal container and atomizer.

The formulation is diluted with water for spraying and sprayed on sugarcane in different proportions (acid equivalents) as follows.

The volume of water is about 185 liters per hectare and sugar cane in treated and untreated areas are harvested at various time intervals and operated as in Example 1. The result is as follows.

Application rate: 0.56kg / hectare.

Application Rate: 0.84kg / ha

Application Rate: 1.12kg / ha

Application cost: 2.24kg / ha

Application Rate: 4.48kg / ha

Example C

Small field trials of sugarcane grown for 14 months in different geographic regions are treated with the same formulation of sesqui salts as used in Example 2. The volume of dilution water is about 300 liters per hectare and application is done using a CO ₂ operated sprayer. Harvest 20 sorghum stems as samples and cut the outer branches at 5-6 stems. The test results are as follows, and ERS is the amount of sugar recovered in tonnes per hectare.

Example D

Small field trials of sugarcane grown 8 months in a third geographically different region are treated with the same formulation of sesqui salts as used in Example 2. Application uses a manual sprayer and the volume of dilution water is between about 385 and 390 liters per hectare. The test results obtained by taking 10 stems at each harvest date are as follows.

Example E

The herbicidal activity after germination of sodium sesquiglyphosate of the present invention is as follows. The active ingredient is sprayed in spray form on several plant species 14 to 21 days old. Spraying or organic solvent solutions containing the active ingredient and the surfactant (65 parts tall oil and 35 parts dodecyl benzenesulfonic acid butylamine salt concentrated with ethylene oxide having an ethylene oxide and tall oil ratio of 11: 1) Spray the plants of the pan (the ratio of active ingredient is changed to various concentrations). Place the treated plants in the greenhouse and record the effects after approximately 2 or 4 weeks. The data is shown below and the plant species are represented by the following symbols.

The herbicidal activity index after germination is as follows.

Suitable rates of spraying for weeding may vary from about 0.28 to 22.4 kg per hectare.

It is contemplated that agriculturally useful compositions incorporating the active ingredient of the present invention may be used in solid or liquid form. The composition is prepared by mixing the active ingredient with a diluent, potentiator, extender or regulator so as to be used as a solid particle, solution or dispersion. From an economical point of view or from a convenient point of view, a liquid composition using water as a diluent is preferable.

It is preferable that agriculturally useful compositions contain 0.5 to 20.0 parts by weight of surfactant to enhance hydration, dispersion, suspension, and absorption. Anionic, cationic, non-ionic and positive forms are included in all surfactants that can be used for this purpose.

Preferred hydrating agents include alkyl benzene and alkyl naphthalene sulfonates, sulfated fatty alcohols, amines or acidamides, long chain acid esters of sodium isothionate, esters of sodium sulfosuccinic acid, sulfated or sulfonated fatty acid esters, petroleum sulfo Polyoxyethylene derivatives of nate, sulfonated vegetable oils, polyoxyethylene derivatives of alkylphenols (particularly isooctylphenol and nonylphenol) and mono-high fatty acid esters of hexitol anhydrides (eg sorbitan). Preferred dispersants are methyl cellulose, polyvinyl alcohol, sodium lignin sulfonate, polymerizable alkylnaphthalenesulfonate, sodium naphthalene sulfonate, polymethylene bisnaphthalene sulfonate and sodium N-methyl-N- (long chain acid) taurate .

Preferred inert weights and potentiators are minerals including natural clays, pyrophylles and vermiculite. Typical microdispersed solids that can be used in the compositions of the present invention are diatomaceous earth, topsoil, kaolinite, atollgigit or monnolylonite crate, bentonite, synthetic silica, calcium carbonate and calcium sulfate dihydrate and the like.

The material may contain from about 3 to about 95 parts by weight in the composition.

Agriculturally useful compositions containing the active ingredients of the present invention may contain various additives up to at least 10% by weight to increase their properties. The additives include anti-caking agents or flow rate regulators, anti-corrosive agents, antifoaming agents, fragrances and dyes.

It should be appreciated that the present invention is described by way of example only, and is not intended to limit the invention. Those skilled in the art will be able to practically recognize that modifications and variations are possible without departing from the spirit and scope of the invention.

Claims (1)

N-phosphonomethylglycine of formula (I) is reacted with a base capable of providing 1.25 to 1.75 moles of sodium per mole of this compound, so that the molar ratio of sodium cation to acid anion is actually 1.5: 1. A process for preparing the sesquisodium salt of N-phosphonomethylglycine of II).