HU214948B - Process for producing non-hygroscopic n-phosphonomethyl-glycine monoammonium salts - Google Patents

Abstract

The present invention relates to a solid, non-hygroscopic N-phosphonomethylglycine monoammonium salt of formula (I) wherein N- (phosphonomethyl) glycine is reacted with an organic ammonium salt of formula (III) or a diammonium salt of formula (IIIA). with the proviso that the organic acid forming the reactive salt has a pK of from 2.27 to 5.58. In the formulas, R is hydrogen, hydroxy, C 1-4 alkyl or phenyl, R 1 is hydrogen or C 1-4 alkyl, R 2 is C 1 -C 4 alkyl, or R 1 and R 2 taken together with the nitrogen to which they are attached are piperidino or morpholino. . O HO — P — CHo-NH-CH0 — COO® HN®R1R2 | 2 2 · 2. OH ω R-COO θ ® r! R2 _>. (in) R1R2H2®N ® O-C00® NK ^ rM2 • (ΠΙΑ) HU 214 948 B The scope of the description is 6 pages (including 1 page figure)

Description

The present invention relates to a process for the preparation of non-hygroscopic N-phosphonomethylglycine (also known as glyphosate) monoammonium salts. In this specification, variable substituents always have the following meanings:

R is hydrogen, hydroxy, C 1-4 alkyl or phenyl,

R ¹ is hydrogen or C 1-4 alkyl,

R ² is C 1 -C 4 alkyl, or

R ¹ and R ^{2 taken} together with the nitrogen atom to which they are attached represent piperidino or morpholino.

Abbreviations and definitions used in this description:

- "glyphosate" - N-phosphonomethylglycine;

- "non-hygroscopic" means that the product does not absorb any appreciable amount of water within 3 weeks at 25 ° C, 60% relative humidity, or that the water uptake is less than 0.1%;

- 'phytoactive' means 'herbicide and / or plant growth regulator'.

More particularly, the present invention relates to a novel preparation of non-hygroscopic glyphosate salts of formula I. A number of processes for the preparation of these non-hygroscopic salts, as well as non-hygroscopic phytoactive compositions made from the salts, their preparation and application are disclosed in U.S. Patent Nos. T / 72428 and T / 66204; are the subject of our patent.

Glyphosate is known as a phytoactive agent that is marketed as an aqueous salt in an aqueous solution (e.g., Roundup®, Glialka®). In addition to its many benefits, the aqueous formulation has some disadvantages. These include water transported as ballast, the risk of release of active ingredients at low temperatures, the risk of leakage of herbicides from damaged vessels, the costs of decontamination, storage, destruction of transport units after use, etc. Recognizing the above, several solutions have been proposed to overcome these difficulties.

The authors of the inventions disclosed in T / 72428 and T / 66204 have prepared solid non-hygroscopic glyphosate monoammonium salts which, at 25 ° C and 60% RH, absorb 3% water over a period of 3 weeks. The preparation was carried out by removing or reducing the formation of the by-product diammonium salt by or after the preparation of the monoammonium salt by one of the known methods of salt formation, either alone or in combination with one another:

a) glyphosate is reacted with a basic reactant capable of forming the desired ion to be introduced in a polar solvent or solvent mixture containing a polar solvent in which the desired salt and glyphosate are not dissolved while the basic reactant and the by-product diammonium salt are readily soluble; obsession

b) the resulting diammonium salt is reacted with glyphosate under the conditions given in process variant a); obsession

c) a glyphosate salt which is hygroscopic and is extracted with an organic polar solvent or a mixture of organic polar solvents in which the monoammonium salt is insoluble while the corresponding diammonium salt is readily soluble. At the end of the process variants, the solid crystalline monoammonium salt formed is preferably isolated by filtration.

In all cases, the authors used liquid isopropylamine for the preparation of glyphosate, which is difficult to add due to its extremely low boiling point, flash point and volatility. The exothermic reaction requires a significant amount of cold energy in order for the measured base to actually remain in the system. This problem did not pose a problem when the glyphosate isopropylamine salt was prepared in an aqueous medium because a few percent (5-15) of an excess of isopropylamine was obtained in a usable aqueous solution, but the excess made the product more expensive.

The present invention is based on the discovery that the above difficulties can be avoided by adding the solid isopropylamine derivative in a well-defined form or by eliminating the uncomfortable (and dangerous) properties of isopropylamine in a reaction that requires accurate stoichiometry cause confusion.

The present invention relates to a process for the preparation of solid non-hygroscopic N- (phosphonomethyl) glycine monoammonium salts of the formula I by reacting N-phosphonomethylglycine

(a) with an ammonium salt of a carboxylic acid of formula III, provided that the carboxylic acid which forms the salt of formula III has a pK of between 2,27 and 5,58; or

(b) carbonic diammonium salt of formula IIIA. Phosphonic acid is known to have a 3 and a pK of 2.27; 5.58; 10.25. Thus, the use of the isopropylamine salt of an acid having an acid strength of between 2.27 and 5.58 guarantees that only the mono (isopropylamine) salt is formed in the system. Examples of such acids include, but are not limited to, acrylic acid 4.26, benzoic acid 4.20, obromobenzoic acid 2.85, m-bromobenzoic acid 3.81, p-bromobenzoic acid 3.31, acetic acid 4.76, glycolic acid 3.81. formic acid 3.75, propionic acid 4.87, lactic acid 3.86, n-butyric acid 4.82, i-butyric acid 4.81, valeric acid 4.81 and so on.

In order to effect the buffering effect of the above acids, it is possible to prepare and isolate a separate system, such as the isopropylamine salt, and measure it to form the glyphosate isopropylamine salt. Alternatively, the reacting salt is not isolated but prepared in a suitable solvent, analytically determined for its amine content and then used to measure the amount required for the reaction. Thus, glyphosate salt formation can be accomplished without the disadvantages of treating a free amine such as isopropylamine.

An advantage of this type of salt formation is that it also avoids the use of hygroscopic N- (phospho

The formation of a phosphonomethylglycine di (monoisopropylamine) salt is used when the isopropylamine salt of the corresponding acid is used in an excess of up to 10-40% molar excess. (The excess can, of course, be recycled and can be used to make the next batch.) This advantage is reflected in the fact that manufacturing does not require as high and carefully monitored a measurement accuracy as is known. This increases the safety of the same product quality.

The salt formers used can be divided according to whether they are volatile or not. The low tension acids can be recovered by washing the filtered material several times with the appropriate solvent after filtration, then concentrating the filtrates by evaporation or preparing the isopropylamine salt for the next batch.

For acids with significant tension, consider the cost of the washing solvent and the acid, and decide whether to recycle after drying or washing.

A special case is the reaction using bis or mono (monoisopropylamine) carbonate as the acid gas formed.

The reaction is preferably carried out using polar protic and / or aprotic solvents such as water, methanol, ethanol, propanol, butanol, DMF, DMSO, pyrrolidine, N-methylpyrrolidine and mixtures thereof.

Primary, secondary and tertiary amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, trimethylamine, iso- and n-propylamine, di (isopropyl) amine, morpholine may be used as basic components. , piperidine, aniline, N-methylaniline, Ν, Ν-dimethylaniline, pyridine, picoline and the like.

The invention is illustrated by the following examples, which are not intended to be limiting.

Examples

Example 1

N-phosphonomethylglycine (16.9 g, 0.1 mol) was stirred in anhydrous ethanol (40 mL) and added.

11.9 g (0.1 mol) of isopropylamine acetate were added and the temperature was raised to 75-80 ° C for 30 minutes. After the reaction mixture had cooled to room temperature, the resulting precipitate was filtered off, washed with 2 x 8 mL of ethanol and dried. 22.03 g of crystalline material were obtained, corresponding to a yield of 96.6%. Melting point: 154-157 ° C; glyphosate content: 73.8%.

Example 2

N-phosphonomethylglycine (16.9 g, 0.1 mol) was stirred in anhydrous alcohol (40 ml), and isopropylamine acetate (14.87 g, 0.125 mol) was added and the temperature of the mixture was 75-80 ° C. and held for 30 minutes. After the reaction mixture had cooled to room temperature, the precipitated crystalline mass was filtered off and washed with 2 x 8 mL of alcohol and dried. 21.66 g was obtained, corresponding to 95% yield. M.p. 153-157 ° C; glyphosate content: 74.1%.

Example 3

To the mother liquor of Example 2 was added 6 g of acetic acid, cooled to 5 ° C, and 5.91 g (about 8.45 ml) of isopropylamine was added dropwise. After the salt-forming reaction was completed, 16.9 g of N-phosphonomethylglycine was added and the procedure of Example 1 was followed. 21.82 g (95.7% yield) were obtained. M.p. 153-157 ° C; glyphosate content: 73.9%.

Example 4

Acetic acid (60 g) was dissolved in ethanol (200 ml), and the solution was cooled to below 5 ° C with stirring and 59.11 g of isopropylamine were added dropwise. After the salt formation was complete, the isopropylamine content of the solution thus prepared was determined and then diluted with ethanol to make the isopropylamine acetate content 250 g / l. 47.6 ml of this solution were added to 16.9 g of N-phosphonomethylglycine. Example 1 gave 21.6 g (94.7%) of crystalline material. Mp 154-156 ° C; glyphosate content: 74.1%.

Example 5

16.9 g of N-phosphonomethylglycine were stirred in 20 ml of water and 11.9 g of isopropylamine acetate was added. The solution was clear, poured onto a watch glass and evaporated gradually. 22.8 g of crystalline material are obtained. Mp 148-156 ° C; glyphosate content: 74.1%.

Example 6

N-phosphonomethylglycine (16.9 g) was stirred in methanol (30 ml) and bis (isopropylamine) carbonate (9 g) was added at such a rate that the reaction mixture did not hesitate. Upon completion of the addition, the procedure of Example 1 was followed to obtain 21.31 g (93.4%) of crystalline material. [The bis (isopropylamine) carbonate used was prepared in a known manner.] M.p. 146-152 ° C; glyphosate content: 73.2%.

Example 7

16.9 g of N-phosphonomethylglycine were stirred in 30 ml of methanol and 9.1 g of dimethyl aminformate was added. Following the above examples gave 20.2 g (94.4%) of the N-phosphonomethylglycine dimethylamine salt. Mp 118-124 ° C; glyphosate content: 78.3%.

Example 8

N-phosphonomethylglycine (16.9 g) was stirred in isopropyl alcohol (30 ml) and ethylamine propionate (11.9 g) was added. Example 1 gave 19.92 g (93.1%) of crystalline material. 131-137 ° C; glyphosate content: 77.9%.

Example 9

N-phosphonomethylglycine (16.9 g) was stirred in DMF (40 mL) and benzoic acid morpholinate (20.9 g) was added. The mixture was stirred at 80 ° C for 30 minutes and then at room temperature the precipitated crystalline material was filtered off with 8 ml of dimethylformamide and 2 x 8 ml of ethyl acetate.

HU 214 948 Β was washed with zero and then dried. 23.1 g (90.2%) of crystals were obtained. Melting point: 171-177 ° C; glyphosate content: 65.1%.

Claims (2)

A process for the preparation of solid, non-hygroscopic N-phosphonomethylglycine monoammonium salts of the formula (I): R * is hydrogen or C 1-4 alkyl; R ² is C 1-4 alkyl; obsession R ¹ and R ^{2 taken} together with the nitrogen atom to which they are attached represent a piperidino or morpholino group characterized in that N-phosphonomethylglycine is reacted a) an ammonium salt of a carboxylic acid of formula III in the formula R is hydrogen, hydroxy, C 1-4 alkyl or phenyl; R 1 and R ² are as defined above with the proviso that the pK of the carboxylic acid of formula III is 2.27-5.58, or b) with a carbon dioxide diammonium salt of formula IIIA 10 of wherein R ¹ and R ² are as defined above. Process according to Claim 1, characterized in that the reaction solvent is water and / or a low molecular weight protic solvent and / or an aprotic solvent. 3. The process according to claim 1, wherein the reaction is carried out at 0-150 ° C, preferably at 20-80 ° C.