JPH0827173A - Production of n-phosphonomethylglycine - Google Patents

Abstract

PURPOSE:To industrially advantageously produce N-phosphonomethylglycine useful as a herbicide or its raw material by hydrolyzing an N- acylaminomethylsulfonic acid in the presence of an alkali (alkaline earth) metal hydroxide and subsequently reacting glycolonitrile with the resultant reaction product without changing its salt state. CONSTITUTION:An N-acylaminomethylphosphonic acid (e.g. N- acetylaminomethylphosphonic acid) is hydrolyzed by using an alkali metal hydroxide (e.g. sodium hydroxide) or an alkaline earth metal hydroxide (e.g. calcium hydroxide). Without converting the obtained alkali metal salt or alkaline earth metal salt of an aminomethylphosphonic acid to an aminomethylphosphonic acid, it is reacted with glycolonitrile at <=60 deg.C and >=pH10.5, The amount of used glycolonitrile is 0.5 to 1.5 time mole based on the amino group of the aminomethylphosphonic acid salt. The resultant reaction product is subsequently hydrolyzed, thus producing the objective N-phosphonomethylglycine useful as a herbicide or its raw material, etc., in a high yield.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an improved method for producing N-phosphonomethylglycine useful as a herbicide or a raw material for a herbicide.

[0002]

N-phosphonomethylglycine and its salts, such as glyphosate, glyphosate sodium salt, glyphosate ammonium, glyphosate-monodimethylamine, glyphosate. Trimesium salt, Glyphosamine
ine) is biodegradable and is effective as a herbicide when used in a small amount, and is widely used or its effectiveness has been investigated.

Although many methods for producing N-phosphonomethylglycine are known, several methods for producing N-phosphonomethylglycine using aminomethylphosphonic acids as a raw material are also known as techniques related to the present invention. ing. For example, a method of adding aminomethylphosphonic acid to an aqueous solution of glyoxal at 40 to 45 ° C. and then heating (JP-A-62-61992), a method of reacting aminomethylphosphonic acid and glyoxal as raw materials in the presence of sulfur dioxide ( European Patent No. 81459 and US Pat. No. 4,369,142), a method of reacting aminomethylphosphonic acid with glyoxylic acid and then hydrogen reducing it in the presence of a palladium catalyst (European Patent No. 186648), aminomethylphosphonic acid and chloroacetic acid in water. A method of heating to about 80 to 120 ° C in the presence of an acid acceptor such as sodium oxide (Polish Patent No. 120759 and Spanish Patent No. 504479), reacting aminomethylphosphonic acid with diethyl malonate bromide under alkaline conditions. And then add water under acidic sulfuric acid. How to construe (Spain No. 5454
No. 56) is known, but these methods are not always satisfactory because they use a gas that is difficult to handle, the reaction operation is complicated, and the yield of the reaction is not sufficient.

Further, in US Pat. No. 4,221,583, formaldehyde is reacted in the presence of an alkali necessary to form a monosalt of aminomethylphosphonic acid and aminomethylphosphonic acid, and aminomethylphosphonic acid is converted into an N-methylol compound. N-phosphonomethylglycinonitrile, which reacts potassium cyanide between pH 7 and 10,
Alternatively, a method for producing the monosalt is disclosed. Further, in the patent, N-phosphonomethylglycinonitrile synthesized by the method is hydrolyzed to give N-
It is described that phosphonomethylglycine is obtained. However, according to the description of the examples of the patent, N-phosphonomethylglycinonitrile is as low as 66% even when the highest yield is obtained, and in order to increase the conversion rate of aminomethylphosphonic acid, A large excess of 2.4 times the molar amount of potassium cyanide with respect to methylphosphonic acid is required. Further, the yield of hydrolysis of N-phosphonomethylglycinonitrile is 90% at maximum according to the examples.
Therefore, N-based on aminomethylphosphonic acid
The yield of phosphonomethylglycine is about 60%.

In Japanese Patent Laid-Open No. 04-279595, aminomethylphosphonic acid and glycolonitrile are reacted in the presence of an alkali metal hydroxide at 60 ° C. or lower, and then an alkali metal hydroxide is further added for hydrolysis. Disclosed is a method for producing N-phosphonomethylglycine. According to the examples of the patent, the reaction yield is 95 based on aminomethylphosphonic acid and glycolonitrile.
%, Which is extremely high. Also, the reaction operation is very easy,
It is regarded as one of the excellent methods for producing N-phosphonomethylglycine. This patent belongs to the patents related to this patent. Several methods for producing aminomethylphosphonic acid, which is a raw material, have been conventionally known. For example, a method of reacting chloromethylphosphonic acid and ammonia under high temperature and pressure (German Patent No. 2315886) and a method of hydrolyzing N-benzylaminomethylphosphonic acid (Pho
sporus Sulfur 7 (3), 337-9
(1979)), after reacting dibenzylamine with phosphorous acid diester and formaldehyde in the presence of an aqueous hydrochloric acid solution,
A method of hydrolyzing the obtained N-dibenzylphosphonic acid (Polish Patent No. 107626), a method of reacting a triazine ester compound and a phosphorous acid diester in the presence of a Lewis acid, and then acid hydrolysis (US Pat. No. 4,368,368).
162), a method of treating N-isopropylaminomethylphosphonic acid with a high temperature alkaline aqueous solution (European Patent No. 1).
99702), a method of reacting urea with phosphorous acid and formalin, followed by hydrolysis (East German Patent No. 251259).
No.) is known, but these methods are not always satisfactory because the starting materials are difficult to obtain, the reaction procedure is complicated, and the yield of the reaction is not sufficient. Absent.

As a method for producing aminomethylphosphonic acid relatively easily and in good yield, there is a method by hydrolysis of N-acylaminomethylphosphonic acid. Various methods for producing N-acylaminomethylphosphonic acids have been conventionally known. Synthetic Communications, 16, (7), 733-73
9 (1986) by reacting N-methylolbenzamide with a mixture of phosphorus trichloride and trimethyl phosphite
-A method for producing benzoylaminomethylphosphonic acid dimethyl ester is disclosed. US Patent 2328
No. 358 and U.S. Pat. No. 2,304,156 disclose a method for producing N-acylaminomethylphosphonic acid by reacting N-methylolamide with phosphorus trihalide in the absence of solvent and then contacting with excess water. There is. JP 02
In No. 262585, after treating acetamide and paraformaldehyde in acetic acid, phosphorus trichloride is added and reacted, and the obtained N-acetylaminomethylphosphonic acid is hydrolyzed with acid or alkali to produce aminomethylphosphonic acid. A method is disclosed and also in Poland Patent No. 117780, aminomethylphosphonic acid is obtained by reacting N-methylolbenzamide with phosphorus trichloride in acetic acid and hydrolyzing the resulting N-benzoylaminomethylphosphonic acid. A method of making an acid is disclosed. In JP-A-5-112586, an N-methylolamide compound is reacted with phosphorus trihalide in an aprotic solvent in the presence of a certain amount of water and then contacted with excess water to give N-acylaminomethylphosphonic acid. A method of manufacturing is disclosed. These methods are, according to the patented examples, at most over 90%.

N-acylaminomethylphosphonic acid is hydrolyzed in the presence of acid or alkali to give
Although it can be converted into aminomethylphosphonic acid or an aminomethylphosphonic acid alkali salt, the cause is unknown, but acid hydrolysis has a problem that the yield is lower than that of alkali hydrolysis. For example, Japanese Patent Laid-Open No. 02-26
According to Examples 1 and 2 of No. 2585, when the obtained N-acetylaminomethylphosphonic acid was hydrolyzed in an aqueous solution of hydrochloric acid, the yield of aminomethylphosphonic acid was compared with that when hydrolyzed in an aqueous solution of sodium hydroxide. The rate is about 16%
Low. The present inventors produced N-acetylaminomethylphosphonic acid based on Example 16 of JP-A-5-112586 and then performed a hydrolysis reaction. As a result, the yield of aminomethylphosphonic acid in alkaline hydrolysis was 95. %, It was 85% in acid hydrolysis, which was about 10% lower.

However, it is necessary to neutralize the alkali salt of aminomethylphosphonic acid obtained by the above-described alkali hydrolysis with a relatively high yield as aminomethylphosphonic acid. In particular, N-acylaminomethylphosphonic acid produced by using phosphorus halide contains an acid which is considered to be caused by phosphorus halide in the reaction solution, so that a more than theoretical amount of alkali is required for the hydrolysis, so that after the hydrolysis, In order to be solvated, at least 3 times equivalent or more, and actually about 4 times equivalent or more of alkali is necessary with respect to aminomethylphosphonic acid, and a large amount of neutralized salt is by-produced.
Moreover, the crude aminomethylphosphonic acid obtained here may need to be further purified in some cases,
There has been a problem that the total yield of aminomethylphosphonic acid from N-acylaminomethylphosphonic acid is significantly reduced.

[0009]

DISCLOSURE OF THE INVENTION The object of the present invention is to simplify the reaction step in the method for producing N-phosphonomethylglycine via aminomethylphosphonic acid, to reduce the amount of neutralized salt produced as a by-product, and to obtain N in high yield. -To provide an industrially excellent method for producing phosphonomethylglycine.

[0010]

Means for Solving the Problems The present inventors have noticed that the reaction of aminomethylphosphonic acid and glycolonitrile is carried out under alkaline conditions, and the amino acid obtained by alkaline hydrolysis of N-acylaminomethylphosphonic acid. After reacting methylphosphonic acid alkali metal salt or alkaline earth metal salt with glycolonitrile at a temperature of preferably 60 ° C. or lower without converting to aminomethylphosphonic acid, if necessary, alkali metal hydroxide or alkaline earth metal salt is added. By further adding a metal hydroxide and hydrolyzing it, the reaction process is simplified, and since there is no neutralization process for the alkaline salt of aminomethylphosphonic acid, the amount of by-product neutralization salt can be greatly reduced, and the It has been found that N-phosphonomethylglycine can be produced in yields.

The method of the present invention will be described in more detail below. One of the most important requirements in the present invention is a method for producing N-phosphonomethylglycine via aminomethylphosphonic acid, in which aminomethylphosphonic acid obtained by alkaline hydrolysis of N-acylaminomethylphosphonic acid is used. The reaction solution containing the alkali metal salt or alkaline earth metal salt is used as it is for the next reaction with glycolonitrile.

The present inventors have conducted various studies on various methods for producing N-phosphonomethylglycine using glycolonitrile, and, surprisingly, amino acids obtained by alkaline hydrolysis of N-acylaminomethylphosphonic acid. Even if the reaction solution containing methylphosphonic acid in the form of an alkali metal salt or an alkaline earth metal salt was directly used for the next reaction with glycolonitrile without any operation such as purification, the yield was almost decreased. I found that there is no. This is compared with the case where aminomethylphosphonic acid is isolated from a reaction solution containing aminomethylphosphonic acid obtained by alkaline hydrolysis of N-acylaminomethylphosphonic acid in the form of an alkali metal salt or an alkaline earth metal salt. There are great advantages like. When N-acylaminomethylphosphonic acid produced by using phosphorus halide as described above is hydrolyzed with an alkali, it is at least 3 times equivalent or more, actually 4 times or more equivalent to N-acylaminomethylphosphonic acid. Alkali is required. When a solution containing the aminomethylphosphonic acid obtained here in the form of an alkali metal salt or an alkaline earth metal salt is neutralized to isolate as aminomethylphosphonic acid, a large amount of salt is by-produced. Furthermore, the crude aminomethylphosphonic acid obtained here may need to be subjected to further purification in some cases, and the overall yield of aminomethylphosphonic acid from N-acylaminomethylphosphonic acid will be greatly reduced. Furthermore, when the obtained aminomethylphosphonic acid is reacted with glycolonitrile, the alkali metal hydroxide or alkaline earth hydroxide is again adjusted to pH 1
It will be added until it becomes 0.5 or more.

However, a reaction solution containing aminomethylphosphonic acid obtained by alkaline hydrolysis of N-acylaminomethylphosphonic acid in the form of an alkali metal salt or an alkaline earth metal salt is used as it is for the subsequent reaction with glycolonitrile. In this case, the isolation and purification step as aminomethylphosphonic acid can be removed, the operation is simplified, and the steps from the production of N-acylaminomethylphosphonic acid to N-phosphonomethylglycine are comprehensively performed. As you can see, the amount of neutralized salt that is generated is greatly reduced,
Since the loss due to the isolation operation of N-acylaminomethylphosphonic acid is small, the yield can be significantly improved.

The N-acylaminomethylphosphonic acid used as a raw material is not particularly limited in the production method, but it is produced by the known method as shown in the section of the prior art. Examples of the representative compounds are N-formylaminomethylphosphonic acid, N-acetylaminomethylphosphonic acid, N-propionylaminomethylphosphonic acid, N- (i- or n-) butyrylaminomethylphosphonic acid, N- (T-, i- or n-) valerylaminomethylphosphonic acid, N-benzoylaminomethylphosphonic acid, N- (o-, m- or p-) toluoylaminomethylphosphonic acid, N- (o-, m- or p-) methoxybenzoylaminomethylphosphonic acid, N- (o-, m- or p-) ethoxybenzoylaminomethylphosphonic acid,
Examples thereof include N- (o-, m- or p-) chlorobenzoylaminomethylphosphonic acid and N- (o-, m- or p-) nitrochlorobenzoylaminomethylphosphonic acid. From a practical viewpoint, N-formylaminomethylphosphonic acid, N-acetylaminomethylphosphonic acid,
N-propionylaminomethylphosphonic acid, N- (i-
Or n-) butyrylaminomethylphosphonic acid, N-benzoylaminomethylphosphonic acid, N- (o-, m- or p-) toluoylaminomethylphosphonic acid, N- (o
-, M- or p-) methoxybenzoylaminomethylphosphonic acid is preferable, and N-formylaminomethylphosphonic acid, N-acetylaminomethylphosphonic acid and N-benzoylaminomethylphosphonic acid are particularly preferable.

The N-acylaminomethylphosphonic acid may be isolated and purified from the reaction product and then used in the reaction, or the unpurified N-acylaminomethylphosphonic acid obtained by distilling off the reaction solvent may be directly used. The obtained N-acylaminomethylphosphonic acid is then hydrolyzed by adding an alkali metal hydroxide or an alkaline earth hydroxide. Representative examples of alkali metal hydroxides are sodium hydroxide and potassium hydroxide,
Typical examples of the alkaline earth metal compounds are calcium hydroxide and magnesium hydroxide. The amount of alkali metal hydroxide or alkaline earth hydroxide added is at least 3 times equivalent or more, preferably 3.5 to 4.5 times mol, and 1.5 times, respectively, of N-acylaminomethylphosphonic acid.
It is at least 2-fold moles, preferably 1.75 to 2.25-fold moles. The reaction temperature may be room temperature, but depending on the case, it may be carried out at a high temperature or a low temperature. When the reaction is carried out at a low temperature, the reaction yield is slightly improved, but the reaction rate is decreased. On the contrary, when the reaction is carried out at a high temperature, the reaction rate is improved, but the reaction yield is slightly lowered. 40 ° C to 7 depending on the balance between reaction yield and reaction rate
It can be said that 0 ° C is preferable. The reaction may be carried out at normal pressure, but may be carried out under pressure or under reduced pressure depending on the case.

The crude solution obtained by the hydrolysis reaction containing the obtained aminomethylphosphonic acid in the form of an alkali metal salt or an alkaline earth metal salt is used as it is, and the crude product obtained by distilling off the reaction solvent is used directly or directly. Methylphosphonic acid alkali metal salt or alkaline earth metal salt that has been simply purified may be used in the subsequent reaction with glycolonitrile. When isolating as an alkali metal salt or alkaline earth metal salt of aminomethylphosphonic acid,
After distilling off the reaction solvent once, recrystallization from water,
This can be easily carried out by simply washing the crude aminomethylphosphonic acid alkali metal salt or alkaline earth metal salt obtained by concentrating the reaction solution with water.

The amount of glycolonitrile used for the reaction may be 1: 1 with respect to the alkali metal salt or alkaline earth metal salt of aminomethylphosphonic acid, but it is acceptable to use either one in a slight excess. . However, when glycolonitrile is large relative to the alkali metal salt or alkaline earth metal salt of aminomethylphosphonic acid, an excess amount of glycolonitrile causes a side reaction,
When the amount is small, relatively expensive alkali metal salt or alkaline earth metal salt of aminomethylphosphonic acid remains unreacted, and therefore it is preferable to avoid both. For this reason, glycolonitrile is used in the reaction in a range of 0.5 to 1.5 times mol, more preferably 0.8 to 1.2 times mol, of the alkali metal aminomethylphosphonate compound. Is desirable. The pH of the reaction solution cannot be generally stated because it changes depending on the charged concentration of the raw materials and the reaction temperature, but the amount of alkali metal hydroxide or alkali metal hydroxide used in the hydrolysis of N-acylaminomethylphosphonic acid is When the hydrolysis reaction is carried out using 4 times equivalent or more with respect to N-acylaminomethylphosphonic acid, it is generally 10.5 or more. If the alkalinity is too high, there is no problem even if the aminomethylphosphonic acid alkali salt aqueous solution is added to a mineral acid such as hydrochloric acid to adjust the pH and then subjected to the reaction.

The reaction system is not particularly limited, but usually, the aqueous solution of glycolonitrile is dropped into the aqueous solution of the alkali metal salt or alkaline earth metal salt of aminomethylphosphonic acid, and the reaction is continued by further stirring. To complete. The reaction temperature between the alkali metal salt or alkaline earth metal salt of aminomethylphosphonic acid and glycolonitrile is 6
0 ° C or lower is desirable. If the temperature is too high, side reactions occur and the yield decreases. On the other hand, if the temperature is too low, the reaction becomes slow, so it is usually 0 to 60 ° C, preferably 10 to 40 ° C.
Is appropriate. Further, the time required for the reaction is about 30 minutes to 3 hours, although it depends on the temperature.

After reacting the alkali metal salt or alkaline earth metal salt of aminomethylphosphonic acid with glycolonitrile, if necessary, alkali is added to carry out hydrolysis. Examples of the alkali to be added include alkali metal hydroxides and alkaline earth hydroxides. When the amount of alkali present in the reaction system is small, the hydrolysis reaction is difficult to proceed, and when it is added in excess, the product N
-It is preferable to avoid phosphonomethylglycine because the amount of salt produced increases during isolation by acid precipitation. This hydrolysis reaction is not limited by temperature, but is usually carried out in the range of 60 ° C. to the boiling point of the reaction solution. The reaction time depends on the temperature, but is usually about 1 to 3 hours. When the reaction is carried out below the boiling point of the reaction solution, it is desirable to boil the reaction solution at least once before the completion of the reaction in order to remove ammonia generated by the hydrolysis reaction.

From the thus obtained reaction solution, N-phosphonomethylglycine can be easily isolated by acid precipitation after appropriately diluting or concentrating the reaction solution. Alternatively, other conventional means such as an ion exchange resin may be used alone or in combination for isolation and purification, or may be further purified by recrystallization.

From the obtained N-phosphonomethylglycine, a salt of N-phosphonomethylglycine effective as a herbicide such as glyphosate or glyphosate.
Sodium salt, glyphosate-ammonium, glyphosate-monodimethyla
mine), glyphosate trimesium salt, glyphosamine
(Glyphosamine) can be produced.

According to the method of the present invention, it is possible to obtain N-phosphonomethylglycine in a high yield with a small amount of salts by-produced by an easy operation.

[0023]

EXAMPLES Hereinafter, a representative example of the method for producing N-phosphonomethylglycine according to the present invention will be specifically described. However, these are examples for facilitating the understanding of the present invention, and it goes without saying that the present invention is not limited thereto and is not construed as being limited thereto.

Comparative Example 1 17.90 g of acetamide (0.
30 mol), 95% paraformaldehyde 9.48 g
(0.30 mol), sodium hydroxide 40% aqueous solution 0.1.
20 g (0.002 mol) and 1,4-dioxane 30
ml was added. This mixture was heated at 60 ° C. for 1.5 hours to obtain a uniform solution, which was then cooled to obtain an N-methylolacetamide solution. Keeping the temperature below about 20 ℃ on a water ice bath 5
To a solution prepared by dissolving 45.32 g (0.33 mol) of phosphorus trichloride in 40 ml of 1,4-dioxane in a 00 ml flask was added 3 parts of the N-methylolacetamide solution prepared above.
A solution dissolved in 0 ml of 1,4-dioxane was gradually added with stirring so that the whole temperature did not exceed 30 ° C., and further 7.02 g (0.39 mol) of water was added to 20 ml of 1,4-dioxane. The solution dissolved in was added dropwise under stirring in the same manner as above so that the temperature did not exceed 30 ° C. After completion of dropping, the flask was gradually heated to 100 ° C. in an oil bath and kept at that temperature for 2 hours. After completion of the reaction, the mixture was cooled to room temperature, 100 ml of water was gradually added dropwise, and the mixture was stirred at room temperature for 30 minutes, then the solvent was distilled off to obtain N-acylaminomethylphosphonic acid. HP
As a result of LC analysis, the yield of N-acetylaminomethylphosphonic acid was 86% based on acetamide.

239.98 g of a 25% aqueous solution of sodium hydroxide was added to the obtained N-acylaminomethylphosphonic acid.
(1.5 mol) was added and reacted at 70 ° C. for 3 hours to obtain an aminomethylphosphonic acid sodium salt solution. The yield obtained from HPLC was 82% based on acetamide. The product obtained was acidified with concentrated hydrochloric acid and concentrated to give a white solid. This solid was put into 300 ml of concentrated hydrochloric acid, and the produced salt was removed by filtration. The filtrate was concentrated, 140 ml of water was added to the remaining compound to dissolve it by heating at 100 ° C., then the mixture was cooled to room temperature, 95 ml of methanol was further added, and the mixture was cooled to 5 ° C. for recrystallization. The yield of aminomethylphosphonic acid obtained was 70% (23.31 g, 98%, based on acetamide).
% Purity).

In a 300 ml flask, 110 g of water,
23.31 g of aminomethylphosphonic acid prepared above
(0.210 mol), 48% sodium hydroxide aqueous solution 3
3.60 g (0.420 mol) was added and stirred. The pH at this time was 13.1. (20 with pH 7 buffer
Measured with a calibrated pH meter at ° C. The same shall apply hereinafter) The reaction solution was cooled in an ice-water bath, and while keeping the reaction solution at 5 ° C or lower, 29.95 g of a 40% glycolonitrile solution (0.2
10 mol) was added dropwise over 30 minutes. After dropping, 5 ℃
The mixture was returned to room temperature for 30 minutes and stirred for 1 hour. The pH at this time was 11.0. Then 16.80 g of 48
% Aqueous sodium hydroxide solution (0.210 mol) was added,
The mixture was heated under reflux for 2 hours. When the liquid after the reaction was analyzed by HPLC, N-phosphonomethylglycine was found to be 0.19.
It contained 7 moles. The reaction yield was 94% based on the starting material aminomethylphosphonic acid, and was 66% based on acetamide. After neutralizing the reaction solution to pH 2 with concentrated hydrochloric acid, it was allowed to stand overnight to filter off N-phosphonomethylglycine. The amount of salt generated from the entire process was 124.48 g (2.13 mol).

Example 1 An aminomethylphosphonic acid sodium salt solution was prepared in the same manner as in Comparative Example 1. In a 300 ml flask, the prepared crude aminomethylphosphonic acid sodium salt solution (0.246
Mol) and stirred. The pH at that time was 13.9. The reaction solution was cooled in an ice-water bath and 35.09 g of a 40% glycolonitrile solution (0.246 mol) was added dropwise over 30 minutes while the reaction solution was kept at 5 ° C or lower. After the dropping was completed, the mixture was stirred at 5 ° C or lower for 30 minutes, returned to room temperature and stirred for 1 hour.
The pH at this time was 13.6. Then, the mixture was heated under reflux for 2 hours. When the liquid after completion of the reaction was analyzed by HPLC, it contained 0.229 mol of N-phosphonomethylglycine. The reaction yield was 94% based on the starting material aminomethylphosphonic acid, and was 77% based on acetamide.
%Met. After neutralizing the reaction solution to pH 2 with concentrated hydrochloric acid, it was allowed to stand overnight to filter off N-phosphonomethylglycine. The amount of salt generated from the whole process is 8
It was 7.66 g (1.50 mol).

Example 2 An aminomethylphosphonic acid sodium salt solution was prepared in the same manner as in Comparative Example 1. After distilling off this solvent, 75 ml of water
In addition, it was filtered to obtain crude aminomethylphosphonic acid sodium salt. When analyzed by HPLC, the yield of aminomethylphosphonic acid sodium salt was 75% based on acetamide.

In a 300 ml flask, 110 g of water,
Prepared crude aminomethylphosphonic acid sodium salt (0.
(225 mol) was added and stirred. The pH at that time was 13.
It was 1. The reaction solution was cooled in an ice-water bath and 32.09 g of a 40% glycolonitrile solution (0.225 mol) was added dropwise over 30 minutes while keeping the reaction solution at 5 ° C or lower. After the dropping was completed, the mixture was stirred at 5 ° C or lower for 30 minutes, returned to room temperature and stirred for 1 hour. The pH at this time was 11.1. Then, 18.
75 g of 48% sodium hydroxide aqueous solution (0.225 mol) was added and the mixture was heated under reflux for 2 hours. H after the reaction is completed
As a result of analysis by PLC, it contained 0.214 mol of N-phosphonomethylglycine. The reaction yield was 95% with respect to the starting material aminomethylphosphonic acid, and was 71% based on acetamide. After neutralizing the reaction solution to pH 2 with concentrated hydrochloric acid, it was allowed to stand overnight to filter off N-phosphonomethylglycine. The amount of salt generated from the whole process was 101.11 g (1.73 mol).

[0030]

INDUSTRIAL APPLICABILITY According to the method of the present invention, in the method for producing N-phosphonomethylglycine via aminomethylphosphonic acid, the reaction process is simplified and the neutralized salt produced as a by-product is small, and the N-phosphonate is produced in high yield Nomethylglycine can be produced.

Claims (5)

[Claims] 1. N-acylaminomethylphosphonic acid is hydrolyzed with an alkali metal hydroxide or an alkaline earth metal hydroxide, and the obtained alkali metal salt or alkaline earth metal salt of aminomethylphosphonic acid is converted into an amino group. A method for producing N-phosphonomethylglycine, which comprises reacting with glycolonitrile without conversion into methylphosphonic acid. 2. N-acylaminomethylphosphonic acid is hydrolyzed with an alkali metal hydroxide or an alkaline earth metal hydroxide, and the resulting alkali metal salt or alkaline earth metal salt of aminomethylphosphonic acid is converted into an amino acid. A method for producing N-phosphonomethylglycine, which comprises reacting with glycolonitrile without conversion into methylphosphonic acid to carry out a hydrolysis reaction. 3. The method for producing N-phosphonomethylglycine according to claim 1, wherein the reaction with glycolonitrile is carried out at 60 ° C. or lower at a pH of 10.5 or higher. 4. The reaction with glycolonitrile is carried out by using 0.5 to 1.5 times mol of glycolonitrile with respect to the amino group of the alkali metal salt or alkaline earth metal salt of aminomethylphosphonic acid. The method for producing N-phosphonomethylglycine according to claim 1. 5. The method for producing N-phosphonomethylglycine according to claim 2, wherein an alkali metal salt or an alkaline earth metal salt is added when the hydrolysis reaction is carried out with glycolonitrile.