CA1196014A - Process for producing n-phosphonomethylglycine - Google Patents
Process for producing n-phosphonomethylglycineInfo
- Publication number
- CA1196014A CA1196014A CA000416768A CA416768A CA1196014A CA 1196014 A CA1196014 A CA 1196014A CA 000416768 A CA000416768 A CA 000416768A CA 416768 A CA416768 A CA 416768A CA 1196014 A CA1196014 A CA 1196014A
- Authority
- CA
- Canada
- Prior art keywords
- process according
- glyoxal
- sulfur dioxide
- suspension
- acid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F9/00—Compounds containing elements of Groups 5 or 15 of the Periodic System
- C07F9/02—Phosphorus compounds
- C07F9/28—Phosphorus compounds with one or more P—C bonds
- C07F9/38—Phosphonic acids RP(=O)(OH)2; Thiophosphonic acids, i.e. RP(=X)(XH)2 (X = S, Se)
- C07F9/3804—Phosphonic acids RP(=O)(OH)2; Thiophosphonic acids, i.e. RP(=X)(XH)2 (X = S, Se) not used, see subgroups
- C07F9/3808—Acyclic saturated acids which can have further substituents on alkyl
- C07F9/3813—N-Phosphonomethylglycine; Salts or complexes thereof
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F9/00—Compounds containing elements of Groups 5 or 15 of the Periodic System
- C07F9/02—Phosphorus compounds
- C07F9/28—Phosphorus compounds with one or more P—C bonds
- C07F9/38—Phosphonic acids RP(=O)(OH)2; Thiophosphonic acids, i.e. RP(=X)(XH)2 (X = S, Se)
Abstract
Process for producing N-phosphonomethylglycine Abstract The novel process for producing N-phosphonomethlglycine comprises reacting aminomethanephosphonic acid with glyoxal, in an aqueous medium, in the presence of sulfur dioxide. The active substance obtained is a herbicide having a very wide spectrum of activity.
Description
-- 1 ~
5-13686/~
Process for producin~ N-phosphonomethylglycine _.
The present invention relates to a novel process ~or producing N-phosphonomethylglycine of the formula I
Ho\~oL
~ -CH NH-CH -COOH (I~
by reaction of aminomethanephosphonic acid with glyoxal in an aqueous medium in the presence of sulfur dioxide.
N-Pllosphonomethylglycine is a herbicide which has a very wide spectrum and which has little or no residual effects. The production and use thereof are described in the U.S. Patent Specification No. 3,799,758.
It is known that on reaction of glycine, formaldehyde and phosphorous acid in the molar ratio of 1:1:1, there is formed, instead oE the desired N-phosphonomethylglycine mainly N,N-bis-phosphono methylglycine (cp. U.S. Patent Specification No. 3,956,370). This product can then be converted electrolytically (U.S. Patent Specification No. 3,835,000) into phosphonomethylglycine.
In order to overcome the difficulties associated with the afore-mentioned process, it has been suggested that N-phosphonomethyl-glycine be produced by a process comprising firstly reacting an N-substituted glycine with formaldehyde and phosphorous acid to the corresponding N-substituted N-phosphonomethylglycine, and subsequently detaching from this the substituent originally present on ., a~
L
the nitrogen atom. There is thus described for example in the U~S.
Patent Specification No. 3,956,370 the production of N-phosphono-methylglycine by reaction of N-benzylethylglycinate with formaldehyde and phosphorous acid with simultaneous hydrolysis of the ester group to give N-benzyl-N-phosphonomethylglycine and subsequent removal of the benzyl group, as benzyl bromide, with strong hydrobromic acid.
N-Yhosphonomethylglycine is obtained in this manner in a yield of about l,o %. This process is not advantageous for commercially producing N-phosphonomethylglycine on account of the low yield and in view of the lacrimatoric action of the benzyl bromide formed as a by-product.
It is therefore the object of the present invention to provide a process by which N-phosphonomethylglycine can be produced in good yield and with the formation of by-products which are easy to handle and environmentally favourable.
It is suggested according to the invention to produce N-phosphonomethyl-glycine by reacting aminomethanephosphonic acid of the formula II
HO\~
/P-CH2-NH2 (II), HO
in an aqueous medium, with glyoxal of the formula III
OHC-CHO (III) in the presence of sulfur dioxide, and isolating the resulting product.
There are two preferred procedures in performing the reaction according to the invention.
The Eirst advantageous procedure for the reaction is to suspend the aminomethanephosphonic acid and glyoxal in water, and to subsequently introduce sulEur dioxide into the suspension.
In this proceclure the introduction of the sulfur dioxide gas can be performed with or without cooling oE the reaction solution. The reaction mixture is however advantageously cooled to 0 to 30C, particularly to 5 to 20C, during the time the sulfur dioxide gas is being introduced. The amount of sulfur dioxide gas introduced is so regulated that the amount is hetween that required to clarify the suspension and that sufficing to saturate the mixture. A saturation of the reaction solution with sulfur dioxide is however an advantage.
The second advantageous procedure for the reaction is to suspend the aminomethanephosphonic acid in water and to subsequently introduce the glyoxal and the sulfur dioxide into the suspension simultaneously.
In this procedure the addition of the glyoxal and the sulfur dioxide gas is with advantage performed in a pre-heated suspension of amino-methanephosphonic acid. The temperature of the suspension is preferably 30 to 90C, and in particular 35 to 75C.
The amount o~ sulfur dioxide employed in this typ of procedure may be less than the equivalent necessary to form the bis-adduct with glyoxal. Preferred amounts of sulfur dioxide are 0.3 to 1.5 mole per mole of glyoxal. Most preferred are 0.5 to 1.0 mole sulfur dioxid gas per mole of glyoxal.
After completion of the introduction of the sulfur dioxide, resp. the glyoxal and the sulfur dioxide, required, in both procedures the solution is heated to a temperatur of between 60 and 1~0C. A
temperature of between 85C and the boiling temperature of the reaction mixture is advantageous. The reaction solution is heated for a period of 5 to 120 minutes. Reaction times of 15 to 60 minutes, and in particular of 20 to 40 minutes, are advantageous. The sulfur dioxide gas introduced is again liberated during heating and can be recovered.
The employed glyoxal can be used, in the reaction according to the invention, both as an aqueous solution of the monomer and as polymer.
In order to obtain a high yield, it is oE advantage to keep the amount of water as small as possible, since the reaction product is soluble in water. The Eurther addition oE water ~as ~olvent can be dispensed with in particular when dilute aqueous solutions of glyoxal are being used.
In the reaction according to the invention~ the sulfur dioxide can also be in the bound form instead of being in the form of sulfur dio~ide gas. Especially suitable in this respect are alkali metal salts and alkaline-earth metal salts of sulfurous acid, particularly hydrogen sulfite of sodium, potassium or calcium.
Using the procedure of adding the glyoxal to a suspension of amino-methanephosphonic acid and an alkali metal hydrogen sulfite very small amounts of the hydrogen sulfite may be used. Even amounts of less than 0.05 mole of sodium hydrogen sulfite per mole of glyoxal do not lower the yield dramatically. In this case a heating of the reaction mixture to temperatures above 75C is not advisable, in order to avoid an evolution of sulfur dioxide gas, which would stop the reaction before having achieved a reasonable conversion of the starting materials. The reaction still works at concentrations of 0.01 mole of alkali metal hydrogen sulfite per mole of glyoxal, but the reaction rates become slower with decreasing concentrations. Reaction times required may be up to 3 hours when low concentrations of alkali metal hydrogen sulfite are employed.
Also adducts of glyoxal and sulfurous acid, cmd salts tllereof, can be used as starting products for the reaction according to the invention.
Suitable in a particular manner for this purpose is the commercially obtainable glyoxal-bis-(sodium hydrogen sulfite) hydrate.
The substitution of sulfur dioxide by salts thereof or by reaction products of these with glyoxal is advantageous with respect to carrying out the process of the invention in the laboratory by virtue of the greater ease of operation; however, also in the case of applying the process on a commercial scale, the use of sulfur dioxide gas is of advantage Eor reasons of cost, in particular because the sulEur dioxide released again during the reaction can be recovered and re-utilised in the reaction of the following reaction batch~
An advantageous embodiment of the process according to the invention comprises saturating at 5 to 20C the suspension of aminomethane-phosphonic acid and glyoxal in water with sulfur dioxide, heating the formed solution at 85 to 105C for 20 to 40 minutes, and isolating the product by crystallisation.
Another advantageous embodiment of the process according to the invention comprises introducing at 30 to 90C into a suspension of aminomethanephosphonic acid simultaneously glyoxal and sulfur dioxide, heating the formed solution at 85 to 105C for 20 to 40 minutes, and isolating the product by crystallisation.
Another advantageous embodiment of the process according to the invention comprises adding at temperatures not above 75C glyoxal to a suspension of aminomethanephosphonic acid and at least 0.01 mole of alkalimetal hydrogen sulfite, heating the mixture of temperatures not above 75C for 0.5 to 3 hours and isolating the product by crystallisation.
The reactants, aminomethanephosphonic acid and glyoxal, are as a rule reacted in equimolar amounts.
The Examples which follow serve to further illustrate the present invention.
Example 1: Sulfur dioxide gas is introduced at 10 to 15C, with vigorous stirring and with cooling" into a suspension of 11.1 g (0.1 mol) of aminomethanephosphonic acid and 11.4 ml (0.1 mol) of 40 % aqueous glyoxal in 40 ml of water until a clear solution has formed. ~fter further stirring at room temperature for half an hour, the solution is refluxed for halE an hour, in the course of which an intense evolution of sulfur dioxide occurs, and the solution turns darlc brown. The reaction mixture is afterwards cooled to 5C; the formed precipitate is separated, washed with a small amount of ice-water and recrystallised from water. The yield is 8.1 g (48%) of pure N-phosphonomethylglycine; decomposition: 236C.
Example 2: A suspension of 11.1 g (0.1 mol) of aminomethane-phosphonic acid and 702 g (0.1 mol) of 80 % polymeric glyoxal in 40 ml of water is treated with sulfur dioxide and further processed in the manner described in Example l; yield: 7.7 g (45.5 %) of N-phosphonomethylglycine; decomposition: 244C.
Example 3: Sulfur dioxide gas is introduced, without cooling and with vigorous stirring, into a suspension of 11.1 g (0.1 mol) of aminomethanephosphonic acid and 7.2 g (Ool mol) of 80 % polymeric glyoxal in 40 ml of water until saturation is attained, in the course of which the solution turns yellowish-orange and the temperature rises to 42C. The solution is subsequently stirred and refluxed, during which time the colour of the solution becomes dark brown. The solution is filtered hot and then cooled to 5C; the precipitate is afterwards separated, washed with a small amount of ice-cold water and dried. The resulting yield is 10,6 g (62.8%) of N-phosphono-methylglycine; decomposition: 235C.
Example 4: A suspension of 15.6 g (0.055 mol) of glyoxal--bis-(sodium hydrogen sulfite) hydrate and S.5 g (0.05 mol) oE amino-methanephosphonic acid in 30 ml of water is refluxed with stirring.
The evolution of sulfur dioxide commences when the temperature reaches 85C; a clear solution is formed and is refluxed for 40 minutes. ~fer cooling of the reaction mixture to room temperature, 11 ml (0.11 mol) of 32 % hydrochloric acid are added, and the mixture is concentrated by evaporation. The oily residue is triturated with 40 ml of 36% hydrochloric acid; the salt which has precipitated is then separated, and the solution is again concentrated by evaporation. The oil obtained is crystallised by the addition of 150 ml of ethanol. This suspension is neutralised to Congo red by propylene oxide being added; the precipitate is separated, washed with ethanol and dried. Recrystallisation from water yields 4.5 g (53.2 %) of N-phosphonomethylglycine; decomposition: 228C.
Example 5: A suspension of 22.2 g (0.2 mol) of aminomethane-phosphonic acid and 58 g (0.2 mol) of glyoxal-bis-(sodiumhydrogen sulfite) hydrate in 80 ml aqueous 5 N hydrochlorid acid is heated slowly, while stirring, until the temperature reaches 95C. When the temperature at the interior of the reaction vessel reaches 70C, a strong evolution of sulfur dioxide occurs and the colour of the solution becomes light brown. After the gas-evolution has ceased, the reaction mixture is boiled for 0.5 hour under reflux, and then slowly cooled down to 0C.The precipitation that falls out, is filtered off, washed with icecold water and with acetone and then dried. Thus 20.2 g (59.8%) of N-phosphonomethylglycine is obtained, which melts while decomposing at 236~C.
Example 6: 26 g (0.4 mol) Sulfur dioxide gas and 58 g of a 40 %
aqueous solution of glyoxal t0.4 mol) are simultaneously introduced at a temperature of 40C into a suspension of 4~s.4 g (0.4 mol) of aminomethanephosphonic acid in 160 ml of water. The resulting solution is refluxed for 30 minutes, in course of which an evolution of sulfur dioxide occurs. The solution is then cooled to 5C; the formecl precipitate is separated, washed with a small amount of ice-water and dried. The resulting yield is 44 g (65 %) of N-phosphono methylglycine; decomposition: ~250"C.
26 g (0.4 mol) Sulfur clioxide gas and 58 g of a 40 %
aqueous solution of glyoxal (0.4 mol3 are simultaneously introduced at a temperature of 60C into a suspension of 44.4 g (0,4 mol) of aminomethanephosphonic acid in 160 ml of water. The resulting solution is refluxed for 30 minutes, in course of which an evolution of sulfur dioxide occurs. The solution is then cooled to 5C; the Eormed precipitate is separated, washed with a small amount of ice-water and dried. The resulting yield is 50 g (74 %) of N-phosponomethylglycine; decomposition:~250C.
Example 8- 13 g (0.2 mol) Sulfur dioxide gas and S8 g of a 40 %
aqueous solution of glyoxal (0.4 mol) are simultaneously introduced at a temperature of 60C into a suspension of 44,4 g (0.4 mol) of aminomethanephosphonic acid in 160 ml of water. The resulting solution is refluxed for 30 minutes, in course of which an evolution of sulfur dioxide occurs. The solution is then cooled to 5C; the formed precipitate is separated, washed with a small amount of ice-water and dried. The resulting yield is 50 g (74 %) of N-phosphono-methylglycine; decomposition: ~ 250C.
Example 9: 50.5 g of a 40 % aqueous solution of glyoxal (0.334 mol) is dropwise added to a solution of 37.1 g (0.334 mol) of amino-methanephosphonic acid and 2.6 g (0.016 mol) of sodium hydrogen sulfite in 150 ml of water at a temperature of 60C. Stirring of the mixture at the same temperature is continued for l hour; the mixture is cooled to 5C; the forMed precipitate is separated, washed with a small amount of ice-water and dried. The resulting yield is 37.6 g (67 %) of N-phosphonomethylglycine; decomposition:
~250~C.
5-13686/~
Process for producin~ N-phosphonomethylglycine _.
The present invention relates to a novel process ~or producing N-phosphonomethylglycine of the formula I
Ho\~oL
~ -CH NH-CH -COOH (I~
by reaction of aminomethanephosphonic acid with glyoxal in an aqueous medium in the presence of sulfur dioxide.
N-Pllosphonomethylglycine is a herbicide which has a very wide spectrum and which has little or no residual effects. The production and use thereof are described in the U.S. Patent Specification No. 3,799,758.
It is known that on reaction of glycine, formaldehyde and phosphorous acid in the molar ratio of 1:1:1, there is formed, instead oE the desired N-phosphonomethylglycine mainly N,N-bis-phosphono methylglycine (cp. U.S. Patent Specification No. 3,956,370). This product can then be converted electrolytically (U.S. Patent Specification No. 3,835,000) into phosphonomethylglycine.
In order to overcome the difficulties associated with the afore-mentioned process, it has been suggested that N-phosphonomethyl-glycine be produced by a process comprising firstly reacting an N-substituted glycine with formaldehyde and phosphorous acid to the corresponding N-substituted N-phosphonomethylglycine, and subsequently detaching from this the substituent originally present on ., a~
L
the nitrogen atom. There is thus described for example in the U~S.
Patent Specification No. 3,956,370 the production of N-phosphono-methylglycine by reaction of N-benzylethylglycinate with formaldehyde and phosphorous acid with simultaneous hydrolysis of the ester group to give N-benzyl-N-phosphonomethylglycine and subsequent removal of the benzyl group, as benzyl bromide, with strong hydrobromic acid.
N-Yhosphonomethylglycine is obtained in this manner in a yield of about l,o %. This process is not advantageous for commercially producing N-phosphonomethylglycine on account of the low yield and in view of the lacrimatoric action of the benzyl bromide formed as a by-product.
It is therefore the object of the present invention to provide a process by which N-phosphonomethylglycine can be produced in good yield and with the formation of by-products which are easy to handle and environmentally favourable.
It is suggested according to the invention to produce N-phosphonomethyl-glycine by reacting aminomethanephosphonic acid of the formula II
HO\~
/P-CH2-NH2 (II), HO
in an aqueous medium, with glyoxal of the formula III
OHC-CHO (III) in the presence of sulfur dioxide, and isolating the resulting product.
There are two preferred procedures in performing the reaction according to the invention.
The Eirst advantageous procedure for the reaction is to suspend the aminomethanephosphonic acid and glyoxal in water, and to subsequently introduce sulEur dioxide into the suspension.
In this proceclure the introduction of the sulfur dioxide gas can be performed with or without cooling oE the reaction solution. The reaction mixture is however advantageously cooled to 0 to 30C, particularly to 5 to 20C, during the time the sulfur dioxide gas is being introduced. The amount of sulfur dioxide gas introduced is so regulated that the amount is hetween that required to clarify the suspension and that sufficing to saturate the mixture. A saturation of the reaction solution with sulfur dioxide is however an advantage.
The second advantageous procedure for the reaction is to suspend the aminomethanephosphonic acid in water and to subsequently introduce the glyoxal and the sulfur dioxide into the suspension simultaneously.
In this procedure the addition of the glyoxal and the sulfur dioxide gas is with advantage performed in a pre-heated suspension of amino-methanephosphonic acid. The temperature of the suspension is preferably 30 to 90C, and in particular 35 to 75C.
The amount o~ sulfur dioxide employed in this typ of procedure may be less than the equivalent necessary to form the bis-adduct with glyoxal. Preferred amounts of sulfur dioxide are 0.3 to 1.5 mole per mole of glyoxal. Most preferred are 0.5 to 1.0 mole sulfur dioxid gas per mole of glyoxal.
After completion of the introduction of the sulfur dioxide, resp. the glyoxal and the sulfur dioxide, required, in both procedures the solution is heated to a temperatur of between 60 and 1~0C. A
temperature of between 85C and the boiling temperature of the reaction mixture is advantageous. The reaction solution is heated for a period of 5 to 120 minutes. Reaction times of 15 to 60 minutes, and in particular of 20 to 40 minutes, are advantageous. The sulfur dioxide gas introduced is again liberated during heating and can be recovered.
The employed glyoxal can be used, in the reaction according to the invention, both as an aqueous solution of the monomer and as polymer.
In order to obtain a high yield, it is oE advantage to keep the amount of water as small as possible, since the reaction product is soluble in water. The Eurther addition oE water ~as ~olvent can be dispensed with in particular when dilute aqueous solutions of glyoxal are being used.
In the reaction according to the invention~ the sulfur dioxide can also be in the bound form instead of being in the form of sulfur dio~ide gas. Especially suitable in this respect are alkali metal salts and alkaline-earth metal salts of sulfurous acid, particularly hydrogen sulfite of sodium, potassium or calcium.
Using the procedure of adding the glyoxal to a suspension of amino-methanephosphonic acid and an alkali metal hydrogen sulfite very small amounts of the hydrogen sulfite may be used. Even amounts of less than 0.05 mole of sodium hydrogen sulfite per mole of glyoxal do not lower the yield dramatically. In this case a heating of the reaction mixture to temperatures above 75C is not advisable, in order to avoid an evolution of sulfur dioxide gas, which would stop the reaction before having achieved a reasonable conversion of the starting materials. The reaction still works at concentrations of 0.01 mole of alkali metal hydrogen sulfite per mole of glyoxal, but the reaction rates become slower with decreasing concentrations. Reaction times required may be up to 3 hours when low concentrations of alkali metal hydrogen sulfite are employed.
Also adducts of glyoxal and sulfurous acid, cmd salts tllereof, can be used as starting products for the reaction according to the invention.
Suitable in a particular manner for this purpose is the commercially obtainable glyoxal-bis-(sodium hydrogen sulfite) hydrate.
The substitution of sulfur dioxide by salts thereof or by reaction products of these with glyoxal is advantageous with respect to carrying out the process of the invention in the laboratory by virtue of the greater ease of operation; however, also in the case of applying the process on a commercial scale, the use of sulfur dioxide gas is of advantage Eor reasons of cost, in particular because the sulEur dioxide released again during the reaction can be recovered and re-utilised in the reaction of the following reaction batch~
An advantageous embodiment of the process according to the invention comprises saturating at 5 to 20C the suspension of aminomethane-phosphonic acid and glyoxal in water with sulfur dioxide, heating the formed solution at 85 to 105C for 20 to 40 minutes, and isolating the product by crystallisation.
Another advantageous embodiment of the process according to the invention comprises introducing at 30 to 90C into a suspension of aminomethanephosphonic acid simultaneously glyoxal and sulfur dioxide, heating the formed solution at 85 to 105C for 20 to 40 minutes, and isolating the product by crystallisation.
Another advantageous embodiment of the process according to the invention comprises adding at temperatures not above 75C glyoxal to a suspension of aminomethanephosphonic acid and at least 0.01 mole of alkalimetal hydrogen sulfite, heating the mixture of temperatures not above 75C for 0.5 to 3 hours and isolating the product by crystallisation.
The reactants, aminomethanephosphonic acid and glyoxal, are as a rule reacted in equimolar amounts.
The Examples which follow serve to further illustrate the present invention.
Example 1: Sulfur dioxide gas is introduced at 10 to 15C, with vigorous stirring and with cooling" into a suspension of 11.1 g (0.1 mol) of aminomethanephosphonic acid and 11.4 ml (0.1 mol) of 40 % aqueous glyoxal in 40 ml of water until a clear solution has formed. ~fter further stirring at room temperature for half an hour, the solution is refluxed for halE an hour, in the course of which an intense evolution of sulfur dioxide occurs, and the solution turns darlc brown. The reaction mixture is afterwards cooled to 5C; the formed precipitate is separated, washed with a small amount of ice-water and recrystallised from water. The yield is 8.1 g (48%) of pure N-phosphonomethylglycine; decomposition: 236C.
Example 2: A suspension of 11.1 g (0.1 mol) of aminomethane-phosphonic acid and 702 g (0.1 mol) of 80 % polymeric glyoxal in 40 ml of water is treated with sulfur dioxide and further processed in the manner described in Example l; yield: 7.7 g (45.5 %) of N-phosphonomethylglycine; decomposition: 244C.
Example 3: Sulfur dioxide gas is introduced, without cooling and with vigorous stirring, into a suspension of 11.1 g (0.1 mol) of aminomethanephosphonic acid and 7.2 g (Ool mol) of 80 % polymeric glyoxal in 40 ml of water until saturation is attained, in the course of which the solution turns yellowish-orange and the temperature rises to 42C. The solution is subsequently stirred and refluxed, during which time the colour of the solution becomes dark brown. The solution is filtered hot and then cooled to 5C; the precipitate is afterwards separated, washed with a small amount of ice-cold water and dried. The resulting yield is 10,6 g (62.8%) of N-phosphono-methylglycine; decomposition: 235C.
Example 4: A suspension of 15.6 g (0.055 mol) of glyoxal--bis-(sodium hydrogen sulfite) hydrate and S.5 g (0.05 mol) oE amino-methanephosphonic acid in 30 ml of water is refluxed with stirring.
The evolution of sulfur dioxide commences when the temperature reaches 85C; a clear solution is formed and is refluxed for 40 minutes. ~fer cooling of the reaction mixture to room temperature, 11 ml (0.11 mol) of 32 % hydrochloric acid are added, and the mixture is concentrated by evaporation. The oily residue is triturated with 40 ml of 36% hydrochloric acid; the salt which has precipitated is then separated, and the solution is again concentrated by evaporation. The oil obtained is crystallised by the addition of 150 ml of ethanol. This suspension is neutralised to Congo red by propylene oxide being added; the precipitate is separated, washed with ethanol and dried. Recrystallisation from water yields 4.5 g (53.2 %) of N-phosphonomethylglycine; decomposition: 228C.
Example 5: A suspension of 22.2 g (0.2 mol) of aminomethane-phosphonic acid and 58 g (0.2 mol) of glyoxal-bis-(sodiumhydrogen sulfite) hydrate in 80 ml aqueous 5 N hydrochlorid acid is heated slowly, while stirring, until the temperature reaches 95C. When the temperature at the interior of the reaction vessel reaches 70C, a strong evolution of sulfur dioxide occurs and the colour of the solution becomes light brown. After the gas-evolution has ceased, the reaction mixture is boiled for 0.5 hour under reflux, and then slowly cooled down to 0C.The precipitation that falls out, is filtered off, washed with icecold water and with acetone and then dried. Thus 20.2 g (59.8%) of N-phosphonomethylglycine is obtained, which melts while decomposing at 236~C.
Example 6: 26 g (0.4 mol) Sulfur dioxide gas and 58 g of a 40 %
aqueous solution of glyoxal t0.4 mol) are simultaneously introduced at a temperature of 40C into a suspension of 4~s.4 g (0.4 mol) of aminomethanephosphonic acid in 160 ml of water. The resulting solution is refluxed for 30 minutes, in course of which an evolution of sulfur dioxide occurs. The solution is then cooled to 5C; the formecl precipitate is separated, washed with a small amount of ice-water and dried. The resulting yield is 44 g (65 %) of N-phosphono methylglycine; decomposition: ~250"C.
26 g (0.4 mol) Sulfur clioxide gas and 58 g of a 40 %
aqueous solution of glyoxal (0.4 mol3 are simultaneously introduced at a temperature of 60C into a suspension of 44.4 g (0,4 mol) of aminomethanephosphonic acid in 160 ml of water. The resulting solution is refluxed for 30 minutes, in course of which an evolution of sulfur dioxide occurs. The solution is then cooled to 5C; the Eormed precipitate is separated, washed with a small amount of ice-water and dried. The resulting yield is 50 g (74 %) of N-phosponomethylglycine; decomposition:~250C.
Example 8- 13 g (0.2 mol) Sulfur dioxide gas and S8 g of a 40 %
aqueous solution of glyoxal (0.4 mol) are simultaneously introduced at a temperature of 60C into a suspension of 44,4 g (0.4 mol) of aminomethanephosphonic acid in 160 ml of water. The resulting solution is refluxed for 30 minutes, in course of which an evolution of sulfur dioxide occurs. The solution is then cooled to 5C; the formed precipitate is separated, washed with a small amount of ice-water and dried. The resulting yield is 50 g (74 %) of N-phosphono-methylglycine; decomposition: ~ 250C.
Example 9: 50.5 g of a 40 % aqueous solution of glyoxal (0.334 mol) is dropwise added to a solution of 37.1 g (0.334 mol) of amino-methanephosphonic acid and 2.6 g (0.016 mol) of sodium hydrogen sulfite in 150 ml of water at a temperature of 60C. Stirring of the mixture at the same temperature is continued for l hour; the mixture is cooled to 5C; the forMed precipitate is separated, washed with a small amount of ice-water and dried. The resulting yield is 37.6 g (67 %) of N-phosphonomethylglycine; decomposition:
~250~C.
Claims (22)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for producing N-phosphonomethylglycine of the formula I
(I) by reacting aminomethanephosphonic acid of the formula II
(II) in an aqueous medium, with glyoxal of the formula III
OHC-CHO (III) in the presence of sulfur dioxide, and isolating the resulting product.
(I) by reacting aminomethanephosphonic acid of the formula II
(II) in an aqueous medium, with glyoxal of the formula III
OHC-CHO (III) in the presence of sulfur dioxide, and isolating the resulting product.
2. A process according to claim 1, wherein the sulfur dioxide is introduced into a suspension of aminomethanephosphonic acid and glyoxal in water.
3. A process according to claim 2, wherein the minimum amount of sulfur dioxide is such that a clear solution is formed.
4. A process according to claim 3, wherein the reaction mixture is saturated with sulfur dioxide.
5. A process according to claim 1, wherein the reaction mixture is heated to 60 to 120°C.
6. A process according to claim 5, wherein the temperature is between 85°C and boiling temperature of the reaction mixture.
7. A process according to claim 1, wherein an aqueous solution of monomeric or polymeric glyoxal is used.
8. A process according to claim 5, wherein the solution is heated for 5 to 120 minutes.
9. A process according to claim 1, wherein the sulfur dioxide is used in the bound form.
10. A process according to claim 9, wherein the sulfur dioxide is used in the form of hydrogen sulfite of sodium, potassium or calcium, or, together with glyoxal, in the form of its bis hydrogen sulfite with sodium, potassium or calcium.
11. A process according to claim 1, wherein a suspension of amino-methanephosphonic acid and glyoxal in water is saturated at 5 to 20°C with sulfur dioxide, the formed solution is heated at 85 to 105°C for 20 to 40 minutes, and the product is isolated by crystallisation.
12. A process according to claim 1, wherein the sulfur dioxide and the glyoxal are simultaneously introduced into a suspension of aminomethanephosphonic acid in water.
13. A process according to claim 12, wherein the suspension of aminomethanephosphonic acid is preheated to 30 to 90°C.
14. A process according to claim 13, wherein the suspension of aminomethanephosphonic acid is preheated to 35 to 75°C.
15. A process according to claim 12, wherein the amount of sulfur dioxide employed is less than 2 mole per mole of glyoxal.
16. A process according to claim 15, wherein the amount of sulfur dioxide employed is 0.3 to 1.5 mole per mole of glyoxal.
17. A process according to claim 1, wherein glyoxal is added to a suspension of aminomethanephosphonic acid and an alkali metal hydrogen sulfite.
18. A process according to claim 17, wherein the amount of alkali metal hydrogen sulfite is at least 0.01 mole per mole of glyoxal.
19. A process according to claim 17, wherein the reaction mixture not heated to temperatures above 75°C.
20. A process according to claim 12, wherein the reaction mixture is heated to 60 to 120°C.
21. A process according to claim 1, wherein sulfur dioxide and glyoxal are added simultaneously to a suspension of aminomethane-phosphonic acid at 30 to 90°C, the formed solution is heated to 85 to 105°C for 20 to 40 minutes, and the product is isolated by crystallisation.
22. A process according to claim 1, wherein glyoxal is added at a temperature not above 75°C to a suspension of aminomethanephosphonic acid and at least 0.01 mol of alkali metal hydrogen sulfite, the mixture is heated at a temperature not above 75°C for 0.5 to 3 hours, and the product is isolated by crystallisation.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/327,138 US4369142A (en) | 1981-12-03 | 1981-12-03 | Process for producing N-phosphonomethylglycine |
| US327,138 | 1981-12-03 | ||
| US39181682A | 1982-06-24 | 1982-06-24 | |
| US442,933 | 1982-11-19 | ||
| US06/442,933 US4486358A (en) | 1982-06-24 | 1982-11-19 | Process for producing N-phosphonomethylglycine |
| US391,816 | 1989-08-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1196014A true CA1196014A (en) | 1985-10-29 |
Family
ID=27406501
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000416768A Expired CA1196014A (en) | 1981-12-03 | 1982-12-01 | Process for producing n-phosphonomethylglycine |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0081459B1 (en) |
| KR (1) | KR880001831B1 (en) |
| BR (1) | BR8206995A (en) |
| CA (1) | CA1196014A (en) |
| DE (1) | DE3264321D1 (en) |
| ES (1) | ES518123A0 (en) |
| HU (1) | HU190428B (en) |
| IL (1) | IL67390A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5874612A (en) * | 1984-12-28 | 1999-02-23 | Baysdon; Sherrol L. | Process for the preparation of glyphosate and glyphosate derivatives |
| DE3532344A1 (en) * | 1985-09-11 | 1987-03-19 | Hoechst Ag | METHOD FOR PRODUCING N-PHOSPHONOMETHYLGLYCINE |
| US5948937A (en) * | 1996-09-12 | 1999-09-07 | Monsanto Company | Method for producing N-phosphonomethylglycine and its salts |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IL48619A (en) * | 1974-12-11 | 1978-04-30 | Monsanto Co | Process for the production of n-(phosphonomethyl)-glycine compounds |
| ES443323A1 (en) * | 1974-12-11 | 1977-04-16 | Monsanto Co | Carbonylaldiminomethanephosphonates |
-
1982
- 1982-11-30 EP EP82810512A patent/EP0081459B1/en not_active Expired
- 1982-11-30 DE DE8282810512T patent/DE3264321D1/en not_active Expired
- 1982-12-01 CA CA000416768A patent/CA1196014A/en not_active Expired
- 1982-12-01 IL IL67390A patent/IL67390A/en not_active IP Right Cessation
- 1982-12-02 ES ES518123A patent/ES518123A0/en active Granted
- 1982-12-02 HU HU823873A patent/HU190428B/en unknown
- 1982-12-02 BR BR8206995A patent/BR8206995A/en unknown
- 1982-12-03 KR KR8205433A patent/KR880001831B1/en active
Also Published As
| Publication number | Publication date |
|---|---|
| BR8206995A (en) | 1983-10-11 |
| ES8401979A1 (en) | 1984-01-16 |
| KR840002846A (en) | 1984-07-21 |
| DE3264321D1 (en) | 1985-07-25 |
| ES518123A0 (en) | 1984-01-16 |
| KR880001831B1 (en) | 1988-09-20 |
| HU190428B (en) | 1986-09-29 |
| IL67390A (en) | 1985-07-31 |
| EP0081459B1 (en) | 1985-06-19 |
| IL67390A0 (en) | 1983-05-15 |
| EP0081459A1 (en) | 1983-06-15 |
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