Process for the preparation of N-phosphonomethylglycine

Abstract

A process for the preparation of N-phosphonomethylglycine by reaction of aminomethanephosphonic acid and glyoxylic acid in the molar ratio 1:2 in aqueous medium.

I claim: 
     
       1. A process for the preparation of N-phosphonomethylglycine of the formula ##STR5## wherein aminomethanephosphonic acid of the formula ##STR6## or salts thereof with strong bases, are reacted with glyoxylic acid in the molar ratio of about 1:2 in aqueous or aqueous-organic medium. 
     
     
       2. The process as claimed in claim 1, wherein the reaction is carried out at temperatures of 10°-100° C. 
     
     
       3. The process as claimed in claim 1, wherein a water-miscible organic solvent is added. 
     
     
       4. The process as claimed in claim 2, wherein the temperatures are 30° to 100° C. 
     
     
       5. The process as claimed in claim 3, wherein the solvent is acetone, acetonitril or methanol. .Iadd. 
     
     
       6.  A process for the preparation of N-phosphonomethylglycine of the formula ##STR7##.Iaddend. wherein aminomethanephosphonic acid of the formula ##STR8## is reacted with glyoxylic acid in the molar ratio of about 1:2 in aqueous or aqueous-organic medium. .Iadd. 
     
     
       7.  The process as claimed in claim 6, wherein the reaction is carried out at temperatures of 60°-100° C. .Iaddend..Iadd.8. The process as claimed in claim 6, wherein the reaction is carried out at temperatures of 40°-85° C. .Iaddend..Iadd.9. The process as claimed in any one of claims 6, 7 or 8, wherein the medium is aqueous medium. .Iaddend..Iadd.10. The process as claimed in claim 8, wherein aminomethanephosphonic acid of the formula (II) is reacted with glyoxylic acid in the molar ratio of 1:2 in aqueous medium. .Iaddend..Iadd.11. A process for the preparation of N-phosphonomethylglycine of the formula ##STR9##.Iaddend. or salts thereof, wherein aminomethanephosphonic acid of the formula ##STR10## or salts thereof with strong bases, respectively, are reacted with glyoxylic acid in the molar ratio of about 1:2 in aqueous or aqueous 
     
     
        organic medium. .Iadd.12.  The process as claimed in claim 11 wherein the salts with a strong base of aminomethanephosphonic acid are ethylamine, triethylamine, isopropylamine, ethanolamine, sodium or potassium salts. .Iaddend..Iadd.13. The process as claimed in claim 12 wherein the reaction is carried out at temperatures of 60°-100° C. and the salts with a strong base are sodium salts. .Iaddend..Iadd.14. The process as claimed in claim 11 in which the salts of the N-phosphonomethylglycine are digested with acid to produce the compound of the formula I. 
     
     
        .Iaddend..Iadd.15.  The process as claimed in claim 14 wherein the reaction is carried out at temperatures of 60°-100° C., the acid is hydrochloric acid and the salts with a strong base are sodium salts. .Iaddend.