Glyphosate → Glyphosate

Participants

Reaction Steps

A solution of the disodium salt of N-phosphonomethylglycine is prepared as described in Example I and 11.0 grams (0.11 mole) of finely ground maleic anhydride is added with stirring. Some sodium hydroxide is added to keep the pH at almost 9, and a small portion of ether is added to help dissolve particles of the anhydride. Stirring is continued for several days, and 2.0 or 4.0 gram portions of maleic anhydride are added until no further N-phosphonomethylglycine remains in the reaction mixture. During this period, small portions of sodium hydroxide are added as needed to maintain a pH of about 8. When reaction is complete, the mixture is filtered, rinsed with water, concentrated and then dried. The product, containing disodium maleate by-product, is obtained as a colorless glass, and it is identified by nuclear magnetic resonance (nmr) as the trisodium salt of N-carboxymethyl-N-(phosphonomethyl)maleamic acid. ##STR4##

Provenance & Evidence