PROCEDE POUR PREPARER N-PHOSPHONOMETHYLGLYCINE

摘要

A process for the production of N-phosphonomethylglycine characterised in that it comprises: (a) reacting a hydantoin or a 3-substituted hydantoin corresponding to the following general formula: wherein R represents hydrogen, C1-C10 alkyl, C6-C12 aryl, C1-C10 alkyl-carbonyl and C6-C12 aryl-carbonyl with paraformaldehyde in the presence of a low molecular weight carboxylic acid to produce a mixture of intermediate products including the 1 -(hydroxymethyl) derivative of the starting hydantoin; (b) converting the 1 -(hydroxymethyl) derivative to the 1 -phosphonomethyl derivative by thereafter adding to the reaction mixture either: (i) a substituted phosphorus compound selected from phosphorus trichloride and phosphorus tribromide; (ii) phosphorus acid and an anhydride selected from acetic anhydride, propionic anhydride, butyric anhydride or a similar asymmetrical anhydride and continuing the reaction to cause completion of the reaction to form the 1 -phosphonomethyl derivative; (c) hydrolyzing the resulting 1 -phosphonomethylhydantoin product with a base selected from alkali metal or alkaline earth hydroxides to produce a salt of N-phosphonomethylglycine; and (d) neutralizing the salt witha strong acid to produce N-phosphonomethylglycine is disclosed. The present process provides advantages over the prior art.