Production process of N-phosphono methyl glycine

The present invention discloses the production prof N-phosphono methyl glycine, and features that N-phosphono methyl imido diacetic acid is made to react with oxygen in the presence of Mn, Fe, Co, Cu or Ni and C catalyst to produce N-phosphono methyl glycine. By means of controlling the oxidation degree via catalyst and oxidant, the destination product has high selectivity and high yield; by means of eliminating formaldehyde from the reaction system, the product glyphosate or its salt has stable quality; by means of eliminating impurity from the reaction system, the reaction mother liquid may be reused for 5 or 6 times; and the preparation of glyphosate has low power consumption and high yield.