Pure N-phosphonomethyl-glycine preparation in high yield for use as herbicide, by peroxide oxidation of N-(phosphonomethyl)-iminodiacetic acid over activated carbon catalyst having specific particle size distribution

摘要

In the preparation of N-phosphonomethyl-glycine (I) the catalyst is activated carbon having 98% of the particles of size 150 mu m or less and not more than 40% of size 10 micro m or less. In the preparation of N-phosphonomethyl-glycine (I) by: (a) oxidizing N-(phosphonomethyl)-iminodiacetic acid (II) with peroxide in an aqueous medium in presence of a heterogeneous catalyst at 50-100 deg C; (b) separating the solid catalyst from the suspension; (c) concentrating the solution (preferably by evaporation); and (d) isolating (I) (preferably by filtration), the catalyst is activated carbon having 98% of the particles of size 150 micro m or less and not more than 40% of size 10 micro m or less.