| abstract |
Process for the preparation of N-phosphonomethylglycine salts by reacting a salt of N-phosphonomethyliminodiacetic acid, whereby the salt-forming cation is selected from the group alkali metals, alkaline earth metals, ammonium and organic ammonium, in the presence of oxygen in an aqueous-basic or aqueous solution and in the presence of a noble metal catalyst on a solid carrier, under excess pressure and at elevated temperature, the process being characterised by the fact that (a) the noble metal is selected from the group platinum, palladium or mixtures of palladium and platinum, and platinum or palladium individually or together in a mixture with ruthenium, rhodium, osmium or iridium, and (b) it is additionally admixed with at least one doping metal from the group bismuth, lead, tin, tellurium, germanium, vanadium, chromium, iron, manganese, molybdenum and tungsten. The known herbicide N-phosphonomethylglycine may be prepared from N-phosphonomethyliminodiacetic acid. |