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AssigneeErcros S.A.
InventorsJuan L. Martin Ramon, Julio Munoz Madronero
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Improvements to a method for preparing N-phosphonomethylglycyne by oxidation of N-phosphonomethyliminodiacetic acid. N-phosphonomethylglycine may be obtained by oxidation of N-phosphonomethyliminodiacetic acid with O.sub.2 or with an oxygen-containing gas, in the presence of a noble metal catalyst on activated carbon. To avoid the catalyst losses, the improvements of the invention consist in a pressure scavaging with N.sub.2, after completion of the oxidation reaction. Owing to such treatment, the catalyst losses are reduced from 30% to 1%, making the processing economically viable on a large industrial scale. The recovered catalyst holds its catalytic activity and may be reused at least 20 consecutive times. N-phosphonomethylglycine is a herbicide of extended application.
Improvements introduced into a method of obtaining N-phosphonomethylglycine by oxidation of N-phosphonomethyliminodiacetic acid with oxygen or a gas containing oxygen, in the presence of a catalyst of noble metal supported on activated carbon, said improvements being characterised in that, once the reaction has been completed and before proceeding with its cooling, a flushing-out with nitrogen under slight pressure is carried out, at a temperature equal to, or greater than that of the reaction, for a definite period of time, which determines the reduction of the losses of noble metal in the solution.
Dependencies are inferred from the claim text.