Nitrokemia Ipartelepek

Csaba Kayos

Csaba Soptei

Zoltan Kolonics

Jeno Pelyva

Bela Karacsonyi

Sandor Balint

Laszlo Lendvai

Janosne Benczik

Sandor Laszlo

Sandor Silye

The invention relates to an improvement of a process for preparing N-phosphonomethyl-glycine by oxydation of N-phosphonomethyl-imino-diacetic acid in an aqueous sulphuric acidic medium with hydrogen peroxide. A characteristic feature is using a waste acid liquor as reaction medium formed as aqueous sulphuric acid and obtained after the separation of N-phosphonomethyl-glycine when carrying out oxydation. This solution is optionally diluted with water until a concentration of 12-18 weight % of sulphuric acid and 3-5 weight % of N-phosphonomethyl-glycine.

Process for preparing N-phosphonomethyl-glycine

The invention relates to the preparation of N-phosphono-methyl-imino-diacetic acid from the calcium salt of imino-diacetic acid in a simplified synthesis. The process comprises in that the imino-diacetic acid calcium salt is heated with concentrated hydrochloric acid in a molar ratio of 2-3:1 at a temperature between 50.degree.-100.degree. C., the obtained imino-diacetic acid hydrogen-chloride is separated then dissolved in water and is reacted with phosphorous acid in a molar ratio of 1.0-1.2:1 calculated for imino-diacetic acid hydrogen chloride and with the aqueous solution of formaldehyde in a molar ratio of 1.0-1.4:1 under stirring, and the obtained product is isolated.

Process for preparing N-phosphono-methyl-imino-diacetic acid

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Veszprem, Hungary

Csaba Kayos