Verfahren zur Herstellung von N-Phosphonomethylglycin

摘要

To prepare N-phosphonomethylglycine, (a) react aminomethylphosphonic acid or one of its salts in water, optionally adding alkaline lyes, with an alkali carbonate and/or alkali hydrogen carbonate or with carbon dioxide and an alkaline lye, (b) hydroxymethylate the resulting alkali salt of the N-phosphonomethylcarbamic acid with formaldehyde, (c) react the resulting salts of the N-hydromethyl-N-phosphonomethylcarbamic acid, optionally adding an alkaline lye, with hydrocyanic acid and/or a cyanide, and (d) adding acids, convert the resulting salts of the N-carboxy-N-phosphonomethylformaldehyde cyanhydrine into N-phosphonomethylglycine through hydrolysis and decarboxylation. This method gives excellent yields and a high degree of purity of N-phosphonomethylglycine.