Formaldehyde → N-(Carboxymethyl)-N-(phosphonomethyl)glycine

Participants

Reaction Conditions

Reaction Steps

In a three-necked round-bottom flask equipped with a mechanical stirrer, 33.28 g (0.25 mol) of iminodiacetic acid (IDA) were mixed with 20.5 g (0.25 mol, 1 eq.) of phosphorous acid and 122.5 g (1.25 mol, 5 eq.) of phosphoric acid. The reaction mixture was heated to 140° C. 20.68 ml of 36.6 wt.-% aqueous solution of formaldehyde (1.1 eq.) were then added over 60 min. During the addition, the temperature of the reaction mixture decreased from 140° C. to 125° C. At the end of the formaldehyde addition the reaction mixture was kept at reflux for 30 min. The precipitate formed by cooling the reaction mixture was isolated by filtration and washed with fresh water. After drying the precipitate was analysed by 1H and 31P NMR and identified as 81.3% pure N-(phosphonomethyl)iminodiacetic acid (PMIDA, 28 g, 61.2% yield).

Provenance & Evidence