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

Participants

Reaction Conditions

Reaction Steps

Concentrated filtrates from reaction 2 was charged to a 250 ml three neck flask fitted with thermometer, condenser, dropping funnel and stirrer. Phosphorous acid (39.1 g, 0.472 moles), iminodiacetic acid (60.9 g, 0.449 moles) and sulphuric acid (4.79 g, 0.0479 moles) were added, with stirring, to the flask. The reaction mixture was then heated to 120° C. and formaldehyde (44.2 g at 36.1% strength, 0.533 moles) was then added over one hour. The temperature was maintained between 110° and 120° C. during addition. On complete addition the reaction mixture was allowed to cool to 25° C. over 90 minutes. The reaction mixture was filtered and the filter cake washed with water (57 ml). The product was dried in a vacuum oven to yield 90.1 g of N-phosphonomethyliminodiacetic acid at 95.6% strength equivalent to a cumulative isolated yield of 78.2%. The filtrates (91.1 g) and the water wash (71.8 g) were analysed at 5.0% and 3.0% N-phosphonomethylimiodiacetic acid respectively. This was equivalent to a total cumulative conversion yield of 82.3% N-phosphonomethyliminodiacetic acid.

Provenance & Evidence