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

Participants

Reaction Conditions

Reaction Steps

Concentrated filtrates from Cycle 3 were charged to a 250 ml three neck flask fitted with therometer, condenser, dropping funnel and stirrer. Phosphorous acid (37.9 g, 0.457 moles), iminodiacetic acid (59.0 g, 0.434 moles) and sulphuric acid (4.64 g, 0.046 moles) were added, with stirring, to the flask. The reaction mixture was then heated to 120° C. and formaldehyde (42.8 g at 36.1% strength, 0.515 moles) was then added over one hour and sulphuric acid (4.64 g, 0.046 moles) were added, with stirring, to the flask. The reaction mixture was then heated to 120° C. and formaldehyde (42.8 g at 36.1% strength, 0.515 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 66.2 g of N-phosphonomethyliminodiacetic acid at 91.4% strength equivalent to a cumulative isolated yield of 74.2%. The filtrates (92.8 g) and the water wash (70.7 g) were analysed at 5.4% and 4.2% N-phosphonomethyliminodiacetic acid respectively. This was equivalent to total cumulative conversion yield of 78.2% N-phosphonomethyliminodiacetic acid.

Provenance & Evidence