反应详情

温度

120 °C

Water (17.3 g, 0.961 moles) was charged to a 250 ml three neck flask fitted with thermometer, condenser, dropping funnel and stirrer. Phosphorous acid (42.6 g, 0.514 moles), sulphuric acid (50.0 g, 0.500 moles--added over 10 minutes during which an exotherm from 20° C. to 60° C. was observed) and iminodiacetic acid (66.5 g,0.490 moles) were added to the stirred reaction flask. The reaction mixture was then heated to 120° C. and formaldehyde (48.2 g at 36.1% strength, 0.580 moles) was 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 and the reaction mixture was filtered. The filter cake was washed with water (57 ml) and the product was dried in a vacuum oven to yield 67.9 g of N-phosphonomethyliminodiacetic acid at 98.0% strength, equivalent to an isolated yield of 59.8%. The filtrates (128.0 g) and the water wash (66.0 g) were analysed at 13.7% and 5.5% N-phosphonomethyliminodiacetic acid respectively. This was equivalent to a total conversion yield of 78.9% N-phosphonomethyliminodiacetic acid.

1. customfitted with thermometer, condenser
2. additionwere added to the stirred reaction flask
3. temperatureThe temperature was maintained between 110° and 120° C. during addition
4. additionOn complete addition
5. temperatureto cool to 25° C. over 90 minutes
6. filtrationthe reaction mixture was filtered
7. washThe filter cake was washed with water (57 ml)
8. customthe product was dried in a vacuum oven