Water → Ethylenediaminediacetic acid

Deionized water (60.6 g), 98% N-acetylethylene-diamine (20.4 g, 0.2 mole), and bromoacetic acid (55.7 g, 0.40 mole) were added to a reaction vessel and cooled in an ice-water bath. The pH of the mix was adjusted, while stirring, to approximately 8.1 with 25% sodium hydroxide solution. The temperature of the mix was maintained at less than 20° C. during the caustic addition. The ice-water bath was removed and the pH maintained between 7 and 8 by the addition of 25% sodium hydroxide solution. The temperature was controlled at less than 37° C. by periodically cooling with an ice-water bath. The reaction mixture was stirred and maintained as above for approximately 31 hours and then transferred to a round-bottom reaction flask equipped with a water-cooled reflux condenser, magnetic stirrer bar, thermometer, addition funnel and a heating mantle. Sodium hydroxide solution (40.1 g of 50% solution) was added and the mix heated, with stirring, at reflux for approximately 15 hours and then cooled and filtered using a medium glass frit funnel and vacuum. The filtrate was transferred quantitatively (using deionized water) to a beaker and cooled in an ice-bath to less than 25° C. Deionized water (100 ml) was added with stirring and the pH adjusted to approximately 4 with concentrated hydrochloric acid while maintaining the temperature at less than 25° C. The mix was filtered using a medium glass frit funnel and vacuum. Approximately 1200 ml of ethanol were added to a large beaker and stirred with a magnetic stirrer bar. The filtrate from above was added to the ethanol with thorough mixing. An oily material forms which gradually turns into a white solid. Agitation was continued for two hours at which time the solids were collected by filtering using a medium glass frit funnel and vacuum. The solids were allowed to dry by exposure to air for about 1.5 hours and then placed in a vacuum oven and dried at 55°-60° C. for several hours. Approximately 42.9 g of white solids containing inorganic salt were collected and identified as unsymmetrical ethylenediaminediacetic acid by proton and carbon NMR.

1. temperaturecooled in an ice-water bath
2. temperatureThe temperature of the mix was maintained at less than 20° C. during the caustic addition
3. customThe ice-water bath was removed
4. temperaturethe pH maintained between 7 and 8 by the addition of 25% sodium hydroxide solution
5. customwas controlled at less than 37° C.
6. temperatureby periodically cooling with an ice-water bath
7. temperaturemaintained as above for approximately 31 hours
8. customtransferred to a round-bottom reaction flask
9. customequipped with a water-
10. temperaturecooled
11. temperaturereflux condenser, magnetic stirrer bar
12. additionthermometer, addition funnel
13. additionSodium hydroxide solution (40.1 g of 50% solution) was added
14. temperaturethe mix heated
15. stirringwith stirring
16. temperatureat reflux for approximately 15 hours
17. temperaturecooled
18. filtrationfiltered
19. temperaturecooled in an ice-bath to less than 25° C
20. additionDeionized water (100 ml) was added
21. stirringwith stirring
22. temperaturewhile maintaining the temperature at less than 25° C
23. filtrationThe mix was filtered
24. additionApproximately 1200 ml of ethanol were added to a large beaker
25. stirringstirred with a magnetic stirrer bar
26. additionThe filtrate from above was added to the ethanol with thorough mixing
27. customthe solids were collected
28. filtrationby filtering
29. customto dry by exposure to air for about 1.5 hours
30. customdried at 55°-60° C. for several hours
31. additionApproximately 42.9 g of white solids containing inorganic salt
32. customwere collected

ORD record

ord-6c1b2cbf2cd24fb59bd4ccaed5c1aa87

Source dataset

uspto-grants-1997_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05696239