Reaktion #347589

Reaktionsgleichung

ammonium hydroxide

maleic anhydride

citric acid monohydrate

→

citric acid

Lösungsmittel

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThis solution was evaporated to dryness over a period of 8 minutes
2. 2
   TemperaturThe solid was then heated at 235°-245° C. for 5 minutes
3. 3
   Sonstigeremoved from the heat
4. 4
   Temperaturto cool
5. 5
   TemperaturThe solid was then heated at 235°-245° C. for a second 10 minute period
6. 6
   Sonstigeremoved from the heat
7. 7
   Temperaturto cool
8. 8
   TemperaturFinally, the solid was heated at 235°-245° C. for a third 10 minute period
9. 9
   Sonstigeremoved from the
10. 10
    Temperaturheat
11. 11
    Temperaturto cool to room temperature
12. 12
    workup.ADDITIONa solution of 8.0 g of sodium hydroxide in 12 ml of water was added over 5 minutes
13. 13
    workup.STIRRINGThe solution was stirred for 10-20 minutes

Vorschrift

A slurry of 19.6 g (0.2 mole) maleic anhydride was dissolved in 40 ml water at 80°-95° C. and 4.2 g (0.02 moles) of citric acid monohydrate (Formula weight 210) was added and the mixture was stirred until all solids were in solution, after which the mixture was allowed to cool to 25° C. To this solution at 25° C. was added 60 g of 30% aqueous solution of ammonium hydroxide (0.44 mol NH3). This solution was evaporated to dryness over a period of 8 minutes. The solid was then heated at 235°-245° C. for 5 minutes, removed from the heat, allowed to cool and broken up with a spatula. The solid was then heated at 235°-245° C. for a second 10 minute period, removed from the heat, allowed to cool and broken up with a spatula. Finally, the solid was heated at 235°-245° C. for a third 10 minute period, removed from the heat and allowed to cool to room temperature. The resulting water insoluble copolymer of polysuccinimide and citric acid (21.7 g) was slurried in 29.1 ml of water and a solution of 8.0 g of sodium hydroxide in 12 ml of water was added over 5 minutes. The solution was stirred for 10-20 minutes to give a clear red-brown solution of a copolymer of polyaspartic acid and citric acid.

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