Maleic Anhydride → Citric Acid

HRID 726159Notes

Reaction equation

HRID 726159 reaction equation
C1(=O)OC(=O)C=C1.O.[C:9]([OH:21])(=[O:20])[CH2:10][C:11]([CH2:16][C:17]([OH:19])=[O:18])([C:13]([OH:15])=[O:14])[OH:12].[OH-].[NH4+]>O>[C:9]([OH:21])(=[O:20])[CH2:10][C:11]([CH2:16][C:17]([OH:19])=[O:18])([C:13]([OH:15])=[O:14])[OH:12]

Participants

5

Reactant 3

HCID 7923Maleic AnhydrideHCID 14923Ammonium HydroxideHCID 222302-Hydroxy-1,2,3-propanetricarboxylic acid hydrate (1:1)

Product 1

HCID 311Citric Acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
25 °C

Procedure

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.

Workup

  1. customThis solution was evaporated to dryness over a period of 8 minutes
  2. temperatureThe solid was then heated at 235°-245° C. for 5 minutes
  3. customremoved from the heat
  4. temperatureto cool
  5. temperatureThe solid was then heated at 235°-245° C. for a second 10 minute period
  6. customremoved from the heat
  7. temperatureto cool
  8. temperatureFinally, the solid was heated at 235°-245° C. for a third 10 minute period
  9. customremoved from the
  10. temperatureheat
  11. temperatureto cool to room temperature
  12. additiona solution of 8.0 g of sodium hydroxide in 12 ml of water was added over 5 minutes
  13. stirringThe solution was stirred for 10-20 minutes

Sources & evidence

ORD record
ord-0c833af8af124430a47cf274d66c0d34
Source dataset
uspto-grants-1998_01
Patent number
US05708126

Reaction notes

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