Maleic Anhydride → Citric Acid

HRID 375225Notes

Reaction equation

HRID 375225 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-5163c7c6c6c345958587a94bc34cb5d5
Source dataset
uspto-grants-1996_01
Patent number
US05484860

Reaction notes

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