Citric Acid → Anhydromethylenecitric acid

HRID 728686Notes

Reaction equation

HRID 728686 reaction equation
[C:1]([OH:13])(=[O:12])[CH2:2][C:3]([CH2:8][C:9]([OH:11])=[O:10])([C:5]([OH:7])=[O:6])[OH:4].[CH2:14]=O>O>[CH2:14]1[O:4][C:3]([CH2:2][C:1]([OH:13])=[O:12])([CH2:8][C:9]([OH:11])=[O:10])[C:5](=[O:7])[O:6]1

Participants

4

Reactant 2

HCID 311Citric AcidHCID 712Formaldehyde

Product 1

HCID 8945Anhydromethylenecitric acidYield 54.1%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

Anhydrous citric acid (1), (120 g, 0.625 mole) and paraformaldehyde (21 g, 0.70 mole) were mixed in a beaker which was then immersed in an oil bath preheated to 145° C. The mixture, with intermittent stirring, was held at this temperature for 2 hours. The mixture melted, then resolidified during this time. The cooled mixture was dissolved in a minimal amount of boiling water on the hot plate (total volume ≈225 ml). On cooling, crystals formed. The mixture was kept overnight in the refrigerator, then, the crystals were collected, washed with cold water and dried on the filter using a heat lamp to give 2 (69 g, 53%) as white crystals, mp 205°-207° C.

Workup

  1. customwas then immersed in an oil bath
  2. custompreheated to 145° C
  3. temperatureOn cooling
  4. customcrystals formed
  5. waitThe mixture was kept overnight in the refrigerator
  6. customthe crystals were collected
  7. washwashed with cold water
  8. customdried on the filter

Sources & evidence

ORD record
ord-0ade11b78661491bae893ae3dc6a2be6
Source dataset
uspto-grants-1991_09
Patent number
US05049699

Reaction notes

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