Hydrochloric Acid → 1-Phenyl-1,2-propanedione

HRID 236285Notes

Reaction equation

HRID 236285 reaction equation
[C:1]([C:5]1[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=1)(=[O:4])[CH2:2][CH3:3].BrBr.[Na].Cl.C[OH:16]>[Cl-].[Al+3].[Cl-].[Cl-].CCOCC>[C:5]1([C:1](=[O:4])[C:2](=[O:16])[CH3:3])[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=1

Participants

8

Reactant 5

HCID 313Hydrochloric AcidHCID 887MethanolHCID 71481-Phenyl-1-propanoneHCID 24408BromineHCID 5360545Sodium

Product 1

HCID 113631-Phenyl-1,2-propanedioneYield 86%

Reagents, catalysts & solvents 2

HCID 6451240Aluminum(III) ChlorideCatalystHCID 3283Diethyl EtherSolvent

Procedure

6.0 kg (44.78 moles) of propiophenone and 92 g of anhydrous aluminum chloride were added to 6 liters of ether followed by 17.2 kg (107.5 mole) of bromine at a rate to maintained a gentle reflux. When the addition was complete (approximately 6 hours), the mixture was heated to reflux overnight and then the solvent was removed under vacuum to obtain a lachrymatory dark red/orange oil. The oil was slowly added to a solution of 2.81 kg (122.2 mmole)of sodium in 45 l of methanol while maintaining the temperature below 20° C. When the addition was complete, 12.5 liters of concentrated hydrochloric acid were added and the mixture was stirred at room temperature for 1 hour. The precipitate was filtered off and the filtrate reduced in volume to approximately 25 liters by distillation of the methanol. The residue was partitioned between 10 liters of chloroform and 10 liters of water. Then, the organic phase was separated and the aqueous phase extracted twice with 5 liters of chloroform. The combined chloroform solutions were dried over sodium sulfate and evaporated to dryness. The residue was fractionally distilled under vacuum through a 30 cm Fenske column to obtain 5.7 kg of 1-phenylpropane-1,2-dione (86% yield) and a boiling point of 77°-85° C. at 1-2 mm Hg.

Workup

  1. temperatureto maintained a gentle reflux
  2. additionWhen the addition
  3. custom(approximately 6 hours)
  4. temperaturethe mixture was heated
  5. temperatureto reflux overnight
  6. customthe solvent was removed under vacuum
  7. customto obtain a lachrymatory dark red/orange oil
  8. temperaturewhile maintaining the temperature below 20° C
  9. additionWhen the addition
  10. filtrationThe precipitate was filtered off
  11. distillationthe filtrate reduced in volume to approximately 25 liters by distillation of the methanol
  12. customThe residue was partitioned between 10 liters of chloroform and 10 liters of water
  13. customThen, the organic phase was separated
  14. extractionthe aqueous phase extracted twice with 5 liters of chloroform
  15. dry with materialThe combined chloroform solutions were dried over sodium sulfate
  16. customevaporated to dryness
  17. distillationThe residue was fractionally distilled under vacuum through a 30 cm Fenske column

Sources & evidence

ORD record
ord-b1a904bd1e344e68992196b60d8b8485
Source dataset
uspto-grants-1987_02
Patent number
US04643999

Reaction notes

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