Hydrogen Bromide → alpha-Hydroxyacetophenone

HRID 839946Notes

Reaction equation

HRID 839946 reaction equation
BrBr.[C:3]([C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1)(=[O:5])[CH3:4].C[OH:13].Br>O>[OH:13][CH2:4][C:3]([C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1)=[O:5]

Participants

6

Reactant 4

HCID 260Hydrogen BromideHCID 887MethanolHCID 7410AcetophenoneHCID 24408Bromine3×

Product 1

HCID 68490alpha-Hydroxyacetophenone

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Conditions

Temperature
60 °C

Procedure

About 13 parts of bromine was added with stirring to a mixture of 474.6 parts of acetophenone in about 640 parts of methanol, while the mixture was stirred and maintained at a temperature between 5°-10° C. Hydrogen bromide gas was then introduced into the mixture until bromine coloration disappeared, at which point an additional amount of bromine was added over a 2 hour period to make a total of 631.3 parts. There was then added 71 parts of water while the mixture was stirred and externally cooled for a period of about 30 minutes. An excess of about 2700 parts of water was then slowly added to effect the precipitation in the form of crystals of α-bromo acetophenone from the mixture. The crystals were decanted by means of a vacuum siphon, washed, then neutralized with a 20% sodium hydroxide solution and decanted to dryness. There was then added about 940 parts water, 1600 parts of methanol, 333 parts of sodium bicarbonate and a sodium formate solution prepared from 161 parts of a 90% formic acid and sufficient sodium hydroxide to neutralize the acid. The mixture was heated at 60° C with vigorous stirring for 7 hours after which time it was cooled to ambient temperature and filtered. Based on method of preparation and gas chromatographic analysis of the mixture there was produced α-hydroxy acetophenone in quantitative yields.

Workup

  1. temperaturemaintained at a temperature between 5°-10° C
  2. additionwas added over a 2 hour period
  3. stirringwas stirred
  4. temperatureexternally cooled for a period of about 30 minutes
  5. customthe precipitation in the form of crystals of α-bromo acetophenone from the mixture
  6. customThe crystals were decanted by means of a vacuum siphon
  7. washwashed
  8. customdecanted to dryness
  9. additionThere was then added about 940 parts water, 1600 parts of methanol, 333 parts of sodium bicarbonate
  10. customa sodium formate solution prepared from 161 parts of a 90% formic acid and sufficient sodium hydroxide
  11. stirringwith vigorous stirring for 7 hours after which time it
  12. temperaturewas cooled to ambient temperature
  13. filtrationfiltered
  14. customBased on method of preparation and gas chromatographic analysis of the mixture there

Sources & evidence

ORD record
ord-ac6617d8d1954ae19a9cdee3ecea2152
Source dataset
uspto-grants-1978_06
Patent number
US04097671

Reaction notes

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