Sulfuric Acid → 2,3-Dibromobenzaldehyde

HRID 1578705Notes

Reaction equation

HRID 1578705 reaction equation
BrBr.[Br:3][C:4]1[C:9]([Br:10])=[CH:8][CH:7]=[CH:6][C:5]=1[CH3:11].S(=O)(=O)(O)[OH:13]>>[Br:3][C:4]1[C:9]([Br:10])=[CH:8][CH:7]=[CH:6][C:5]=1[CH:11]=[O:13]

Participants

4

Reactant 3

HCID 1118Sulfuric AcidHCID 24408BromineHCID 346801,2-Dibromo-3-methylbenzene

Product 1

HCID 133810282,3-Dibromobenzaldehyde

Conditions

Temperature
100 °C

Procedure

Bromine (168 g., 1.05 m.) is added over about one hour, with vigorous stirring, to 117.5 g. (0.47 m.) of 2,3-dibromotoluene at 190°C. After the addition is complete, the mixture is cooled to 100°C., then 120 cc. of concentrated sulfuric acid is added and the mixture is stirred for one hour at 100°C. Temperature is raised to 140°C. for 5 minutes, then the mixture is cooled and the reaction is quenched in ice water. The solid is extracted into ether, and the ether extract is washed with water, then dilute aqueous sodium bicarbonate until the acid is completely removed, and filtered. Removing the ether by evaporation gives 2,3-dibromobenzaldehyde as the residue.

Workup

  1. customat 190°C
  2. additionAfter the addition
  3. temperatureTemperature is raised to 140°C. for 5 minutes
  4. temperaturethe mixture is cooled
  5. customthe reaction is quenched in ice water
  6. extractionThe solid is extracted into ether
  7. extractionthe ether extract
  8. washis washed with water
  9. customdilute aqueous sodium bicarbonate until the acid is completely removed
  10. filtrationfiltered
  11. customRemoving the ether
  12. customby evaporation

Sources & evidence

ORD record
ord-dba64879933644d8a47c5701c7b4214c
Source dataset
uspto-grants-1976_02
Patent number
US03939164

Reaction notes

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