Dimethyl Sulfoxide → 2,3,4,5-Tetrafluorobenzoic acid

HRID 2231407Notes

Reaction equation

HRID 2231407 reaction equation
[F:1][C:2]1[C:3]([F:16])=[C:4]([F:15])[C:5]([F:14])=[C:6](C(O)=O)[C:7]=1[C:8]([OH:10])=[O:9].CS(C)=O.C(OCCCC)CCC.S(=O)(=O)(O)O>O.C1(C)C=CC=CC=1.C(N(CC)CC)C>[F:1][C:2]1[C:3]([F:16])=[C:4]([F:15])[C:5]([F:14])=[CH:6][C:7]=1[C:8]([OH:10])=[O:9]

Participants

8

Reactant 4

HCID 679Dimethyl SulfoxideHCID 1118Sulfuric AcidHCID 8909Butyl etherHCID 695443,4,5,6-Tetrafluorophthalic acid

Product 1

HCID 2975492,3,4,5-Tetrafluorobenzoic acidYield 95.3%

Reagents, catalysts & solvents 3

HCID 962WaterSolvent2×HCID 1140TolueneSolventHCID 8471TriethylamineSolvent

Conditions

Temperature
118 °C

Procedure

A 22 liter flask was charged with 2.085 kg tetrafluorophthalic acid followed by 8.4 liter dimethylsulfoxide and 303 g triethylamine. The reaction mixture was warmed with stirring over a 50 minute period to 118° C. The resulting solution was stirred at 115°-118° C. for another 45 minutes before ice bath cooling was applied. When the temperature had reached 25° C. the solution was added with stirring to a mixture of 10 kg ice, 8 liter demineralized water, 8.4 liter n-butyl ether and 10 liter toluene in a 50 liter flask. Sulfuric acid (99%) was added dropwise to the mixture to bring the pH to 2. After stirring the organic layer was separated from the aqueous layer which was extracted two more times first with toluene (15 liters) and then with a mixture of toluene (7 liters) and n-butyl ether (1 liter). The combined organic extracts were back extracted three times with six liter portions of an aqueous sulfuric acid solution prepared from 360 ml 99% sulfuric acid and 18 liters demineralized water. The organic extract was treated with anhydrous sodium sulfate (2 kg) and Darco S-51 (300 g) filtered and the filtrate concentrated under reduced pressure on the rotary evaporator to a solid which was finally dried under vacuum at 35°-40° C. for 21 hours to give 1.62 kg (95%) 2,3,4,5-tetrafluorobenzoic acid; mp 82°-84° C.

Workup

  1. temperatureThe reaction mixture was warmed
  2. stirringThe resulting solution was stirred at 115°-118° C. for another 45 minutes before ice bath
  3. temperaturecooling
  4. customhad reached 25° C.
  5. additionwas added
  6. stirringAfter stirring the organic layer
  7. customwas separated from the aqueous layer which
  8. extractionwas extracted two more times first with toluene (15 liters)
  9. additionwith a mixture of toluene (7 liters) and n-butyl ether (1 liter)
  10. extractionThe combined organic extracts were back extracted three times with six liter portions of an aqueous sulfuric acid solution
  11. customprepared from 360 ml 99% sulfuric acid and 18 liters
  12. extractionThe organic extract
  13. additionwas treated with anhydrous sodium sulfate (2 kg) and Darco
  14. filtration(300 g) filtered
  15. concentrationthe filtrate concentrated under reduced pressure on the rotary evaporator to a solid which
  16. customwas finally dried under vacuum at 35°-40° C. for 21 hours

Sources & evidence

ORD record
ord-4192fc9ccdbc4ccb9af5ecd3c324714d
Source dataset
uspto-grants-1988_11
Patent number
US04782180

Reaction notes

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