Hydroquinone → Potassium dobesilate

HRID 587811

Reaction equation

HRID 587811 reaction equation
[C:1]1([CH:8]=[CH:7][C:5]([OH:6])=[CH:4][CH:3]=1)[OH:2].[S:9](=O)(=[O:12])([OH:11])[OH:10].C(C(CCCC)C([O-])=O)C.[K+:24]>C(OCC)(=O)C>[K+:24].[OH:2][C:1]1[CH:8]=[CH:7][C:5]([OH:6])=[CH:4][C:3]=1[S:9]([O-:12])(=[O:11])=[O:10]

Participants

5

Reactant 3

HCID 785HydroquinoneHCID 1118Sulfuric AcidHCID 23669619Potassium 2-ethylhexanoate

Product 1

HCID 23672329Potassium dobesilateYield 77.9%

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent2×

Conditions

Temperature
12.5 °C

Procedure

Hydroquinone (10 g, 0.09 mol) was taken in a round bottom flask, after cooling the flask to about 10-15° C., sulfuric acid (36 N, 8.9 g) was added dropwise at the same temperature and stirring continued further for about 10-15 min. Temperature was slowly raised to 50-60° C. then stirred for 3-8 h. The reaction mass was then cooled to 25-35° C. and ethyl acetate (100 mL) added to dissolve the solid formed. A solution of potassium 2-ethylhexanoate (18.2 g, 0.099 mol) in ethyl acetate (100 mL) was added slowly. The reaction was further stirred for an hour. The precipitated crude solid was filtered, washed with ethyl acetate to give 16 g of 2,5-dihydroxybenzenesulfonic acid potassium salt.

Workup

  1. temperatureTemperature was slowly raised to 50-60° C.
  2. stirringthen stirred for 3-8 h
  3. temperatureThe reaction mass was then cooled to 25-35° C.
  4. dissolutionto dissolve the solid
  5. customformed
  6. stirringThe reaction was further stirred for an hour
  7. customThe precipitated crude solid
  8. filtrationwas filtered
  9. washwashed with ethyl acetate

Sources & evidence

ORD record
ord-a1d51e9620bc4d46b9702780e94cd91b
Source dataset
uspto-grants-2016_01
Patent number
US09227928B2

Linked notes

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