Potassium Carbonate → 6-Hydroxy-2-naphthoic acid

HRID 263365Notes

Reaction equation

HRID 263365 reaction equation
[CH:1]([O-:3])=[O:2].[K+].[C]=O.[C:7]1([O-])[C:16]2[C:11](=[CH:12][CH:13]=[CH:14][CH:15]=2)[CH:10]=[CH:9][CH:8]=1.[K+].C(=O)([O-])[O-:20].[K+].[K+]>O>[OH:20][C:8]1[CH:9]=[CH:10][C:11]2[C:16](=[CH:15][CH:14]=[C:13]([C:1]([OH:3])=[O:2])[CH:12]=2)[CH:7]=1

Participants

6

Reactant 4

HCID 11430Potassium CarbonateHCID 2735122Potassium FormateHCID 236723231-Naphthalenol, potassium salt (1:1)HCID 178418416HCID 178418416, compound

Product 1

HCID 855576-Hydroxy-2-naphthoic acidYield 72%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
280 °C

Procedure

A stainless steel pressure autoclave is charged with 100 parts of potassium formate and the melt is freed from residual moisture at 230° C., with stirring and in vacuo. It is then heated to 280° C. and 50 bar of carbon monoxide are injected. Using a metering pump, a mixture of 20 parts of potassium naphtholate with 25 parts of potassium carbonate are metered in as a suspension in kerosene over a period of 5 hours. Some of this kerosene is removed from the reaction vessel by distillation under reduced pressure, and is condensed and expelled. After it has been cooled, the reaction mixture is taken up in water, and the upper, kerosene phase is separated off after settling. The reaction mixture is acidified with sulfuric acid to a pH of 7 and then the unreacted β-naphtholate precipitates and is separated off. On further acidification to pH 4, first the 2-hydroxynaphthalene-6-carboxylic acid precipitates, and finally at pH 1 the other acids do likewise. The reaction mixture is worked up to give 2-hydroxynaphthalene-6-carboxylic acid in a yield of 72% based on the potassium naphtholate employed. Secondary products are 8% of unreacted γ-naphthol, 4% of 2-hydroxynaphthalene-3-carboxylic acid and 12% of 2-hydroxynaphthalene-3,6-dicarboxylic acid.

Workup

  1. customis freed from residual moisture at 230° C.
  2. customSome of this kerosene is removed from the reaction vessel by distillation under reduced pressure
  3. customcondensed
  4. temperatureAfter it has been cooled
  5. customthe upper, kerosene phase is separated off
  6. customthe unreacted β-naphtholate precipitates
  7. customis separated off
  8. customOn further acidification to pH 4, first the 2-hydroxynaphthalene-6-carboxylic acid precipitates

Sources & evidence

ORD record
ord-8f4f51cb15654d51a39c20f3166e62c5
Source dataset
uspto-grants-1997_07
Patent number
US05643494

Reaction notes

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