2-Naphthol → 3-Hydroxy-2-naphthoic acid

HRID 259475Notes

Reaction equation

HRID 259475 reaction equation
[CH:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH:4]=[CH:3][C:2]=1[OH:11].[OH-:12].[Na+].O(CCCC[O:25][C:26]1C=CC=CC=1)C1C=CC=CC=1>>[OH:11][C:2]1[C:3]([C:26]([OH:25])=[O:12])=[CH:4][C:5]2[C:10](=[CH:9][CH:8]=[CH:7][CH:6]=2)[CH:1]=1

Participants

4

Reactant 3

HCID 86632-NaphtholHCID 14798Sodium HydroxideHCID 137944Benzene, 1,1'-(1,4-butanediylbis(oxy))bis-

Product 1

HCID 71043-Hydroxy-2-naphthoic acidYield 77%

Conditions

Temperature
260 °C

Procedure

A stirred autoclave is charged with 1220 parts of β-naphthol, 620 parts of caustic soda solution of 50% by weight strength and 360 parts of 1,4-diphenoxybutane. As described in Example 4 the autoclave is heated to an internal temperature of 260° C. while stirring and kept at this temperature for ten minutes. Residual moisture is removed from the autoclave for five minutes at a pressure of 40 mm. Dehydration is practically complete. Carbon dioxide is then passed into the autoclave at the internal temperature of 260° C. up to a pressure of 7 atmospheres. Carboxylation followed by processing are carried out analogously to Example 4. The mixture of organic phase and aqueous phase is acidified to pH about 5 at a temperature of 95° C. with vigorous stirring so that the β-naphthol liberated is taken up by the solvent. The organic phase is separated from the aqueous layer. The clear aqueous phase is heated to 85° to 90° C., acidified with hydrochloric acid to pH about 3 and stirred for another 10 minutes. After cooling to 50° C. the yellowish crystals of 2-hydroxynaphthalene-3-carboxylic acid are suction filtered and dried in vacuo at 70° C. 560 parts of 2-hydroxynaphthalene-3-carboxylic acid (77% of theory based on β-naphthol reacted) is obtained with a melting point of 214° to 217° C.

Workup

  1. waitkept at this temperature for ten minutes
  2. customResidual moisture is removed from the autoclave for five minutes at a pressure of 40 mm
  3. customis then passed into the autoclave at the internal temperature of 260° C. up to a pressure of 7 atmospheres
  4. additionThe mixture of organic phase and aqueous phase
  5. customis acidified to pH about 5 at a temperature of 95° C.
  6. stirringwith vigorous stirring so that the β-naphthol
  7. customThe organic phase is separated from the aqueous layer
  8. temperatureThe clear aqueous phase is heated to 85° to 90° C.
  9. stirringstirred for another 10 minutes
  10. temperatureAfter cooling to 50° C. the yellowish crystals of 2-hydroxynaphthalene-3-carboxylic acid
  11. filtrationfiltered
  12. customdried in vacuo at 70° C

Sources & evidence

ORD record
ord-c2f758d31eea4c5b800adcc75e6b74ea
Source dataset
uspto-grants-1977_07
Patent number
US04038309

Reaction notes

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