Formaldehyde → 1,3-Dihydro-1-oxoisobenzofuran-5-carboxylic acid

HRID 2186520Notes

Reaction equation

HRID 2186520 reaction equation
OS(O)(=O)=O.O=S(=O)=O.[C:10]([OH:21])(=[O:20])[C:11]1[CH:19]=[CH:18][C:14]([C:15]([OH:17])=[O:16])=[CH:13][CH:12]=1.[CH2:22]=O>O>[C:15]([C:14]1[CH:18]=[C:19]2[C:11](=[CH:12][CH:13]=1)[C:10](=[O:21])[O:20][CH2:22]2)([OH:17])=[O:16]

Participants

5

Reactant 3

HCID 712FormaldehydeHCID 7489Terephthalic AcidHCID 24681Fuming sulfuric acid

Product 1

HCID 785171,3-Dihydro-1-oxoisobenzofuran-5-carboxylic acidYield 82%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
143 °C

Procedure

Oleum (20-25% SO3 43 kg) is charged into a reactor. Terephthalic acid (13 Kg) and then paraformaldehyde (3.8 Kg) is added. The mixture is agitated at 138-148° C. for 4½ hours. Water (87 L) is added and the temperature is adjusted to about 100° C. The precipitate is filtered of, washed with water and suspended in water. The pH of the suspension is adjusted to about 7 with NaOH (about 10%), activated carbon, 0.5 Kg is added, and then the mixture is filtered, the precipitate is rinsed with water. The temperature of the filtrate is adjusted to about 85° C. and the pH is adjusted to about 2 with 96% sulfuric acid. The 5-carboxyphthalide precipitated is separated by filtration washed and dried. Yield 82%.

Workup

  1. customis adjusted to about 100° C
  2. filtrationThe precipitate is filtered of,
  3. washwashed with water
  4. additionis added
  5. filtrationthe mixture is filtered
  6. washthe precipitate is rinsed with water
  7. customis adjusted to about 85° C.
  8. customThe 5-carboxyphthalide precipitated
  9. customis separated by filtration
  10. washwashed
  11. customdried

Sources & evidence

ORD record
ord-d5c5e4dec4204e779a5e065c2dbd0caf
Source dataset
uspto-grants-2002_06
Patent number
US06403813B1

Reaction notes

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