Hydrochloric Acid → 1,3-Dihydro-1-oxoisobenzofuran-5-carboxylic acid

HRID 48531

Reaction equation

HRID 48531 reaction equation
S(=O)(=O)(O)O.[C:6]([OH:17])(=[O:16])[C:7]1[CH:15]=[CH:14][C:10]([C:11]([OH:13])=[O:12])=[CH:9][CH:8]=1.O1COCO[CH2:19]1.[OH-].[Na+].Cl>O>[C:11]([C:10]1[CH:14]=[C:15]2[C:7](=[CH:8][CH:9]=1)[C:6](=[O:17])[O:16][CH2:19]2)([OH:13])=[O:12]

Participants

7

Reactant 5

HCID 313Hydrochloric Acid2×HCID 1118Sulfuric AcidHCID 7489Terephthalic AcidHCID 80811,3,5-TrioxaneHCID 14798Sodium Hydroxide2×

Product 1

HCID 785171,3-Dihydro-1-oxoisobenzofuran-5-carboxylic acidYield 75.8%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
120 °C

Procedure

To 800 ml of fuming sulfuric acid, containing about 27% of SO3, 260 g (1.56 m) of terephthalic acid are added, under stirring, in 15 minutes and without exceeding the temperature of 25° C. To the thick suspension thus obtained, 120 g (1.33 m) of 1,3,5-trioxane are added under stirring without exceeding the temperature of 35° C., then stirring is continued for 20-30 minutes without cooling, whereby the temperature of the mixture rises to 45-50° C. The mixture is heated to 120° C. and it is noted that, already at 90° C., the mass becomes clear whilst at 120° C. a light exothermia is observed which brings the temperature to 135-140° C. The mixture is kept 6 hour under stirring at this temperature, then it is cooled to 20° C. and poured in 3000 g of coushed ice without exceeding the temperature of 25° C. To the mixture thus obtained, a 15% w/w solution of sodium hydroxide is added to a pH≡6 (about 6500-7000 ml thereof are needed), by keeping the temperature at 35-40° C. by water-cooling, then a 5% w/w solution of sodium hydroxide is added thereto at the temperature of 35-40° C. up to pH≡8 (about 300 ml are needed). The solid is removed by filtration on Dicalite® in a buchner and washed with water. To the filtered solution thus obtained, 35% hydrochloric acid is added up to pH≡1 (requiring about 1600-1800 ml of 35% HCl) and the suspension thus obtained is heated to 35° C. The solid is filtered, washed 3 times with 500 ml of deionized water at 40° C. and suspended in 1000 ml of deionized water. The suspension is heated under stirring at 50-55° C. and kept 1 hour under these conditions, then it is hot filtered. The solid is washed with deionized water and dried in vacuo at 50° C. to constant weight. Thus, 180 g of light-brown coloured 5-carboxyphthalide with a purity (HPLC) >95% are obtained.

Workup

  1. additionare added
  2. customthe temperature of 25° C
  3. customTo the thick suspension thus obtained
  4. stirringunder stirring
  5. customthe temperature of 35° C.
  6. stirringstirring
  7. waitis continued for 20-30 minutes
  8. temperaturewithout cooling
  9. customrises to 45-50° C
  10. customalready at 90° C.
  11. custombecomes clear whilst at 120° C.
  12. customto 135-140° C
  13. waitThe mixture is kept 6 hour
  14. stirringunder stirring at this temperature
  15. temperatureit is cooled to 20° C.
  16. customthe temperature of 25° C
  17. customTo the mixture thus obtained
  18. customat 35-40° C.
  19. temperaturecooling
  20. customat the temperature of 35-40° C.
  21. customThe solid is removed by filtration on Dicalite® in a buchner
  22. washwashed with water
  23. customTo the filtered solution thus obtained
  24. customthe suspension thus obtained
  25. temperatureis heated to 35° C
  26. filtrationThe solid is filtered
  27. washwashed 3 times with 500 ml of deionized water at 40° C.
  28. temperatureThe suspension is heated
  29. stirringunder stirring at 50-55° C.
  30. waitkept 1 hour under these conditions
  31. washThe solid is washed with deionized water
  32. customdried in vacuo at 50° C. to constant weight

Sources & evidence

ORD record
ord-a59707413fd24982859560b6228e86e8
Source dataset
uspto-grants-2004_03
Patent number
US06703516B2

Linked notes

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