Sulfuric Acid → Dibenzoylmethane

HRID 2188352Notes

Reaction equation

HRID 2188352 reaction equation
COCC(O)C.[OH-].[Na+].[C:9]([O:17]C)(=O)[C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1.[C:19]([C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=1)(=[O:21])[CH3:20].S(=O)(=O)(O)O.C(=O)(O)[O-].[Na+]>>[C:19]([CH2:20][C:9](=[O:17])[C:10]1[CH:11]=[CH:12][CH:13]=[CH:14][CH:15]=1)(=[O:21])[C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=1

Participants

7

Reactant 6

HCID 1118Sulfuric AcidHCID 7150Methyl BenzoateHCID 7410AcetophenoneHCID 79001-Methoxy-2-propanolHCID 14798Sodium HydroxideHCID 516892Sodium Bicarbonate

Product 1

HCID 8433Dibenzoylmethane

Procedure

1-Methoxy-2-propanol (923 g; 10.24 mol), sodium hydroxide (256 g; 6.4 mol), and xylenes (1820 g; 2.12 L) were placed into a four-necked, round bottom, five liter flask equipped with a stirrer, a thermometer, and an Oldershaw column with a Dean-Stark trap and a condenser. The mixture was heated to boiling with stirring under a blanket of nitrogen and the water was azeotroped out (temperature of reflux 106-116° C.). When no more water was collected (280 mL of lower phase), some solvent was distilled off (1,200 mL), while xylenes (432.2 g, dry) were replaced, until no more alcohol was detected in the distillate. The mixture in the flask was cooled down to and kept at 95° C., and the fractionation column and trap were replaced with a reflux condenser, while maintaining the nitrogen stream. Methyl benzoate (1089 g; 8.0 mol) was added and slow addition (over a period of 38 minutes) of acetophenone (481 g; 4.0 mol) by means of a peristaltic pump was begun. After 75 minutes from the beginning of the addition of the ketone, the mixture was cooled down (an ice bath was used), and then acidified by the slow addition of 98% sulfuric acid (392 g) with stirring. Sodium bicarbonate (185 g) was added for neutralizing the mixture. The slurry was distilled under vacuum (18 cm Hg, Tpot=84° C.), and at the same time 1,400 g of xylenes was added. The distillate (2,094 g) contains methoxypropanol, which can be recovered (see below).

Workup

  1. customequipped with a stirrer
  2. temperatureThe mixture was heated
  3. customthe water was azeotroped out (temperature of reflux 106-116° C.)
  4. customWhen no more water was collected (280 mL of lower phase)
  5. distillationsome solvent was distilled off (1,200 mL)
  6. temperatureThe mixture in the flask was cooled down to and
  7. customkept at 95° C.
  8. customthe fractionation column and trap were replaced with a reflux condenser
  9. temperaturewhile maintaining the nitrogen stream
  10. temperaturethe mixture was cooled down (an ice bath was used)
  11. stirringwith stirring
  12. distillationThe slurry was distilled under vacuum (18 cm Hg, Tpot=84° C.)
  13. additionat the same time 1,400 g of xylenes was added
  14. customcan be recovered (see below)

Sources & evidence

ORD record
ord-99b64ecab5e94ae38ef4eb3bd088b6ac
Source dataset
uspto-grants-2002_06
Patent number
US06410795B1

Reaction notes

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