Methyl Benzoate → Dibenzoylmethane

HRID 2051048Notes

Reaction equation

HRID 2051048 reaction equation
CO[C:3](=[O:10])[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1.[C:11]([C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1)(=[O:13])[CH3:12].C[O-].[Na+]>C1(C)C(C)=CC=CC=1.CO>[C:11]([CH2:12][C:3](=[O:10])[C:4]1[CH:5]=[CH:6][CH:7]=[CH:8][CH:9]=1)(=[O:13])[C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1

Participants

6

Reactant 3

HCID 7150Methyl BenzoateHCID 7410AcetophenoneHCID 10942334Sodium Methoxide

Product 1

HCID 8433DibenzoylmethaneYield 95%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 7237O-XyleneSolvent3×

Procedure

Methylbenzoate (136.0 grams; 1.0 mol), acetophenone (30.0 grams; 0.25 mol), sodium methoxide (17.3 grams; 0.3 mol) and xylene (300 ml) were placed into a four-necked, round bottom, one liter flask equipped with stirrer, nitrogen addition adapter, thermometer and Oldershaw column connected with distillation head and a trap. The mixture was heated with stirring to 135°-140° C. and maintained there for 6 hours while under a blanket of nitrogen. At 110°-120° C. methanol started to evolve and the reaction mixture became semi-solid. After two hours of heating the contents of the flask somewhat liquified. Towards the end of the reaction, nearly 25 ml of liquid consisting of methanol and xylene had been collected in the trap. The reaction mixture was cooled to room temperature and acidified with hydrochloric acid (500 ml of 6N). Stirring was continued for about 30 minutes until all the solid was dissolved. The xylene layer was separated and washed twice with water, then twice with aqueous sodium carbonate and then twice again with water. The xylene layer was removed by evaporation from the dibenzoylmethane (53.1 grams; 95% yield). Analysis by GLC showed the product to be 95% pure. This product after recrystallized from methanol had a melting point of 77°-78° C. The distillate (347.0 grams) containing xylene, methylbenzoate and water was subjected to azeotropic distillation.

Workup

  1. customequipped with stirrer, nitrogen addition adapter
  2. distillationthermometer and Oldershaw column connected with distillation head and a trap
  3. temperatureThe mixture was heated
  4. temperaturemaintained there for 6 hours while under a blanket of nitrogen
  5. customAt 110°-120° C.
  6. temperatureAfter two hours of heating the contents of the flask somewhat liquified
  7. customTowards the end of the reaction, nearly 25 ml of liquid
  8. customhad been collected in the trap
  9. stirringStirring
  10. dissolutionuntil all the solid was dissolved
  11. customThe xylene layer was separated
  12. washwashed twice with water

Sources & evidence

ORD record
ord-ff6375a7da904ff2ba774459e086cb58
Source dataset
uspto-grants-1991_05
Patent number
US05015777

Reaction notes

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