Benzene → Mesityl oxide

HRID 1283176Notes

Reaction equation

HRID 1283176 reaction equation
[C:1]([O:7][CH3:8])(=[O:6])[CH2:2][C:3]([CH3:5])=[O:4].[O:9]=[C:10]([CH:12]=[C:13]([CH3:15])[CH3:14])[CH3:11].CCCCCCC.C1C=CC=CC=1>[Cl-].[Zn+2].[Cl-].O>[C:1]([O:7][CH2:8][CH3:10])(=[O:6])[CH2:2][C:3]([CH3:5])=[O:4].[O:9]=[C:10]([CH:12]=[C:13]([CH3:15])[CH3:14])[CH3:11]

Participants

8

Reactant 4

HCID 241BenzeneHCID 7757Methyl acetoacetateHCID 8858Mesityl oxideHCID 8900Heptane

Product 2

HCID 8858Mesityl oxideHCID 8868Ethyl Acetoacetate

Reagents, catalysts & solvents 2

HCID 3007855ZincchlorideCatalystHCID 962WaterSolvent

Procedure

A mixture of 2.6 kg. of methyl acetoacetate, 2.75 kg. of mesityl oxide, 400 g. of zinc chloride, 2 l. of heptane, and 2 l. of benzene was refluxed for 5 days. The water formed during the reaction was azeotropically distilled off and collected in a separator. A brown oily produce remained in the flask. The oily product was then washed with water, sodium bicarbonate solution, and again with water. The oil which remained after washing was dried over calcium chloride and the heptane-benzene solvent removed under vacuum. The remaining oil was distilled under high vacuum over a packed column. From the distillation, there was obtained first a forecut of unreacted ethyl acetoacetate and mesityl oxide, a second fraction of isophorone by product and finally crude 3,5,5-trimethyl-2-cyclohexen-1-on-4-carboxylic acid methyl ester with a boiling range of 95° - 104° at 0.4 - 0.6 mm. Hg. This crude material was utilized for all experiments without further purification. Pure 3,5,5-trimethyl-2-cyclohexen-1-on-4-carboxylic acid methyl ester was obtained by chromatographic separation on silica gel G (finely divided powdered silica containing trace amounts of calcium sulfate) using petroleum ether and ethyl ether in a volume ratio of 7 to 3.

Workup

  1. additionA mixture of 2.6 kg
  2. distillationwas azeotropically distilled off
  3. customcollected in a separator
  4. customA brown oily produce
  5. washThe oily product was then washed with water, sodium bicarbonate solution
  6. washafter washing
  7. dry with materialwas dried over calcium chloride
  8. customthe heptane-benzene solvent removed under vacuum
  9. distillationThe remaining oil was distilled under high vacuum over a packed column
  10. distillationFrom the distillation

Sources & evidence

ORD record
ord-369f0850973b4cca88c1cdb115ed4416
Source dataset
uspto-grants-1976_08
Patent number
US03974181

Reaction notes

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