Ethanol → 3-Furancarboxylic acid, 4,5-dihydro-2-methyl-5-propyl-, ethyl ester

HRID 1029833Notes

Reaction equation

HRID 1029833 reaction equation
C(C1[CH2:8][CH:7](CCC)[O:6][C:5]1=[O:12])(=O)C.[CH2:13](O)[CH:14]([OH:16])[CH3:15].[CH2:18]1[CH2:23][CH2:22][CH2:21][CH2:20]C1.C(O)C>S([O-])(O)(=O)=O.[Na+].S(=O)(=O)(O)O.[OH-].[Na+].O>[CH2:22]([CH:21]1[CH2:20][C:13]([C:5]([O:6][CH2:7][CH3:8])=[O:12])=[C:14]([CH3:15])[O:16]1)[CH2:23][CH3:18]

Participants

9

Reactant 4

HCID 702EthanolHCID 1030Propylene GlycolHCID 8078CyclohexaneHCID 2402563-acetyl-5-propyldihydrofuran-2(3h)-one

Product 1

HCID 861113-Furancarboxylic acid, 4,5-dihydro-2-methyl-5-propyl-, ethyl esterYield 126.8%

Reagents, catalysts & solvents 4

HCID 1118Sulfuric AcidCatalystHCID 14798Sodium HydroxideCatalystHCID 516919Sodium BisulfateCatalystHCID 962WaterSolvent

Conditions

Temperature
110 °C

Procedure

A mixture of 201.3 grams of crude 3-acetyl-5-propyl-dihydro-2 (3H)-furanone (1.18 mols), 90.0 grams of propylene glycol (1.18 mols), 50.3 grams of cyclohexane and 1.16 grams of sodium hydrogen sulfate were heated and refluxed for four hours. The water produced by reaction was collected in a Dean Stark trap. After refluxing for 4 hours, the cyclohexane was stripped from the reaction mixture at 80° C. and a vacuum which increased up to 20 inches vacuum. To the residue was added 271.4 grams of anhydrous ethanol (5.9 mols) and 2.8 grams of concentrated sulfuric acid. The mixture was heated to 110° C. in an autoclave for 2.5 hours. The mixture was cooled and neutralized with 2.6 grams of sodium hydroxide and stripped under 15 inches of vacuum at a temperature up to 100° C. The residue was washed with water and the organic layer separated and distilled to yield 150.2 grams of 2 -propyl-4-carbethoxy-5-methyl-2,3-dihydrofuran for a yield of 64.3 percent based on a 92.8% conversion of the Ketal. As shown in the examples, the process of the present invention provides for a high yield of the dihydrofuran product without the use of large excesses of alcohol and the formation of large amounts of by-products formed by the processes of the prior art.

Workup

  1. temperaturewere heated
  2. temperaturerefluxed for four hours
  3. customwas collected in a Dean Stark trap
  4. temperatureAfter refluxing for 4 hours
  5. customwas stripped from the reaction mixture at 80° C.
  6. temperaturea vacuum which increased up to 20 inches vacuum
  7. temperatureThe mixture was cooled
  8. customstripped under 15 inches of vacuum at a temperature up to 100° C
  9. washThe residue was washed with water
  10. customthe organic layer separated
  11. distillationdistilled

Sources & evidence

ORD record
ord-043b1f6cc5384aa9acdd9bcb4d1191eb
Source dataset
uspto-grants-1992_04
Patent number
US05103026

Reaction notes

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