Carbon Dioxide → 2,3,6-Trimethylphenol

HRID 65800

Reaction equation

HRID 65800 reaction equation
[CH3:1][C:2]1[C:3](=[O:10])[CH:4]([CH3:9])[CH:5]([CH3:8])[CH2:6][CH:7]=1.CC1C(=O)C(C)CCC=1C.CC1CCC(=O)C(C)=C1C.C(=O)=O.[H][H]>[Pd]>[CH3:9][C:4]1[C:5]([CH3:8])=[CH:6][CH:7]=[C:2]([CH3:1])[C:3]=1[OH:10]

Participants

7

Reactant 5

HCID 280Carbon DioxideHCID 892642-Cyclohexen-1-one, 2,5,6-trimethyl-HCID 30168432,3,6-Trimethylcyclohex-2-en-1-oneHCID 13360364Trimethyl-2-cyclohexen-1-one3×HCID 178418361HCID 178418361, compound

Product 1

HCID 170162,3,6-TrimethylphenolYield 95%

Reagents, catalysts & solvents 1

HCID 23938PalladiumCatalyst

Procedure

Dehydrogenation may be carried out in an inert solvent. It is advantageous however to dehydrogenate the 2,5,6-trimethyl-2-cyclohexen-1-one or 2,3,6-trimethyl-2-cyclohexen-1-one in the gas phase, for example by passing it as a gas at the dehydrogenation temperature over a palladium/silica gel catalyst. In gas-phase dehydrogenation the trimethyl-2-cyclohexen-1-one is preferably passed over the catalyst in admixture with an extraneous gas such as nitrogen, steam, carbon dioxide and particularly hydrogen; generally a ratio by volume of extraneous gas to gaseous trimethyl-2-cyclohexen-1-one of from about 1:2 to 5:1 is chosen. Temperatures of from 200° to 400° C., preferably from 250° to 350° C., are usually used in gas-phase dehydrogenation. The time that the trimethyl-2-cyclohexen-1-one is in contact with the catalyst is generally from half to fifty, preferably from two to ten seconds. The 2,3,6-trimethylphenol is obtained in a more than 95% yield in gas-phase dehydrogenation.

Workup

  1. customof from 200° to 400° C.
  2. custompreferably from 250° to 350° C.
  3. waitis generally from half to fifty, preferably from two to ten seconds

Sources & evidence

ORD record
ord-4aab1458444845a2a8ad075eb5623b03
Source dataset
uspto-grants-1978_12
Patent number
US04128728

Linked notes

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