(-)-Isopulegol → (-)-Menthol

HRID 1882331Notes

Reaction equation

HRID 1882331 reaction equation
[CH3:1][C@H:2]1[CH2:7][C@@H:6]([OH:8])[C@H:5]([C:9]([CH3:11])=[CH2:10])[CH2:4][CH2:3]1.[H][H]>>[CH3:1][C@H:2]1[CH2:7][C@@H:6]([OH:8])[C@H:5]([CH:9]([CH3:11])[CH3:10])[CH2:4][CH2:3]1

Participants

3

Reactant 2

HCID 170833(-)-IsopulegolHCID 178418361HCID 178418361, compound

Product 1

HCID 16666(-)-Menthol

Procedure

By means of a centrifugal pump, a circulation was pumped through the main reactor at a rate of about 500 g/h at a feed of L-isopulegol of 24.5 g/h (total amount 588 g) with a purity of 99.9% by weight and 99.8% ee. The hydrogen pressure was kept constant at 40 bar. The main reactor was operated at a temperature of 85° C. and the postreactor at 75° C. All pipelines were provided with electrical trace heating to prevent the crystallization of the enantiomerically pure L-menthol (m.p. 44° C.). This gave L-menthol in an amount of 597 g, corresponding to a rate of 24.9 g/h. The L-menthol obtained in this way (99.8% ee) was analyzed by gas chromatography. The chemical purity of the L-menthol discharge is listed in Table 1.

Workup

  1. customwas operated at a temperature of 85° C.
  2. customat 75° C
  3. customAll pipelines were provided with electrical trace
  4. temperatureheating
  5. customthe crystallization of the enantiomerically pure L-menthol (m.p. 44° C.)

Sources & evidence

ORD record
ord-4b4d1bc4648a41eb96504eacaffb582d
Source dataset
uspto-grants-2012_11
Patent number
US08318985B2

Reaction notes

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