Phosphoric Acid → Cyclohexene, 1-(2-methylpropyl)-

HRID 417793Notes

Reaction equation

HRID 417793 reaction equation
[CH2:1]([C:5]1(O)[CH2:10][CH2:9][CH2:8][CH2:7][CH2:6]1)[CH:2]([CH3:4])[CH3:3].P(=O)(O)(O)O>>[CH2:1]([C:5]1[CH2:10][CH2:9][CH2:8][CH2:7][CH:6]=1)[CH:2]([CH3:4])[CH3:3]

Participants

3

Reactant 2

HCID 1004Phosphoric Acid2×HCID 1111630468366-16-52×

Product 1

HCID 138091Cyclohexene, 1-(2-methylpropyl)-Yield 253.2%

Conditions

Temperature
145 °C

Procedure

In a flask equiped with a Vigreux-distillation apparatus, crude 1-isobutylcyclohexanol (200 g, 1.28 mol) was treated with phosphoric acid (100 g) and heated at 145° C. under vacuum (170 mbar). While 1-isobutylcyclohex-1-ene and water distilled (boiling point 60° C.), a second fraction of 1-isobutylcyclohexanol (492 g, 3.15 mol) was added dropwise in the reaction flask. At the end of the addition, the thick reaction mixture was diluted with paraffin oil (100 ml) and additional phosphoric acid (50 g) and heated further (vacuum from 170 to 40 mbar). The distillate was decanted and the water phase extracted with pentane (100 ml). The combined org. phases were dried (MgSO4) and the solvent evaporated to give 1-isobutylcyclohex-1-ene (448 g, 78%).

Workup

  1. distillationWhile 1-isobutylcyclohex-1-ene and water distilled (boiling point 60° C.)
  2. additionAt the end of the addition
  3. temperatureheated further (vacuum from 170 to 40 mbar)
  4. customThe distillate was decanted
  5. extractionthe water phase extracted with pentane (100 ml)
  6. dry with materialphases were dried (MgSO4)
  7. customthe solvent evaporated

Sources & evidence

ORD record
ord-ab2a28c1adfe4deebdda3398ff38730e
Source dataset
uspto-grants-2012_01
Patent number
US08093204B2

Reaction notes

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