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

Participants

Reaction Conditions

Reaction Steps

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%).

Provenance & Evidence