Hydrochloric Acid → 2-Pentylidenecyclopentanone

Participants

Reaction Conditions

Reaction Steps

A 3-L reaction flask was charged with cyclopentanone (500 g, 6 mol), water (H2O) (500 mL) and sodium hydroxide (NaOH) (10 g, 0.25 mol). Valeraldehyde (430 g, 5 mol) was fed into the reaction flask over 3 hours while the temperature was maintained at 25-30° C. After the feeding was completed, the reaction was aged for 2 hours and neutralized with hydrochloric acid (HCl) (30 g, 0.3 mol) while the temperature was maintained at 25-30° C. The reaction mass was further aged for 2 hours. The organic layer was separated and washed with saturated aqueous sodium bicarbonate (NaHCO3) (200 mL). The obtained crude product was fractionated to provide 2-pentylidene-cyclopentanone (523 g) having a boiling point of 122° C. at 3 mmHg A 1-L zipper autoclave was charged with 2-pentylidine cyclopentanone (523 g) and palladium on carbon (Pd/C) (2 g). The autoclave was purged three times with nitrogen followed by three times with hydrogen. The autoclave agitator was then turned on to 1500 rpm and the pressure was set to 100 psi. The reaction was allowed to exotherm to about 120° C. and maintained at this temperature for 2 hours. The autoclave was cooled to an ambient temperature. The hydrogen was then vented and the autoclave was subsequently purged three times with nitrogen. The Pd/C was removed by filtration through Celite®. The crude product 2-pentyl-cyclopentanone (520 g) was obtained and used in following steps without further purification.

Provenance & Evidence