Hydrochloric Acid → Propofol

Temperature

142.5 °C

To the solution of 4-hydroxy-3,5-diisopropyl benzoic acid 100 g (0.45 M) (example 1) in ethylene glycol (150 ml) was added sodium hydroxide pallets 41.5 g (1.03M) and heated to 140-145° C. under inert atmosphere. After 7 hrs of continued heating at 140-145° C., the reaction mass was cooled to room temperature and diluted with 5 times water. The pH of the mass was then adjusted to 1-2 using concentrated Hydrochloric acid, reaction mixture was stirred for one hour and extracted three times with 200 ml toluene, combined toluene layers were washed twice with 5% aq. sodium bicarbonate solution (50 ml) and finally with water (200 ml), solvent was removed under reduced pressure and a dark brown colored residue which remained was distilled under high vacuum condition (0.2 mm/Hg) to yield 75 g (93.5%) of 2,6-diisopropyl phenol collected as a colourless to pale yellow oily liquid, HPLC Purity 99.93%.

1. temperatureAfter 7 hrs of continued heating at 140-145° C.
2. temperaturethe reaction mass was cooled to room temperature
3. extractionextracted three times with 200 ml toluene
4. washwere washed twice with 5% aq. sodium bicarbonate solution (50 ml) and finally with water (200 ml), solvent
5. customwas removed under reduced pressure
6. distillationa dark brown colored residue which remained was distilled under high vacuum condition (0.2 mm/Hg)

ORD record

ord-624393e0f39340bcb53a9fe61bcc0624

Source dataset

uspto-grants-2014_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08664452B2