4-Hydroxybenzoic Acid → 4-Hydroxy-3,5-diisopropylbenzoic acid

Temperature

62.5 °C

360 ml sulphuric acid was added slowly to 25 ml chilled water at 10-15° C. to a round bottom flask supplied with a mechanical stirrer. To this stirred mass was charged p-hydroxy benzoic acid 100 g (0.72M) lot wise followed by Isopropyl alcohol 130 g (2.16M) at a temperature below 15° C. The reaction mass was finally heated to 60-65° C. for 4 hrs. After reaction completion the reaction mass was quenched in caustic solution and washed two times with toluene (400 ml). The aqueous layer obtained was acidified using aq. HCl solution. Precipitated solid was washed twice, each time with 250 ml of hot water and dried to obtain crude product. Crude solid was dissolved in 350 ml of methanol and treated with activated carbon, filtered and added into 1000 ml chilled water at about 10-15° C. The precipitate was filtered off and washed twice with 200 ml of water each time. After drying under vacuum at 70-75° C. up to a constant weight, 4-hydroxy-3,5-diisopropyl benzoic acid was obtained.

1. customsupplied with a mechanical stirrer
2. customAfter reaction completion the reaction mass
3. customwas quenched in caustic solution
4. washwashed two times with toluene (400 ml)
5. customThe aqueous layer obtained
6. customPrecipitated solid
7. washwas washed twice
8. dry with materialeach time with 250 ml of hot water and dried
9. customto obtain crude product
10. additiontreated with activated carbon
11. filtrationfiltered
12. additionadded into 1000 ml
13. temperaturechilled water at about 10-15° C
14. filtrationThe precipitate was filtered off
15. washwashed twice with 200 ml of water each time
16. customAfter drying under vacuum at 70-75° C. up to a constant weight

ORD record

ord-a7dbb40be07a4fe799d76193e4a92149

Source dataset

uspto-grants-2014_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08664452B2