Hydrogen Bromide → o-Bromocumene

Temperature

80 °C

To an initial charge of 65 ml of 48% aqueous HBr are added, in portions, 13.5 g [0.1 mol] of 2-isopropylaniline. The resulting thick suspension is stirred at 80° C. for 15 minutes. It is then cooled to −10° C., and a solution of 8 g [0.116 mol] of NaNO2 in 35 ml of water is added dropwise within approx. 1 h at such a rate that the temperature does not exceed −5° C. 80 mg of sulphamic acid are added. Then the thin suspension of the diazonium salt, cooled to −10° C., is metered within about 30 minutes into a solution, heated to 70° C., of 13.9 g [0.05 mol] of FeSO4×7H2O in 65 ml of 62% aqueous HBr. The reaction mixture is then stirred for another 1 hour without further heating and allowed to cool to room temperature, and admixed with 125 ml of water, the phases are separated and the aqueous phase is extracted three times with 50 ml each time of methylene chloride. The combined organic phases are washed twice with 25 ml each time of water, dried and concentrated under reduced pressure. This gives 18.75 g of an oil which, according to GC, contains 82.3% 2-isopropylbromobenzene (77.5% of theory).

1. temperatureIt is then cooled to −10° C.
2. customdoes not exceed −5° C
3. temperaturecooled to −10° C.
4. waitis metered within about 30 minutes into a solution
5. stirringThe reaction mixture is then stirred for another 1 hour
6. temperaturewithout further heating
7. temperatureto cool to room temperature
8. customthe phases are separated
9. extractionthe aqueous phase is extracted three times with 50 ml each time of methylene chloride
10. washThe combined organic phases are washed twice with 25 ml each time of water
11. customdried
12. concentrationconcentrated under reduced pressure

ORD record

ord-f6a85cb3c1754ee49ece2fa7dc0bdbe0

Source dataset

uspto-grants-2012_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08334417B2