Hydrogen Bromide → 1-Bromo-2,3-dichlorobenzene

Temperature

37.5 °C

32.7 g 2,3-Dichloroaniline (0.20 mole) is added to a mixture of 21.4 g of NaBr (0.20 mole, 1.0 equivalent), 110.0 g of 48% aqueous HBr (0.66 mole, 3.3 equivalents) and 70 ml water at 30-45° C. The mixture is stirred for 15 minutes at 30-45° C. and then heated to 60° C. Then 2.9 g Cu(I)Br (0.02 mole, 0.10 equivalent) is added and the mixture is stirred for 15 minutes at 60° C. After this, an aqueous solution of NaNO2 (40% solution in water, 37.6 g, 0.22 mole, 1.1 equivalents) is added via subsurface feeding over a period of 2 hours at 60-65° C. The reaction mixture is stirred for 30 minutes at 60-65° C. The organic phase containing the reaction product is separated from the aqueous phase and is cooled to ambient temperature, leading to solidification of the reaction product. The remaining liquid is discarded and the crude product is washed two times with 10 ml water and dried under vacuum. 44.0 g (89% of theory) of 1-bromo-2,3-dichlorobenzene is obtained in the form of a light brown solid (purity: 91%). For further characterisation, the crude product was purified by vacuum distillation (130° C./20 mmHg). 38.0 g (84% of theory) of pure 1-bromo-2,3-dichlorobenzene is obtained in the form of white crystals.

1. temperatureheated to 60° C
2. stirringthe mixture is stirred for 15 minutes at 60° C
3. waitfeeding over a period of 2 hours at 60-65° C
4. stirringThe reaction mixture is stirred for 30 minutes at 60-65° C
5. additionThe organic phase containing the reaction product
6. customis separated from the aqueous phase
7. temperatureis cooled to ambient temperature
8. washthe crude product is washed two times with 10 ml water
9. customdried under vacuum

ORD record

ord-c1520105a17a4c1bb46a23d7c302621f

Source dataset

uspto-grants-2012_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08088960B2