18282-59-2

95-50-1

18282-59-2

General procedure for the synthesis of 4-bromo-1,2-dichlorobenzene from o-dichlorobenzene: 26.2 g of 1,2-dichlorobenzene was mixed with 2.75 g of iron powder, heated to 45 °C and 26 g of bromine was added slowly and dropwise at a rate of 0.2 mL/min. The reaction was completed after the dropwise addition process lasted for 2 hours. At the end of the reaction, the reaction was quenched by the addition of sodium sulfite solution and the reaction mixture was extracted with dichloromethane and the solvent was subsequently removed to give 41.6 g of crude product. Compositional analysis of the crude product showed the presence of 5.5% of 1,2-dichlorobenzene, 2.1% of 2,3-dichlorobromobenzene isomers and 0.6% of high-boiling substances (mainly dibrominated or polybrominated products). The unreacted 1,2-dichlorobenzene was recovered by distillation purification by first collecting the 100-110 °C fraction at pressures of -0.09 to -0.1 MPa, followed by collecting the 160-165 °C fraction at the same pressures to give 33.2 g of 4-bromo-1,2-dichlorobenzene with a purity of 98.5% and a molar yield of 90.3%.