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56961-77-4

Example P4: Preparation of 1-bromo-2,3-dichlorobenzene (compound AD). 163 g of 2,3-dichloroaniline (1.0 mol) was added to a mixture of 3250 g of 30% HBr aqueous solution (12.0 mol) with 25.4 g of copper powder. The mixture was stirred at 35-37 °C for 15 min, followed by the slow addition of 766 g of 40% NaNO2 aqueous solution (4.44 mol) by subsurface addition, which was maintained for 3 hours. Simultaneously with the addition of NaNO2, 489 g of 2,3-dichloroaniline (3.0 mol) was added over 2.5 hours at the same temperature. Fifteen minutes after the start of NaNO2 addition, the addition of dichloroquinoline was started. After all additions were completed, the reaction mixture was continued to be stirred at 35°C for 30 minutes. Subsequently, the reaction mixture was heated to 60-65°C and the organic phase containing the reaction product was separated from the aqueous phase. The aqueous phase was discarded and the crude product was washed twice with 200 ml of water. 792.2 g of crude 1-bromo-2,3-dichlorobenzene was finally obtained (yield 87.7% of the theoretical value, purity 86.2%).