To a reaction flask was added 138.8 g (1.04 mol, 2.9 eq.) of aluminum trichloride. 700 ml of dichloromethane was added and the system was cooled to 0-10 °C and stirred. 174.6 g (0.87 mol, 2.4 eq.) of bromoacetyl bromide was slowly added dropwise, controlling the temperature to be maintained at 0 to 10 °C during the dropwise addition. After the dropwise addition, stirring of the reaction mixture was continued for 10 to 30 minutes. Subsequently, 150 ml of dichloromethane solution containing 55.8 g (0.36 mol, 1.0 equiv) of biphenyl was slowly added. After the addition was completed, the reaction mixture was gradually warmed to room temperature with continuous stirring. Next, 200 ml of n-heptane was added to the system, the temperature was raised to reflux, and the reaction was maintained at this temperature for 4 to 5 hours until the alkaline reaction was complete and a large amount of product precipitated. The reaction mixture was continued to be stirred at room temperature for 3 to 5 hours, followed by diafiltration to give the crude product 4,4'-bis(2-bromoacetyl)biphenyl (I). The crude product I was suspended in 500 ml of water and stirred for 1 to 2 hours at room temperature and diafiltrated to give 4,4'-bis(2-bromoacetyl)biphenyl crude oil (II). The crude product II was pulped in 300 ml of dichloromethane, stirred for 1 to 2 hours at room temperature and filtered to give purified 4,4'-bis(2-bromoacetyl)biphenyl. Finally, the product was dried under vacuum at 70 °C to give 121.3 g solid with 99.4% purity and 84.9% yield.
