The general procedure for the synthesis of 3,4,6-trichloropyridazine from 3,6-dichloropyridazine is as follows: 44 g of 3,6-dichloropyridazine and 22 g of aluminum trichloride were mixed and heated to 140°C. The mixture was then heated to 140°C for 4 hours. At this temperature, 10.6 liters of chlorine gas were slowly passed over a period of 4 hours. Upon completion of the reaction, the reaction mixture was cooled and extracted with toluene. The extract was subsequently washed with 10% sodium chloride solution and finally the product was purified by distillation to collect a fraction with a boiling point of 127-129 °C. Finally 44.1 g of 3,4,6-trichloropyridazine was obtained.
