In this embodiment, 4-methyl-4-(trichloromethyl)cyclohexa-2,5-dienone is prepared, comprising the following steps:
S1: 160 g of aluminum trichloride was weighed and added to 670 g of dichloroethane, placed in a reaction flask with stirring, and cooled to 5 °C. Weigh 100g of p-toluol dissolved in 330g of dichloroethane, placed in a constant pressure dropping funnel, and slowly added dropwise to the dichloroethane reaction system of aluminum trichloride. The reaction temperature was maintained at 11°C during the dropwise addition. After the dropwise addition was completed, 140 g of carbon tetrachloride was added, the temperature was raised to 38°C, and the reaction was continued with stirring for 2 hours. Upon completion of the reaction, the heating was stopped. In this step, p-toluene and carbon tetrachloride were used as the reaction feedstock, aluminum trichloride was used as the catalyst, and dichloroethane was used as the solvent.
S2: The reaction mixture was cooled to room temperature and then slowly added to 1000 g of ice water and stirred for 30 min.
S3: Liquid-liquid separation was carried out at 5°C, and vacuum distillation was used to remove the organic solvent to obtain 195 g of residue.
S4: 488 g of methanol and 10 g of activated carbon were added to the residue, heated to reflux (78°C) and stirred for 30 minutes. After hot filtration, the precipitated solid was cooled, filtered and dried to give 184g of wet crystalline product, which showed higher purity by HPLC.
S5: 184 g of crude product was mixed with 460 g of methanol, 9.2 g of activated charcoal was added and heated to reflux at 65 °C for 30 min. After hot filtration, the precipitated solid was cooled, filtered and dried to give 71 g of white crystalline pure product with HPLC purity greater than 98% and 34% yield.
