Method for preparing Grignard reagent benzyl magnesium chloride by sonochemical method

　The invention discloses a method for preparing a Grignard reagent benzylmagnesium chloride by a sonochemical method. The method uses industrial grade tetrahydrofuran or * as a solvent, and does not require special treatment of the solvent; it only needs to be evacuated with nitrogen at the beginning The treatment does not require continuous nitrogen flow and does not need to add an initiator. The ultrasonic reaction is performed in the ultrasonic source of the reactor device tube. The reaction is initiated in about 10-20 seconds, and the yield is 70-82%. Benzyl magnesium has the characteristics of mild reaction conditions, high yield, low cost, and easy industrialization.