The reactor equipped with reflux condenser tube and dropping funnel was added with magnesium powder 48.0g (2.0mol), tetrahydrofuran (THF) solution 400mL, and ethidium bromide 218.0g (2.0mol) was added slowly from the dropping funnel, the temperature of the reaction solution was controlled at 50-60C, so that the solution was kept in a slightly boiled state all the time, and the solution was heated and refluxed for 1.0-1.5h after completion of the dropwise addition to ensure that magnesium The reaction was complete to obtain Grignard reagent. Under stirring, m-chlorobenzonitrile 275.2g (2.0 mol) was slowly added dropwise to the Grignard reagent prepared above, and after the dropwise addition was completed, the reaction was carried out for 3.0-4.0h to produce the intermediate, the reaction was completed without separation, and the hydrolysis of the intermediate was carried out by slowly adding dropwise 3 mol/L hydrochloric acid, the inorganic phase was separated out, and the organic phase was frequently distilled at atmospheric pressure to remove THF, and then distilled under reduced pressure to obtain 3-chloropropiophenone.
In a four-necked reaction flask equipped with an electric stirrer, a reflux condenser and a thermometer, 33.7 g of 3-chloropropiophenone, 16.8 g of liquid bromine, 50.0 g of solvent, and 0.75 g of catalyst were added sequentially, a reflux condenser tube and a thermometer were fitted, and the stirrer was turned on, and the timing was started when the temperature was controlled to be 15 , and the reaction time was 2.5 h. After the reaction was finished, the solvent was distilled out, the remaining The solution was washed with water, added the refined solvent for dissolution, then cooled down, crystallized, and filtered to get the refined 2-bromo-3'-chloropropiophenone product, the yield of 2-bromo-3'-chloropropiophenone reached 97.13%, and the melting point was 76-77 .
