Benzene → 4-(Bromomethyl)benzophenone

Participants

Reaction Conditions

Reaction Steps

30 g (0.153 mol) of 4-methylbenzophenone are introduced into a 250 ml three-necked flask equipped with a reflux condenser and a dropping funnel containing 8.7 ml (0.168 mol) of bromine. In a first step, the reaction medium is heated to 70° C. and then, after complete dissolution of the solid, to 150° C. The bromine is then added dropwise over a period of 3 hours. The reaction is exothermic. The initially colorless solution becomes orange-yellow. Heating is maintained at 150° C. for 15 hours. At the end of the reaction, the temperature of the reaction medium is allowed to return to room temperature. The solution is brown in color. 75 ml of benzene and 35 ml of diethyl ether are added. Washing is carried out with a saturated Na2CO3 solution, then with a saturated Na2S2O3 solution and finally with a saturated NaCl solution, in order to remove the salts formed and to bring the solution to a pH of the order of 6-7. The organic phase is recovered and the solvents are evaporated. A caramel-colored paste is obtained. It is recrystallized from 100 ml of ethanol. The cream-colored crystals are collected and dried under vacuum. The mother liquors are collected and a second crystallization is carried out. The crystals obtained are dried under vacuum. The yield of expected product is 50%, m=20.81 g.

Provenance & Evidence