Hydrochloric Acid → 2,4-Dichlorobenzophenone

Participants

Reaction Conditions

Reaction Steps

was prepared as follows. To a 2-liter flask equipped with a mechanical stirrer, argon inlet, Dean Stark trap, condenser, stopper and situated in an oil bath was added benzene (200 grams). The oil bath temperature was raised to 100° C. and 19 grams of benzene were removed. There was no indication of water. The flask was removed from the oil bath and allowed to cool to 25° C. 2,4-Dichlorobenzoyl chloride (0.683 mol, 143 grams) was added to form a solution. Thereafter, anhydrous aluminum chloride (0.8175 mol, 109 grams) was added portion-wise over 15 minutes with vigorous gas evolution. Large volumes of hydrochloric acid were evolved as determined by odor. The solution turned orange-yellow and then red. The reaction was stirred for 16 hours under argon and was then added to 1 liter of ice water in a 2-liter beaker. The mixture was stirred until it became white and was then extracted with methylene chloride (1 liter). The methylene chloride layer was dried over sodium bicarbonate and filtered. The filtrate was concentrated using a rotary evaporator and a vacuum pump to yield an oil which, upon cooling, became a solid crystalline mass (154.8 grams). Recrystallization from methanol gave 133.8 grams of benzoyl-2,4-dichlorobenzene as white needles (melting point 41-43° C.) in the first crop.

Provenance & Evidence