Thionyl Chloride → 2,3,4,5-Tetrafluorobenzoyl chloride

Participants

Reaction Steps

In a 500 ml round bottom flask equipped with a magnetic stirrer, a reflux condenser and an inert gas supply 97.05 g of 2,3,4,5-tetrafluorobenzoic acid (2, 500 mmol) were suspended under argon and with stirring in 100 ml of n-hexane and 0.5 ml of N,N-dimethyl formamide. To this suspension 44 ml of thionyl chloride (d=1.64, 600 mmol) were added at room temperature, and the mixture was heated to reflux for 15 hours. The light yellowish solution was evaporated in a rotary evaporator at 50° C. reducing the pressure first to 200 torr until distillation ceased, then to 30 torr holding this pressure for 3 minutes to yield 107.1 g of the crude acid chloride 2a as a pale yellow liquid, which was kept under argon and directly used for step 3).

Provenance & Evidence