Hydrochloric Acid → 3,4-Difluorobenzaldehyde

Participants

Reaction Steps

57 g (0.5 mol) of ortho-difluorobenzene in 250 ml of methylene chloride is added to 100 g (0.75 mol) of anhydrous aluminum chloride. The mixture is stirred (motor) and cooled in an ice bath while 85.5 g (0.75 mol) of dichloromethyl methylether is added dropwise. Vigorous HCl evolution takes place, and the reaction mixture turns orange-red. After the addition, the mixture is stirred at room temperature for 15 minutes, and the liquid phase is decanted into 500 ml of ice and water. The unreacted residue of aluminum chloride is washed with methylene chloride until colorless, and the washings are added to the water. The mixture is shaken well in a separation funnel until the methylene chloride layer is green. The organic layer is washed with saturated potassium carbonate solution until neutral, then dried (MgSO4) and distilled to give 3,4-difluorobenzaldehyde, B.P. 70-74° C./20 min. The dark residue in the distillation pot solidifies on cooling to give tris-(3,4-difluorophenyl)methane, M.P. 95-96° C.

Provenance & Evidence