反应详情

106.6 g of 2,4-dichloro-5-fluoro-3-nitro-benzoic acid are heated at the boiling point under reflux with 250 ml of thionyl chloride for 2 hours. The excess thionyl chloride is then distilled off under normal pressure and the residue is fractionated under a fine vacuum. 104.7 g of 2,4-dichloro-5-fluoro-3-nitro-benzoyl chloride pass over at 110°-115° C./0.08-0.09 mbar. On standing, crystals of melting point 35°-37° C. form.

1. distillationThe excess thionyl chloride is then distilled off under normal pressure
2. customover at 110°-115° C./0.08-0.09 mbar