Chlorodifluoromethane: Chloroform and Hydrogen Fluoride over Hot Charcoal

Chlorodifluoromethane is chloroform with two of its chlorines swapped for fluorine; heated strongly it gives the monomer of PTFE. Kinetic Chemicals' Daudt and Youker (US 2,062,743, 1936) passed hydrogen fluoride through boiling chloroform and led the vapours over charcoal at about 300 °C. The condensed product was about 10 % chlorodifluoromethane, 60 % fluorodichloro-methane and 30 % unchanged chloroform, separated by fractional distillation. Hydrogen fluoride is a deadly poison: full protection, never alone. The picture: our diagram.