How is R-22 made?

R-22, chemically chlorodifluoromethane with formula CHClF2 and also called HCFC-22, is made through industrial chemical synthesis involving fluorination of chloroform. The primary manufacturing process reacts chloroform CHCl3 with hydrogen fluoride HF in the presence of a catalyst such as antimony pentachloride or other metal fluorides at elevated temperature and pressure. The reaction is CHCl3 plus 2HF produces CHClF2 plus 2HCl, with some over-fluorination producing side products like R-23 and under-fluorinated intermediates. The process occurs in reactors with careful control of temperature, pressure, and HF ratio to maximize R-22 yield. The crude product is then purified through distillation to remove HCl byproduct, unreacted starting materials, and impurities to meet AHRI 700 purity specifications of 99.9 percent. Additional steps include drying to remove moisture, filtering, and analysis. The manufacturing requires handling highly corrosive and toxic chemicals like HF and HCl, so it is done in specialized chemical plants with safety systems. Due to ozone depletion concerns, production has been banned in developed countries since 2020, so new R-22 is no longer made there, though it may still be produced in some developing countries under phase-out allowances.