When was R-22 invented?

R-22, or chlorodifluoromethane CHClF2, was invented in the early development of halogenated refrigerants that followed the invention of CFCs. The broader family of chlorofluorocarbon refrigerants was invented in 1928 by Thomas Midgley Jr. and Charles Franklin Kettering at General Motors who were searching for safer alternatives to toxic and flammable refrigerants like ammonia and sulfur dioxide. Freon-12, or R-12, was the first CFC commercialized in 1930 by DuPont under Freon brand. R-22 was developed shortly after as part of the same research into HCFCs that contained hydrogen to make them less stable and less ozone depleting than CFCs, with commercial production beginning in the 1930s to 1940s. It became widely used after World War II as air conditioning became popular in homes and businesses, especially from the 1950s onward as the dominant refrigerant for residential AC due to its favorable properties. So while exact year is often cited as early 1930s for lab synthesis and 1936 for commercial introduction, its mass popularity came in the 1950s to 2000s before phase-out began due to ozone concerns identified in the 1980s.