Freon is a registered trademark of DuPont, INC used to refer to a large number of halogenated hydrocarbons. Freon R12 is, I believe, trichorofluromethane, Freon R134a is tetrafluorethylene, there are many others. All are solvents, some are refridgerants (R34 is the one normally used in household and industrial units rather than R12).
Tetrachloroethane (I forget the number at the moment) is an industrial solvent often used to determine hydrocarbon contamination in soils and water, because it is fairly simple to evaporate and it has no carbon-hydrogen bonds. This means an infared spectorphotometer can easily be used to measure the presence of hydrocarbons, which do have carbon-hydrodgen bonds. Banned by the EPA since 1999 or so.
R12 was used in automobiles as being the cheapest and the lowest pressure cycle, not because it was the best.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!