Chemistry: Some Fun with Freon

I recently get some vintage spray cans containing chlorofluorocarbons. Chlorofluorocarbons, commonly known as CFCs, are a group of man-made compounds of carbon, chlorine and fluorine produced as non-flammable, inert derivatives of methane and ethane. The Belgian scientist Frédéric Swarts pioneered the synthesis of CFCs as early as in the 1890s. The industrial production of CFCs began in the 1930s. Since then, they've been extensively utilised as propellants in aerosols, as blowing agents in foam manufacture and as refrigerants.
By the late 1970s, more and more the destructive effect of CFCs on the ozone layer revealed. There are no removal processes or sinks for CFCs in the troposphere. As a result they are slowly transported up into the stratosphere where they are broken down by UV-radiation from the sunlight, releasing free chlorine atoms (see formula mentioned below). The chlorine radicals initiate the ozone depletion by a chain reaction with ozone molecules. Also the strong IR-absorption bands of CFCs, mainly located in the spectral region, make them strong greenhouse gases. Since the dangers caused by CFCs to the ozone layer were first identified, their use has gradually been phased out, according to the Montreal Protocol in 1987.  However, CFCs have long lifetimes in the atmosphere before they are broken down by sunlight, and consequently they will continue to enhance the greenhouse effect well into the 21st century.
Today the antropogenic release of nitrous oxide replaced CFCs as the biggest ozone depletor.

So far on their history. The most common CFCs were CFC-11 (Trichloromonofluoromethane) and even more CFC-12 (Dichlorodifluoromethane). CFC-11 was used as a non-toxic and non-flammable solvent mainly for aerosol applications (b.p. 23.7°C), whereas CFC-12 was used as propellant or in refrigeration (b.p.-29.8°C) often called R-12. I extracted some of the CFC-11/12 (30%/70%) mixture from one spray can to show you the nature of CFCs: They look like ordinary water and are not inflammable. The mixture was odorless too, but on contact with fire a stinging odor like burning PVC from hydrochloric and hydrofluoric acid emerged. The mixture quickly evaporated at room temperature and boiled on contact with warm surfaces like my finger tipps.

Freon spray cans

Liquid Freon (Dichlorodifluoromethane and Trichloromonofluoromethane)

The CFC-11 / CFC-12 mixture already boils on contact with the skin