1. Freon, also known as Freon, its name comes from the English Freon, which is a refrigerant trademark registered by DuPont Company of the United States. In China, there are differences in the definition of Freon. It is generally defined as the general term for the halogenated compounds of saturated hydrocarbons (mainly methane, ethane and propane). According to this definition, Freon can be divided into four categories: CFC, HCFC, HFC; some scholars Freon is defined as a CFC refrigerant; in some data, Freon only refers to dichlorodifluoromethane (a type of CFC).

2. Freon is a volatile liquid or colorless gas at room temperature, odorless or slightly odorless, non-toxic or low-toxic, and has stable chemical properties. Freon is widely used as a refrigerant, foaming agent, cleaning agent, and is widely used in air conditioners and other electrical appliances, foam plastics, daily chemicals, automobiles, fire-fighting equipment and other fields.