Freon is a common refrigerant. There are many types of Freon, the most common of which are R22, R32, R134a, etc. Freon is generally a gas at room temperature and pressure with a slight aromatic smell. It becomes a transparent liquid under low temperature and pressure. It can be miscible with halogenated hydrocarbons, monohydric alcohols or other organic solvents in any proportion, and fluorine refrigerants can also be miscible with each other. Freon is widely used in refrigeration, foaming, solvents, sprays, electronic component cleaning and other industries because of its strong chemical stability, thermal stability, low surface tension, easy vapor-liquid phase change, non-toxicity, lipophilicity, and low price.
However, the emission of Freon into the atmosphere will cause a decrease in ozone content, causing serious ultraviolet damage to organisms on Earth, and rising temperatures in the lower stratosphere and troposphere. Therefore, people are working hard to solve the problem of Freon pollution. The ways to solve the environmental pollution problem mainly include restriction and prohibition, development of substitutes and harmlessness of Freon.
The main physical and chemical properties of Freon are: (1) strong chemical stability and no decomposition; (2) good thermal stability, non-flammable and non-explosive; (3) easy change of vapor-liquid phase; (4) low surface tension and permeability; (5) non-toxic, non-irritating and non-corrosive; (6) high electrical insulation; (7) appropriate lipophilicity; (8) low price and easy mass production; (9) the more fluorine atoms in the chemical formula, the less harmful it is to the human body, the less corrosive it is to metals, and the better the chemical stability; (10) the flammability decreases significantly with the decrease of the number of hydrogen atoms in the molecule, and the evaporation temperature increases with the increase of the number of chlorine atoms.
write by Shelley from Faithgrit.