Freon 12 (CF2Cl2) code R12. Freon 12 is a colorless, odorless, transparent, and almost non-toxic refrigerant, but it can cause people's suffocation when the air content exceeds 80%. Freon 12 does not burn or explode. When exposed to open flames or temperatures above 400°C, it can decompose hydrogen fluoride, hydrogen chloride, and phosgene (CoCl2), which are harmful to the human body. R12 is a widely used medium-temperature refrigerant and is suitable for small and medium-sized refrigeration systems such as refrigerators and freezers. R12 can dissolve a variety of organic substances, so you can not use the general rubber gasket (ring), usually use chloroprene elastomeric rubber or butyl rubber sheet or seal.
Freon 22 (CHF2Cl) code R22. R22 does not burn or explode. Its toxicity is slightly greater than that of R12. Although the solubility of water is larger than that of R12, it may still cause the ice-plug phenomenon in the refrigeration system. R22 can partially dissolve with lubricating oil and its solubility varies with the type and temperature of the lubricating oil. Therefore, the R22 refrigeration system must have oil return measures.
The corresponding evaporation temperature of R22 at the standard atmospheric pressure is -40.8°C, the condensation pressure at room temperature does not exceed 15.68×105 Pa, and the capacity per unit volume is more than 60% larger than R12. Most of the air-conditioning equipment use R22 refrigerant.