Chemical Properties:

Chemical Stability and Inertness

This should be chemically constant for the operating ranges of temperature. It should also not react along the materials of the refrigeration system or along which it comes into contact. Furthermore, this should be chemically inert and ought to not undergo polymerization reactions at either the higher or lower ranges of temperatures.

Action on Rubber or Plastics

Plastics and Rubber are utilized extensively in the refrigeration system. Mostly these materials are utilized in the gaskets and seals of the refrigeration system. They help to stop the outflow of the refrigerant and ensure the smooth performance of the compressor. The refrigerant must not react with them or else there may be leakage of refrigerant through the system or loss of performance of the compressor.

Flammability

The refrigerant must be inert and not catch fire while subjected to high temperatures. From this point of view CO₂ is the most appropriate as this is not only non-flammable, but also behaves as a fire-extinguisher. Butane, ethane isobutene are highly unwanted since they catch fire rapidly.

Effect on Oil

The refrigerant must not react along the lubricating oil else, there is a possibility of loss of lubricating action because of either thinning or thickening of the oil. It must not be soluble in the oil else there shall be decrease in the viscosity of the lubricating oil.

Effect on Commodity

If the directly refrigerant is utilized for chilling, then this should not affect the product kept in the conditioned space. As well, in case where direct cooling is not working, the refrigerant must still not influence the commodity if there is any leakage.

Toxicity

The refrigerant utilized in food preservation, air conditioning, etc. must not be toxic as they shall come into contact with human beings.