The purpose of adding copper to propane gas used in cooking stoves is to produce a distinctive odorant that helps detect gas leaks. Propane gas, like natural gas, is odorless, which makes it difficult to detect leaks or potential hazards in the event of a gas leak.
For safety reasons, a chemical compound called ethyl mercaptan or thiophane is added to propane gas. This is where copper comes into play. Copper is used as a catalyst in the manufacturing process to help convert a small amount of the propane into ethyl mercaptan. Ethyl mercaptan has a strong, pungent smell often described as similar to rotten eggs or sulfur. By adding this odorant, even in small amounts, to the otherwise odorless propane gas, any leak is immediately recognizable by its distinctive smell.
This "rotten egg" smell is highly recognizable and serves as an essential safety feature to alert users of gas leaks, allowing them to take immediate action, such as shutting off the gas supply, evacuating the area, and contacting professionals for assistance. It is crucial to be aware of gas leaks promptly, as propane is highly flammable and can pose a significant safety risk if not properly handled.