Ethylene

Ethylene, also known as ethene, is a hydrocarbon with the formula C2H4. It is the simplest alkene and occurs as a colorless, flammable gas at room temperature, with a mild, sweet odor. The molecule contains a carbon–carbon double bond, giving it high reactivity in addition reactions and enabling polymerization.

In nature, ethylene acts as a plant hormone involved in fruit ripening and other developmental processes. Industry produces ethylene predominantly by steam cracking of hydrocarbon feedstocks such as naphtha, LPG, or gas oil, with feedstocks derived from petroleum. It is a leading petrochemical feedstock used to make a wide range of materials.

The most important application is polymerization to polyethylene, one of the most widely used plastics. Ethylene also serves as a building block for other chemicals, including ethylene oxide (used to make ethylene glycols), ethylbenzene (a precursor to styrene), and vinyl acetate. It can be hydrated to produce ethanol.

Safety and environmental aspects: ethylene is highly flammable and poses fire and explosion hazards to handling and storage. In the atmosphere, it is a reactive trace gas that can contribute to ozone formation. Leak detection and appropriate ventilation are standard safety measures in industrial settings.