etilén

Etilén, also known as ethene or ethylene, is a hydrocarbon with the formula C2H4. It is the simplest alkene and consists of two carbon atoms connected by a carbon–carbon double bond, with each carbon carrying two hydrogen atoms. The molecule is planar and the carbons are sp2-hybridized. Etilén is a foundational building block for many plastics and organic chemicals.

It is a colorless gas at room temperature and pressure, with a boiling point of about −103.7 °C. It is highly flammable and forms explosive mixtures with air. The molecule readily participates in addition reactions across the C=C bond and serves as a starting material for polymerization to polyethylene.

Industrial production mainly occurs by steam cracking of hydrocarbon feedstocks such as naphtha, gas oil, ethane, or propane. It can also be produced by dehydrogenation of ethane. The choice of process and feedstock affects energy use and by-products, but steam cracking remains the principal route for large-scale production.

Major uses include serving as a key feedstock for the manufacture of polyethylene and as an input to produce other important chemicals, such as ethylene oxide, vinyl chloride (for polyvinyl chloride), and ethylbenzene (for styrene production). Ethene is also utilized in various chemical syntheses and as a reactive intermediate in many industrial processes.

Occurrence and biological role: Ethene is present in small amounts in natural gas and crude oil. In biology, it acts as a plant hormone released by ripening fruits and vegetables, influencing growth, development, and aging. In plants, it participates in signaling pathways that regulate ripening and responses to stress.

History and safety: Ethene was identified as a hydrocarbon in the 19th century, with large-scale industrial use developing in the 20th century through steam cracking and related technologies. It is stored under pressure as a flammable gas, requiring proper handling, ventilation, and avoidance of ignition sources.