ethene

Ethene, also called ethylene, is a hydrocarbon with the formula C2H4. It is the simplest member of the alkenes and contains a carbon–carbon double bond. The molecule is planar and consists of two sp2-hybridized carbon atoms. At room temperature it is a colorless gas and is highly reactive due to the C=C bond.

Ethene occurs in trace amounts in natural gas and crude oil as a minor component and is not readily isolated in nature. It is produced on an industrial scale by steam cracking of hydrocarbon feedstocks such as ethane from natural gas or heavier fractions like naphtha or propane. The resulting ethene is purified and separated for use as a chemical feedstock; some production also arises from dehydrogenation of ethane.

Chemically, ethene participates in addition reactions across the carbon–carbon double bond. It can be hydrogenated to ethane, halogenated to form dihalides or ethyl halides, and reacts with water in hydration to give ethanol. It also undergoes various oxidation and polymerization processes. A major use is as a monomer for polyethylene production, which accounts for a large share of global ethene demand. Polyethylene is made by polymerizing ethene under high pressure or with catalysts to yield low-, linear low-, or high-density grades.

Other important industrial routes start from ethene to produce ethylbenzene (for styrene), vinyl chloride monomer (for PVC), and ethylene oxide (which leads to ethylene glycols). Ethene is flammable and stored under appropriate conditions to prevent leaks and ignition; handling requires standard precautions for volatile organic compounds and compressed gases.