Alkenien

Alkenien is not a standard term in English; it may refer to alkenes, a class of unsaturated hydrocarbons characterized by one or more carbon–carbon double bonds. In common usage the correct term is alkene (singular) or alkenes (plural). This article uses alkenien to denote that class in cases where the term appears in non-English sources; for most readers the content below applies to alkenes.

Alkenes have the general formula CnH2n for acyclic members, and they exhibit restricted rotation around the C=C bond and geometrical isomerism. They are typically nonpolar and less dense than water; boiling points increase with rising chain length and branching affects properties.

Nomenclature and examples: The suffix -ene indicates an alkene. The simplest examples are ethene (ethylene, C2H4), propene (propylene, C3H6), and butene. More complex alkenes are named according to IUPAC rules, with common names often used for smaller members.

Reactions: Alkenes undergo electrophilic addition across the double bond, including hydrogenation (to alkanes), halogenation, hydrohalogenation, and hydration. They can polymerize to polyolefins, notably polyethylene from ethene. They also participate in oxidation and metathesis under suitable catalysts.

Occurrence and production: In industry, alkenes are mainly produced by steam cracking of hydrocarbon feedstocks such as ethane, propane, and naphtha. They serve as key building blocks for plastics, solvents, and agrochemicals.

Safety and handling: Vapors are generally flammable; handling requires adequate ventilation and avoidance of ignition sources. Alkenes can pose risks of asphyxiation in enclosed spaces; appropriate storage and handling practices apply.

See also: Alkynes, Alkanes, Polymerization.