1alkene

1-alkene, commonly called a terminal alkene or alpha-olefin, is an alkene in which the double bond is between carbon 1 and carbon 2 of the carbon chain. The general formula for an acyclic 1-alkene with n carbons is CnH2n; the simplest examples are ethene (C2H4) and propene (C3H6). Straight-chain 1-alkenes include 1-hexene, 1-octene, and related members, in which the double bond is at the end of the chain.

Nomenclature and characterization: In systematic naming, the double bond starting at carbon 1 defines a 1-alkene. They are also referred to as terminal alkenes or alpha-olefins. The double bond is less substituted than in many internal alkenes, influencing both reactivity and selectivity in chemical reactions.

Production and occurrence: Industrially, alpha-olefins are produced primarily by processes such as the Shell Higher Olefin Process (SHOP), which oligomerizes smaller alkenes to give a mixture of terminal alkenes suited for conversion into polymers and specialty chemicals. They can also be prepared by dehydration of primary alcohols (for example, dehydration of 1-alkanols yields the corresponding 1-alkene) or by other hydrocarbon upgrading routes. Alpha-olefins range in carbon number typically from C4 to well beyond C20 and are widely used as monomers and co-monomers.

Reactions and applications: The terminal double bond is reactive toward electrophilic and radical additions, hydrogenation, and hydrohalogenation, with Markovnikov and anti-Markovnikov outcomes depending on reagents and conditions. Hydration of 1-alkenes yields 1-alkanols via anti-Markovnikov hydration (hydroboration-oxidation) or Markovnikov hydration under acid catalysis. A major application is their use as monomers or comonomers in polymerization to produce polyolefins, plastics, and specialty polymers. They also serve as precursors to fragrances, surfactants, and lubricants in larger chemical supply chains.