Nalkenes

Nalkenes, also known as normal alkenes, are a series of straight‑chain, unsaturated hydrocarbons that contain at least one carbon–carbon double bond (C=C) and follow the general formula CnH2n. The term “n‑alkene” distinguishes these compounds from their branched or cyclic analogues, emphasizing a linear carbon skeleton with the double bond typically located at the terminal position, although internal double bonds are also encountered in some members of the series.

In systematic IUPAC nomenclature, n‑alkenes are named by the parent alkane root with the suffix –ene, and the position of the double bond is indicated by a locant when necessary (e.g., 1‑pentene, 2‑hexene). The simplest member, ethene (C2H4), is the fundamental building block of the series, while longer members such as 1‑octene, 1‑decene, and 1‑dodecene find extensive industrial use.

Physical properties of n‑alkenes depend on chain length. Low‑molecular‑weight members are gases at room temperature (e.g., ethene, propene), whereas those with eight to twelve carbon atoms are liquids, and higher members become waxy solids. Boiling points increase with molecular weight, and all n‑alkenes are less dense than water, immiscible with it, and soluble in non‑polar organic solvents.

Nalkenes are produced primarily by catalytic cracking of petroleum fractions, steam cracking of naphtha, and the dehydrogenation of corresponding alkanes. Their reactivity is centered on the double bond, which undergoes electrophilic addition, polymerization, oxidation, and hydroformylation. Commercially, n‑alkenes serve as precursors to polymers (e.g., polyethylene from ethene, linear low‑density polyethylene from 1‑octene), synthetic detergents, plasticizers, and specialty chemicals.

Safety considerations include flammability, potential for peroxide formation in storage, and irritant properties of vapors. Proper handling requires ventilation, avoidance of ignition sources, and adherence to occupational exposure limits.