Octadecane

Octadecane, also known as n-octadecane, is a saturated acyclic hydrocarbon with the chemical formula C18H38. It is a straight-chain alkane and belongs to the higher members of the alkane series.

At room temperature, octadecane is a colorless, waxy solid. It has a melting point around 28–30 °C, so it can be solid or slightly viscous liquid depending on the ambient temperature. It has a high boiling point, typically well above 300 °C, and is virtually insoluble in water while being soluble in nonpolar organic solvents.

Octadecane occurs in petroleum fractions and is produced commercially through refining and distillation of heavier hydrocarbons. It can also be prepared by hydrogenation of unsaturated hydrocarbons. In industry, it is used as a component of paraffin wax blends and is sold as a pure hydrocarbon for various formulation purposes.

One notable application area is its use in phase-change materials for thermal energy storage, where its melting point near room temperature provides a useful latent heat effect. It also serves as a nonpolar diluent or carrier in certain cosmetic and industrial formulations, and as a low-toxicity hydrocarbon in laboratory contexts.

Safety and handling are typical of alkanes: octadecane is relatively inert but flammable. It should be kept away from heat, sparks, and open flames, and handled with standard precautions for hydrocarbon liquids and solids.