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Pentane is any or one of the organic compounds with the formula C5H12. This alkane is a component of some fuels and is employed as a specialty solvent in the laboratory. Its properties are very similar to those of butane and hexane. It exists in three structural isomers, the branched isomers are called isopentane and neopentane.
|| neopentane |
The branched isomers are more stable. That is, they have lower heat of formation and heat of combustion. Isopentane is more stable than pentane by 1.8 kcal/mol, and neopentane by 5 kcal/mol.
As the most volatile hydrocarbon that is liquid at room temperature, pentane is often used in the laboratory as a solvent
that can be conveniently evaporated. Also because of its nonpolarity
and lack of functionality
, its dissolving power is poor, thus only non-polar and alkyl-rich compounds are soluble in it. Pentane is miscible
, however, with most common nonpolar solvents such as chlorocarbons
, and ethers
One of its applications as a laboratory solvent is in liquid chromatography.
Pentane burns to form carbon dioxide and water:
- C5H12 + 8 O2 → 5 CO2 + 6 H2O
As with other hydrocarbons, pentane undergoes free radical chlorination:
- C5H12 + Cl2 → C5H11Cl + HCl
Such reactions are unselective, yielding a mixture of the 1-, 2-, and 3-chloropentanes, as well as more highly chlorinated derivatives. Other radical halogenations
can also occur.
While n-butane is the conventional feedstock in the production of maleic anhydride, pentane is also a substrate:
- CH3CH2CH2CH2CH3 + 5 O2 → C2H2(CO)2O + 5 H2O + CO2
Pentane is one of the primary blowing agents
used in the production of polystyrene foam.