Pentane
From Wikipedia, the free encyclopedia
| Pentane | |
|---|---|
 |
|
 |
|
| IUPAC name |
|
| Other names | n-pentane amyl hydride Skellysolve A |
| Identifiers | |
| CAS number | [] |
| PubChem | |
| RTECS number | RZ9450000 |
| SMILES |
|
| InChI |
|
| ChemSpider ID | |
| Properties | |
| Molecular formula | C5H12 |
| Molar mass | 72.15 g/mol |
| Appearance | Colourless liquid |
| Density | 0.626 g/cm³, liquid |
| Melting point |
−129.8 °C (143 K) |
| Boiling point |
36.1 °C (308 K) |
| Solubility in water | 0.004 g/100 mL (20 °C)[1] |
| Acidity (pKa) | ~45 |
| Viscosity | 0.240 cP at 20 °C |
| Hazards | |
| MSDS | External MSDS |
| R/S statement | R: R12, R51/53, R65, R66, R67 S: (S2), S9, S16, S29, S33, S61, S62 |
| NFPA 704 |
 4
1
0
|
| Flash point | −49 °C |
| Related compounds | |
| Related alkanes | Butane, Isopentane, Neopentane, Hexane |
| Related compounds | Cyclopentane |
| Supplementary data page | |
| Structure and properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references |
|
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.
| pentane | isopentane | 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.[2] Rotation about two central single C-C bonds produces four different conformations.[3]
Contents |
[edit] Laboratory use
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, aromatics, and ethers.
One of its applications as a laboratory solvent is in liquid chromatography.
[edit] Reactions
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
[edit] Industrial Uses
Pentane is one of the primary blowing agents used in the production of polystyrene foam.
Pentane is used as a working medium in geothermal power stations.
[edit] References
- ^ BIA GESTIS - Stoffdatenbank
- ^ From the values listed at Standard enthalpy change of formation (data table).
- ^ Roman M. Balabin (2009). "Enthalpy Difference between Conformations of Normal Alkanes: Raman Spectroscopy Study of n-Pentane and n-Butane". J. Phys. Chem. A 113 (6): 1012. doi:.
[edit] External links
- International Chemical Safety Card 0534
- NIOSH Pocket Guide to Chemical Hazards
- Material Safety Data Sheet for Pentane
- Phytochemical database entry
|
||||||||
