Isopentane
| Isopentane | |
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2-Methylbutane[1] |
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Other names
Methylbutane[citation needed] |
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| Identifiers | |
| CAS number | 78-78-4  |
| PubChem | 6556 |
| ChemSpider | 6308 |
| UNII | ZH67814I0O |
| EC number | 201-142-8 |
| UN number | 1265 |
| MeSH | isopentane |
| ChEBI | CHEBI:30362 |
| RTECS number | EK4430000 |
| Beilstein Reference | 1730723 |
| Gmelin Reference | 49318 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C5H12 |
| Molar mass | 72.15 g mol−1 |
| Exact mass | 72.093900384 g mol−1 |
| Appearance | Colorless, transparent liquid |
| Odor | Odorless |
| Density | 616 mg mL−1[2] |
| Melting point |
-161--159 °C, 112-114 K, -258--254 °F |
| Boiling point |
28-28 °C, 300.9-301.3 K, 82-83 °F |
| Solubility in water | Miscible |
| Vapor pressure | 76.992 kPa (at 20 °C) |
| kH | 7.2 nmol Pa−1 kg−1 |
| λmax | 192 nm |
| Refractive index (nD) | 10.354 |
| Thermochemistry | |
| Std enthalpy of formation ΔfH |
−179.1–−177.3 kJ mol−1 |
| Std enthalpy of combustion ΔcH |
−3.5052–−3.5036 MJ mol−1 |
| Standard molar entropy S |
260.41 J K−1 mol−1 |
| Specific heat capacity, C | 164.85 J K−1 mol−1 |
| Hazards | |
| GHS pictograms |     |
| GHS signal word | DANGER |
| GHS hazard statements | H224, H304, H336, H411 |
| GHS precautionary statements | P210, P261, P273, P301+310, P331 |
| EU Index | 601-006-00-1 |
| EU classification |  F+  Xn  N |
| R-phrases | R12, R51/53, R65, R66, R67 |
| S-phrases | (S2), S16, S29, S33 |
| NFPA 704 |
 4
1
0
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| Flash point | −51 °C |
| Autoignition temperature |
420 °C |
| Explosive limits | 1.4–8.3% |
| Related compounds | |
| Related alkanes | |
| Related compounds | 2-Ethyl-1-butanol |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Isopentane, C5H12, also called methylbutane or 2-methylbutane, is a branched-chain alkane with five carbon atoms. Isopentane is an extremely volatile and extremely flammable liquid at room temperature and pressure. The normal boiling point is just a few degrees above room temperature and isopentane will readily boil and evaporate away on a warm day. Isopentane is commonly used in conjunction with liquid nitrogen to achieve a liquid bath temperature of -160 °C. It is 1% or less of natural gas.[3]
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[edit] Nomenclature
Isopentane is the name recommended by the International Union of Pure and Applied Chemistry (IUPAC).[4]An isopentyl group is a subset of the generic pentyl group. It has the chemical structure -CH2CH2CH(CH3)2.
[edit] Isomers
Isopentane is one of three structural isomers with the molecular formula C5H12, the others being pentane (n-pentane) and neopentane (dimethyl propane).
[edit] Uses
Isopentane is one of the ingredients in both Aquafresh® and Sensodyne®.[5]
[edit] References
- ^ "isopentane - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Identification and Related Records. http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=6556&loc=ec_rcs#x291. Retrieved 5 March 2012.
- ^ James Wei (1999), Molecular Symmetry, Rotational Entropy, and Elevated Melting Points. Ind. Eng. Chem. Res., volume 38 issue 12, pp. 5019–5027 doi:10.1021/ie990588m
- ^ Georg Hammer, Torsten Lübcke, Roland Kettner, Mark R. Pillarella, Herta Recknagel, Axel Commichau, Hans-Joachim Neumann and Barbara Paczynska-Lahme “Natural Gas“ in Ullmann's Encyclopedia of Industrial Chemistry 2006, Wiley-VCH, Weinheim. doi:10.1002/14356007.a17_073.pub2
- ^ Panico, R.; & Powell, W. H. (Eds.) (1994). A Guide to IUPAC Nomenclature of Organic Compounds 1993. Oxford: Blackwell Science. ISBN 0-632-03488-2. http://www.acdlabs.com/iupac/nomenclature/93/r93_679.htm.
- ^ Aquafresh Website
[edit] External links
- International Chemical Safety Card 1153
- IUPAC Nomenclature of Organic Chemistry (online version of the "Blue Book")
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