Isopentane
| Isopentane | |
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2-Methylbutane[1] |
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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 |
| 1730723 | |
| 49318 | |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C5H12 |
| Molar mass | 72.15 g mol−1 |
| Appearance | Colorless liquid |
| Odor | Odorless |
| Density | 616 mg mL−1[2] |
| Melting point | −161 to −159 °C; −258 to −254 °F; 112 to 114 K |
| Boiling point | 27.8 to 28.2 °C; 81.9 to 82.7 °F; 300.9 to 301.3 K |
| Vapor pressure | 76.992 kPa (at 20 °C) |
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Henry's law
constant (kH) |
7.2 nmol Pa−1 kg−1 |
| UV-vis (λmax) | 192 nm |
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Refractive index (nD)
|
1.354 |
| Thermochemistry | |
| 164.85 J K−1 mol−1 | |
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Std molar
entropy (S |
260.41 J K−1 mol−1 |
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Std enthalpy of
formation (ΔfH |
−179.1–−177.3 kJ mol−1 |
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Std enthalpy of
combustion (ΔcH |
−3.5052–−3.5036 MJ mol−1 |
| Hazards | |
| GHS pictograms |     |
| GHS signal word | DANGER |
| H224, H304, H336, H411 | |
| 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 | |
| Flash point | −51 °C (−60 °F; 222 K) |
| Explosive limits | 1.4–8.3% |
| Related compounds | |
| Related alkanes | |
| Related compounds | 2-Ethyl-1-butanol |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 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]
Nomenclature[edit]
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.
Isomers[edit]
Isopentane is one of three structural isomers with the molecular formula C5H12, the others being pentane (n-pentane) and neopentane (dimethyl propane).
Uses[edit]
Isopentane is used in a closed loop in in geothermal power production to drive turbines.[5] Isopentane is one of the ingredients in both Aquafresh and Sensodyne.[6][not in citation given]
References[edit]
- ^ "isopentane - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Identification and Related Records. 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.
- ^ HS Orka HF Energy Plant IV
- ^ Aquafresh Website
External links[edit]
- International Chemical Safety Card 1153
- IUPAC Nomenclature of Organic Chemistry (online version of the "Blue Book")
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