isopentane
{{Chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 464398176
| ImageFile = Isopentane-2D-skeletal.svg
| ImageFile_Ref = {{chemboximage|correct|??}}
| ImageSize = 100
| ImageName = Skeletal formula of isopentane
| ImageFile1 = Isopentane.PNG
| ImageFile1_Ref = {{chemboximage|correct|??}}
| ImageSize1 = 160
| ImageName1 = Skeletal formula of isopentane with all implicit carbons shown, and all explicit hydrogens added
| ImageFile2 = Isopentane-3D-balls.png
| ImageFile2_Ref = {{chemboximage|correct|??}}
| ImageSize2 = 100
| ImageName2 = Ball and stick model of isopentane
| PIN = 2-Methylbutane{{cite book | title = Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book) | publisher = The Royal Society of Chemistry | date = 2014 | location = Cambridge | page = 652 | doi = 10.1039/9781849733069-FP001 | isbn = 978-0-85404-182-4 | quote = The names ‘isobutane’, ‘isopentane’ and ‘neopentane’ are no longer recommended.}}
| OtherNames = Isopentane
|Section1={{Chembox Identifiers
| CASNo = 78-78-4
| CASNo_Ref = {{cascite|correct|CAS}}
| PubChem = 6556
| ChemSpiderID = 6308
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| UNII = ZH67814I0O
| UNII_Ref = {{fdacite|correct|FDA}}
| EINECS = 201-142-8
| UNNumber = 1265
| MeSHName = isopentane
| ChEBI = 30362
| ChEBI_Ref = {{ebicite|correct|EBI}}
| RTECS = EK4430000
| Beilstein = 1730723
| Gmelin = 49318
| SMILES = CCC(C)C
| StdInChI = 1S/C5H12/c1-4-5(2)3/h5H,4H2,1-3H3
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = QWTDNUCVQCZILF-UHFFFAOYSA-N
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
}}
|Section2={{Chembox Properties
| C=5 | H=12
| Appearance = Colorless liquid
| Odor = Gasoline-like
| Density = 616 mg mL−1James 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}}
| BoilingPtK = 300.9 to 301.3
| MeltingPtK = 112 to 114
| VaporPressure = 76.992 kPa (at 20 °C)
| HenryConstant = 7.2 nmol Pa−1 kg−1
| LambdaMax = 192 nm
| RefractIndex = 1.354
| Viscosity = 0.214 cP (at 20 °C)
}}
|Section4={{Chembox Thermochemistry
| DeltaHf = −179.1–−177.3 kJ mol−1
| DeltaHc = ~ 3.3 MJ mol−1, 19,664 Btu/lb
| Entropy = 260.41 J K−1 mol−1
| HeatCapacity = 164.85 J K−1 mol−1
}}
|Section5={{Chembox Hazards
| GHSPictograms = {{GHS flame}} {{GHS exclamation mark}} {{GHS health hazard}} {{GHS environment}}
| GHSSignalWord = DANGER
| HPhrases = {{H-phrases|224|301|302|305|336|411}}
| PPhrases = {{P-phrases|210|261|273|301+310|331}}
| NFPA-H = 1
| NFPA-F = 4
| NFPA-R = 0
| FlashPtC = −51
| AutoignitionPtC = 420
| ExploLimits = 1.4–8.3%
}}
|Section6={{Chembox Related
| OtherFunction_label = alkanes
| OtherFunction = {{Unbulleted list|Isobutane|2-Methylpentane|3-Methylpentane|3-Ethylpentane}}
| OtherCompounds = 2-Ethyl-1-butanol
}}
}}
Isopentane, also called methylbutane or 2-methylbutane, is a branched-chain saturated hydrocarbon (an alkane) with five carbon atoms, with formula {{chem|C|5|H|12}} or {{chem|CH(CH|3|)|2|(C|2|H|5|)}}.
Isopentane is a volatile and flammable liquid. It is one of three structural isomers with the molecular formula C5H12, the others being pentane (n-pentane) and neopentane (2,2-dimethylpropane).
Isopentane is commonly used in conjunction with liquid nitrogen to achieve a liquid bath temperature of −160 °C. Natural gas typically contains 1% or less isopentane,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}} but it is a significant component of natural gasoline.Ivan F. Avery, L. V. Harvey (1958): [https://books.google.com/books?id=sC2JHAYfJb0C&pg=PA6 Natural-gasoline and Cycling Plants in the United States], Information circular, U.S. Department of the Interior, Bureau of Mines. 12 pages.
History
Although the mixture of pentanes was first isolated from the destructive distillation (pyrolysis) products of the boghead coal by Charles Greville Williams in 1862.{{Cite journal |last=Williams |first=C. Greville |date=1862 |title=On the hydrocarbons produced by destructive distillation of boghead coal |url=https://zenodo.org/records/2068495/files/article.pdf |journal=Journal of the Chemical Society |language=en |volume=15 |issue=0 |pages=130–134 |doi=10.1039/JS8621500130 |issn=0368-1769}} In 1864–1865 two chemists tried to extract same hydrocarbons from the Pennsylvanian oil. Carl Schorlemmer noted "that a mere trace of the liquid boiled below 30°C",{{Cite book |last= |first= |url=https://books.google.com/books?id=fTw9AQAAMAAJ&pg=RA1-PA84 |title=Proceedings of the Literary and Philosophical Society of Manchester |date=1864 |language=en}} but the first to properly separate isomers (and thus discover isopentane) was American chemist Cyrus Warren (1824–1891) slightly later, who measured the boiling point of the more volatile one at 30°C.{{Cite book |url=https://books.google.com/books?id=v4FIAQAAMAAJ&pg=PA226 |title=The American Journal of Science |date=1865 |publisher=Kline Geology Laboratory, Yale University. |language=en}}
Nomenclature
The traditional name isopentane, attested in English as early as 1875,{{Cite book |last=Watts (F.C.S.) |first=Henry |url=https://books.google.com/books?id=_FLgRj4L4b0C&pg=PA63 |title=A Dictionary of Chemistry and Allied Branches of Other Sciences |date=1875 |language=en}} was still retained in the 1993 IUPAC recommendations,[http://www.acdlabs.com/iupac/nomenclature/93/r93_679.htm Table 19(a) Acyclic and monocyclic hydrocarbons. Parent hydrocarbons]{{cite book | editor=Panico, R. | editor2= Powell, W. H. | name-list-style= amp | title=A Guide to IUPAC Nomenclature of Organic Compounds 1993 | location=Oxford | publisher=Blackwell Science | year=1994 | isbn=0-632-03488-2}}
but is no longer recommended according to the 2013 recommendations. The preferred IUPAC name is the systematic name 2-methylbutane. An isopentyl group is a subset of the generic pentyl group. It has the chemical structure -CH3CH2CH(CH3)2.
Uses
Isopentane is used in a closed loop in geothermal power production to drive turbines.Byproduct Isopentane also used in some of the LPG plant to run the boiler and generate the power.
[http://hsorka.is/english/HSProduction/Svartsengi/OrkuverIV.aspx HS Orka HF Energy Plant IV] {{Webarchive|url=https://web.archive.org/web/20141018154915/http://hsorka.is/english/HSProduction/Svartsengi/OrkuverIV.aspx |date=2014-10-18 }}
Isopentane is used, in conjunction with dry ice or liquid nitrogen, to freeze tissues for cryosectioning in histology.
Isopentane is a major component (sometimes 30% or more) of natural gasoline, an analog of common petroleum-derived gasoline that is condensed from natural gas. Its share in commercial car fuel is highly variable: 19–45% in 1990s Sweden,{{Cite journal |last=Östermark |first=Ulf |last2=Petersson |first2=Göran |date=1992-09-01 |title=Assessment of hydrocarbons in vapours of conventional and alkylate-based petrol |url=https://publications.lib.chalmers.se/records/fulltext/local_72590.pdf |journal=Chemosphere |volume=25 |issue=6 |pages=763–768 |doi=10.1016/0045-6535(92)90066-Z |issn=0045-6535}} 4–31% in 1990s US{{Cite journal |last=Doskey |first=Paul V. |last2=Porter |first2=Joseph A. |last3=Scheff |first3=Peter A. |date=November 1992 |title=Source Fingerprints for Volatile Non-Methane Hydrocarbons |url=https://www.tandfonline.com/doi/full/10.1080/10473289.1992.10467090 |journal=Journal of the Air & Waste Management Association |language=en |volume=42 |issue=11 |pages=1437–1445 |doi=10.1080/10473289.1992.10467090 |issn=1047-3289}} and 3.6–11% in the US in 2011.{{cite web |date=2011 |title=Hydrocarbon Composition of Gasoline Vapor Emissions from Enclosed Fuel Tanks |url=https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P100GPED.TXT |website=nepis.epa.gov |publisher=United States Environmental Protection Agency}} It has a substantially higher octane rating (RON 93.7) than n-pentane (61.7), and therefore there is interest in conversion from the latter.Sheng Wang, Ying Zhang, Mao-Gang He, Xiong Zheng, and Li-Bin Chen (2014): "Thermal Diffusivity and Speed of Sound of Saturated Pentane from Light Scattering". International Journal of Thermophysics, volume 35, pages 1450–1464. {{doi|10.1007/s10765-014-1718-x}}
References
{{Reflist}}
External links
- [http://www.inchem.org/documents/icsc/icsc/eics1153.htm International Chemical Safety Card 1153]
- [http://www.acdlabs.com/iupac/nomenclature/ IUPAC Nomenclature of Organic Chemistry] (online version of the "Blue Book")
{{Alkanes}}
{{Authority control}}