Isopentane

Isopentane
Names
Preferred IUPAC name
2-Methylbutane[1]
Other names
Isopentane (no longer recommended[1])
Identifiers
78-78-4 YesY
3D model (Jmol) Interactive image
1730723
ChEBI CHEBI:30362 YesY
ChemSpider 6308 YesY
ECHA InfoCard 100.001.039
EC Number 201-142-8
49318
MeSH isopentane
PubChem 6556
RTECS number EK4430000
UNII ZH67814I0O YesY
UN number 1265
Properties
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)
7.2 nmol Pa−1 kg−1
UV-vis (λmax) 192 nm
1.354
Viscosity 0.214 cP (at 20 °C)
Thermochemistry
164.85 J K−1 mol−1
260.41 J K−1 mol−1
−179.1–−177.3 kJ mol−1
~ 3.3 MJ mol−1, 19,664 Btu/lb
Hazards
GHS pictograms
GHS signal word DANGER
H224, H304, H336, H411
P210, P261, P273, P301+310, P331
F+ Xn N
R-phrases R12, R51/53, R65, R66, R67
S-phrases (S2), S16, S29, S33
NFPA 704
Flammability code 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g., propane Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
4
1
0
Flash point −51 °C (−60 °F; 222 K)
420 °C (788 °F; 693 K)
Explosive limits 1.4–8.3%
Related compounds
Related alkanes
Related compounds
 2-Ethyl-1-butanol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
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

The traditional name isopentane was still retained in the 1993 IUPAC recommendations,[4][5] but is no longer recommended according to the 2013 recommendations.[1] 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.

Isomers

Isopentane is one of three structural isomers with the molecular formula C5H12, the others being pentane (n-pentane) and neopentane (dimethyl propane).

Uses

Isopentane is used in a closed loop in geothermal power production to drive turbines.[6]

Isopentane is used, in conjunction with dry ice or liquid nitrogen, to freeze tissues for cryosectioning in histology. [7]

References

  1. 1 2 3 Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 652. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4. The names ‘isobutane’, ‘isopentane’ and ‘neopentane’ are no longer recommended.
  2. ↑ 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
  3. ↑ 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
  4. ↑ Table 19(a) Acyclic and monocyclic hydrocarbons. Parent hydrocarbons
  5. ↑ Panico, R.; & Powell, W. H. (Eds.) (1994). A Guide to IUPAC Nomenclature of Organic Compounds 1993. Oxford: Blackwell Science. ISBN 0-632-03488-2.
  6. ↑ Byproduct Isopentane also used in some of the LPG plant to run the boiler and generate the power. HS Orka HF Energy Plant IV
  7. ↑ http://www.uab.edu/research/administration/offices/ARP/ComparativePathology/Pathology/Histopathology/TissueSubmission/Pages/Freezing-Tissues-for-Cryosectioning.aspx
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