Isopentane

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Isopentane
Skeletal formula of isopentane
Skeletal formula of isopentane with all implicit carbons shown, and all explicit hydrogens added
Ball and stick model of isopentane
Names
Preferred IUPAC name
2-Methylbutane[1]
Other names
Isopentane
Identifiers
3D model (
JSmol
)
1730723
ChEBI
ChemSpider
ECHA InfoCard
100.001.039 Edit this at Wikidata
EC Number
  • 201-142-8
49318
MeSH isopentane
RTECS number
  • EK4430000
UNII
UN number 1265
  • InChI=1S/C5H12/c1-4-5(2)3/h5H,4H2,1-3H3 checkY
    Key: QWTDNUCVQCZILF-UHFFFAOYSA-N checkY
  • CCC(C)C
Properties
C5H12
Molar mass 72.151 g·mol−1
Appearance Colorless liquid
Odor Gasoline-like
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-vismax) 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
Std enthalpy of
formation
fH298)
−179.1–−177.3 kJ mol−1
Std enthalpy of
combustion
cH298)
~ 3.3 MJ mol−1, 19,664 Btu/lb
Hazards
GHS labelling:
GHS02: Flammable GHS07: Exclamation mark GHS08: Health hazard GHS09: Environmental hazard
Danger
H224, H301, H302, H305, H336, H411
P210, P261, P273, P301+P310, P331
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 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. propaneInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
4
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).
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Isopentane, also called methylbutane or 2-methylbutane, is a branched-chain saturated hydrocarbon (an alkane) with five carbon atoms, with formula C
5
H
12
or CH(CH
3
)
2
(C
2
H
5
)
.

Isopentane is a

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,[3] but it is a significant component of natural gasoline.[4]

Nomenclature

The traditional name isopentane was still retained in the 1993 IUPAC recommendations,[5][6] 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.

Uses

Isopentane is used in a closed loop in geothermal power production to drive turbines.[7]

Isopentane is used, in conjunction with

cryosectioning in histology
. [8]

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.[4] 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.[9]

References

External links