2-Methylpentane

2-Methylpentane, trivially known as isohexane, is a branched-chain alkane with the molecular formula C₆H₁₄. It is a structural isomer of hexane composed of a methyl group bonded to the second carbon atom in a pentane chain.

2-Methylpentane

Skeletal formula of 2-methylpentane
Names
Preferred IUPAC name 2-Methylpentane[1]
Other names Isohexane[2]
Identifiers
CAS Number	107-83-5 Y
3D model (JSmol)	Interactive image
Beilstein Reference	1730735
ChEBI	CHEBI:88374 N
ChEMBL	ChEMBL30909 Y
ChemSpider	7604 Y
ECHA InfoCard	100.003.204
EC Number	203-523-4
MeSH	2-methylpentane
PubChem CID	7892
RTECS number	SA2985000
UNII	49IB0U6MLD N
UN number	1208
CompTox Dashboard (EPA)	DTXSID4029143
InChI InChI=1S/C6H14/c1-4-5-6(2)3/h6H,4-5H2,1-3H3 Y Key: AFABGHUZZDYHJO-UHFFFAOYSA-N Y
SMILES CCCC(C)C
Properties
Chemical formula	C6H14
Molar mass	86.178 g·mol−1
Appearance	Colorless liquid
Odor	Odorless
Density	653 mg mL−1
Melting point	−160 to −146 °C; −256 to −231 °F; 113 to 127 K
Boiling point	60 to 62 °C; 140 to 143 °F; 333 to 335 K
log P	3.608
Vapor pressure	46.7 kPa (at 37.7 °C)
Henry's law constant (kH)	5.7 nmol Pa−1 kg−1
Magnetic susceptibility (χ)	−75.26·10−6 cm3/mol
Refractive index (nD)	1.371
Thermochemistry
Heat capacity (C)	194.19 J K−1 mol−1
Std molar entropy (S⦵298)	290.58 J K−1 mol−1
Std enthalpy of formation (ΔfH⦵298)	−205.3 – −203.3 kJ mol−1
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H225, H304, H315, H336, H411
Precautionary statements	P210, P261, P273, P301+P310, P331
NFPA 704 (fire diamond)	2 3 0
Flash point	−7 °C (19 °F; 266 K)
Autoignition temperature	306 °C (583 °F; 579 K)
Explosive limits	1.2–7%
NIOSH (US health exposure limits):
PEL (Permissible)	none[3]
Related compounds
Related alkanes	Isopentane 3-Methylpentane 3-Ethylpentane 2-Methylhexane 3-Methylhexane
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 YN ?) Infobox references

As of early 1990s, it was present in American^[4] and European^[5] gasoline in small amounts, and by 2011 its share in US gas varied between 2 and 8%.^[6] Using a quantitative structure-activity relationship (QSAR) prediction model, 2-Methylpentane has a research octane number (RON) of 75, motor octane number (MON) of 77, and cetane number (CN) of 29.^[7]

See also

• Heteropoly acid