Heptane

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Heptane
Image:Heptane.png
General
Molecular formula	C₇H₁₆
SMILES	CCCCCCC
Molar mass	100.21 g/mol
Appearance	colorless liquid
CAS number	[142-82-5]
Properties
Density and phase	0.684 g/ml, liquid
Solubility in water	Immiscible
Melting point	−90.61 °C (182.55 K)
Boiling point	98.42 °C (371.58 K)
Viscosity	0.386 cP at 25 °C
Hazards
MSDS	External MSDS
EU classification	Flammable (F) Harmful (Xn) Dangerous for the environment (N)
NFPA 704	Template:Nfpa
R-phrases	Template:R11, Template:R38, Template:R50/53, Template:R65, Template:R67
S-phrases	Template:S2, Template:S9, Template:S16, Template:S29, Template:S33, Template:S60, Template:S61, Template:S62
Flash point	−4 °C
Autoignition temperature	285 °C
Explosive limits	1.1–6.7%
RTECS number	MI7700000
Supplementary data page
Structure and properties	n, ε_r, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Related alkanes	Hexane Octane
Related compounds	Methylcyclohexane
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Heptane (also known as dipropyl methane, gettysolve-C or heptyl hydride) is an alkane with the chemical formula H₃C(CH₂)₅CH₃. Heptane has nine isomers:

Heptane (n-heptane)
2-Methylhexane
3-Methylhexane
2,2-Dimethylpentane
2,3-Dimethylpentane
2,4-Dimethylpentane
3,3-Dimethylpentane
3-Ethylpentane
2,2,3-Trimethylbutane

The straight-chain isomer n-heptane is the zero point of the octane rating scale. It is undesirable in petrol, as it burns explosively, causing engine knocking, as opposed to branched-chain octane isomers, which burn more slowly and give better performance. Its choice for the zero point of the scale was due to the availability of very high purity n-heptane, unmixed with other isomers of heptane or other alkanes, distilled from the resin of Jeffrey pine. Other sources of heptane and octane, produced from crude oil, contain a mixture of different isomers with greatly differing ratings, so do not give a precise zero point.

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