Octane
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Octane | |
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General | |
Molecular formula | C8H18 |
SMILES | CCCCCCCC |
Molar mass | 114.2285 g/mol |
Appearance | colorless liquid |
CAS number | [111-65-9] |
Properties | |
Density and phase | 0.703 g/ml, liquid |
Solubility in water | Immiscible |
Melting point | −57 °C (216 K) |
Boiling point | 125.52 °C (398.7 K) |
Viscosity | 0.542 cP at 20 °C |
Thermodynamic data | |
Std enthalpy change of formation, ΔfH |
−250 kJ/mol |
Std enthalpy change of combustion, ΔcH |
−5430 kJ/mol |
Standard molar entropy, S |
360 J·K−1·mol−1 |
Hazards | |
MSDS | External MSDS |
EU classification | Flammable (F) Harmful (Xn) Dangerous for the environment (N) |
NFPA 704 | |
R-phrases | R11, R38, R50/53, R65, R67 |
S-phrases | S2, S9, S16, S29, S33, S60, S61, S62 |
Flash point | 13 °C |
Autoignition temperature | 220 °C |
Explosive limits | 1.0–6.5% |
RTECS number | RG8400000 |
Supplementary data page | |
Structure and properties |
n, εr, etc. |
Thermodynamic data |
Phase behaviour Solid, liquid, gas |
Spectral data | UV, IR, NMR, MS |
Related compounds | |
Related alkanes | Heptane 2,2,4-Trimethylpentane |
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
Octane is an alkane with the chemical formula CH3(CH2)6CH3. It has 18 isomers.
One of the isomers, 2,2,4-trimethylpentane or isooctane, is of major importance, as it has been selected as the 100 point on the octane rating scale, with n-heptane as the zero point. Octane ratings are ratings used to represent the anti-knock performance of petroleum-based fuels (octane is less likely to prematurely combust under pressure than heptane), given as the percentage of 2,2,4-trimethylpentane in an 2,2,4-trimethylpentane / n-heptane mixture that would have the same performance. It is an important constituent of gasoline.
Octane has 18 isomers :
- Octane (n-octane)
- 2-Methylheptane
- 3-Methylheptane
- 4-Methylheptane
- 3-Ethylhexane
- 2,2-Dimethylhexane
- 2,3-Dimethylhexane
- 2,4-Dimethylhexane
- 2,5-Dimethylhexane
- 3,3-Dimethylhexane
- 3,4-Dimethylhexane
- 2-Methyl-3-ethylpentane
- 3-Methyl-3-ethylpentane
- 2,2,3-Trimethylpentane
- 2,2,4-Trimethylpentane (isooctane)
- 2,3,3-Trimethylpentane
- 2,3,4-Trimethylpentane
- 2,2,3,3-Tetramethylbutane
[edit] External links
- International Chemical Safety Card 0933 (n-octane)
- International Chemical Safety Card 0731 (2-methylheptane)
- NIOSH Pocket Guide to Chemical Hazards
- Material Safety Data Sheet for Octane
- Phytochemical database entry
- Links to external chemical sources
Alkanes | |||||||||||||||||||||||||||||||
Methane |
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Ethane |
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Propane |
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Butane |
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Pentane |
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Hexane |
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Heptane |
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Octane |
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Nonane |
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Decane |
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Undecane |
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Dodecane |
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