Octane

Hydrocarbon compound with the formula C8H18

Not to be confused with octene or octyne.

For the gasoline rating system, see Octane rating. For other uses, see Octane (disambiguation).

Octane

Names
Systematic IUPAC name

Octane[1]

Other names

n-Octane

Identifiers

CAS Number

* 111-65-9 Y

3D model (JSmol)

* Interactive image

Beilstein Reference

| 1696875
ChEBI |

* CHEBI:17590 N

ChEMBL |

* ChEMBL134886 Y

ChemSpider |

* 349 Y

DrugBank |

* DB02440 N

ECHA InfoCard | 100.003.539
EC Number |

* 203-892-1

Gmelin Reference

| 82412
KEGG |

* C01387 Y

MeSH | octane

PubChem CID

* 356

RTECS number |

* RG8400000

UNII |

* X1RV0B2FJV Y

UN number | 1262

CompTox Dashboard (EPA)

* DTXSID0026882

InChI

* InChI=1S/C8H18/c1-3-5-7-8-6-4-2/h3-8H2,1-2H3 Y

Key: TVMXDCGIABBOFY-UHFFFAOYSA-N Y

SMILES

* CCCCCCCC

Properties

Chemical formula

| CH3(CH2)6CH3
Molar mass | 114.232 g·mol−1
Appearance  | Colourless liquid
Odor | Gasoline-like[2]
Density | 0.703 g/cm3
Melting point | −57.1 to −56.6 °C; −70.9 to −69.8 °F; 216.0 to 216.6 K
Boiling point | 125.1 to 126.1 °C; 257.1 to 258.9 °F; 398.2 to 399.2 K

Solubility in water

| 0.007 mg/dm3 (at 20 °C)
log P | 4.783
Vapor pressure | 1.47 kPa (at 20.0 °C)

Henry's law
constant (kH)

| 29 nmol/(Pa·kg)
Conjugate acid | Octonium

Magnetic susceptibility (χ)

| −96.63·10−6 cm3/mol

Refractive index (nD)

| 1.398
Viscosity |

* 0.509 mPa·s (25 °C)[3]
* 0.542 mPa·s (20 °C)

Thermochemistry

Heat capacity (C)

| 255.68 J/(K·mol)

Std molar
entropy (S⦵298)

| 361.20 J/(K·mol)

Std enthalpy of
formation (ΔfH⦵298)

| −252.1 to −248.5 kJ/mol

Std enthalpy of
combustion (ΔcH⦵298)

| −5.53 to −5.33 MJ/mol
Hazards
GHS labelling:

Pictograms

Signal word

| Danger

Hazard statements

| H225, H304, H315, H336, H410

Precautionary statements

| P210, P261, P273, P301+P310, P331
NFPA 704 (fire diamond)  |

Flash point | 13.0 °C (55.4 °F; 286.1 K)

Autoignition
temperature

| 220.0 °C (428.0 °F; 493.1 K)
Explosive limits | 0.96 – 6.5%
Lethal dose or concentration (LD, LC):

LDLo (lowest published)

| 428 mg/kg (mouse, intravenous)[4]
NIOSH (US health exposure limits):

PEL (Permissible)

| TWA 500 ppm (2350 mg/m3)[2]

REL (Recommended)

| TWA 75 ppm (350 mg/m3) C 385 ppm (1800 mg/m3) [15-minute][2]

IDLH (Immediate danger)

| 1000 ppm[2]
Related compounds

Related alkanes

* Methane
* Ethane
* Propane
* Butane
* Pentane
* Hexane
* Heptane

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

Chemical compound

Octane is a hydrocarbon and also an alkane with the chemical formula C8H18, and the condensed structural formula CH3(CH2)6CH3. Octane has many structural isomers that differ by the location of branching in the carbon chain. One of these isomers, 2,2,4-trimethylpentane (commonly called iso-octane), is used as one of the standard values in the octane rating scale.

Octane is a component of gasoline and petroleum. Under standard temperature and pressure, octane is an odorless, colorless liquid. Like other short-chained alkanes with a low molecular weight, it is volatile, flammable, and toxic. Octane is 1.2 to 2 times more toxic than heptane.[5]

## Isomers

[edit]

N-octane has 23 constitutional isomers. 8 of these isomers have one stereocenter; 3 of them have two stereocenters.

(3S,4S)-3,4-Dimethylhexane (top left) and (3R,4R)-3,4-Dimethylhexane (top right) are non-superimposable mirror images, so they are chiral enantiomers. (meso)-3,4-Dimethylhexane (bottom) has a superimposable mirror image, so it is an achiral meso compound.

Achiral isomers:

* 2-Methylheptane
* 4-Methylheptane
* 3-Ethylhexane
* 2,2-Dimethylhexane
* 2,5-Dimethylhexane
* (meso)-3,4-Dimethylhexane
* 3,3-Dimethylhexane
* 3-Ethyl-2-methylpentane
* 3-Ethyl-3-methylpentane
* 2,2,4-Trimethylpentane (i.e. iso-octane)
* 2,3,3-Trimethylpentane
* 2,3,4-Trimethylpentane
* 2,2,3,3-Tetramethylbutane

Chiral isomers:

* (3R)-3-Methylheptane
* (3S)-3-Methylheptane
* (3R)-2,3-Dimethylhexane
* (3S)-2,3-Dimethylhexane
* (4R)-2,4-Dimethylhexane
* (4S)-2,4-Dimethylhexane
* (3R,4R)-3,4-Dimethylhexane
* (3S,4S)-3,4-Dimethylhexane
* (3R)-2,2,3-Trimethylpentane
* (3S)-2,2,3-Trimethylpentane

## Production and use

[edit]

In petrochemistry, octanes are not typically differentiated or purified as specific compounds. Octanes are components of particular boiling fractions.[6]

A common route to such fractions is the alkylation reaction between iso-butane and 1-butene, which forms iso-octane.[7]

Octane is commonly used as a solvent in paints and adhesives.

N-octane is the octane isomer that has the longest carbon skeleton. Unlike its constitutional isomers, it has a very low knock resistance. | The octane isomer, iso-octane, is used as one of the standards for octane ratings. It has a rating of 100 by definition. | The octane isomer 2,3,3-Trimethylpentane has an octane rating exceeding 100.

|
|

## References

[edit]

1. ^ "octane - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Identification and Related Records. Retrieved 6 January 2012.
2. ^ a b c d NIOSH Pocket Guide to Chemical Hazards. "#0470". National Institute for Occupational Safety and Health (NIOSH).
3. ^ Dymond, J. H.; Oye, H. A. (1994). "Viscosity of Selected Liquid n-Alkanes". Journal of Physical and Chemical Reference Data. 23 (1): 41–53\. Bibcode:1994JPCRD..23...41D. doi:10.1063/1.555943. ISSN 0047-2689.
4. ^ "Octane". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
5. ^ "1988 OSHA PEL Project - Octane | NIOSH | CDC". www.cdc.gov. 2020-02-27. Retrieved 2024-04-19.
6. ^ "Fractionation". www.appliedcontrol.com. Retrieved 2024-04-19.
7. ^ Ross, Julian (January 1986). "Ullmann's Encyclopedia of industrial chemistry". Applied Catalysis. 27 (2): 403–404\. doi:10.1016/s0166-9834(00)82943-7. ISSN 0166-9834.

## External links

[edit]

* International Chemical Safety Card 0933
* NIOSH Pocket Guide to Chemical Hazards. "#0470". National Institute for Occupational Safety and Health (NIOSH).
* Dr. Duke's Phytochemical and Ethnobotanical Databases, Octane, [1]

* v
* t
* e

Alkanes

* Methane (CH4)
* Ethane (C2H6)
* Propane (C3H8)
* Butane (C4H10)
* Pentane (C5H12)
* Hexane (C6H14)
* Heptane (C7H16)
* Octane (C8H18)
* Nonane (C9H20)
* Decane (C10H22)
* Undecane (C11H24)
* Dodecane (C12H26)
* Tridecane (C13H28)
* Tetradecane (C14H30)
* Pentadecane (C15H32)
* Hexadecane / Cetane (C16H34)
* Heptadecane (C17H36)
* Octadecane (C18H38)
* Nonadecane (C19H40)
* Eicosane (C20H42)
* Heneicosane (C21H44)
* Tetracosane (C24H50)
* Nonacosane (C29H60)
* Hentriacontane (C31H64)

* Higher alkanes
* List of alkanes

* v
* t
* e

Binary compounds of hydrogen

Alkali metal
(Group 1) hydrides|

* LiH
* NaH
* KH
* RbH
* CsH

Alkaline (Group 2)
earth hydrides|

| Monohydrides|

* BeH
* MgH
* CaH
* SrH
* BaH

|

Dihydrides|

* BeH2
* MgH2
* CaH2
* SrH2
* BaH2

|

Group 13
hydrides|

| Boranes|

* BH3
* BH
* B2H6
* B2H2
* B2H4
* B4H10
* B5H9
* B5H11
* B6H10
* B6H12
* B10H14
* B18H22

|

Alanes|

* AlH3
* Al2H6

|

Gallanes|

* GaH3
* Ga2H6

|

Indiganes|

* InH3
* In2H6

|

Thallanes|

* TlH3
* Tl2H6

|

Nihonanes (predicted)|

* NhH
* NhH3
* Nh2H6
* NhH5

|

Group 14 hydrides|

| Hydrocarbons|

* alkanes
* alkenes
* alkynes
* Cycloalkanes
* Cycloalkenes
* Cycloalkynes
* Annulenes

|

* CH
* CH2
* CH3
* C2H

Silanes|

* SiH4
* Si2H6
* Si3H8
* Si4H10
* Si5H12
* Si6H14
* Si7H16
* Si8H18
* Si9H20
* Si10H22
* more...

|

Silenes|

* Si2H4

|

Silynes|

* Si2H2
* SiH

|

Germanes|

* GeH4
* Ge2H6
* Ge3H8
* Ge4H10
* Ge5H12

|

Stannanes|

* SnH4
* Sn2H6

|

Plumbanes|

* PbH4

|

Flerovanes (predicted)|

* FlH
* FlH2
* FlH4

|

Pnictogen
(Group 15) hydrides|

| Azanes|

* NH3
* N2H4
* N3H5
* N4H6
* N5H7
* N6H8
* N7H9
* N8H10
* N9H11
* N10H12
* more...

|

Azenes|

* N2H2
* N3H3
* N4H4

|

Phosphanes|

* PH3
* P2H4
* P3H5
* P4H6
* P5H7
* P6H8
* P7H9
* P8H10
* P9H11
* P10H12
* more...

|

Phosphenes|

* P2H2
* P3H3
* P4H4

|

Arsanes|

* AsH3
* As2H4

|

Stibanes|

* SbH3

|

Bismuthanes|

* BiH3

|

Moscovanes|

* McH3 (predicted)

|

* HN3
* NH
* HN5
* NH5 (hypothetical)

Hydrogen
chalcogenides
(Group 16 hydrides)|

| Polyoxidanes|

* H2O
* H2O2
* H2O3
* H2O4
* H2O5
* more...

|

Polysulfanes|

* H2S
* H2S2
* H2S3
* H2S4
* H2S5
* H2S6
* H2S7
* H2S8
* H2S9
* H2S10
* more...

|

Selanes|

* H2Se
* H2Se2

|

Tellanes|

* H2Te
* H2Te2

|

Polanes|

* PoH2

|

Livermoranes|

* LvH2 (predicted)

|

* HO
* HO2
* HO3
* H2O+–O– (hypothetical)
* H2S+-S-
* HS
* HS2
* HDO
* D2O
* T2O

Hydrogen halides
(Group 17 hydrides)|

* HF
* HCl
* HBr
* HI
* HAt
* HTs (predicted)

Transition
metal hydrides|

* ScH2
* YH2
* YH3
* YH6
* YH9
* LuH2
* LuH3
* TiH2
* TiH4
* ZrH2
* ZrH4
* HfH2
* HfH4
* VH
* VH2
* NbH
* NbH2
* TaH
* TaH2
* CrH
* CrH2
* CrHx
* FeH
* FeH2
* FeH5
* CoH2
* RhH2
* IrH3
* NiH
* PdHx (x < 1)
* PtHx (x< 1)
* DsH2 (predicted)
* CuH
* AgH
* AuH
* RgH (predicted)
* ZnH2
* CdH2
* HgH
* Hg2H2
* HgH2
* CnH2 (predicted)

Lanthanide
hydrides|

* LaH2
* LaH3
* LaH10
* CeH2
* CeH3
* PrH2
* PrH3
* NdH2
* NdH3
* SmH2
* SmH3
* EuH2
* GdH2
* GdH3
* TbH2
* TbH3
* DyH2
* DyH3
* HoH2
* HoH3
* ErH2
* ErH3
* TmH2
* TmH3
* YbH2
* LuH2
* LuH3

Actinide
hydrides|

* AcH2
* ThH2
* ThH4
* Th4H15
* PaH3
* UH3
* UH4
* NpH2
* NpH3
* PuH2
* PuH3
* AmH2
* AmH3
* CmH2
* BkH2
* BkH3
* CfH2
* CfH3

Exotic matter hydrides|

* PsH

*[CID]: Compound ID
*[EPA]: U.S. Environmental Protection Agency
*[H225]: H225: Highly flammable liquid and vapour
*[H304]: H304: May be fatal if swallowed and enters airways
*[H315]: H315: Causes skin irritation
*[H336]: H336: May cause drowsiness or dizziness
*[H410]: H410: Very toxic to aquatic life with long lasting effects
*[P210]: P210: Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
*[P261]: P261: Avoid breathing dust/fume/gas/mist/vapours/spray.
*[P273]: P273: Avoid release to the environment.
*[P301+P310]: P301+P310: IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician.
*[P331]: P331: Do NOT induce vomiting.
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