# Higher alkane

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**Higher alkanes** are [alkanes](/source/Alkane) with a high number of [carbon](/source/Carbon) atoms. It is common jargon.[1] One definition says higher alkanes are alkanes having nine or more carbon atoms. Thus, according to this definition, [nonane](/source/Nonane) is the lightest higher alkane.[2] As pure substances, higher alkanes are rarely significant, but they are major components of useful lubricants and fuels.[3]

## Synthesis

The preparation of specific long-chain hydrocarbons typically involves manipulations of long chain precursors or the coupling of two medium-chain components. For the first case, fatty acids can be a source of higher alkanes via [decarboxylation](/source/Decarboxylation) reaction. Such processes have been investigated as a route to [biodiesel](/source/Biodiesel).[4]

Fatty acid esters and fatty acid nitriles react with long chain [Grignard reagents](/source/Grignard_reagent) to give, after suitable workup, long-chain ketones. The [Wolff-Kishner Reaction](/source/Wolff-Kishner_Reaction) provides a way to remove the [ketone](/source/Ketone) functionality, giving long-chain hydrocarbons.[1]

Even-numbered, long-chain hydrocarbons can also be synthesized through [electrolysis](/source/Kolbe_electrolysis)[5] and the [Wurtz reactions](/source/Wurtz_reaction) of alkyl bromides.

## Occurrence

Higher alkanes can also be isolated and purified from natural or synthetic mixtures. [Coal tar](/source/Coal_tar) is a traditional source of mixtures of long-chain hydrocarbons.[3] Careful fractionation, first using [urea clathrates](/source/Urea_extraction_crystallization) to remove branched hydrocarbons, and then distillation, produces pure n-hydrocarbons from petroleum.[6]

Regarding synthetic sources, the [Fischer-Tropsch process](/source/Fischer-Tropsch_process) (or FT process) produces a mixture of hydrocarbons by the [hydrogenation](/source/Hydrogenation) of [carbon monoxide](/source/Carbon_monoxide). The products obtained are liquid hydrocarbons and waxy solids, mostly *n-paraffins*. The liquid fraction ranges from C6 to C20, while the solid fraction consists of hydrocarbons above C21.[7]

### Bioactivity

Some branched higher alkanes are [insect](/source/Insect) [pheromones](/source/Pheromone). 7-methyltricosane and 9-methyltricosane are active for [ladybird](/source/Ladybird) beetles (*Adalia bipunctata*).[8] The [emerald ash borer](/source/Emerald_ash_borer) (*Agrilus planipennis Fairmaire*) responds to 9-methylpentacosane.[9] Female [Asian long-horned beetles](/source/Asian_long-horned_beetle) *Anoplophora glabripennis*, which are very damaging, secrete 2-methyldocosane.[10]

## Reactions

Higher alkanes in general are relatively inert, just like low molecular weight alkanes they can react with oxygen and start a [combustion](/source/Combustion) reaction. They can undergo [cracking](/source/Cracking_(chemistry)) in the presence of alumina or silica [catalysts](/source/Catalysts), forming lower alkanes and alkenes.

## Uses

Alkanes from [nonane](/source/Nonane) to [hexadecane](/source/Hexadecane) (those alkanes with nine to sixteen carbon atoms) are liquids of higher [viscosity](/source/Viscosity), which are less suitable for use in [gasoline](/source/Gasoline). They form instead the major part of [diesel](/source/Diesel_fuel), [kerosene](/source/Kerosene), and [aviation fuel](/source/Aviation_fuel). Diesel fuels are characterised by their [cetane number](/source/Cetane_number), cetane being an older name for hexadecane. However the higher melting points of these alkanes can cause problems at low temperatures and in [polar regions](/source/Polar_regions_of_Earth), where the fuel becomes too [thick](/source/Viscosity) to flow correctly. Mixtures of the normal alkanes are used as [boiling point](/source/Boiling_point) standards for simulated [distillation](/source/Distillation) by [gas chromatography](/source/Gas_chromatography).[11]

Alkanes from hexadecane upwards form the most important components of [fuel oil](/source/Fuel_oil) and [lubricating oil](/source/Lubricant). In latter function they work at the same time as anti-corrosive agents, as their [hydrophobic](/source/Hydrophobic) nature means that water cannot reach the metal surface. Many solid alkanes find use as [paraffin wax](/source/Paraffin_wax), used for [lubrication](/source/Lubrication), [electrical insulation](/source/Electrical_insulation), and [candles](/source/Candle). Paraffin wax should not be confused with [beeswax](/source/Beeswax), which consists primarily of [esters](/source/Ester).

Alkanes with a chain length of approximately 30 or more carbon atoms are found in [bitumen](/source/Bitumen) (asphalt), used (for example) in road surfacing. However, the higher alkanes have little value and are usually split into lower alkanes by [cracking](/source/Fluid_catalytic_cracking).

## Names

Some alkanes have non-IUPAC trivial names:

- cetane, for [hexadecane](/source/Hexadecane)
- cerane, for hexacosane[12]

## Properties

[Nonane](/source/Nonane) is the lightest alkane to have a [flash point](/source/Flash_point) above 25 °C, and is classified as [flammable](/source/Flammable_liquid) under the US National Library of Medicine. [13]

The properties listed here refer to the straight-chain alkanes (or: *n-alkanes*).

### Nonane to hexadecane

This group of n-alkanes is generally liquid under standard conditions.[3]

Nonane Decane Undecane Dodecane Tridecane Tetradecane Pentadecane Hexadecane Formula C9H20 C10H22 C11H24 C12H26 C13H28 C14H30 C15H32 C16H34 CAS number [111-84-2] [124-18-5] [1120-21-4] [112-40-3] [629-50-5] [629-59-4] [629-62-9] [544-76-3] Molar mass (g/mol) 128.26 142.29 156.31 170.34 184.37 198.39 212.42 226.45 Melting point (°C) −53.5 −29.7 −25.6 −9.6 −5.4 5.9 9.9 18.2 Boiling point (°C) 150.8 174.1 195.9 216.3 235.4 253.5 270.6 286.8 Density (g/ml at 20 degC) 0.71763 0.73005 0.74024 0.74869 0.75622 0.76275 0.76830 0.77344 Viscosity (cP at 20 degC) 0.7139 0.9256 1.185 1.503 1.880 2.335 2.863 3.474 Flash point (°C) 31 46 60 71 79 99 132 135 Autoignition temperature (°C) 205 210 205 235 201 Explosive limits 0.9–2.9% 0.8–2.6% 0.45–6.5%

### Heptadecane to tetracosane

From this group on, the n-alkanes are generally solid at standard conditions.

Heptadecane Octadecane Nonadecane Eicosane Heneicosane Docosane Tricosane Tetracosane Formula C17H36 C18H38 C19H40 C20H42 C21H44 C22H46 C23H48 C24H50 CAS number [629-78-7] [593-45-3] [629-92-5] [112-95-8] [629-94-7] [629-97-0] [638-67-5] [646-31-1] Molar mass (g/mol) 240.47 254.50 268.53 282.55 296.58 310.61 324.63 338.66 Melting point (°C) 21 28–30 32–34 36.7 40.5 42 48–50 52 Boiling point (°C) 302 317 330 342.7 356.5 224 at 2 kPaa 380 391.3 Density (g/ml) 0.777 0.777 0.786 0.7886 0.792 0.778 0.797 0.797 Flash point (°C) 148 166 168 176

a

### Pentacosane to triacontane

Pentacosane Hexacosane Heptacosane Octacosane Nonacosane Triacontane Formula C25H52 C26H54 C27H56 C28H58 C29H60 C30H62 CAS number [629-99-2] [630-01-3] [593-49-7] [630-02-4] [630-03-5] [638-68-6] Molar mass (g/mol) 352.69 366.71 380.74 394.77 408.80 422.82 Melting point (°C) 54 56.4 59.5 64.5 63.7 65.8 Boiling point (°C) 401 412.2 422 431.6 440.8 449.7 Density (g/ml) 0.801 0.778 0.780 0.807 0.808 0.810

### Hentriacontane to hexatriacontane

Hentriacontane Dotriacontane Tritriacontane Tetratriacontane Pentatriacontane Hexatriacontane Formula C31H64 C32H66 C33H68 C34H70 C35H72 C36H74 CAS number [630-04-6] [544-85-4] [630-05-7] [14167-59-0] [630-07-9] [630-06-8] Molar mass (g/mol) 436.85 450.88 464.90 478.93 492.96 506.98 Melting point (°C) 67.9 69 70–72 72.6 75 74–76 Boiling point (°C) 458 467 474 285.4 at 0.4 kPa 490 265 at 130 Pa Density (g/ml) 0.781 at 68 °C[14] 0.812 0.811 0.812 0.813 0.814

### Heptatriacontane to dotetracontane

Heptatriacontane Octatriacontane Nonatriacontane Tetracontane Hentetracontane Dotetracontane Formula C37H76 C38H78 C39H80 C40H82 C41H84 C42H86 CAS number [7194-84-5] [7194-85-6] [7194-86-7] [4181-95-7] [7194-87-8] [7098-20-6] Molar mass (g/mol) 520.99 535.03 549.05 563.08 577.11 591.13 Melting point (°C) 77 79 78 84 83 86 Boiling point (°C) 504.14 510.93 517.51 523.88 530.75 536.07 Density (g/ml) 0.815 0.816 0.817 0.817 0.818 0.819

### Tritetracontane to octatetracontane

Tritetracontane Tetratetracontane Pentatetracontane Hexatetracontane Heptatetracontane Octatetracontane Formula C43H88 C44H90 C45H92 C46H94 C47H96 C48H98 CAS number [7098-21-7] [7098-22-8] [7098-23-9] [7098-24-0] [7098-25-1] [7098-26-2] Molar mass (g/mol) 605.15 619.18 633.21 647.23 661.26 675.29 Boiling point (°C) 541.91 547.57 553.1 558.42 563.6 568.68 Density (g/ml) 0.82 0.82 0.821 0.822 0.822 0.823

### Nonatetracontane to tetrapentacontane

Nonatetracontane Pentacontane Henpentacontane Dopentacontane Tripentacontane Tetrapentacontane Formula C49H100 C50H102 C51H104 C52H106 C53H108 C54H110 CAS number [7098-27-3] [6596-40-3] [7667-76-7] [7719-79-1] [7719-80-4] [5856-66-6] Molar mass (g/mol) 689.32 703.34 717.37 731.39 745.42 759.45 Boiling point (°C) 573.6 578.4 583 587.6 592 596.38 Density (g/ml) 0.823 0.824 0.824 0.825 0.825 0.826

### Pentapentacontane to hexacontane

Pentapentacontane Hexapentacontane Heptapentacontane Octapentacontane Nonapentacontane Hexacontane Formula C55H112 C56H114 C57H116 C58H118 C59H120 C60H122 CAS number [5846-40-2] [7719-82-6] [5856-67-7] [7667-78-9] [7667-79-0] [7667-80-3] Molar mass (g/mol) 773.48 787.50 801.53 815.58 829.59 843.6 Boiling point (°C) 600.6 604.7 ? 612.6 ? 620.2 Density (g/ml) 0.826 0.826 ? 0.827 ? 0.827

## See also

- [Alkene](/source/Alkene)
- [Alkyne](/source/Alkyne)
- [Cycloalkane](/source/Cycloalkane)
- [Hydrocarbon](/source/Hydrocarbon)
- [Paraffin wax](/source/Paraffin_wax), composed mostly of higher linear alkanes
- [Polyethylene](/source/Polyethylene), a linear alkane of [polymeric](/source/Polymer) length

## References

1. Whitmore, Frank C.; Herr, C. H.; Clarke, D. G.; Rowland, C. S.; Schiessler, Robert W. (1945). "Higher Hydrocarbons. III.2 the Wolff-Kishner Reaction". *Journal of the American Chemical Society*. **67** (12): 2059–2061. [Bibcode:1945JAChS..67.2059W](https://ui.adsabs.harvard.edu/abs/1945JAChS..67.2059W). [doi:10.1021/ja01228a001](https://doi.org/10.1021/ja01228a001)

1. ["Higher alkanes"](https://www.wartsila.com/encyclopedia/term/higher-alkanes). *Wartsila.com*. Retrieved 2025-05-06.

1. Schmidt, Roland; Griesbaum, Karl; Behr, Arno; Biedenkapp, Dieter; Voges, Heinz-Werner; Garbe, Dorothea; Paetz, Christian; Collin, Gerd; Mayer, Dieter; Höke, Hartmut (2014). "Hydrocarbons". *Ullmann's Encyclopedia of Industrial Chemistry*. pp. 1–74. [doi:10.1002/14356007.a13_227.pub3](https://doi.org/10.1002/14356007.a13_227.pub3). ISBN 978-3-527-30673-2.

1. Silva, Maria do S. B. da; Araujo, Jhudson G. L. de; Bento, Júlia C. C. V.; Azevedo, Amanda M. de; Souto, Carlos R. O.; Anjos, Aécia S. D. dos; Araújo, Aruzza M. M. de; Silva, Djalma R. da; Menezes, Fabrício G.; Gondim, Amanda D.; Cavalcanti, Lívia N. (2022). "Nickel-catalyzed reductive decarboxylation of fatty acids for drop-in biofuel production". *RSC Advances*. **12** (43): 27889–27894. [Bibcode:2022RSCAd..1227889S](https://ui.adsabs.harvard.edu/abs/2022RSCAd..1227889S). [doi:10.1039/D2RA04057C](https://doi.org/10.1039/D2RA04057C). [PMC 9521194](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9521194). [PMID 36320252](https://pubmed.ncbi.nlm.nih.gov/36320252)

1. Poizot, Philippe; Jouikov, Viatcheslav; Simonet, Jacques (2009). "Glassy carbon modified by a silver–palladium alloy: Cheap and convenient cathodes for the selective reductive homocoupling of alkyl iodides". *Tetrahedron Letters*. **50** (7): 822–824. [doi:10.1016/j.tetlet.2008.12.008](https://doi.org/10.1016/j.tetlet.2008.12.008)

1. Schaerer, A. A.; Busso, C. J.; Smith, A. E.; Skinner, L. B. (1955). "Properties of Pure Normal Alkanes in the C17 to C36 Range". *Journal of the American Chemical Society*. **77** (7): 2017–2019. [Bibcode:1955JAChS..77.2017S](https://ui.adsabs.harvard.edu/abs/1955JAChS..77.2017S). [doi:10.1021/ja01612a097](https://doi.org/10.1021/ja01612a097)

1. Gruber, Hannes; Groß, Peter; Rauch, Reinhard; Reichhold, Alexander; Zweiler, Richard; Aichernig, Christian; Müller, Stefan; Ataimisch, Nabeel; Hofbauer, Hermann (December 2021). "Fischer-Tropsch products from biomass-derived syngas and renewable hydrogen". *Biomass Conversion and Biorefinery*. **11** (6): 2281–2292. [Bibcode:2021BioCB..11.2281G](https://ui.adsabs.harvard.edu/abs/2021BioCB..11.2281G). [doi:10.1007/s13399-019-00459-5](https://doi.org/10.1007/s13399-019-00459-5). [hdl:20.500.12708/730](https://hdl.handle.net/20.500.12708/730)

1. Hemptinne†, J.-L; Lognay, G.; Dixon, A.F.G (1998). "Mate recognition in the two-spot ladybird beetle, Adalia bipunctata: Role of chemical and behavioural cues". *Journal of Insect Physiology*. **44** (12): 1163–1171. [Bibcode:1998JInsP..44.1163H](https://ui.adsabs.harvard.edu/abs/1998JInsP..44.1163H). [doi:10.1016/s0022-1910(98)00081-x](https://doi.org/10.1016/s0022-1910(98)00081-x). [PMID 12770316](https://pubmed.ncbi.nlm.nih.gov/12770316)

1. Silk, Peter J.; Ryall, Krista; Barry Lyons, D.; Sweeney, Jon; Wu, Junping (2009). "A contact sex pheromone component of the emerald ash borer Agrilus planipennis Fairmaire (Coleoptera: Buprestidae)". *Naturwissenschaften*. **96** (5): 601–608. [Bibcode:2009NW.....96..601S](https://ui.adsabs.harvard.edu/abs/2009NW.....96..601S). [doi:10.1007/s00114-009-0513-1](https://doi.org/10.1007/s00114-009-0513-1). [PMID 19238346](https://pubmed.ncbi.nlm.nih.gov/19238346)

1. Hoover, Kelli; Keena, Melody; Nehme, Maya; Wang, Shifa; Meng, Peter; Zhang, Aijun (2014). "Sex-Specific Trail Pheromone Mediates Complex Mate Finding Behavior in Anoplophora glabripennis". *Journal of Chemical Ecology*. **40** (2): 169–180. [Bibcode:2014JCEco..40..169H](https://ui.adsabs.harvard.edu/abs/2014JCEco..40..169H). [doi:10.1007/s10886-014-0385-5](https://doi.org/10.1007/s10886-014-0385-5). [PMID 24510414](https://pubmed.ncbi.nlm.nih.gov/24510414)

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## External links

- [International Chemical Safety Card 1245](http://www.inchem.org/documents/icsc/icsc/eics1245.htm) (nonane)
- [NIOSH Pocket Guide to Chemical Hazards](https://www.cdc.gov/niosh/npg/npgd0466.html) (nonane)
- [International Chemical Safety Card 0428](http://www.inchem.org/documents/icsc/icsc/eics0428.htm) (decane)

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Adapted from the Wikipedia article [Higher alkane](https://en.wikipedia.org/wiki/Higher_alkane) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Higher_alkane?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.