Higher alkanes

Short description: Alkanes having nine or more carbon atoms

Higher alkanes are alkanes having nine or more carbon atoms. Nonane is the lightest alkane to have a flash point above 25 °C, and is not classified as dangerously flammable.

The term higher alkanes is sometimes used literally as "alkanes with a higher number of carbon atoms". One definition distinguishes the higher alkanes as the n-alkanes that are solid under natural conditions.[who?]

## Contents

* 1 Uses
* 2 Names
* 3 Properties
* 3.1 Nonane to hexadecane
* 3.2 Heptadecane to tetracosane
* 3.3 Pentacosane to triacontane
* 3.4 Hentriacontane to hexatriacontane
* 3.5 Heptatriacontane to dotetracontane
* 3.6 Tritetracontane to octatetracontane
* 3.7 Nonatetracontane to tetrapentacontane
* 4 See also
* 5 References
* 6 External links

## Uses

Alkanes from nonane to hexadecane (those alkanes with nine to sixteen carbon atoms) are liquids of higher viscosity, which are less suitable for use in gasoline. They form instead the major part of diesel and aviation fuel. Diesel fuels are characterised by their 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, where the fuel becomes too thick to flow correctly. Mixtures of the normal alkanes are used as boiling point standards for simulated distillation by gas chromatography.[1]

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

Alkanes with a chain length of approximately 35 or more carbon atoms are found in bitumen (asphalt), used (for example) in road surfacing. However, the higher alkanes have little value and are usually split into lower alkanes by cracking.

## Names

Some alkanes have non-IUPAC trivial names:

* cetane, for hexadecane
* cerane, for hexacosane[2]

## Properties

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

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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 °C)  | 0.71763  | 0.73005  | 0.74024  | 0.74869  | 0.75622  | 0.76275  | 0.76830  | 0.77344
Viscosity (cP at 20 °C)  | 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 | Icosane | Heneicosane | Docosane  | Tricosane  | Tetracosane

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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 kPa  | 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  |  |  |  |

### Pentacosane to triacontane

| Pentacosane  | Hexacosane  | Heptacosane  | Octacosane  | Nonacosane | Triacontane

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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

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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[4] | 0.812  | 0.811  | 0.812  | 0.813  | 0.814

### Heptatriacontane to dotetracontane

| Heptatriacontane  | Octatriacontane  | Nonatriacontane  | Tetracontane  | Hentetracontane  | Dotetracontane

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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

| Triatetracontane  | Tetratetracontane  | Pentatetracontane  | Hexatetracontane  | Heptatetracontane  | Octatetracontane

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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

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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

## See also

* Alkene
* Alkyne
* Cycloalkane
* Hydrocarbon
* Paraffin wax, composed mostly of higher linear alkanes
* Polyethylene, a linear alkane of polymeric length

## References

1. ↑ ASTM D5399-09, Standard Test Method for Boiling Point Distribution of Hydrocarbon Solvents by Gas Chromatography
2. ↑ Donald Mackay, Handbook of Physical-Chemical Properties and Environmental Fate for Organic Chemicals, ISBN 1420044397, p. 206
3. ↑ Karl Griesbaum, Arno Behr, Dieter Biedenkapp, Heinz-Werner Voges, Dorothea Garbe, Christian Paetz, Gerd Collin, Dieter Mayer Hartmut Höke "Hydrocarbons" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. doi: 10.1002/14356007.a13_227
4. ↑ Weast, Robert C., ed (1982). CRC Handbook of Chemistry and Physics (63rd ed.). Boca Raton, Fl: CRC Press. p. C-561.

## External links

| Wikimedia Commons has media related to Higher alkanes.

|

* International Chemical Safety Card 1245 (nonane)
* NIOSH Pocket Guide to Chemical Hazards (nonane)
* International Chemical Safety Card 0428 (decane)

* 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)
* Icosane (C20H42)
* Heneicosane (C21H44)
* Tetracosane (C24H50)
* Nonacosane (C29H60)
* Hentriacontane (C31H64)

* Higher alkanes
* List of alkanes

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