The alkanes form a group of hydrocarbon compounds with straight or branched chain, saturated, non-cyclic (acyclic) and non-aromatic (aliphatic) carbon chains. The general formula of alkanes is CnH2n+2 where n = number of carbon atoms.
Unterschieden werden:
n-alkanes:
n-alkanes or normal alkanes form a homologous series of organic chemical compounds with linear (straight-chain, unbranched) linked carbon atoms that differ in the number of CH2 units:
Paraffins:
The paraffins consist of single or mixed alkanes with 18 or more carbon atoms. Depending on the number of carbon atoms, the paraffins are liquid, viscous or solid masses with increasing melting and boiling points.
Cycloalkanes:
The cyclic alkanes or cycloalkanes represent a special group of hydrocarbons in which the carbon chains are arranged in a ring.
Properties of n-alkanes
The table below shows some properties of the unbranched alkanes or n-alkanes:
| n-Alkane | Formula | Molecular Mass [g mol-1] | Melting Point [°C] | Boiling Point [°C] | Density at 20 °C [g cm-3] | Flash Point [°C] | Ignition Point [°C] | CAS [PubChem] |
|---|---|---|---|---|---|---|---|---|
| Methane | CH4 | 16.04 | - 182.48 | - 161.49 | gaseous | - | - | 74-82-8 [297] |
| Ethane | C2H6 | 30.07 | - 183.27 | - 88.63 | gaseous | - | - | 74-84-0 [6324] |
| Propane | C3H8 | 44.10 | - 187.69 | - 42.07 | gaseous | - | - | 74-98-6 [6334] |
| Butane | C4H10 | 58.12 | - 138.35 | - 0.50 | gaseous | - | - | 106-97-8 [7843] |
| Pentane | C5H12 | 72.15 | - 129.72 | 36.07 | 0.626 | - | - | 109-66-0 [8003] |
| Hexane | C6H14 | 86.18 | - 95.35 | 68.74 | 0.659 | - | - | 110-54-3 [8058] |
| Heptan | C7H16 | 100.21 | - 90.55 | 98.38 | 0.679 | -7 | 220 | 142-82-5 [8900] |
| Octane | C8H18 | 114.23 | - 56.80 | 125.67 | 0.703 | 12 | 205 | 111-65-9 [356] |
| Nonane | C9H20 | 128.26 | - 53.52 | 150.80 | 0.718 | 31 | 205 | 111-84-2 [8141] |
| Decane | C10H22 | 142.29 | - 29.66 | 174.12 | 0.730 | 46 | 210 | 124-18-5 [15600] |
| Undecane | C11H24 | 156.31 | - 25.60 | 195.89 | 0.740 | 62 | - | 1120-21-4 [14257] |
| Dodecane | C12H26 | 170.34 | - 9.60 | 216.30 | 0.749 | 71 | 205 | 112-40-3 [8182] |
| Tridecane | C13H28 | 184.37 | - 5.39 | 235.43 | 0.756 | 79 | 220 | 629-50-5 [12388] |
| Tetradecane | C14H30 | 198.39 | 5.86 | 253.52 | 0.763 | 99 | 235 | 629-59-4 [12389] |
| Pentadecane | C15H32 | 212.42 | 9.93 | 270.61 | 0.768 | 132 | 200 | 629-62-9 [12391] |
| Hexadecane | C16H34 | 226.45 | 18.17 | 286.80 | 0.773 | 135 | 215 | 544-76-3 [11006] |
| Heptadecane | C17H36 | 240.47 | 21.98 | 302.15 | 0.778 | 149 | - | 629-78-7 [12398] |
| Octadecane | C18H38 | 254.50 | 28.18 | 316.71 | 0.782 | 154 | - | 593-45-3 [11635] |
| Nonadecane | C19H40 | 268.53 | 31.90 | 330.6 | 0.785 | 168 | - | 629-92-5 [12401] |
| Icosane Eicosane | C20H42 | 282.55 | 36.7 | 342.7 | 0.789 | 176 | 202 | 112-95-8 [8222] |
| Heneicosane | C21H44 | 296.58 | 40.5 | 356.1 | 0.792 | 110 | - | 629-94-7 [12403] |
| Docosane | C22H46 | 310.61 | 43.8 | 368.6 | 0.794 | 113 | - | 629-97-0 [12405] |
| Tricosane | C23H48 | 324.63 | 47.4 | 380 | 0.797 | 113 | - | 638-67-5 [12534] |
| Tetracosane | C24H50 | 338.66 | 50.3 | 391.3 | 0.799 | 113 | - | 646-31-1 [12592] |
| Pentacosane | C25H52 | 352.69 | 53.3 | 401.9 | 0.801 | 120 | - | 629-99-2 [12406] |
| Hexacosane | C26H54 | 366.71 | 56.4 | 412.2 | 0.803 | - | - | 630-01-3 [12407] |
| Heptacosane | C27H56 | 380.74 | 59.5 | 428.05 | 0.780 | - | - | 593-49-7 [11636] |
| Octacosane | C28H58 | 394.77 | 61.3 | 431.6 | 0.807 | - | - | 630-02-4 [12408] |
| Nonacosane | C29H60 | 408.80 | 63.7 | 440.8 | 0.808 | - | - | 630-03-5 [12409] |
| Triacontane | C30H62 | 422.82 | 65.8 | 449.7 | 0.810 | - | - | 638-68-6 [12535] |
| Hentriacontane | C31H64 | 436.85 | 67.9 | 458 | - | - | - | 630-04-6 [12410] |
| Dotriacontane | C32H66 | 450.88 | 69.7 | 467 | 0.812 | - | - | 544-85-4 [11008] |
| Tritriacontane | C33H68 | 464.90 | 71 | 474 | 0.811 | - | - | 630-05-7 [12411] |
| Tetratriacontane | C34H70 | 478.93 | 72.6 | - | 0.812 | - | - | 14167-59-0 [26519] |
| Pentatriacontane | C35H72 | 492.96 | 75 | 490 | 0.813 | - | - | 630-07-9 [12413] |
| Hexatriacontane | C36H74 | 506.98 | 76 | - | 0.814 | - | - | 630-06-8 [12412] |
| Heptatriacontane | C37H76 | 520.99 | 77 | 504.14 | 0.815 | - | - | 7194-84-5 [23598] |
| Octatriacontane | C38H78 | 535.03 | 79 | 510.93 | 0.816 | - | - | 7194-85-6 [23599] |
| Nonatriacontane | C39H80 | 549.05 | 82 | 517.51 | 0.817 | - | - | 7194-86-7 [114842] |
| Tetracontane | C40H82 | 563.08 | 84 | 523.88 | 0.817 | - | - | 4181-95-7 [20149] |
| Hentetracontane | C41H84 | 577.11 | 85 | 530.75 | 0.818 | - | - | 7194-87-8 [81613] |
| Dotetracontane | C42H86 | 591.13 | 86 | 536.07 | 0.819 | - | - | 7098-20-6 [123244] |
| Tritetracontan | C43H88 | 605.15 | - | 541.91 | 0.82 | - | - | 7098-21-7 [522398] |
| Tetratetracontane | C44H90 | 619.18 | - | 547.57 | 0.82 | - | - | 7098-22-8 [23494] |
| Pentatetracontane | C45H92 | 633.21 | - | 553.1 | 0.821 | - | - | 7098-23-9 [14598280] |
| Hexatetracontane | C46H94 | 647.23 | - | 558.42 | 0.822 | - | - | 7098-24-0 [522399] |
| Heptatetracontane | C47H96 | 661.26 | - | 563.6 | 0.822 | - | - | 7098-25-1 [15043573] |
| Octatetracontane | C48H98 | 675.29 | - | 568.68 | 0.823 | - | - | 7098-26-2 [138925] |
| Nonatetracontane | C49H100 | 689.32 | - | 573.6 | 0.823 | - | - | 7098-27-3 [15043574] |
| Pentacontane | C50H102 | 703.34 | - | 578.4 | 0.824 | - | - | 6596-40-3 [81067] |
| Henpentacontane | C51H104 | 717.37 | - | 583 | 0.824 | - | - | 7667-76-7 [15043575] |
| Dopentacontane | C52H106 | 731.39 | - | 587.6 | 0.825 | - | - | 7719-79-1 [522643] |
| Tripentacontane | C53H108 | 745.42 | - | 592 | 0.825 | - | - | 7719-80-4 [15043576] |
| Tetrapentacontane | C54H110 | 759.45 | - | 596.38 | 0.826 | - | - | 5856-66-6 [521846] |
Category: compound classes
Literature sources and further information:
[1] - NN:
Alkanes.
In: IUPAC Gold Book, DOI 10.1351/goldbook.A00222.
Last update: 04 November 2022
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