Higher alkanes

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General structural formula of n -alkanes

As higher alkanes are alkanes referred whose longest chain of at least nine carbon atoms has.

use

As the number of carbon atoms increases , so does the viscosity of the substances, which is why they are hardly present in gasoline . Instead, alkanes with a chain length of up to 16 atoms ( hexadecane ) are the main components of diesel and kerosene . These are therefore also characterized by the cetane number , which is derived from the old name cetane for hexadecane. Due to the already high viscosity at room temperature, the use of these fuels at low temperatures and in cold regions is problematic.

Higher alkanes from hexadecane are the most important components of heating oil , heavy oil and many lubricating oils . The latter are often used as corrosion protection due to their hydrophobic properties . Since these alkanes are also often solid at room temperature, they are used in paraffin to make candles, for example.

Alkanes with a chain length of around 35 atoms and up are also used as a component of bitumen in road construction . Most of these alkanes, however, are broken down into lower alkanes by cracking , as these are of greater value in further processing.

Very long n -alkanes are used for research purposes, e.g. B. as model systems for polyethylene , synthetically produced. This can e.g. B. by oxidative coupling of α, ω-decadiyne with copper acetate and subsequent chromatographic separation of the oligomers. Another method starts with 12-chlorododecanal and doubles the chain length in several steps by repeated Wittig reaction with the educt protected as an acetal . Defined alkanes with up to 390 carbon atoms have been specifically synthesized in this way.

Physical Properties

Sum
formula		 CAS
number
 Molar mass
(g / mol)		 Melting
point (° C)		 Boiling
point (° C)		 Density
(g / ml)		 Viscosity
(mN s m −2 )
Nonane C 9 H 20 [111-84-2] 128.26 −54 151 0.72 0.713
Decane C 10 H 22 [124-18-5] 142.28 −30 174 0.73 0.928
Undecane C 11 H 24 [1120-21-4] 156.31 −26 196 0.74 1.186
Dodecane C 12 H 26 [112-40-3] 170.34 −10 216 0.75 1.508
Tridecane C 13 H 28 [629-50-5] 184.37 −5 235 0.76 1,883
Tetradecane C 14 H 30 [629-59-4] 198.39 6th 254 0.76 2.131
Pentadecane C 15 H 32 [629-62-9] 212.42 9 270 0.77 2.814
Hexadecane C 16 H 34 [544-76-3] 226.45 18th 287 0.77 3,591
Heptadecane C 17 H 36 [629-78-7] 240.47 21st 302 0.778
Octadecane C 18 H 38 [593-45-3] 254.50 28 316 0.777
Nonadecane C 19 H 40 [629-92-5] 268.53 32 330 0.786
Eicosan C 20 H 42 [112-95-8] 282.55 37 343 0.789
Heneicosan C 21 H 44 [629-94-7] 296.58 40 357 0.792
Docosane C 22 H 46 [629-97-0] 310.61 44 369 0.794
Tricosan C 23 H 48 [638-67-5] 324.63 48 380 0.779
Tetracosane C 24 H 50 [646-31-1] 338.66 50 391 0.799
Pentacosane C 25 H 52 [629-99-2] 352.69 54 402 0.801
Hexacosane C 26 H 54 [630-01-3] 366.71 56 412 0.778
Heptacosan C 27 H 56 [593-49-7] 380.74 59 422 0.780
Octacosane C 28 H 58 [630-02-4] 394.77 61 432 0.807
Nonacosan C 29 H 60 [630-03-5] 408.80 64 441 0.808
Triacontane C 30 H 62 [638-68-6] 422.82 65 452 0.810
Hentriacontane C 31 H 64 [630-04-6] 436.85 68 458 0.781
Dotriacontane C 32 H 66 [544-85-4] 450.88 69 467 0.812
Tritriacontane C 33 H 68 [630-05-7] 464.90 71
Tetratriacontane C 34 H 70 [14167-59-0] 478.93 72 481 0.773
Pentatriacontane C 35 H 72 [630-07-9] 492.96 75 490 0.816
Hexatriacontane C 36 H 74 [630-06-8] 506.98 76 496 0.780
Heptatriacontane C 37 H 76 [7194-84-5] 521.00 77 504
Octatriacontane C 38 H 78 [7194-85-6] 535.03 79  509
Nonatriacontane C 39 H 80 [7194-86-7] 549.05 80  
Tetracontane C 40 H 82 [4181-95-7] 563.08 82 522 0.817
Hentetracontan C 41 H 84 [7194-87-8] 577.11 81
Dotetracontan C 42 H 86 [7098-20-6] 591.13 83 534
Tritetracontan C 43 H 88 [7098-21-7] 605.16 85
Tetratetracontane C 44 H 90 [7098-22-8] 619.19 85-86 545
Hexatetracontane C 46 H 94 [7098-24-0] 647.24 88 556
Octatetracontane C 48 H 98 [7098-26-2] 675.29 88 566
Pentacontane C 50 H 102 [6596-40-3] 703.35 92 575
Hexacontane C 60 H 122 [7667-80-3] 843.61 615
  1. ↑ at 20 ° C
  2. ↑ at 22 ° C
  3. ↑ at 22 ° C
  4. ↑ at 22 ° C
  5. ↑ For Eicosan, the substance names Icosan or Eikosan are still used in the Beilstein and CAS index.
  6. ↑ at 48 ° C
  7. ↑ at 60 ° C
  8. ↑ at 60 ° C
  9. ↑ at 68 ° C
  10. ↑ at 90 ° C
  11. ↑ at 80 ° C

Safety-related parameters

For the higher n -alkanes still present as liquids at room temperature , safety-related parameters have been determined. As the chain length of the n- alkanes increases and the vapor pressure decreases, the flash point rises. The expansion of the explosion area results from the fact that with increasing chain length it is only reached at higher temperatures. No trend can be derived for the ignition temperatures.

Nonane to hexadecane

Nonane Decane Undecane Dodecane Tridecane Tetradecane Pentadecane Hexadecane
Molecular formula C 9 H 20 C 10 H 22 C 11 H 24 C 12 H 26 C 13 H 28 C 14 H 30 C 15 H 32 C 16 H 34
Flash point ° C 31 46 61 80 85-95 110 122 133
Lower explosion limit (LEL) Vol .-% 0.7 0.7 0.6 0.6 0.6 0.5 0.45 0.4
g m −3 37 41 42 40
Upper explosion limit (UEL) Vol .-% 5.6 5.4 6.5 6.5 6.5 6.5 6.5
g m −3 300 320 425
Ignition temperature ° C 205 200 195 200 220 200 220 215
Temperature class T3 T4 T4 T4 T3 T4 T3 T3

See also

proof

  1. ↑ Gerald M. Brooke, Simon Burnett, Shahid Mohammed, David Proctor, Mark C. Whiting: A versatile process for the syntheses of very long chain alkanes, functionalized derivatives and some branched chain hydrocarbons. In: J. Chem. Soc., Perkin Trans. 1, No. 13, 1996, pp. 1635-1645, doi: 10.1039 / P19960001635 .
  2. ↑ a b Entry for CAS no. 111-84-2 in the GESTIS substance database of the IFA , accessed on April 16, 2018(JavaScript required) .
  3. ↑ a b c d e f g h George W. Gokel: Dean's Handbook of Organic Chemistry. 2nd Edition. McGraw-Hill, 2004, ISBN 0-07-137593-7 , pp. 4.57-4.93.
  4. ↑ a b Entry for CAS no. 124-18-5 in the GESTIS substance database of the IFA , accessed on April 16, 2018(JavaScript required) .
  5. ↑ a b Entry for CAS no. 1120-21-4 in the GESTIS substance database of the IFA , accessed on April 16, 2018(JavaScript required) .
  6. ↑ a b Entry for CAS no. 112-40-3 in the GESTIS substance database of the IFA , accessed on April 16, 2018(JavaScript required) .
  7. ↑ a b Entry for CAS no. 629-50-5 in the GESTIS substance database of the IFA , accessed on April 16, 2018(JavaScript required) .
  8. ↑ a b Entry for CAS no. 629-59-4 in the GESTIS substance database of the IFA , accessed on April 16, 2018(JavaScript required) .
  9. ↑ a b Entry for CAS no. 629-62-9 in the GESTIS substance database of the IFA , accessed on November 16, 2015(JavaScript required) .
  10. ↑ a b Entry for CAS no. 544-76-3 in the GESTIS substance database of the IFA , accessed on November 16, 2015(JavaScript required) .
  11. ↑ a b c d e f g h i j k l m n o p q r s t u v David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 88th edition. (Internet version: 2008), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-1 - 3-523.
  12. ↑ a b c d e f g h i DIN EN 15199-1: 2006 - Gas chromatographic determination of the boiling curve - Part 1: Middle distillates and base oils
  13. ^ CC Buchler, GD Graves: Ind. Eng. Chem. 19, 1927, p. 718.
  14. ^ A b c C. L. Yaws: Thermophysical Properties of Chemicals and Hydrocarbons. 2nd Edition. Elsevier 2008, ISBN 978-0-8155-1596-8 , p. 94.
  15. ↑ a b c David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 88th edition. (Internet version: 2008), CRC Press / Taylor and Francis, Boca Raton, FL, Enthalpy of Fusion, pp. 6-115-6-119.
  16. ↑ H. Yamamoto, N. Nemoto, K. Tashiro: Crystal Structure of 20-Methyl-Nonatriacontane ((C 19 H 39 ) 2 CHCH 3 ) and Its Compatibility with Nonatriacontane (C 39 H 80 ). In: J. Phys. Chem. B 108, 2004, pp. 5827-5835, doi: 10.1021 / jp035629d .
  17. ^ A b W. F. Seyer, RF Patterson, JL Keays: The Density and Transition Points of the n-Paraffin Hydrocarbons. In: J. Am. Chem. Soc. 46, 1944, pp. 179-182.
  18. ↑ World Cup Mazee: Some properties of hydrocarbons having more than twenty carbon atom. In: Recl. Trav. Chim. Pays-Bas. 67, 1948, pp. 197-213.
  19. ↑ J.–P. Gorce, SJ Spells, X. -B. Zeng, G. Ungar: J. Phys. Chem. B. 108, 2004, pp. 3130-3139.
  20. ↑ S. Geiger-Berschandy: Bull. Soc. Chim. Fr. 1955, p. 994.
  21. ^ R. Lukes, S. Dolezal: The Action of Grignard Reagents on the Amide Group XXI. Synthesis of Some Higher Monocarboxylic Acids. In: Chem. Listy. 51, 1957, p. 2065.