Wax acids

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The wax acids are mostly long-chain, saturated fatty acids with ≥ 22 carbon atoms, which are the typical components of waxes . They form a subgroup of the unbranched alkanoic acids . The boundary between fatty acids and wax acids is fluid. It is set at the number of carbon atoms of 22, i.e. starting with behenic acid  (C 22 H 44 O 2 / C 21 H 43 COOH). Both even and odd numbers of carbon are possible.

The wax acids actually also include shorter-chain fatty acids z. B. the saturated hydroxy acids sabinic acid and juniperic acid which occur in the leaf waxes of conifers, and thapsic acid , a dicarboxylic acid found in thapsia resin ( Thapsia garganica ).

Wax acids from C 22
Number of carbon atoms: double bonds Common name Chemical name Gross formula Occurrence Melting point boiling point
22: 0 Behenic acid Docosanoic acid C 21 H 43 COOH in small amounts in plant seeds and animal fats, wool fat , carnauba wax and montan wax 79.5-80.5  ° C 306 ° C (50 torr)
23: 0 Tricosanoic acid C 22 H 45 COOH Plant lipids 77-79 ° C
24: 0 Lignoceric acid Tetracosanoic acid C 23 H 47 COOH some bark waxes , tall oil , carnauba wax, various vegetable oils, part of the sphingomyeline 81.5-84.5 ° C
25: 0 Pentacosanoic acid C 24 H 49 COOH Montan wax, beeswax 82.5-84.5 ° C
26: 0 Cerotic acid Hexacosanoic acid C 25 H 51 COOH Beeswax, carnauba wax, montan wax, wool sweat 88.5 ° C -
27: 0 Carboceric acid Heptacosanoic acid C 26 H 53 COOH Montan wax , peat wax , china wax 82 ° C; 87.6 ° C
28: 0 Montanic acid Octacosanoic acid C 27 H 55 COOH Montan wax, beeswax and china wax 90.9 ° C -
29: 0 Nonacosanoic acid C 28 H 57 COOH Montan wax, peat wax 90.3 ° C
30: 0 Melissic acid Triacontanoic acid C 29 H 59 COOH Selinum , Trichosanthes and Pericampylus species, beeswax and montan wax 93.6 ° C -
31: 0 Hentriacontanoic acid C 30 H 61 COOH Leaf waxes 93.1 ° C
32-0 Laccic acid Dotriacontanoic acid C 31 H 63 COOH Stick varnish , wool fat, montan wax, leaf wax 96 ° C
33: 0 Psylic acid Tritriacontanoic acid C 32 H 65 COOH Psylla wax (alder leaf flea Psylla alni ), propolis from bees and bumblebees 96.5 ° C
34: 0 Geddic acid Tetratriacontanoic acid C 33 H 67 COOH Cotton , carnauba, candelilla wax , Geddah wax  (wild bees wax ) 98.4 ° C

Carnaubic acid is also found in the literature (24: 0), but the constitution is indefinite, whereas the melting point of 72.5 ° C seems to be roughly clear. It is sometimes equated with the isomer, lignoceric acid (24: 0), but this is unlikely due to the vastly different melting point. It seems very likely that the carnaubic acid is not a fatty acid in its own right, but samples of lignoceric acid which are contaminated with other acids.

See also

Individual evidence

  1. ↑ a b K. Boresch, F. Dühring u. a .: Plant nutrition. Springer, 1931, ISBN 978-3-642-98786-1 (reprint), p. 91.
  2. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 92nd edition. (Internet version: 2011), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-236.
  3. ^ A b Walter Karrer : Constitution and occurrence of organic plant substances. Springer, 1958, ISBN 978-3-0348-6808-2 (reprint), p. 294 f.
  4. ↑ a b c d e f g David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-4 - 3-523.
  5. ^ A b c d Albin H. Warth: The Chemistry and Technology of Waxes. Second Edition, Reinhold Publ., 1956, p. 34 f, online at babel.hathitrust.org, accessed on November 1, 2017.
  6. ^ JE Gieseking: Soil Components. Volume 1: Organic Components , Springer, 1975, ISBN 978-3-540-06861-7 .
  7. ^ A b J. Buckingham: Dictionary of Organic Compounds. Vol. 4: F-Mer , Sixth Edition, Chapman & Hall, 1996, ISBN 0-412-54090-8 , pp. 3391, 3395.
  8. ↑ a b c David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 93rd edition. (Internet version: 2012), CRC Press / Taylor and Francis, Boca Raton, FL, Biochemistry, pp. 7-8.
  9. ↑ Raymond E. Kirk, Donald F. Othmer: Encyclopedia of Chemical Technology. Vol. 6, 1951, p. 258.
  10. ^ John Buckingham: Dictionary of Natural Products . CRC Press, 1993, pp. 1957 ( limited preview in Google Book Search).
  11. ^ John Buckingham: Dictionary of Natural Products. Supplement 4, Chapman & Hall, 1998, ISBN 0-412-60440-X , p. 336.
  12. ↑ Derek Marsh: Handbook of Lipid Bilayers, Second Edition . CRC Press, 2013, pp. 36 ( limited preview in Google Book search).
  13. ↑ Emil Abderhalden (Ed.): Biochemisches Handlexikon. 1st volume, 2nd half, Springer, 1911, ISBN 978-3-642-88963-9 , p. 1018.

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