Fatty Acids

Authored by: Marsh Derek

Handbook of Lipid Bilayers

Print publication date:  February  2013
Online publication date:  February  2013

Print ISBN: 9781420088328
eBook ISBN: 9781420088335
Adobe ISBN:

10.1201/9781420088335-4

 

Abstract

The melting points, Tm , and melting enthalpies, ΔHm , of saturated fatty acids display an odd-even alternation that arises from differences in packing of the terminal parts of the molecule in the crystalline phase.

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Fatty Acids

I.3.1  Melting Temperatures, Enthalpies, and Entropies

The melting points, Tm , and melting enthalpies, ΔHm , of saturated fatty acids display an odd-even alternation that arises from differences in packing of the terminal parts of the molecule in the crystalline phase.

 

The melting enthalpies (and entropies, ΔSm = ΔHm /Tm ) of normal saturated fatty acids increase linearly with chain length, n. The incremental values (ΔHinc and ΔSinc ), per CH2 group, are almost equal for odd and even chain lengths (4.1–4.3 kJ.mol−1/CH2), but the overall intercept, ΔHo , is approximately 5 kJ.mol−1 greater for the even chain lengths than for the odd chain lengths.

  Incremental Melting Enthalpies and Entropies

n:0 normal fatty acids

chains

n

ΔH inc /kJ.mol−1/CH2 (kcal.mol−1/CH2)

ΔH o /kJ.mol−1 (kcal.mol−1)

ΔS inc /J.mol−1.K−1/CH2 (cal.mol−1.K−1/CH2)

ΔS o /J.mol−1.K−1 (cal.mol−1.K−1)

even

10–24

4.28±0.04(1.02±0.01)

−14.7±0.8(3.5±0.2)

11.0±0.2(2.63±0.04)

−16.5 ± 2.7(3.9±0.6)

odd

11–25

4.09±0.08(0.98±0.02)

−19.4±1.4−(4.6±0.3)

10.5±0.3(2.51±0.006)

−29.5±4.9−(7.1±1.2)

Note: ΔHm = ΔHinc × n + ΔHo

ΔSm = ΔSinc × n + ΔSo

Interestingly, the fatty acids of odd chain lengths undergo a crystalline polymorphic transition below the melting point with an enthalpy that is approximately equal to the difference in melting enthalpies of the odd and even chain lengths (6.0±1.2 kJ.mol−1, n = 9 – 25, see, e.g., ref. [1]).

The melting temperatures of the normal saturated (n:0) fatty acids increase with increasing chain length for both odd and even n. This is seen also for the methylisobranched (in:0) and anteisobranched (ain:0) fatty acids.

 

At long chain lengths, the melting points tend to a limiting value, when the end contributions to the melting enthalpy and entropy become a negligible fraction of the whole. The chain-length dependence, assuming a linear n-dependence of ΔHm and ΔSm is given by (see Section II.12.1 and ref. [2]):

T m = T m ( 1 Δ n n n s )

where T m

is the melting temperature extrapolated to infinite chain length, ns is the chain length at which the melting entropy extrapolates to zero and Δn is the increase in this quantity for the melting enthalpy.

  Chain-Length Dependence of Melting Temperatures

n:0 normal, in:0 isobranched and ain:0 anteisobranched fatty acids

chains

n

T m ( K )

Δn

n s

n:0 even

6–38

418.6±2.0

4.45±0.17

−6.48±0.40

n:0 odd

5–35

424.4±2.2

4.97±0.18

−6.31±0.36

in:0 even

12–28

397.7±1.1

2.45±0.09

0.31±0.34

ain:0 odd

13–31

398.3±8.2

3.29±0.60

2.03±1.55

The melting points of unsaturated fatty acids are lower than those of the saturated counterparts of equal chain length. The decrease is greater for cis-unsaturated than for trans-unsaturated fatty acids and depends on the position of the double bond:

 

Both this and the odd-even alternation with double-bond position, as well as the cis-trans differences, are again related to differences in packing of the unsaturated fatty acids in the crystalline state.

I.3.2  Formulae, Molecular Weights, Melting Points, and Calorimet-Ric Properties

This list was originally adapted from a compilation in the CRC Handbook of Biochemistry and Molecular Biology, Lipids, Carbohydrates, and Steroids, 3rd ed. (Fasman, G. D., Ed.) and in Markley, K.S. (1964) Biology Data Book, pp. 370-380, which should be consulted for data on other physical and chemical characteristics of fatty acids. Data are now modified and extended from other sources.

I.3.2.1  Saturated Fatty Acids

acid

chemical formula

molecular weight

(exact mass

melting point (°C)

enthalpy, ΔH m a

entropy, ΔS m a

symbol

systematic name

common name

 

 

 

 

(kJ.mol−1)

(kcal.mol−1)

(J.mol−1 K−1)

(cal.mol−1 K−1)

1:0

methanoic

formic

HCOOH

46.03

(46.005)

8.4

10.54

2.52

37.45

8.95

2:0

ethanoic

acetic

CH3COOH

60.05

(60.021)

16.7

11.59

2.77

39.99

9.56

3:0

propanoic

propionic

C2H5COOH

74.08

(74.037)

−22

9.46

2.26

37.65

9.00

4:0

butanoic

butyric

C3H7COOH

88.11

(88.052)

−7.9

11.05

2.64

41.64

9.95

5:0

pentanoic

valeric

C4H9COOH

102.13

(102.068)

−34.5

 

 

 

 

6:0

hexanoic

caproic

C5H11COOH

116.16

(116.084)

−3.4

15.06

3.60

55.84

13.35

7:0

heptanoic

heptylic

C6H13COOH

130.18

(130.099)

−10.5

14.98

3.58

57.03

13.63

8:0

octanoic

caprylic

C7H15COOH

144.21

(144.115)

16.7

21.38

5.11

73.76

17.63

9:0

nonanoic

pelargonic

C8H17COOH

158.24

(158.131)

12.5

20.29

4.85

71.04

16.98

10:0

decanoic

capric

C9H19COOH

172.26

(172.146)

31.6

28.03

6.70

91.99

21.99

11:0

undecanoic

undecylic

C10H21COOH

186.29

(186.162)

29.3

25.06

5.99

82.86

19.80

12:0

dodecanoic

lauric

C11H23COOH

200.32

(200.178)

44.2

36.61

8.75

115.36

27.57

13:0

tridecanoic

tridecylic

C12H25COOH

214.34

(214.193)

41.5

33.56

8.02

106.64

25.49

14:0

tetradecanoic

myristic

C13H27COOH

228.37

(228.209)

53.9

44.77

10.70

136.89

32.72

15:0

pentadecanoic

pentadecylic

C14H29COOH

242.40

(242.225)

52.3

43.10

10.30

132.42

31.65

16:0

hexadecanoic

palmitic

C15H31COOH

256.42

(256.240)

63.1

54.39

13.0

161.76

38.66

17:0

heptadecanoic

margaric

C16H33COOH

270.45

(270.256)

61.3

51.04

12.2

152.62

36.48

18:0

octadecanoic

stearic

C17H35COOH

284.48

(284.272)

69.6

63.18

15.1

184.33

44.06

19:0

nonadecanoic

nonadecylic

C18H37COOH

298.50

(298.287)

68.6

57.74

13.8

168.95

40.38

20:0

icosanoic

arachidic

C19H39COOH

312.53

(312.303)

75.4

70.92

16.95

203.47

48.63

21:0

henicosanoic

-

C20H41COOH

326.56

(326.318)

74.3

 

 

 

 

22:0

docosanoic

behenic

C21H43COOH

340.58

(340.334)

80.0

78.66

18.8

222.74

53.24

23:0

tricosanoic

-

C22H45COOH

354.61

(354.350)

79.1

73.64

17.60

209.05

49.96

24:0

tetracosanoic

lignoceric

C23H47COOH

368.64

(368.365)

84.2

88.28

21.1

247.05

59.05

25:0

pentacosanoic

 

C24H49COOH

382.66

(382.381)

83.5

83.68

20.00

234.63

56.08

26:0

hexacosanoic

cerotic

C25H51COOH

396.69

(396.397)

88.5

 

 

 

 

27:0

heptacosanoic

carboceric

C26H53COOH

410.72

(410.412)

87.7

 

 

 

 

28:0

octacosanoic

montanic

C27H55COOH

424.74

(424.428)

90.9

 

 

 

 

29:0

nonacosanoic

-

C28H57COOH

438.77

(438.444)

90.3

 

 

 

 

30:0

triacontanoic

melissic

C29H59COOH

452.80

(452.459)

93.6

 

 

 

 

31:0

hentriacontanoic

-

C30H61COOH

466.82

(466.475)

93.1

 

 

 

 

32:0

dotriacontanoic

lacceric

C31H63COOH

480.85

(480.491)

96.2

 

 

 

 

33:0

tritriacontanoic

 

C32H65COOH

494.88

(494.506)

 

 

 

 

 

34:0

tetratriacontanoic

gheddic

C33H67COOH

508.90

(508.522)

98.4

 

 

 

 

35:0

pentatriacontanoic

ceroplastic

C34H69COOH

522.93

(522.538)

98.4

 

 

 

 

36:0

hexatriacontanoic

-

C35H71COOH

536.96

(536.553)

99.9

 

 

 

 

Notes:

a   ΔHm = melting enthalpy, ΔSm = melting entropy. For sources of enthalpies, see refs. [3; 4].

I.3.2.2  Monoenoic Unsaturated Fatty Acids

acid

chemical formula

molecular weight

(exact mass)

melting point (°C)

symbol

systematic name

common name

 

 

 

 

4:1tΔ 2

2E-butenoic

crotonic

C4H6O2

86.09

(86.037)

72.0

4:1cΔ 2

2Z-butenoic

isocrotonic

C4H6O2

86.09

(86.037)

14.5

5:1cΔ 2

2Z-pentenoic

β-ethylacrylic

C5H8O2

100.12

(100.052)

8

5:1Δ 4

4Z-pentenoic

allylacetic

C5H8O2

100.12

(100.052)

−18

6:1cΔ 2

2Z-hexenoic

isohydrosorbic

C6H10O2

114.14

(114.068)

32

6:1cΔ 3

3Z-hexenoic

hydrosorbic

C6H10O2

114.14

(114.068)

12

6:1cΔ 4

4Z-hexenoic

γ-hexenoic

C6H10O2

114.14

(114.068)

10

7:1cΔ 3

3Z-heptenoic

β-heptenoic

C7H12O2

128.17

(128.084)

−12

7:1Δ6

6Z-heptenoic

-heptenoic

C7H12O2

128.17

(128.084)

−6.5

8:1cΔ 3

3Z-octenoic

cis-β-octenoic

C8H14O2

142.20

(142.099)

−25

8:1tΔ 3

3E-octenoic

trans-β-octenoic

C8H14O2

142.20

(142.099)

1

8:1cΔ 4

4Z-octenoic

γ-octenoic

C8H14O2

142.20

(142.099)

−35

8:1cΔ6

6Z-octenoic

cis--octenoic

C8H14O2

142.20

(142.099)

−17

8:1tΔ6

6E-octenoic

trans--octenoic

C8H14O2

142.20

(142.099)

6

9:1cΔ 2

2Z-nonenoic

α-nonylenic

C9H16O2

156.22

(156.115)

4

9:1cΔ8

8Z-nonenoic

8-nonylenic

C9H16O2

156.22

(156.115)

5

10:1cΔ 2

2Z-decenoic

2-decylenic

C10H18O2

170.25

(170.131)

12

10:1cΔ 3

3Z-decenoic

3-decylenic

C10H18O2

170.25

(170.131)

18

10:1cΔ 4

4Z-decenoic

obtusilic

C10H18O2

170.25

(170.131)

-

10:1Δ9

9Z-decenoic

caproleic

C10H18O2

170.25

(170.131)

26.5

11:1cΔ9

9Z-undecenoic

9-undecylenic

C11H20O2

184.28

(184.146)

11.4

11:1Δ10

10Z-undecenoic

10-undecylenic

C11H20O2

184.28

(184.146)

24.5

12:1cΔ 2

2Z-dodecenoic

2-lauroleic

C12H22O2

198.30

(198.162)

17

12:1cΔ 4

4Z-dodecenoic

linderic

C12H22O2

198.30

(198.162)

1.0–1.3

12:1cΔ5

5Z-dodecenoic

denticetic

C12H22O2

198.30

(198.162)

-

12:1cΔ9

9Z-dodecenoic

lauroleic

C12H22O2

198.30

(198.162)

-

12:1cΔ10

10Z-dodecenoic

-

C12H22O2

198.30

(198.162)

18

12:1Δ11

11Z-dodecenoic

-

C12H22O2

198.30

(198.162)

20

13:1cΔ 2

2Z-tridecenoic

-

C13H24O2

212.33

(212.178)

38–39

13:1cΔ11

11Z-tridecenoic

-

C13H24O2

212.33

(212.178)

28–29

13:1Δ12

12Z-tridecenoic

-

C13H24O2

212.33

(212.178)

38–39

14:1cΔ 2

2Z-tetradecenoic

 

C14H26O2

226.36

(226.193)

33; 50–53

14:1cΔ 4

4Z-tetradecenoic

tsuzuic

C14H26O2

226.36

(226.193)

18.0–18.5

14:1cΔ5

5Z-tetradecenoic

physeteric

C14H26O2

226.36

(226.193)

20

14:1cΔ9

9Z-tetradecenoic

myristoleic

C14H26O2

226.36

(226.193)

−4.5

15:1cΔ 2

2Z-pentadecenoic

-

C15H28O2

240.38

(240.209)

4.5

16:1cΔ 2

2Z-hexadecenoic

gaidic

C16H30O2

254.41

(254.225)

40.5–41.7

16:1tΔ 2

2E-hexadecenoic

-

C16H30O2

254.41

(254.225)

46.5–47.6

16:1tΔ 3

3E-hexadecenoic

-

C16H30O2

254.41

(254.225)

53–54

16:1cΔ7

7Z-hexadecenoic

-

C16H30O2

254.41

(254.225)

32–33(α); 40–41(β)

16:1cΔ9

9Z-hexadecenoic

palmitoleic

C16H30O2

254.41

(254.225)

−0.5 to +0.5

16:1tΔ9

9E-hexadecenoic

palmitelaidic

C16H30O2

254.41

(254.225)

32–33

16:1cΔ10

10Z-hexadecenoic

 

C16H30O2

254.41

(254.225)

15–16

17:1cΔ 2

2Z-heptadecenoic

 

C17H32O2

268.43

(268.240)

51.8–53.7

17:1tΔ 2

2E-heptadecenoic

 

C17H32O2

268.43

(268.240)

56.6–58.5

17:1cΔ7

7Z-heptadecenoic

 

C17H32O2

268.43

(268.240)

3.5–4.5

17:1cΔ8

8Z-heptadecenoic

 

C17H32O2

268.43

(268.240)

5.5–7

17:1cΔ9

9Z-heptadecenoic

 

C17H32O2

268.43

(268.240)

11.4–12.2

17:1tΔ9

9E-heptadecenoic

 

C17H32O2

268.43

(268.240)

38

17:1Δ16

16Z-heptadecenoic

 

C17H32O2

268.43

(268.240)

52–54

18:1cΔ 2

2Z-octadecenoic

 

C18H34O2

282.46

(282.256)

50.5

18:1tΔ 2

2E-octadecenoic

 

C18H34O2

282.46

(282.256)

58.5

18:1cΔ 3

3Z-octadecenoic

 

C18H34O2

282.46

(282.256)

49.5–50.5

18:1tΔ 3

3E-octadecenoic

 

C18H34O2

282.46

(282.256)

64.5–65.5

18:1cΔ 4

4Z-octadecenoic

 

C18H34O2

282.46

(282.256)

45.5–46.5

18:1tΔ 4

4E-octadecenoic

 

C18H34O2

282.46

(282.256)

58.5–59.5

18:1cΔ5

5Z-octadecenoic

 

C18H34O2

282.46

(282.256)

12.5–13.5

18:1tΔ5

5E-octadecenoic

 

C18H34O2

282.46

(282.256)

(43–44); 47.5

18:1cΔ6

6Z-octadecenoic

petroselinic

C18H34O2

282.46

(282.256)

32–33

18:1tΔ6

6E-octadecenoic

petroselaidic

C18H34O2

282.46

(282.256)

52.7–53.4; 54–59

18:1cΔ7

7Z-octadecenoic

 

C18H34O2

282.46

(282.256)

12.5–13.1

18:1tΔ7

7E-octadecenoic

 

C18H34O2

282.46

(282.256)

44.2–44.5

18:1cΔ9

9Z-octadecenoic

oleic

C18H34O2

282.46

(282.256)

13.4(α), 16.3(β)

18:1tΔ9

9E-octadecenoic

elaidic

C18H34O2

282.46

(282.256)

44.5–46.5

18:1cΔ10

10Z-octadecenoic

 

C18H34O2

282.46

(282.256)

22.2–22.8

18:1tΔ10

10E-octadecenoic

 

C18H34O2

282.46

(282.256)

52–52.6

18:1cΔ11

11Z-octadecenoic

asclepic

C18H34O2

282.46

(282.256)

14.5–15.5

18:1tΔ11

11E-octadecenoic

vaccenic

C18H34O2

282.46

(282.256)

44

18:1cΔ12

12Z-octadecenoic

 

C18H34O2

282.46

(282.256)

26.5–27.5

18:1tΔ12

12E-octadecenoic

 

C18H34O2

282.46

(282.256)

39.7–40.1

18:1cΔ13

13Z-octadecenoic

 

C18H34O2

282.46

(282.256)

26.5–27

18:1tΔ13

13E-octadecenoic

 

C18H34O2

282.46

(282.256)

43.5–44.5

18:1cΔ15

15Z-octadecenoic

 

C18H34O2

282.46

(282.256)

41–42

18:1tΔ15

15E-octadecenoic

 

C18H34O2

282.46

(282.256)

59; 61–65

18:1cΔ16

16Z-octadecenoic

 

C18H34O2

282.46

(282.256)

54

18:1tΔ16

16E-octadecenoic

 

C18H34O2

282.46

(282.256)

65.6–66.2

18:1Δ17

17-octadecenoic

 

C18H34O2

282.46

(282.256)

55–55.5

19:1Δ 2

2-nonadecenoic

 

C19H36O2

296.49

(296.272)

66.5

20:1cΔ5

5Z-icosenoic

 

C20H38O2

310.51

(310.287)

26–27

20:1tΔ5

5E-icosenoic

 

C20H38O2

310.51

(310.287)

52.5–54

20:1cΔ9

9Z-icosenoic

gadoleic

C20H38O2

310.51

(310.287)

24–24.5

20:1tΔ9

9E-icosenoic

gadelaidic

C20H38O2

310.51

(310.287)

54

20:1cΔ11

11Z-icosenoic

gondoic

C20H38O2

310.51

(310.287)

23.5–24

20:1tΔ11

11E-icosenoic

 

C20H38O2

310.51

(310.287)

52–53

20:1cΔ14

14Z-icosenoic

 

C20H38O2

310.51

(310.287)

42.5

20:1cΔ17

17Z-icosenoic

 

C20H38O2

310.51

(310.287)

50–51

22:1cΔ11

11Z-docosenoic

cetoleic

C22H42O2

338.57

(338.318)

32.5–33

22:1cΔ13

13Z-docosenoic

erucic

C22H42O2

338.57

(338.318)

34.7

22:1tΔ13

13E-docosenoic

brassidic

C22H42O2

338.57

(338.318)

61.9

22:1cΔ19

19Z-docosenoic

 

C22H42O2

338.57

(338.318)

60–62

24:1cΔ15

15Z-tetracosenoic

nervonic

C24H46O2

366.62

(366.350)

42.5–43.0

24:1tΔ15

15E-tetracosenoic

 

C24H46O2

366.62

(366.350)

66–67; (65.5)

26:1cΔ17

17Z-hexacosenoic

ximenic

C26H50O2

394.67

(394.381)

50.5–50.9

28:1cΔ19

19Z-octacosenoic

 

C28H54O2

422.73

(422.412)

57.8–58.2

30:1cΔ21

21Z-triacontenoic

lumequeic

C30H58O2

450.78

(450.444)

60.8–61.2

I.3.2.3  Dienoic Unsaturated Fatty Acids

acid

chemical formula

molecular weight

(exact mass)

melting point (°C)

symbol

systematic name

common name

 

 

 

 

5:2cΔ 2,4

2Z,4Z-pentadienoic

β-vinylacrylic

C5H6O2

98.10

(98.037)

80

6:2cΔ 2,4

2Z,4Z-hexadienoic

sorbic

C6H8O2

112.13

(112.052)

134.5

10:2tcΔ 2,4

2E,4Z-decadienoic

stillingic

C10H16O2

168.23

(168.115)

-

10:2ttΔ 2,4

2E,4E-decadienoic

 

C10H16O2

168.23

(168.115)

49–50

10:2tΔ 2,6

2E,6E-decadienoic

 

C10H16O2

168.23

(168.115)

42–43

10:2tΔ 4,6

4E,6E-decadienoic

 

C10H16O2

168.23

(168.115)

39

12:2tΔ 2,4

2E,4E-dodecadienoic

 

C12H20O2

196.29

(196.146)

49–51

12:2tΔ 2,8

2E,8E-dodecadienoic

 

C12H20O2

196.29

(196.146)

35

16:2tΔ 3,9

3E,9E-hexadecadienoic

 

C16H28O2

252.39

(252.209)

20–22

16:2cΔ9,12

9Z,12Z-hexadecadienoic

 

C16H28O2

252.39

(252.209)

-

18:2cΔ 2,5

2Z,5Z-octadecadienoic

 

C18H32O2

280.45

(280.240)

34–36

18:2cΔ 3,6

3Z,6Z-octadecadienoic

 

C18H32O2

280.45

(280.240)

22–23

18:2cΔ 4,7

4Z,7Z-octadecadienoic

 

C18H32O2

280.45

(280.240)

11–12

18:2cΔ5,8

5Z,8Z-octadecadienoic

sebaleic

C18H32O2

280.45

(280.240)

−8

18:2cΔ5,12

5Z,12Z-octadecadienoic

 

C18H32O2

280.45

(280.240)

−30

18:2tΔ5,12

5E,12E-octadecadienoic

 

C18H32O2

280.45

(280.240)

16–19; 26.5–27

18:2tcΔ5,12

5E,12Z-octadecadienoic

 

C18H32O2

280.45

(280.240)

−12

18:2ctΔ5,12

5Z,12E-octadecadienoic

 

C18H32O2

280.45

(280.240)

−4

18:2tΔ6,8

6E,8E-octadecadienoic

 

C18H32O2

280.45

(280.240)

52–52.5

18:2cΔ6,9

6Z,9Z-octadecadienoic

petroslinoleic

C18H32O2

280.45

(280.240)

−11.5

18:2tΔ6,9

6E,9E-octadecadienoic

 

C18H32O2

280.45

(280.240)

14–16

18:2tΔ6,10

6E,10E-octadecadienoic

 

C18H32O2

280.45

(280.240)

40.5–41

18:2tΔ6,11

6E,11E-octadecadienoic

 

C18H32O2

280.45

(280.240)

27–27.5

18:2tΔ6,12

6E,12E-octadecadienoic

 

C18H32O2

280.45

(280.240)

37–37.5

18:2cΔ7,10

7Z,10Z-octadecadienoic

 

C18H32O2

280.45

(280.240)

−15

18:2tΔ7,12

7E,12E-octadecadienoic

 

C18H32O2

280.45

(280.240)

26.5–27

18:2tΔ8,10

8E,10E-octadecadienoic

 

C18H32O2

280.45

(280.240)

56–56.5

18:2cΔ8,11

8Z,11Z-octadecadienoic

 

C18H32O2

280.45

(280.240)

−16(−12.5 to −19.5)

18:2tΔ8,12

8E,12E-octadecadienoic

 

C18H32O2

280.45

(280.240)

38.5–39

18:2cΔ9,11

9Z,11Z-octadecadienoic

ricinenic

C18H32O2

280.45

(280.240)

42–43.2

18:2tΔ9,11

9E,11E-octadecadienoic

 

C18H32O2

280.45

(280.240)

54

18:2ctΔ9,11

9Z,11E-octadecadienoic

rumenic

C18H32O2

280.45

(280.240)

20

18:2cΔ9,12

9Z,12Z-octadecadienoic

α-linoleic

C18H32O2

280.45

(280.240)

−5.2 to −5.0

18:2tΔ9,12

9E,12E-octadecadienoic

linolelaidic

C18H32O2

280.45

(280.240)

28–29

18:2ctΔ9,12

9Z,12E-octadecadienoic

 

C18H32O2

280.45

(280.240)

1

18:2tcΔ9,12

9E,12Z-octadecadienoic

 

C18H32O2

280.45

(280.240)

1

18:2cΔ10,12

10Z,12Z-octadecadienoic

 

C18H32O2

280.45

(280.240)

38–39

18:2tΔ10,12

10E,12E-octadecadienoic

 

C18H32O2

280.45

(280.240)

55.5–56

18:2tcΔ10,12

10E,12Z-octadecadienoic

 

C18H32O2

280.45

(280.240)

22–23

18:2cΔ10,13

10Z,13Z-octadecadienoic

 

C18H32O2

280.45

(280.240)

−10.5

18:2cΔ11,14

11Z,14Z-octadecadienoic

 

C18H32O2

280.45

(280.240)

4.5–5.5

18:2cΔ11,15

11Z,15Z-octadecadienoic

 

C18H32O2

280.45

(280.240)

11

18:2cΔ12,15

12Z,15Z-octadecadienoic

-

C18H32O2

280.45

(280.240)

18–18.5

18:2cΔ13,16

13Z,16Z-octadecadienoic

-

C18H32O2

280.45

(280.240)

20.5–21.5

18:2cΔ14,17

14Z,17Z-octadecadienoic

-

C18H32O2

280.45

(280.240)

37–37.5

20:2cΔ11,14

11Z,14Z-icosadienoic

-

C20H36O2

308.50

(308.272)

-

22:2cΔ5,13

5Z,13Z-docosadienoic

-

C22H40O2

336.55

(336.303)

−4

22:2cΔ13,16

13Z,16Z-docosadienoic

-

C22H40O2

336.55

(336.303)

-

26:2cΔ17,20

17Z,20Z-hexacosadienoic

-

C26H48O2

392.66

(392.365)

61

I.3.2.4  Trienoic Unsaturated Fatty Acids

acid

chemical formula

molecular weight

(exact mass)

melting point (°C)

symbol

systematic name

common name

 

 

 

 

16:3cΔ6,10,14

6Z,10Z,14Z-hexadecatrienoic

hiragonic

C16H26O2

250.38

(250.193)

-

18:3tccΔ 3,9,12

3E,9Z,12Z-octadecatrienoic

 

C18H30O2

278.43

(278.225)

61–61.5

18:3cΔ6,9,12

6Z,9Z,12Z-octadecatrienoic

γ-linolenic

C18H30O2

278.43

(278.225)

-

18:3ttcΔ8,10,12

8E,10E,12Z-octadecatrienoic

α-calendic

C18H30O2

278.43

(278.225)

40–40.5

18:3tΔ8,10,12

8E,10E,12E-octadecatrienoic

β-calendic

C18H30O2

278.43

(278.225)

77–78

18:3ctcΔ8,10,12

8Z,10E,12Z-octadecatrienoic

jacaric

C18H30O2

278.43

(278.225)

43.5–44

18:3cΔ9,12,15

9Z,12Z,15Z-octadecatrienoic

α-linolenic

C18H30O2

278.43

(278.225)

−11 to −11.3

18:3tΔ9,12,15

9E,12E,15E-octadecatrienoic

linolenelaidic

C18H30O2

278.43

(278.225)

29–30

18:3cttΔ9,11,13

9Z,11E,13E-octadecatrienoic

α-eleostearic

C18H30O2

278.43

(278.225)

48–49

18:3tΔ9,11,13

9E,11E,13E-octadecatrienoic

β-eleostearic

C18H30O2

278.43

(278.225)

71.5

18:3ctcΔ9,11,13

9Z,11E,13Z-octadecatrienoic

punicic

C18H30O2

278.43

(278.225)

43.5–44

18:3ttcΔ9,11,13

9E,11E,13Z-octadecatrienoic

catalpic

C18H30O2

278.43

(278.225)

31.5–32

18:3cctΔ9,11,13

9Z,11Z,13E-octadecatrienoic

 

C18H30O2

278.43

(278.225)

61.5–62.5

18:3tΔ10,12,14

10E,12E,14E-octadecatrienoic

pseudoeleostearic

C18H30O2

278.43

(278.225)

77–77.5

20:3ctcΔ8,12,14

8Z,12E,14Z-icosatrienoic

 

C20H34O2

306.48

(306.256)

8

I.3.2.5  Tetraenoic Unsaturated Fatty Acids

acid

chemical formula

molecular weight

(exact mass)

melting point (°C)

symbol

systematic name

common name

 

 

 

 

16:4cΔ6,9,12,15

6Z,9Z,12Z,15Z-hexadecatetraenoic

 

C16H24O2

248.36

(248.178)

-

18:4tcctΔ 3,9,12,15

3E,9Z,12Z,15E-octadecatetraenoic

 

C18H28O2

276.41

(276.209)

−30

18:4cΔ 4,8,12,15

4Z,8Z,12Z,15Z-octadecatetraenoic

morotic

C18H28O2

276.41

(276.209)

-

18:4cΔ6,9,12,15

6Z,9Z,12Z,15Z-octadecatetraenoic

stearidonic

C18H28O2

276.41

(276.209)

−57.4 to −56.6

18:4cttcΔ9,11,13,15

9Z,11E,13E,15Z-octadecatetraenoic

α-parinaric

C18H28O2

276.41

(276.209)

85–86

18:4tΔ9,11,13,15

9E,11E,13E,15E-octadecatetraenoic

β-parinaric

C18H28O2

276.41

(276.209)

95–96

20:4cΔ5,8,11,14

5Z,8Z,11Z,14Z-icosatetraenoic

arachidonic

C20H32O2

304.47

(304.240)

−49.5

22:4cΔ7,10,13,16

7Z,10Z,13Z,16Z-docosatetraenoic

adrenic

C22H36O2

332.52

(332.272)

-

I.3.2.6  Pentaenoic and Hexaenoic Unsaturated Fatty Acids

acid

chemical formula

molecular weight

(exact mass)

melting point (°C)

symbol

systematic name

common name

 

 

 

 

20:5cΔ5,8,11,14,17

5Z,8Z,11Z,14Z,17Z-icosapentaenoic

timnodonic

C20H30O2

302.45

(302.225)

−54.4 to 53.8

22:5cΔ 4,8,12,15,19

4Z,8Z,12Z,15Z,19Z-docosapentaenoic

 

C22H34O2

330.50

(330.256)

−78

22:6cΔ 4,7,10,13,16,19

4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoic

clupanodonic

C22H32O2

328.49

(328.240)

−44.5 to −44.1

24:6cΔ 4,8,12,15,18,21

4Z,8Z,12Z,15Z,18Z,21Z-tetracosahexaenoic

nisinic

C24H36O2

356.54

(356.272)

-

I.3.2.7  Branched-Chain Fatty Acids

acid

chemical formula

molecular weight

(exact mass)

melting point (°C)

symbol

systematic name

common name

 

 

 

 

i5:0

3-methylbutanoic

isovaleric

C5H10O2

102.13

(102.068)

−37.6

i8:0

6-methylheptanoic

isocaprylic

C8H16O2

144.21

(144.115)

0

ai9:0

d-6-methyloctanoic

-

C9H18O2

158.24

(158.131)

-

i9:0

7-methyloctanoic

 

C9H18O2

158.24

(158.131)

−18.5

ai11:0

8-methyldecanoic

-

C11H22O2

186.29

(186.162)

−18.5

i12:0

10-methylundecanoic

isolauric

C12H24O2

200.32

(200.178)

41.2

ai13:0

d-10-methyldodecanoic

-

C13H26O2

214.34

(214.193)

6.2–6.5

i13:0

11-methyldodecanoic

isoundecylic

C13H26O2

214.34

(214.193)

39.4–40

i14:0

12-methyltridecanoic

isomyristic

C14H28O2

228.37

(228.209)

53.6

ai15:0

d-12-methyltetradecanoic

-

C15H30O2

242.40

(242.225)

25.8

i15:0

13-methyltetradecanoic

isopentadecylic

C15H30O2

242.40

(242.225)

52.2

i16:0

14-methylpentadecanoic

isopalmitic

C16H32O2

256.42

(256.240)

62.4

ai17:0

d-14-methylhexadecanoic

-

C17H34O2

270.45

(270.256)

38.0

i17:0

15-methylhexadecanoic

-

C17H34O2

270.45

(270.256)

60.5

-

10-methylheptadecanoic

-

C18H36O2

284.48

(284.272)

33.5

i18:0

16-methylheptadecanoic

isostearic

C18H36O2

284.48

(284.272)

69.5

-

l-d-10-methyloctadecanoic

tuberculostearic

C19H38O2

298.50

(298.287)

13.2

ai19:0

d-16-methyloctadecanoic

-

C19H38O2

298.50

(298.287)

49.9–50.7

i19:0

17-methyloctadecanoic

 

C19H38O2

298.50

(298.287)

67.3–67.8

i20:0

18-methylnonadecanoic

isoarachidic

C20H40O2

312.53

(312.303)

75.3

ai21:0

d-18-methylicosanoic

-

C21H42O2

326.56

(326.318)

55.6

i22:0

20-methylhenicosanoic

isobehenic

C22H44O2

340.58

(340.334)

79.5

ai23:0

d-20-methyldocosanoic

-

C23H46O2

354.61

(354.350)

62.1

i23:0

21-methyldocosanoic

 

C23H46O2

354.61

(354.350)

73.5

i24:0

22-methyltricosanoic

isolignoceric

C24H48O2

368.64

(368.365)

83.1

ai25:0

d-22-methyltetracosanoic

-

C25H50O2

382.66

(382.381)

67.8

i25:0

23-methyltetracosanoic

 

C25H50O2

382.66

(382.381)

82.4–82.6

i26:0

24-methylpentacosanoic

isocerotic

C26H52O2

396.69

(396.397)

86.9

ai27:0

d-24-methylhexacosanoic

-

C27H54O2

410.72

(410.412)

72.9

i28:0

26-methylheptacosanoic

isomontanic

C28H56O2

424.74

(424.428)

89.3

ai31:0

d-28-methyltriacontanoic

-

C31H62O2

466.82

(466.475)

80.7

-

2,4,6-(D)-trimethyloctacosanoic

mycoceranic (mycocerosic)

C31H62O2

466.82

(466.475)

27–28

i5:1cΔ 2

2-methyl-2Z-butenoic

angelic

C5H8O2

100.12

(100.052)

45

i5:1tΔ 2

2-methyl-2E-butenoic

tiglic

C5H8O2

100.12

(100.052)

65.5

i6:1cΔ 3

4-methyl-3-pentenoic

pyroterebic

C6H10O2

114.14

(114.068)

-

-

d-2,4(L),6(L)-trimethyl-trans-2-tetracosenoic

C27 phthienoic (mycolipenic)

C27H52O2

408.70

(408.397)

39.5–41

References

Small, D. M. The Physical Chemistry of Lipids. From Alkanes to Phospholipids, Plenum Press, New York and London, 1986.
Marsh, D. , Biochim. Biophys. Acta, 1062, 1, 1991.
Lutton, E. S. , in: Markley, K. S. (Ed.) Fatty Acids. Their Chemistry, Properties, Production and Uses, Wiley Interscience, New York, 1967, 2583.
Bailey, A. E. , in: Bailey, A. E. (Ed.) Melting and Solidification of Fats, Wiley Interscience, New York, 1950, 117.
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