This document provides information about fatty acids and triglycerides. It discusses the structure, properties, and reactions of fatty acids, including their length, degree of saturation, and location of double bonds. Triglycerides are introduced as esters composed of glycerol and three fatty acid chains. Their physical properties depend on the fatty acid components, and they undergo hydrolysis, saponification, and hydrogenation reactions. The learning outcomes are to understand fatty acids and triglycerides, and distinguish between their physical and chemical properties.

1. CHM4201:SPECIAL TOPIC IN
ORGANIC CHEMISTRY
Triglycerides and Chemistry
of Fatty acids
Group Members:
Nur Fatihah binti Abas (154120)
Faridah binti Sulaiman (154603)
Wan Fatihah Nasuha binti Wan Nor (154115)
Lecturer’s Name:
Prof. Mawardi Rahmadi

2. Learning outcomes:
1) To understand about fatty acid and triglycerides.
2) To know the physical and chemical properties of
fatty acid and triglycerides.
3) To distinguish between fatty acid and triglycerides.

3. Fatty Acids
• Long straight-chain carboxylic acids
▫ no branching
• Most common chains range from 10–20 carbons in
length
• Usually, an even number of carbons in the chain,
including the carboxyl carbon
• Can be saturated or unsaturated, but usually no other
functional groups present
▫ Any fatty acid that cannot be synthesized by the body
is called an essential fatty acid

4. Structure of fatty acids
• A fatty acid is nothing
more than a long C-H
chain with a carboxyl
group (COOH) on the
end.
• The COOH gives it an
acid property.
• The 3….dots represent
the chain is very long.

5. Physical Properties of Fatty Acids
• Solubility
>Longer chains
• more hydrophobic, less soluble.
>Double bonds increase solubility.
• Melting points
• Depend on chain length and saturation
• Double bonds lead chain disorder and low melting
temperature.
• Unsaturated FAs are solids at Room Temperature.

6. Fatty Acids
• The most common fatty acids.
Carbon Atoms: Common Melting Point
Double Bonds Name (°C)
Satur ated Fatty Acids
12:0 Lauric acid 44
Higher mp
14:0 Myristic acid 58
16:0 Palmitic acid 63
18:0 Ste aric acid 70
20:0 Arachidic acid 77
Uns aturated Fatty Acids
Lower mp 16:1 Palmitoleic acid 1
18:1 Oleic acid 16
18:2 Linole ic acid -5
18:3 Linole nic acid -11
20:4 Arachidonic acid -49

7. Types of fatty acids
The Length of • long-chain
the Carbon • medium-chain
Chain • short-chain
The Degree of • saturated
Unsaturation • unsaturated
The Location of • omega-3 fatty acid
Double Bonds • omega-6 fatty acid

8. The Length of the Carbon Chain
Short-chain Fatty Acid
(less than 6 carbons)
Medium-chain Fatty Acid
(6-10 carbons)
Long-chain Fatty Acid
(12 or more carbons)

10. Saturated
The Degree of
Unsaturation
Monounsaturated
Unsaturated
(cis or trans
configuration)
Polyunsaturated

11. Saturated and Unsaturated FAs
• Saturated FAs have no
double bonds. (C-C)
Double bonds lower the
melting temperature
• Unsaturated FAs have at
least one double bond
(C=C) in one of the fatty
acids

12. Saturated Fatty Acid
 All single bonds between carbons

13. Monounsaturated Fatty Acid
One carbon-carbon double bond

14. Polyunsaturated Fatty Acid
More than one carbon-carbon double bond

15. Structure
• Stearic acid: a typical saturated fatty acid with
18 carbons in the chain
• Oleic acid: a typical unsaturated fatty acid with
18 carbons in the chain

16. Cis-fatty acid: H’s on same side of the double bond; fold into
U-like formation; naturally occurring.
Trans-fatty acid: H’s on opposite side of double bond; more
linear; occur in partially hydrogenated foods

19. Location of Double Bonds
• Polyunsaturated fatty acid (PUFA) are identified by
position of the double bond nearest the methyl end
(CH3) of the carbon chain; this is described as a
omega number.
• If PUFA has first double bond 3 carbons away from
the methyl end => omega 3 FA
• 6 carbons from methyl end => omega 6 FA

20. Omega-3
Omega-6

21. Fatty Acid Nomenclature
• Nomenclature reflects location of double
bonds
• Also used are common names (e.g: oleic,
stearic, palmitic)
• Linoleic is also known as 18:2 n-6
• This means the FA is 18 carbons in length, has
2 double bonds, the first of which is on the 6th
carbon
• Arachidonic => 20:4 n-6

22. Classification and Structure-Saturated Fatty Acids
Common Name Systematic Name Formula
O
Butyric acid n-butanoic CH3(CH2)2C OH
O
Caproic acid n-hexanoic CH3(CH2)4C OH
O
Caprylic acid n-octanoic CH3(CH2)6C OH
O
Capric acid n-decanoic CH3(CH2)8C OH
O
Lauric acid n-dodecanoic CH3(CH2)10C OH

23. Common Name Systematic Name Formula
O
Myristic acid n-tetradecanoic CH3(CH2)12C OH
O
Palmitic acid n-hexadecanoic CH3(CH2)14C OH
O
Stearic acid n-octadecanoic CH3(CH2)16C OH
O
Arachidic acid n-eicosanoic CH3(CH2)18C OH
O
Behenic acid n-docosanoic CH3(CH2)20C OH
O
Lignoceric acid n-tetracosanoic CH3(CH2)22C OH

24. Naming for Unsaturated FAs
10 9 8 7 6 5 4 3 2 1
O
1 9
C H3(C H2)7 HC CH C H2 CH2 CH2 CH2 C H2 CH2 C H2 C OH
Δ 9, 10 - Octadecenoic acid
9 - Octadecenoic acid

25. Common Name of Fatty Acids
Common Name Systematic Name
Myristoleic 9-tetradecenoic acid
Palmitoleic 9-hexadecenoic acid
Oleic 9-octadecenoic acid
Vaccenic 11-octadecenoic acid
Erucic 13-docosenoic acid

26. Chemical Reactions of Fatty
Acids
Esterification reacts fatty acids with alcohols to
form esters and water

27. Fatty Acid Hydrolysis
• Acid Hydrolysis reverses esterification
▫ Fatty acids are produced from esters

28. Saponification
• Saponification is the base-catalyzed hydrolysis of
an ester
• Products of the reaction are
▫ An alcohol
▫ An ionized salt which is a soap
 Soaps have a long uncharged hydrocarbon tail
 Also have a negatively charged carboxylate group at
end
 Form micelles that dissolve oil and dirt particles

29. Reaction at the Double Bond
• Hydrogenation is an addition reaction
• Unsaturated fatty acids can be converted to
saturated fatty acids
• Hydrogenation is used in the food industry
O
CH3 CH2 4CH CH CH2CH CH CH2 7 C OH
2 H2, Ni
O
CH3 CH2 16 C OH

30. Hydrogenation

31. Triglycerides
• An ester of glycerol with
three fatty acids.
• Also known as
triacylglycerols
• One type of lipid
categorised as simple lipid.

32. Structure of Triglycerides
• Glycerides are lipid esters
• A triglyceride places fatty acid chains at each
alcohol group of the glycerol
O
CH2O C R1
Glycerol O
part
CH O C R2 Fatty acid
O chains
CH2O C R3

33. Glycerol
• Glycerol Always
looks the same
• 3 C’s with 3 OH’s and
everything else H’s.

34. Formation of Triglycerides

36. Example of triglycerides
▫ Triglyceride derived from one molecule each of
palmitic acid, oleic acid, and stearic acid, the three
most abundant fatty acids in the biological world.
O p almitate (16:0)
oleate (18:1)
O CH2 OC(CH2 ) 1 4 CH3
stearate (18:0)
CH3 ( CH2 ) 7 CH=CH(CH2 ) 7 COCH O
CH2 OC(CH2 ) 1 6 CH3

37. Physical properties of triglycerides
• Physical properties depend on the fatty acid
components.
▫ Melting point increases as the number of carbons in
its hydrocarbon chains increases and as the number
of double bonds decreases.
▫ Oils: Triglycerides rich in unsaturated fatty acids
are generally liquid at room.
▫ Fats: Triglycerides rich in saturated fatty acids are
generally semisolids or solids at room temperature.

38. Physical properties of triglycerides
▫ Hydrocarbon chains of saturated fatty acids can lie
parallel with strong dispersion forces between their
chains; they pack into well-ordered, compact
crystalline forms and melt above room temperature.
▫ Because of the cis configuration of the double bonds in
unsaturated fatty acids, their hydrocarbon chains have
a less ordered structure and dispersion forces between
them are weaker; these triglycerides have melting
points below room temperature.

39. Chemical Properties
Triglycerides have typical ester and alkene chemical
properties as they are composed of these two groups:-
▫ Saponification: replace H with salt from a strong
base
▫ Hydrolysis: produces the fatty acids and glycerol, a
reverse of formation
▫ Hydrogenation: saturates the double bonds

40. Triglyceride Reactions
• Triglycerides undergo three basic reactions
• These reactions are identical to those studied in
carboxylic acids
Triglyceride
H2O, H+ H2, Ni
NaOH
Glycerol
Fatty Acids More saturated
Glycerol triglyceride
Fatty Acid Salts

41. Hydrolysis

42. Saponification

43. Hydrogenation

47. What’s What?
• Identify the glycerol
molecule
• The fatty acids