It prepared for Undergraduate students teaching purpose

1. FAT T Y A C I D C L U S T E R S A N D
R E A C T I O N A N D D E R I V AT I V E S
5 . 3 M e t h y l e n e - i n t e r r u p t e d p o l y u n s a t u r a t e d a c i d s
5 . 4 B r a n c h e d f a t t y a c i d s
5 . 5 R e a c t i o n w i t h 5 . 5 . 1 M e t h y l e n e g r o u p , 5 . 5 . 2 D o u b l e b o n d
5 . 6 D e r i v a t i v e s 5 . 6 . 1 h i g h e r a l i p h a t i c 5 . 6 . 2 P o l y c a r b o x y l i c a c i d
5 . 6 . 3 Fa t t y a l d e h y d e s
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2. METHYLENE INTERRUPTED
POLYUNSATURATED FATTY ACIDS
• In polyunsaturated fatty acids, when two or more double bonds are separated by one –
CH2- groups are called methylene interrupted polyunsaturated fatty acids
• This pattern results from the operation of a few specific desaturates and chain-
elongation enzymes.
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3. CONJUGATED FATTY ACID
• Fatty acids with two or more conjugated double bonds are found in some plants and
animals.
• Alternate single and doubles are called conjugated double bonds.
• Example of conjugated fatty acids
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4. BRANCHED FATTY ACIDS
• There are many branched-chain acids, but branched chain fatty acids are seldom occur
at a significant levels.
• Examples include the iso fatty acids (mainly with an even number of carbon atoms),
anteiso fatty acid (mainly with an even number of carbon atoms) found in wool wax
and other animal fats.
• Phytol-based fatty acids present at low level in fish oils.
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5. REACTIONS WITH METHYLENE GROUP
• The methylene groups flanked by doubly bonded atoms present in highly unsaturated
faty acids very reactive.
• The –CH2– group present in linoleic acid component of the unsaturated glyceride is
readily attacked by oxygen of the air to form hydroperoxyl group (-O-O-H) at these
sites.
• These hydroperoxyl groups then react with unchanged –CH2 – groups in other fatty
acid molecules to form peroxide bridges.
• The hydroperoxide formation accompanied by polymerization converts
polyunsaturated fatty acids into vast network of interlinked units.
• Such a network forms a dry, tough and durable film when exposed to air.
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6. 11/3/2020 Dr. Mohammed Danish/CPB30303 Oil & Fat Technology 6
H3C (CH2)4 CH CH CH2 CH CH (CH2)3
C
O
OH
O2 from air
H3C (CH2)4 CH CH CH CH CH (CH2)3
C
O
OH
O O H
H3C (CH2)4 CH2 CH2 CH CH CH2 (CH2)3
C
O
OH
O O
H3C (CH2)4 CH2 CH2 CH CH CH2 (CH2)3
C
O
OH
Polymerization

7. REACTION WITH DOUBLE BONDS
• Hydrogenation is an addition reaction at double sites.
• Unsaturated fatty acids can be converted into saturated fatty acids.
• Hydrogenation is used in the food industry.
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C H 3 (C H 2 )4 C H C H
C H 2
C H C H (C H 2 )7 C
O
O H
N i2 H 2
C H 3 (C H 2 )1 6 C
O
O H

8. HIGHER ALIPHATIC
• Higher aliphatic compounds can be prepared by reducing
the acid group in fatty acid into alcohol with lithium
aluminium hydride (LiAlH4) & diethylether reagents.
• Then Alcohols further reduced into aliphatic compound
using tosyle chloride (p-toluenesulfonyl chloride) and
LiAlH4.
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CH3 (CH2)4 CH CH
CH2
CH CH (CH2)7 C
O
OH
Ni2H2
CH3 (CH2)16 C
O
OH
1. LiAlH4, diethylether
2. H2O
CH3 (CH2)16
H2
C OH
1. TsCl/pyridine
2. LiAlH4
CH3 (CH2)16
H2
C H

9. 11/3/2020 Dr. Mohammed Danish/CPB30303 Oil & Fat Technology 9
CH3 (CH2)4 CH CH
CH2
CH CH (CH2)7 C
O
OH
1. LiAlH4, diethylether
2. H2O
1. TsCl/pyridine
2. LiAlH4
CH3 (CH2)4 CH CH
CH2
CH CH (CH2)7
H2
C OH
CH3 (CH2)4 CH CH
CH2
CH CH (CH2)7
H2
C H

10. POLYCARBOXYLIC
ACID
• Unsaturated fatty acid can be
converted into polycarboxylic acids
with conc. KMnO4, the reaction
takes place at unsaturated bonds.
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C H 3 ( C H 2 ) 4 C H
O H
C H
O H
C H 2
C H
O H
C H
O H
( C H 2 ) 7 C
O
O H
Transition Phase

11. FATTY
ALDEHYDES
• Fatty aldehydes can be prepared from
fatty acid in two stages.
• In first stage fatty acids converted into acid
chlorides with SOCl2 reagent.
• In second stage acid chlorides converted
in aldehydes using LiAlH(O-t-Bu) catalyst.
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CH3 (CH2)4 CH CH
CH2
CH CH (CH2)7 C
O
OH
SOCl2
CH3 (CH2)4 CH CH
CH2
CH CH (CH2)7 C
O
Cl
CH3 (CH2)4 CH CH
CH2
CH CH (CH2)7 C
O
H
LiAlH(O-t-Bu)

12. S L I D E S E N D H E R E !
T H A N K S F O R
Y O U R
AT T E N T I O N !
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Dr. Mohammed Danish
Senior Lecturer, Food
Technology Section,
UniKL-MICET, Alor Gajah
78000, Melaka, Malaysia