Fatty Acid Isolation (Unit 4 a)

4.0 FATT Y ACIDS
ISOL ATION AND
GLYCERINE RECOVERY
C H E M I C A L M O D I F I C A T I O N
T R A N S E S T E R I F I C A T I O N
H Y D R O L Y S I S
A M I N O L Y S I S
S A P O N I F I C A T I O N
E N Z Y M E M O D I F I C A T I O N S
29/2/2020
CPB30303 Oil & Fat Technol
Dr. Mohammed Danish
1

WHY
ISOLATION OF
FATTY ACIDS
AND
GLYCERINE IS
INDUSTRIALLY
IMPORTANT?
The importance of fatty acid and glycerine in chemical industry is
well known, they are the key constituents in wide range of the
daily use products such as:
• Fatty acids: used in production of soap & detergents,
cosmetics, lubricants, paints, rubber, textile and emulsifier.
• Glycerine: used in production of toothpaste, alkyd resins,
explosive, cosmetics, food & beverages, pharmaceuticals.
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HOW FATTY ACID AND
GLYCERINE SEPARATED FROM
THE TRIGLYCERIDES (OIL &
FAT)?
Splitting of triglycerides (oil & fat) can be
carried out by two methods:
• Chemical modification (catalysed or
uncatalyzed)
• Enzyme modifications
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Danish 3

CHEMICAL MODIFICATIONS
Chemical modification in oil and fat can be performed by the following methods:
o Transesterification
o Hydrolysis
o Aminolysis
o Saponification
Chemical agents required to perform above reactions are
o Salt of methanol = Transesterification
o Water = Hydrolysis
o Amines = Aminolysis
o Caustic soda = Saponification
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REVERSIBLE REACTION
o Glycerol react with three molecules of fatty acid gives ester product named
triglycerides and three molecules of water.
o Triglycerides in presence of water under suitable condition break into glycerol and
three molecules of fatty acids.
G l y c e r o l + 3 F a t t y a c i d s
E s t e r i f i c a t i o n
S p l i t t i n g
T r i g l y c e r i d e + 3 H 2 O
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TRANSESTIFICATION
• Transesterification includes chemical reactions where an ester is reacted with alcohol
(alcoholysis), acid (acidolysis), or another ester (interesterification or ester exchange),
to generate a new ester.
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ALCOHOLYSIS
• When alcohol reacts with triglycerides the products formed are fatty acid alkyl ester and
glycerol. Most common alcoholysis is methanol reaction with triglycerides, called
methanolysis in this reaction fatty acid methyl ester and glycerol are generated.
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• Fatty acid methyl ester can be used an alternative fuel for diesel engine (biodiesel).
Biodiesel is a substitute or extender for traditional petroleum diesel.
• Biodiesel can be used in conventional diesel engines, and the use of biodiesel is
advantageous for reducing emission of CO2, CO, SO2 and particle materials.
• Use of biodiesel spreading worldwide, in France, all the diesel fuel marketed contains
5% of biodiesel.
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• Another common alcoholysis is glycerolysis, in which triglycerides react with glycerol
(alcohol) in the presence of alkaline catalyst to form partial glyceride such as
monoacylglycerol.
• A mixture of triacylglycerol and glycerol are heated at 200-250 °C in the presence of
sodium hydroxide, the resulting main product is monoacylglycerol, which is used as
food emulsifier after purification by molecular distillation.
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ACIDOLYSIS
• An Industrial Application of acidolysis is production of long chain fatty acids vinylesters
from vinylacetate (this can be obtained by chemical reaction of ethylene and acetic
acid) and fatty acids. Long chain fatty acid vinyl esters are industrial raw material for
making plastics.
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INTERESTERIFICATION
• Interesterification of oil changes its molecular composition. Oils or fats are mixture of
various triacylglycerol molecules having different fatty acids and positional distribution.
• Treating oils and fats with sodium methoxide as a catalyst at 80 °C causes
intermolecular ester exchange, changing the molecular composition, while leaving the
fatty acid composition unchanged.
• As a result of it, the oil changes its physical properties such as melting point and
consistency.
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• An important application of interesterification is improvement of natural lard.
• Natural lard tends to form a rough crystal, which is difficult to handle, during storage.
This is because 64% of palmitic acid is attached to 2nd position of triacylglycerol
molecules.
• Randomization of the positional distribution of fatty acids of natural lard by
interesterification improves its physical property, making it a smooth.
• Another example of interesterification is in the margarine production. Interesterification
of soyabean oil and completely hydrogenated soybean oil provides a material for
margarine.
• This rearranged oil has an advantage that it does not contain trans fatty acid, because it
is not made through partial hydrogenation.
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WHY CATALYST IS IMPORTANT IN
INTERESTERIFCATION REACTION?
• Although fatty acid can be rearranged in the triglycerides without the use of a catalyst at
a temperature of 250 °C (475 °F) or higher, but most oil and fat processors use alkali
metal alkylates or alkali metals to speed up the reaction.
• Oil and fat at higher temperature without the assistance of a catalyst proceed slowly to
equilibrium and have other undesirable changes such as, isomerization, polymerization,
and decomposition reactions.
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CHEMICAL INTERESTERIFICATIONS
Some of the chemical catalyst used frequently in interesterification reaction of the oil and
fat are:
oSodium methylate: it is most widely used as low temperature catalyst for conducting
interesterification. It can be used as powder or dispersion in solvent such as xylene at
very low level, 0.1% if the oil and fat have low free fatty acids.
o Sodium potassium alloy: it is liquid at room temperature so no need any solvent for
dispersion, it can also used in very low level 0.05 % to 0.1%. it can catalysed low
temperature reactions at faster rate than any other catalyst but requires high shear
agitation and is physically more expensive even though it offer low oil loss. The oil must
be dried before the use of this catalyst, otherwise it form H2 gas which inactivate the
catalyst. It can create explosion with H2 gas and heat generated during deactivation.
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• Sodium or potassium hydroxide: it is lowest cost catalyst, but they must be used in
combination with glycerol. It require a two stage reaction under vacuum at high
temperature. In first stage at 60 °C to neutralize any free fatty acids, dry the oil and
disperse the catalyst. In second stage the reaction mixture should heated at 140- 160
°C to effect the rearrangement.
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STEPS INVOLVED IN
INTERESTERIFICATION PROCESS
The chemical rearrangement of the fats and oil can be accomplished using either batch
or continuous process. Both processes performed the three important rearrangement
steps:
o Pre-treatment of the oil.
o Reaction with the catalyst, and
o Deactivation of the catalyst.
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BATCH INTERESTERIFICATION
PROCESS• A typical batch interesterification rearrangement reaction vessel should be equipped
with an agitator, coils for heating and cooling, nitrogen sparging, and vacuum
capabilities.
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The process steps for batch rearrangement are:
o Heat fat to 120-150 °C, in the reaction vessel under a vacuum to dry the oil.
o After drying the fat is cooled to the reaction temperature, which ranges from 70 °C to
100 °C depending upon the product and desired processing conditions.
o Catalyst such as sodium methylate powder is sucked into the reaction vessel with the
vacuum. The catalyst requirement can be calculated as: % catalyst required = (FFA x
0.19) + 0.06.
oWhen the reaction completion is confirmed by the laboratory results, the catalyst is
neutralized in the reaction vessel.
o The neutralization may be done by adding phosphoric acid or carbon dioxide prior to
water washing to deactivate the catalyst.

CONTINUOUS INTERESTERIFICATION
PROCESS
The process flow for one continuous system is as follow:
oThe oil heated with a heat exchanger and flash dried with a vacuum oil dryer o bring the
moisture level to 0.01% or less.
o The catalyst is introduced into the hot oil stream and homogenized for dispersion.
oThe homogenized mixture then passed through a tubular reactor. The reactor residence
time can be adjusted by changing the length of the tube.
o The catalyst is deactivated with water and centrifuged to separate the soap and oil.
o After separation the product is vacuum dried to remove the remaining traces of
moisture.
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HYDROLYSIS
• Hydrolysis is the breakdown of a substance by the addition of water: fats and oils
(triglycerides) are hydrolysed by moisture to yield glycerol and 3 fatty acids.
• Chemically fats and oil are ester, so they liable to hydrolysis. This reaction is either
catalysed by by enzymes or non enzymatic chemical catalyst.
• Partial hydrolysis or triglycerides will yield mon- and di-glycerides and free fatty acids.
• When hydrolysis is carried to completion with water in the presence of an acid catalyst,
the mono-, di-, and triglycerides will hydrolysed to yield glycerol and free fatty acids.
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AMINOLYSIS
• Triglycerides reacts with ammonia to form amides of fatty acids and glycerol.
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H2C
H
C CH2
O O O
CO CO CO
R R R
+
NH3
H2C
H
C CH2
O O O
H H H
+ 3 H2N C
O
R
Triglycerides
Amm onia
Glycerol
Alkyl am ide

SAPONIFICATION
What is saponification process?
• A process in which ester in fats are hydrolysed
with sodium or potassium hydroxide (NaOH or
KOH) to produce a carboxylate anion which can
act as a surfactant, i.e. soap.
Or
• When triglyceride are hydorlyzed (saponified) by
alkalis, glycerol plus the salts of fatty acids are
produced. Generally the sodium or potassium
salts are obtained which are termed soaps.
Danish 25

• The triglycerides are most often animal fats or vegetable oils. When sodium hydroxide is
used, a hard soap is produced. Using potassium hydroxide results in a soft soap.
• Saponification is the name of the reaction that produces soap.
• In the process, animal or vegetable fat is converted into soap and glycerol (alcohol). The
reaction requires a solution of an alkali (e.g. sodium hydroxide or potassium hydroxide) in
water and also heat.
• The reaction is used commercially to make soap, lubricants and fire extinguishers.
There are two methods to produce soaps:
• One step process
• Two step process

• One-step triglyceride reaction with lye (base) is most frequently used, there is also two step saponification
reaction.
• In the two step reaction, steam hydrolysis of the triglyceride yields carboxylic acid (rather than salt of it) and
glycerol. In the second step of the process, alkali neutralizes the fatty acid to produce soap.
Advantage of two step process:
• The advantage of the process is that it allows for purification of the fatty acids and thus produces a higher
quality soap.
Disadvantage of two step process:
• The two-step process if slower.

ENZYMES MODIFICATION
• Enzymatic interesterification is now used to produce high-value added structured fat and oil products.
• Specific lipase such as lipolytic enzymes (Candida Rugosa, Aspergillus Niger and Rhizopus Arrhizus) can
produce useful glycerides mixtures that can not be produced by the chemical modification.
• In all glyceride reactions, the lipases catalysed either the removal or the exchange of fatty acid groups on the
glycerol backbone. Different lipases can show preferences for both the position of the fatty acid groups on the
glycerides and the nature of the fatty acids.
• Two types of lipase catalyst identified by application specificity:
o Random lipases, which catalyse reactions at all three positions on the glycerides randomly.
o 1,3-specific lipases, which catalyse reactions only at the outer 1- and 3- positions of the glycerides.

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RANDOM LIPASE
INTERESTERIFICATION
• It is very little advantages over standard chemical techniques.
• Non-specific catalysed reactions with triglycerides produce products similar to those
obtained by chemical interesterification.
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1,3-SPECIFIC LIPASES
• With 1,3-specific lipase as a catalyst, fatty acid migration is confined to the 1- and 3-
position to produce a mixture of triglycerides not possible with chemical
interesterification.

PREPARATION OF LIPASE
• Lipase are manufactured by fermentation of selected microorganisms followed by a
purification process.
• The enzymatic interesterification catalysts are prepared by the addition of a solvent such as
acetone, ethanol, or methanol to a slurry of an inorganic particulate material in buffered
lipase solution.
• The precipitated enzyme coats the inorganic material, and the lipase-coated particles are
recovered by filtration and dried.

ADVANTAGES OF LIPASE-CATALYSED
INTERESTERIFICATION
• Lipase-catalysed interesterification of fat and oil can performed either by stirred batch
reactor or with continuous processing using a fixed-bed reactor.
• The continuous processing using fixed bed reactor is preferred process offering following
advantages:
o It minimize the reaction time due to the high catalyst substrate ratio.
o The catalyst used recovered without damage
oImprove operability

STEPS OF LIPASE-CATALYSED INTERESTERIFICATION
• The continuous fixed-bed interesterification process begins:
• by dissolving the feed stock in a solvent
• followed by treatment to remove enzyme catalyst inhibitors, catalyst terminator (poison)s, and particulate
matter.
• The resulting solution is then partially saturated with water prior to pumping through a bed of hydrated catalyst
particles.
• The reaction products are a mixture of triglycerides and free fatty acids.
• After reaction, the FFA are removed by evapouration and processed for recovery.
• The FFA-free oil is then solvent fractionated to yield the desired triglyceride composition.

SLIDE ENDS HERE
T H A N K S F O R Y O U R AT T E N T I O N !
29/2/2020
CPB30303 Oil & Fat Technol Dr. Mohammed
Danish 34

Fatty Acid Isolation (Unit 4 a)

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