The document discusses fats, oils, detergents and their analysis. It begins by defining fats and oils as glycerol esters of fatty acids. It describes the different types of fats and oils that occur in nature, including vegetable oils like olive oil and palm oil, and animal oils like whale oil and lard oil. It then discusses the manufacture of soybean oil using solvent extraction. The document concludes by explaining the analysis of fats and oils using tests like acid value, saponification value and iodine value. It also describes the different types of detergents like sodium alkyl sulfates and their cleansing action.

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B. Sc. Third Year
Semester-V
CH-04:- Module-1 : Fats, Oils and Detergents
Welcome
CH-04: Fats, Oils and Detergents
Dr. Bhimraj N. Gawade
M. Sc. CSIR-UGC-NET (JRF), Ph. D.
Assistant Professor
Department of Chemistry
Anandrao Dhonde Alias Babaji Mahavidyalaya, Kada.
Tal. Ashti. Dist. Beed - 414 202, Maharashtra, INDIA

2. CH-04: Fats, Oils and Detergents
 Fats, Oils and Detergents Points to be studied
1. Fats and Oils
2. Kinds of oils occur in nature
3. Vegetable oils
4. Animal oils
5. Manufacture of Soyabean Oil by Solvent Extraction
6. Analysis of oils and fats
7. Acid value
8. Saponification value
9. Iodine value
10. Detergents
11. Cleansing action of detergent
12. Sodium alkyl sulphonate
13. Alkyl benzene sulphonate
14. Amide sulphonate
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3. C
H2C
CH
H2C
C
C
R
R'
R''
O
O
O
O
O
O
A] Fats and Oils:- Fats and Oils are compounds of glycerol & various organic acids
i.e. They are glyceryl esters or glycerides.
Chemically, Fats & oils are triesters of glycerol with long chain carboxylic acids and their
structures are represented as
A] Fats and Oils
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4. Oils at ordinary temperatures are liquids contain a larger proportion of unsaturated acids
than the fats, which are solids at ordinary temperature.
These acids are straight chain acids with even number of carbon atoms.
The chief saturated acids are lauric, myristic, palmitic and stearic.
The unsaturated acids are oleic, linolenic etc.
The palmitic and is most abundant of saturated acids.
Glycerides are named according to the nature of the acids present.
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5. Simple Glycerides: It is when the alkyl groups present in a glyceride are the same.
C
H2C
CH
H2C
C
C
C17H35
C17H35
C17H35
O
O
O
Tristearin (Simple glyceride, fat)
O
O
O
Glyceryl tristearate
e.g. ii) Tripalmitin (Simple glyceride, fat)
e.g. i) Tristearin (Simple glyceride, fat)
C
H2C
CH
H2C
C
C
C15H31
C15H31
C15H31
O
O
O
Tripalmitin (Simple glyceride, fat)
O
O
O
Glyceryl tripalmitate
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6. Mixed Glycerides: It is when the alkyl groups are different from each other.
e.g. iv) Palmito-diolein (Mixed glyceride, oil)
e.g. iii) Oleo-palmito- stearin
(Mixed glyceride, fat)
C
H2C
CH
H2C
C
C
C15H31
C17H33
C17H35
O
O
O
(Mixed glyceride, fat)
O
O
O
Glyceryl Oleo-Palmito-Stearate
C
H2C
CH
H2C
C
C
C15H31
C17H33
C17H33
O
O
O
(Mixed glyceride, oil)
O
O
O
Glyceryl Palmito-Dioleate
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7. Formula Molecular formula Common name
Saturated fatty acids
CH3(CH2)10COOH C11H23COOH Lauric acid
CH3(CH2)12COOH C13H27COOH Myristic acid
CH3(CH2)14COOH C15H31COOH Palmitic acid
CH3(CH2)16COOH C17H35COOH Stearic acid
Unsaturated fatty acids
CH3(CH2)7CH=CH(CH2)7COOH C17H33COOH Oleic acid
CH3(CH2)3(CH2-CH=CH)2(CH2)7COOH C17H31COOH Linoleic acid
CH3(CH2-CH=CH)3(CH2)7COOH C17H29COOH Linolenic acid
Common Fatty Acids
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8.  There are three types of fats and oils occur in nature
1. Mineral oils:- They consist of a mixture of aliphatic hydrocarbons and occur underground like
minerals e.g. kerosene, petrol etc.
2. Essential oils:- They are volatile pleasant smelling liquids and occur in the various parts of the
plants e.g. flowers, leaves, stem. Mostly they are cyclic and belong to the family of
terpenes and camphor’s. e.g. oils of rose, lavender etc.
3. Fixed oils:- They are non-volatile fats, found in animals and plants. Also known as "vegetable
oils". They are glycerides of higher fatty acids. In the plants they chiefly occur in
seeds & form reserves for germination of embryo.
In the animals they occur under the skin, in muscles
and serve as store house of energy in time of hunger.
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9.  Vegetable oils
a) Olive oil:- Olive oil is a colourless to golden yellow oil obtained from olive tree. The higher
grades are used for edible purpose, while lower grade oils are used as lubricants for bearing
and machine parts subjected to low pressure but high speeds.
b) Palm oil:- It is a pleasant smelling pale yellers oil m. p. 280C. It is obtained by compressing
the kernels of palm fruits. It is mostly used for the lubrication of delicate apparatus like
watches and scientific instruments etc.
c) Castor oil:- It is a colourless to pale green oil obtained by compressing castor seeds.
It possesses excellent oiliness, but is insoluble in petroleum.
It is used for lubrication of bearing & machine parts subjected
to low pressure but high speeds and as edible oil.
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10. d) Rape-seed or colza oil:- It is a colourless characteristic smelling pale yellow oil extracted
from colza plant. It is used for lubrications of steam cylinder and delicate apparatus.
e) Hazel nut oil:- It is obtained from hazel nuts. It is used for lubrications of watches.
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11.  Animal oils
a) Whale oil:- It is a very this plate yellow oil obtained by the distillation of different parts of
sperm whale fish, on exposure to air it gets solidified giving sperm wax. It is used
to lubricate light machinery.
b) Neat foot oil:- It is a characteristic smelling pale yellow oil obtained by boiling foot of neat
with water. It is widely used for lubrication of sewing machines, guns, watches etc.
c) Lard oil:- It is colourless oil obtained from kidneys and intestine of pigs. It is used for
lubrication of ordinary machines.
d) Tallow oil:- It is a transparent oil obtained by compressing
cattle fat under high pressure. It is used for
lubrication of high speed machines.
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12.  Manufacture of Soybean Oil by Solvent Extraction
Crude soybean
Air blower
Crusher Crushed
material
Material
Pure Oil
Benzene
vapours
Condenser
Steam
Solvent
extractor
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13. Soybean seeds are obtained in the crude form.
It consists of dirt and other impurities.
They are removed by blowing air.
These seeds are first crushed by feeding through a hopper into the crushing chamber of
corrugated rolls.
The crushed material is then cooked at low temperature in a stacked cooker or in a steam tube
heater. The albumin is coagulated.
The heated crushed material is called as meat, which flows into moulding machines & slowly
transferred into solvent extractor.
It works on counter current extraction principle.
Extractor contains number of containers moving in
circular, vertical and horizontal directions.
Crushed material is placed on perforated plates.
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14. Benzene or hexane vapours are passed through perforated plates into crushed material.
The portion of solvent with oil or fat condenses in the space below the perforated plates.
The uncondensed solvent vapours are expelled away through an outlet pipe by steam coils.
They are condensed together with water in a condenser.
The solvent is separated from water in separator and again used for extraction.
The extraction is complete when no steam passes out with the solvent vapour.
The oil or fat collected at the bottom of the extractor is again blown with steam whereby
solvent associated with oil is taken out of the extractor, screened, filtered and then stored for
refining.
This method gets oil or fat about 90%.
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15.  Analysis of fats and oils
Fats and oils are characterized by means of physical as well as chemical tests. The usual
physical constants those are determined are melting point, solidifying point, specific gravity
and refractive index. The chemical tests give an indication of the type of fatty acids present in
oil and fat.
1) Acid value:- Acid value is indicates the amount of free fatty acids present in oil or fat. The
acid value of a fat or oil is the number of milligrams of potassium hydroxide required to
neutralise the free organic acids present in 1 g of fat or oil. It is determined by dissolving a
weighed quantity of oil and fat in alcohol and titrating against
standard alkali, using phenolphthalein as indicator. A high acid
value is indicative of a stale oil or fat stored under improper
conditions.
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16. 2) Saponification value:- Saponification value is defined as the number of milligrams of potassium
hydroxide required to neutralise completely the fatty acids resulting from complete hydrolysis of
1 g fat or oil.
It is determined by refluxing a weighed amount (1-2 g) of the fat or oil with known excess of
standard alcoholic caustic potash solution and back titrating the excess alkali with a standard acid.
The saponification value gives an idea about the molecular weight of fat or oil. The smaller the
saponification value, the higher the molecular weight.
It is also useful in calculating the amount of alkali needed for converting a definite amount of fat
or oil into soap and in detecting the adulteration of a fat
or oil by one of lower or higher saponification value.
The difference between saponification value and acid
value is known as ester value of the fat or oil.
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17. 3) Iodine value:- Iodine value is defined as the number of gram of iodine combine with 100 g of fat
or oil gives the degree of unsaturation of the acids in the substance.
As iodine does not react readily, in actual practice iodine monochloride is used.
Iodine value of a fat or oil is a measure of its degree of unsaturation and gives an idea of its drying
character.
It also helps in finding the adulteration in a fat or oil and judging its suitability for making soap.
A weighed amount of fat or oil is taken in iodine value flask, dissolves in 15 mL of pure
chloroform or carbon tetra-chloride and treated with 25 mL of Wijs' reagent (ICl).
The stopper of the flask is moistened with potassium iodide
solution and the flask is kept in dark for 30-60 minutes.
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18. The solution is then mixed with 15 mL of 10 percent potassium iodide and titrated with standard
thiosulphate solution, using starch as indicator.
A blank determination is also carried out in the absence of oil or fat.
The difference between the volumes in mL of thiosulphate solution (say N/10) in the two titrations
indicates the equivalent of iodine absorbed.
Thus, Iodine value = (a-b) x 1.27
W
Where,
a = reading for the blank experiment.
b = reading for actual experiment.
W = weight of fat or oil taken.
The iodine value of non-drying oils (groundnut, mustard)
ranges from 85-105, for semi-drying oils (cotton seed,
sesame) from 105-120, while for drying oils
(linseed, soyabean) it is above 120. 18

19. B] Detergents
Certain organic substances have cleaning action on cloths. They remove dust and greasy material
without disturbing the colour of the cloth. These substances added in soup. They are called as
detergents. There are three types of detergents.
1) Sodium alkyl sulphates:- When oils f fats are reduced by means of excess of hydrogen in the
presence of copper salts as catalysts of high temperature and under pressure, glycerol and higher
monohydric alcohols are formed. Tristearin gives octadecyl alcohol. The alcohols containing ten
or more carbon atoms are prepared. The sodium alkyl sulphates of these alcohols act as
detergents.
eg. C12H25OSO2O-Na+ sodium lauryl sulphates and
C16H33OSO2O-Na+ sodium Cetyl sulphate.
These salts produce leather with water and are not affected by
hard water. Unlike ordinary soaps they do not produce alkali
on hydrolysis and woollen garments do not shrink on washing. 19

20. 2) Some quaternary ammonium salts:- It having one or more long chain alkyd groups are used as
detergents.
e.g. Trimethyl stearyl ammonium bromide
N
C18H37
H3C
CH3
CH3
Br
Trimethyl stearyl ammonium bromide
3) Partially esterified polyhydroxy compounds:- They are obtained by partial esterification of
polyhydroxy compounds acts as detergents. e.g. Monostearate of penta-erythritol.
OH
H2C
C
H2C
HO
CH2
HO
CH2
OH
Pentaerythritol
OH
H2C
C
H2C
OH
CH2
HO H2
C
O
Pentaerythritol monostearate
C
O
C17H35
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21.  Cleansing action of detergent
Greasy material (oily) is always coming out of the skin which holds the dirt on the skin or cloths.
On rubbing with soap and water the dirt is washed away due to the two-fold action of soap.
1. Soap emulsifies the grease and looses its grip on the dirt
2. Soap forms a colloidal solution in water, which absorbs the dirt particles and removes them.
A more scientific explanation is that detergents act by lowering the surface tension of water.
An aqueous solution of detergent will act more speedily than simple water.
The molecules of detergent contain one group which has strong attraction for water
(hydrophilic group) & another group which has the opposite
effect (hydrophobic group).
Thus in fatty acids -COOH is hydrophilic,
while alkyl group is hydrophobic.
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22. When the fatty acid is converted into a soap i.e. sodium or
potassium salt, the hydrophilic end of the detergent is in the
water, while the hydrophobic end is towards.
The emulsified particles i.e. the detergents particle act on
grease and are separated from cloth & cleaning it.
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23. Some examples of detergent
1) Sodium alkyl sulphate:-
a) The sodium alkyl sulphates are prepared by treating the sodium salt of the acid with
respective dimethyl or diethyl sulphate.
e.g. Sodium alkyl sulphate
Na
C
H3C
O
O
Sodium acetate
S
O
O
O O
C2H5
C2H5
Diethyl sulphate
+ Na
C
H3C
O
OC2H5
Ethyl acetate
S
O
O
O O
C2H5
+
Sodium ethyl sulphate
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24. b) The Sodium alkyl sulphates are prepared by treating lauryl alcohol with sulphuric acid gives
lauryl hydrogen sulphate, which on further hydrolysis with NaOH.
e.g. Sodium lauryl sulphate
H2
C
C11H23 OH
Lauryl alcohol
H2SO4
S
O
O
OH
CH2
C11H23
O Na
S
O
O
O
CH2
C11H23
O
Lauryl hydrogen sulphate
NaOH
Sodium lauryl sulphate
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25. c) The Sodium alkyl sulphates are prepared by treating cetyl alcohol with sulphuric acid
gives cetyl hydrogen sulphate, which on further hydrolysis with NaOH.
e.g. Sodium cetyl sulphate
H2
C
C15H31 OH
Cetyl alcohol
H2SO4
S
O
O
OH
CH2
C15H31
O Na
S
O
O
O
CH2
C15H31
O
Cetyl hydrogen sulphate
NaOH
Sodium cetyl sulphate
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26. 2) Alkyl benzene sulphonate:-
Alkyl benzene sulphonate are prepared from benzene. It is treated with long chain alkyl
halide in the presence of anhydrous AlCl3 and the product treated with HCl to form
alkyl benzene (Friedal -craft's reaction).
+ R-Cl
Benzene
Anhydrous AlCl3
Alkyl benzene
R
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27. Alkyl benzene is sulphonated with fuming H2SO4 to form sulphonic acid.
Alkyl benzene
R R R
SO3H
SO3H
+
Fuming
H2SO4
Ortho
Para
At low temperature ortho isomer is formed, whereas at high temperature
para isomer is formed.
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28. Sulphonic acid is neutralized with sodium hydroxide to form alkyl benzene sulphonate
sodium salt.
R
SO3H
NaOH
R
SO3 Na
Alkyl benzene sulphonate
sodium salt
Alkyl benzene
sulphonic acid
Where, R= C12 to C18 carbon chains.
The sulphates and sulphonates retain their efficiency in hard water because their calcium
and sodium salt are soluble in water.
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29. 3) Amide sulphonate:-
Alkyl benzene sulphonate amide derivatives are prepared from hydrocarbon
e.g. Alkyl benzene is treated with chlorosulphonic acid to form chlorosulphonic acid
derivatives.
R R
SO2Cl
Alkyl benzene
+ Cl S
O
O
OH
Chlorosulphonic acid
2 + HCl + H2SO4
Chlorosulphonic acid
derivatives
It is then treated with Ammonia (Con.) to form sulphonamide derivative.
R
SO2Cl
+ + NH4Cl
Chlorosulphonic acid
derivatives
2 NH3
R
SO2NH2
Alkyl benzene sulphonate
amide derivative
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