1. Oils and Fats Major Component (%95-99) Triglycerides
Minor Components (%1-5)
Triglyceride Derivatives
Glycerol
Free Fatty Acids
Mono- and Diglycerides
Non-Triglyceride Derivatives
Phospholipids
Sterols
Pigments
Vitamins
Antioxidants
Oxidation Products
Trace Metals
Hydrocarbons

2. Triglyceride StructureO C
- R1
triacylglycerol =
- R2
- R3 HC
H2C OH
glycerol HC
H2C
HO - C O
- R1
3 fatty acids +
- R3
- R2
+3H20 O R
One chiral carbon with 1-3 acyl groups
simpler stereochemistry than sugars - C
more possible substituents
acyl

3. Saponification General reaction Fat + Base  Soap + glycerine
Base = chemical that contains OH at the end
Creating soap from fats or oils.
Soaps are usually made from vegetable fats and oils. These consist of 3 fatty acid chains, held together by a glycerol molecule.
Fatty acid
glycerine

4. Triglycerides differ from each other in regard to
Number of Carbon Atoms in fatty acid chains
Number of double bonds
Isomerization
Distribution of FA on glycerol backbone

5. How are soaps made?

6. This reaction is basically the opposite of an esterification
Esterification – remove HOH to connect molecules
Saponification – Add NaOH to break molecules
Esterification
Saponification H HO Na HO

7. The sodium part has a + and – charge, so it’s polar at this end.
What is a soap?
Because a soap molecule has a long carbon chain, it is partially nonpolar.
The sodium part has a + and – charge, so it’s polar at this end.
On end can attract polar molecules like water (hydrophilic), the other end can attract nonpolar molecules like oil (hydrophobic)
Nonpolar +
Polar Na
Attracts oil
Attracts water

8. Saponification Reaction:
Fat Lye  Soap + Glycerol

9. Lye - Caustic solution made from ashes.
Soda Lye = NaOH
Potash Lye = KOH
Combining potash K2CO3 with slaked lime Ca(OH)2 yields KOH and CaCO3
NaOH obtained from reacting sodium compounds.

10. O H
C17H35-C-O-C-H NaOH  O H
Fat Lye
(Triglyceride)

11. O H
C17H35-C-ONa H-C-OH O
C17H35-C-ONa H-C-OH H
Soap! Glycerol

12. How does it happen?? O
Break the ester linkages C – O- by hydrolyzing the bonds between the carbon backbone and the fatty acid chains.
(Reversal of esterification reaction)
Form the sodium salt of a fatty acid (soap) and a trihydroxy alcohol (glycerol).

13. The Chemistry http://en.wikipedia.org/wiki/Saponification

14. If oil is added to water, the two liquids do not mix.
Because of this, grease stains can be difficult to remove during washing.
soap molecule
Soaps are compounds which act as emulsifiers.
This means that they help the oil to mix with the water.
water
oil

15. How do soaps work?

16. Organic Reaction: Slow!
Must break covalent bonds.
Refluxing: Technique which allows a volatile solvent to boil, condense and return to the reaction vessel. It helps to maintain a fairly constant temperature throughout the reaction period.

17. Strange but true…
Fat in cadavers: saponifies if conditions are right. Alkalai environment, moist, minimal oxygen.
Adipocere or grave wax is formed.

18. Saponification Value
Saponification - hydrolysis of ester under alkaline condition.
The saponification value of an oil or fat is defined as the number of mg of potassium hydroxide (KOH) required to neutralize the fatty acids resulting from the complete hydrolysis of 1 g of the sample.

19. Saponification Value Determination
Saponification # --mgs of KOH required to saponify 1 g of fat.
1. 5 g in 250 ml Erlenmeyer.
2. 50 ml KOH (0.5 N) in Erlenmeyer.
3. Boil for saponification.
4. Titrate with HCl (0.5 N) using phenolphthalein.
Conduct blank determination.
B - ml of HCl required by Blank.
S - ml of HCl required by Sample.
N- Factor of 0.5 N HCL.