Saponification is a process that produces soap, usually from fats and lye.Learn more with VidyaBharti Educational Institutions

3. • Saponification is an organic chemical
reaction that utilizes an alkali to cleave an
ester into a carboxylic acid and alcohol. As
we will see shortly, the primary use for this
reaction is during the production of soap
products. The terms ester, carboxylic acid,
and alcohol are functional groups. A
functional group is simply a group of
molecules or atoms that we can easily
identify in a compound.

4. Saponification Reaction:
Fat + Lye  Soap + Glycerol

5. What is LYE ?
Lye - Caustic solution made from ashes.
Soda Lye = NaOH
Potash Lye = KOH
How to obtain KOH and NAOH?
Combining potash K2CO3 with slaked lime
Ca(OH)2 yields KOH and CaCO3
NaOH obtained from reacting sodium
compounds.

6. O H
C17H35-C-ONa H-C-OH
O
C17H35-C-ONa + H-C-OH
O
C17H35-C-ONa H-C-OH
H
Soap Glycerol

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

8. 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).

9. What is the significance of saponification
number?
The saponification number (sap) measures the
bonded and unbonded acids present in an oil or
fat. It defines the exact amount of potassium
hydrate in mg necessary to emulsify 1g of fat or
oil. The smaller the molar mass of the fat, the
higher the saponification value.

10. Saponification Table & characteristics of Oils in Soap
oil or fat (acid) SAP Hard/Soft cleansing
fluffy
lather
stable
lather
skin care
Castor oil 128.6 soft fair yes yes great
Olive oil 135.3 soft good no no great
Palm oil 142 hard great no yes fair
Peanutoil 137 soft fair no yes great