• 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.

Saponification Reaction:

Fat + Lye Soap + Glycerol

What is LYE ?Lye - Caustic solution made from ashes.Soda Lye = NaOHPotash 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.

O H

C17H35-C-ONa H-C-OH

OC17H35-C-ONa + H-C-OH

OC17H35-C-ONa H-C-OH

H

Soap Glycerol

O HC17H35-C-O-C-H + NaOH

OC17H35-C-O-C-H + NaOH

OC17H35-C-O-C-H + NaOH

H

Fat Lye (Triglyceride)

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).

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.

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

Peanut oil 137 soft fair no yes great