What is meant by #"saponification"#?

1 Answer
Mar 6, 2017

I think you mean #"saponification"#, #"soap manufacture"#.


Unless you are a total grub, you would have used soap to have a wash this morning. You also would have used detergents to wash your breakfast dishes.

Saponification is the process that produces soap from vegetable oils and animal fats. Typically fats are tri-esters of long chain (so-called) fatty acids, and glycerol, #"HOH"_2"CCH(OH)CH"_2"OH"#, to give a #"R'OH"_2"CCH(OR')CH"_2"OR'"#, where #"R'={(O=C)R"}"#. Upon base hydrolysis (saponification), the tri-ester is hydrolyzed to give carboxylate salts of the form #"M"^(+)""^(-)"O(O=C)R"#, and glycerol, which separates.

All soaps and detergents have a molecular structure of this form #"M"^(+)""^(-)"O(O=C)R"#; they offer some aqueous solubility by reason of the carboxylate function, but they tend to aggregate by association of the long hydrocarbyl tails in water, and this aggregation hopefully traps any grime and grease, and helps to prevent it from redepositing onto your skin or onto the breakfast plates.


(I would have made that picture LARGER had I a clue as to how to use the editor!)