saponification - Saponification in corpses, Saponification in fire extinguishers

The hydrolysis of a fat (glyceride) in a basic solution, yielding glycerol and the salts of the fatty acids (soaps). The reaction is an example of an ester hydrolysis.

Saponification is the hydrolysis of an ester under basic conditions to form an alcohol and the salt of the acid. Saponification is commonly used to refer to the reaction of a metallic alkali (base) with a fat or oil to form soap.

CH2-OOC-R - CH-OOC-R - CH2-OOC-R (fat) + 3 NaOH ( or KOH)

both heated →

CH2-OH -CH-OH - CH2-OH (glycerol) + 3 R-CO2-Na (soap) R=(CH2)14CH3 (for example)

Lye is a form of sodium hydroxide (NaOH) which is a caustic base. If NaOH is used a hard soap is formed, whereas a soft soap is formed when potassium hydroxide (KOH) is used.

Vegetable oils and animal fats are fatty esters in the form of triglycerides.

Saponification in corpses

Saponification can also refer to the conversion of fat and other soft tissue in a corpse into adipocere, often called "grave wax."

Saponification in fire extinguishers

Fires involving cooking fats and oils should be extinguished with a wet chemical extinguisher.