Introducing Our Science Advisor

Katherine Leslie Soaps is delighted to introduce our readers to someone who has an incredible talent for explaining molecular goings on, and a sense of humor as well . He has chosen to keep his day job for now, and be identified on this blog only as "Uber Brainiac". I will address him as "Doc". Doc is a high school friend who has since reached dizzying heights in the research laboratory. He has very generously agreed to occasion us with helpful descriptions as needed. We thought that a good place to begin would be with a definition of the word "saponification".

Picking the Big Brain: Saponification

Saponification is a chemical reaction whereby a fat or oil (fatty acid ester) is hydrolyzed with an alkali to produce an alcohol and the alkali salt of the fatty acid.

1. Mostly, we think of fats or oils as triglycerides (three fatty acids connected to the same alcohol-end of a molecule).

2. When the alkali (also called “caustic soda” or “caustic” or “sodium hydroxide” or “lye”), typically in a water solution, reacts with the ester, the reaction takes place that we call saponification.

3. As soon as all of the ester linkages are hydrolyzed by the caustic, one molecule of glycerin is created, and, in the case of a triglyceride being used, 3 molecules of the “soap” are created. The soap is actually the sodium (Na) or potassium (K) salt of the triglyceride acid. Neat thing about this is: the end of the molecule with the K or Na on it is “water-loving” or hydrophilic and the “fatty” end is water-fearing, or hydrophobic. That’s what makes soap work. The fatty end attaches to the dirt (grease, oil, etc…) on your skin, and the water-soluble hydrophilic end allows the soap-encrusted grease particle to be rinsed away. This soap-encrusted grease particle is sometimes called a “micelle.” (MY-sell)

4. Glycerin, or glycerol, is a by-product of this reaction, and is actually an alcohol by chemistry classification. Although glycerin is classified as such, it is an emollient and humectant...
   

   (from Wiki)

   Pharmaceutical and personal care applications:

   Glycerol is used in medical and pharmaceutical and personal care preparations, mainly as a means of improving smoothness, providing lubrication and as a humectant. It is found in cough syrups, elixirs and expectorants, toothpaste, mouthwashes, skin care products, shaving cream, hair care products, and soaps.

Cool stuff! ~U.B.