Soap Making A 20-mule team hauling borax out of the valley. Photo provided by the National Park Service. Borax (Na 2 B 4 O 7 _ 10H 2 O), the most widespread borate mineral was found to help remove dirt from people and cloth. Borax is crumbly and powdery, and dissolves easily in water. Borax became an alternative to the very harsh soap which was used prior to the discovery of borax in the late 1800's. This light and easy to use substance was hailed the world over as a washing, cleansing, antiseptic, preservative, and medicine miracle. In the 1880s, large borate deposits were discovered in Death Valley, California. However, the Death Valley borate deposits were located almost 170 miles from the nearest railway. In order to get the borate to the railway economically, the owners of the Death Valley mines used large wagons pulled by teams of 20 mules. The detergents made from this borate were thus sold as "20 Mule Team Borax". A 20 mule team hauling borax in Death Valley

Soap Article KeysKeys ChemMatters Feb QuestionsQuestions The Story on Suds (8 min 19 sec) Soap Article ChemMatters Feb QuestionsQuestions

Saponification glyceryl tripalmitate (tripalmitin) glycerol 3 sodium palmitate (soap) CH 2 – O – C – (CH 2 ) 14 CH 3 CH – O – C – (CH 2 ) 14 CH 3 CH 2 – O – C – (CH 2 ) 14 CH 3 O O O CH 2 – OH CH – OH CH 2 – OH O 3 Na + - OC – (CH 2 ) 14 CH 3 3 NaOH + + sodium hydroxide Process of making soap from animal fat or vegetable oil using a base.

A Phospholipid polar head nonpolar tails (a) chemical structure of a phospholipid (b) simplified way to draw a phospholipid polar head nonpolar tails Timberlake, Chemistry 7 th Edition, page 576

Phospholipid Graphics: Jane Wang

Lipid Bilayers Micelle Bilayer Liposome Individual units are cylindrical (cross-section of head equals that of side chain) Individual units are wedge-shaped (cross-section of head greater than that of side chain) Aqueous cavity

A Model of a Cell Membrane Timberlake, Chemistry 7 th Edition, page 587 Polar Nonpolar Cholesterol Proteins Phospholipid bilayer

Formation of a Triglyceride

Stearic Acid Kelter, Carr, Scott, Chemistry A Wolrd of Choices 1999, page 257 Fatty acid Carboxylic acid group Soap COO - bonds to a metal ion (Na + ) Na + H + lost from COOH

Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

Sodium stearate: a soap Sodium dodecyl sulfate: a detergent

Cleaning Action of Soap Micelle Timberlake, Chemistry 7 th Edition, page 573

Micelle Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

micelle Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

SOAP vs.DETERGENT -- made from animal and-- made from petroleum vegetable fats-- works better in hard water Hard water contains minerals w /ions like Ca 2+, Mg 2+, and Fe 3+ that replace Na 1+ at polar end of soap molecule. Soap is changed into an insoluble precipitate (i.e., soap scum). micelle: a liquid droplet covered w /soap or detergent molecules

Solvation NONPOLAR POLAR “Like Dissolves Like”

Solvation Soap / DetergentSoap / Detergent –polar “head” with long nonpolar “tail” –dissolves nonpolar grease in polar water micelle

Lab - Soap Making KeysKeys Lab: SOAP making