Sodium Stearate
Soaps, detergents, paints, deodorants, ink, latex have a common constituent- Sodium Stearate or Sodium Octadecanoate. This compound is formed by the ‘saponification’ of animal fat and sodium hydroxide. Conventionally, soaps have contained this compound as an essential ingredient even though newer varieties of soaps are bucking the trend. But still, this compound is very much in use, even today.
Let us glance at the manufacturing process of soaps to understand the significance of Sodium Stearate. Beef fat is treated with steam to produce tallow, which is a mixture of fats. One amongst those fats is glyceryl tristearate which is a tri-glyceride with three molecules of stearic acid attached to one molecule of glycerine. When this fat (glyceryl tristearate) is boiled in sodium hydroxide, the product fromed is a mixture of sodium stearate and glycerin.
Henceforth glycerin is detached from this to produce the end result- soap. However, a lot of manufacturers nowadays retain the glycerin, and these kinds of soaps are called glycerin soaps. The sodium end attracts water particles while the hydrocarbon end attracts oil and fat particles.
You may be wondering that if soaps contain oil and fats, how is it that they do not cling on to your skin and clothes. The answer lies in the structure of compounds in the soap. Soap essentially breaks oil and fat into small and fine particles. These particles are encased by soap with the hydrocarbons attached to ends of fat particles and the sodium stearate particles left dangling in water. Therefore the oil particles are surrounded by water molecules, leaving the skin and clothes devoid of oil.
But not all oil particles are encompassed by water particles. Select oil particles escape the layering to settle on the skin or clothes, whichever is subjected to soap and water. Hence, a lot of face-washes have glycerine content in them, which doesn’t allow a trace of oil to be left on the skin, thus preventing acnes and pimple breakouts which happen due to excess oil retention in the skin.
Sodium stearate can also be manufactured using stearin which can be formed using stearic acid and glycerol. Herbs found in palm trees also contain traces of this compound. Apart from all the uses mentioned already, this compound is also used in food additives and various flavoring in food. Easy to manufacture and with such multiple uses, it is no wonder that this compound is such a necessity in our day to day life.