Stearic acid

Stearic acid (IUPAC systematic name: octadecanoic acid) is one of the useful types of saturated esters of stearic acid.

Production

Stearic acid is prepared by treating animal fat with water at a high pressure and temperature, leading to the hydrolysis of palmitic acid, although purified stearic acid is available separately.

Uses

Stearic acid is useful as an ingredient in making candles, rubber. Stearic acid is used to harden soaps, particularly those made with vegetable oil.

Stearic acid is also used as a parting compound when making plaster castings from a plaster piece mold or waste mold and when making the mold from a shellacked clay original. In this use, powdered stearic acid is dissolved in water and the solution is brushed onto the surface to be parted after casting.

glycol stearate and glycol distearate are used to produce a pearly effect in shampoos, soaps, and other cosmetic products. They are added to the product in molten form and allowed to crystalize under controlled conditions.

In fireworks, stearic acid is often used to coat oxidation allowing compositions to be stored for longer.

It is used along with simple sugar or corn syrup as a hardener in candies.

Reactions

Stearic acid undergoes the typical reactions of saturated carboxylic acids, notably reduction to stearyl alcohol, and esterification with a range of alcohols.

Metabolism

An cholesterol esters. These findings may indicate that stearic acid is less unhealthy than other saturated fatty acids.

See also

• Magnesium stearate

References

1. ^ Emken, Edward A. (1994). "Metabolism of dietary stearic acid relative to other fatty acids in human subjects" (PDF). American Journal of Clinical Nutrition 60: 1023S–1028S. Retrieved on 2006-08-07.

• Merck Index, 11th Edition, 8761.