Stearic Acid Overview

Stearic Acid (IUPAC systematic name: octadecanoic acid) is one of the useful types of saturated fatty acids that comes from many animal and vegetable fats and oils. It is a waxy solid, and its chemical formula is CH3(CH2)16COOH. Its name comes from the Greek word stéar (genitive: stéatos), which means tallow. The term stearate is applied to the salts and esters of Stearic Acid.

Stearic Acid (also called Octadecanoic Acid)  is nature’s most common long-chain fatty acids, derived from animal and vegetable fats. It is widely used as a lubricant and as an additive in industrial preparations. It is used in the manufacture of metallic stearates, pharmaceuticals, soaps, cosmetics, and food packaging. It is also used as a softener, accelerator activator and dispersing agent in rubbers.

Stearic Acid is prepared by treating animal fat with water at a high pressure and temperature, leading to the hydrolysis of triglycerides. It can also be obtained from the hydrogenation of some unsaturated vegetable oils. Common Stearic Acid is actually a mix of Stearic Acid and palmitic acid, although purified Stearic Acid is available separately.

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

An isotope labeling study in humans concluded that the fraction of dietary Stearic Acidoxidatively desaturated to oleic acid was 2.4 times higher than the fraction of palmitic acid analogously converted to palmitoleic acid. Also, Stearic Acid was less likely to be incorporated into cholesterol esters. These findings may indicate that Stearic Acid is less unhealthy than other saturated fatty acids.