Stearic Acid

Stearic acid is a fatty acid composed of 17 carbons in a linear chain plus a carboxylic acid group. It is bonded to as many hydrogen atoms as possible, so it is said to be a saturated fatty acid.

Stearic acid may be obtained from many animal and vegetable fats and oils. At room temperature it is a waxy solid.Since animal fats are typically triglycerides, stearic acid can be obtained from them by treatment with water at a high pressure and temperature to accomplish hydrolysis of the triglycerides. It can also be obtained from the hydrogenation of some unsaturated vegetable oils.

Stearic acid is used in making candles, soaps, and some plastics. It is used to harden soaps made from vegetable oils. Stearic acid compounds are used to give the pearly effect in shampoos, liquid soaps and cosmetics. Stearic acid is the source of the common scent of crayons. Further details can be found in Wikipedia, from which these details were excerpted.

Linoleic Acid

Linoleic acid is a fatty acid composed of 17 carbons in a linear chain plus a carboxylic acid group. With two double bonds between carbons in the chain, it is said to be an unsaturated fatty acid.

Linoleic acid is called an unsaturated omega-6 fatty acid since the first double bond is located at the sixth carbon atom from the omega end. At room temperature it is a colorless liquid. The word linoleic comes from the Greek word linon (flax). It is abundant in many vegetable oils, especially safflower and sunflower oils.

Physiologically, it is used in the biosynthesis of prostaglandins. It is a member of the essential fatty acids called omega-6 fatty acids, so called because they are an essential dietary requirement for all mammals. The other group of essential fatty acids is the omega-3 fatty acids. A deficiency of linoleic acid can lead to dry hair, hair loss and poor wound healing.

Industrially, linoleic acid is used in making soaps, emulsifiers, and quick-drying oils. Further details can be found in Wikipedia, from which these details were excerpted.