Fatty alcohols

Fatty alcohols, if they occur naturally, are usually higher, unbranched (linear) aliphatic alcohols. They are mainly obtained from the corresponding fatty acids by a chemical reaction. In this process, the carboxyl group (-COOH) typical of carboxylic acids is converted into the hydroxyl group (-OH) typical of alcohols. The carbon atom of the -COOH group is retained as -CH2-OH.

Just like fatty acids, fatty alcohols can also have double bonds, i.e. be unsaturated. The term fatty alcohol is used for alcohols with a chain length of 6 (hexanol) up to 22 carbon atoms.

The higher primary alcohols with 24 to 36 carbon atoms are called wax alcohols (because of their waxy consistency). Wax alcohols are found in bound form as carboxylic acid esters in natural waxes, such as wool wax from sheep.

Examples of saturated fatty alcohols are: Hexanol (C6H13OH), Octanol (C8H17OH), Decanol (C10H21OH), Dodecanol (Lauryl alcohol -C12H25OH), Tetradecanol (Myristyl alcohol -C14H29OH), Hexadecanol (cetyl alcohol -C16H33OH), heptadecanol (C17H35OH), octadecanol (stearyl alcohol- C18H37OH), eicosanol (C20H41OH), behenyl alcohol (C22H45OH).

Examples of monounsaturated fatty alcohols are: Delta-9-cis-hexadecenol (C16H31OH), Delta-9-octadecenol (C18H35OH) and others.

Example of a polyunsaturated fatty alcohol is octadecatrienol (C18H31OH).

Fatty alcohols are not miscible with water. However, they can be converted into fatty alcohol sulphates by reaction with chlorosulphonic acid. These are of great importance as anionic surfactants. In addition, fatty alcohols are used as a base for many creams and ointments due to their good compatibility.