Cholesteryl benzoate, also called 5-cholesten-3-yl benzoate, is an organic chemical, an ester

Ester

Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...

 of cholesterol

Cholesterol

Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...

 and benzoic acid

Benzoic acid

Benzoic acid , C7H6O2 , is a colorless crystalline solid and the simplest aromatic carboxylic acid. The name derived from gum benzoin, which was for a long time the only source for benzoic acid. Its salts are used as a food preservative and benzoic acid is an important precursor for the synthesis...

. It is a liquid crystal

Liquid crystal

Liquid crystals are a state of matter that have properties between those of a conventional liquid and those of a solid crystal. For instance, an LC may flow like a liquid, but its molecules may be oriented in a crystal-like way. There are many different types of LC phases, which can be...

 material forming cholesteric liquid crystal

Cholesteric liquid crystal

A cholesteric liquid crystal is a type of liquid crystal with a helical structure and which is therefore chiral. Cholesteric liquid crystals are also known as chiral nematic liquid crystals. They organize in layers with no positional ordering within layers, but a director axis which varies with...

s with helical structure.

It can be used with cholesteryl nonanoate

Cholesteryl nonanoate

Cholesteryl nonanoate, also called cholesteryl pelargonate, 3β-cholest-5-en-3-ol nonaoate or cholest-5-ene-3-β-yl nonanoate, is an ester of cholesterol and nonanoic acid. It is a liquid crystal material forming cholesteric liquid crystals with helical structure...

 and cholesteryl oleyl carbonate

Cholesteryl oleyl carbonate

Cholesteryl oleyl carbonate is an organic chemical, an carbonate ester of cholesterol and oleyl alcohol with carbonic acid. It is a liquid crystal material forming cholesteric liquid crystals with helical structure. It is a transparent liquid, or a soft crystalline material with melting point...

 in some thermochromic liquid crystals.

It is used in some hair colors, make-ups, and some other cosmetic preparations.

It can be also used as a component of the liquid crystals used for liquid crystal display

Liquid crystal display

A liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....

s.

Cholesteryl benzoate was the first material in which liquid crystal properties were discovered. In the late 1880s Friedrich Reinitzer

Friedrich Reinitzer

Friedrich Richard Reinitzer was an Austrian botanist and chemist. In late 1880s, experimenting with cholesteryl benzoate, he discovered properties of liquid crystals ....

, an Austria

Austria

Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...

n botanist, while studying the chemicals in plants, heated cholesteryl benzoate. At 145 °C the material melted, yielding a cloudy fluid, which changed to the originally expected clear liquid at 178.5 °C. In 1888, the German physicist Otto Lehmann

Otto Lehmann

Otto Lehmann was a German physicist and "father" of liquid crystal technology.-Life:...

concluded the cloudy fluid presents a new phase of matter, and coined the term liquid crystal.