Sorbitan is a mixture of

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. Is ...

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

s derived from the

dehydration In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mil ...

sorbitol Sorbitol (), less commonly known as glucitol (), is a sugar alcohol with a sweet taste which the human body metabolizes slowly. It can be obtained by reduction of glucose, which changes the converted aldehyde group (−CHO) to a primary alcoho ...

and is an intermediate in the conversion of sorbitol to isosorbide. Sorbitan is primarily used in the production of

surfactant Surfactants are chemical compounds that decrease the surface tension between two liquids, between a gas and a liquid, or interfacial tension between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsion#Emulsifiers , ...

s such as polysorbates; which are important

emulsifying agent An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although ...

s, with a total annual demand of more than 10000 tons in 2012.

Synthesis

Sorbitan is produced by the dehydration of

and is an intermediate in the conversion of sorbitol to isosorbide. The dehydration reaction usually produces sorbitan as a mixture of five- and six-membered cyclic ethers (1,4-anhydrosorbitol, 1,5-anhydrosorbitol and 1,4,3,6-dianhydrosorbitol) with the five-membered 1,4-anhydrosorbitol form being the dominate product. The rate of formation of sorbitan is typically greater than that of isosorbide, which allows it to be produced selectively, providing the reaction conditions are carefully controlled. The dehydration reaction has been shown to work even in the presence of excess water. Sorbitol-Sorbitan-Isosorbid

Surfactant derivatives

Esters

Sorbitan esters (also known as Spans) are

nonionic surfactant Surfactants are chemical compounds that decrease the surface tension between two liquids, between a gas and a liquid, or interfacial tension between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming ...

s that are used as emulsifying agents in the preparation of emulsions, creams, and ointments for pharmaceutical and cosmetic use. When used alone they produce stable water-in-oil emulsions but they are frequently used with a polysorbate in varying proportions to produce water-in-oil or oil-in-water emulsions or creams with a variety of different textures and consistencies. Sorbitan esters are also used as emulsifiers and stabilisers in food. File:Sorbitan monostearate.svg,

Sorbitan monostearate Sorbitan monostearate is an ester of sorbitan (a sorbitol derivative) and stearic acid and is sometimes referred to as a synthetic wax.

File:Sorbitan_tristearate.png,

Sorbitan tristearate Sorbitan tristearate is a nonionic surfactant. It is variously used as a dispersing agent, emulsifier, and stabilizer, in food and in aerosol sprays. As a food additive, it has the E number E numbers ("E" stands for "Europe") are codes fo ...

File:Sorbitan_monolaurate.svg,

Sorbitan monolaurate Sorbitan monolaurate is a mixture of esters formed from the fatty acid lauric acid and polyols derived from sorbitol, including sorbitan and isosorbide. As a food additive, it is designated with the E number E493. See also * Sorbitan monostearat ...

Polysorbate

Ethoxylated sorbitan esters are known as polysorbates (trade name: Tweens). They are an important class of emulsifiers used in a variety of settings, including pharmaceuticals and food. Polysorbate 60

References

{{Reflist Tetrahydrofurans Non-ionic surfactants Monosaccharide derivatives