sorbitan

Sorbitan is a mixture of isomeric organic compounds derived from the dehydration of sorbitol and is an intermediate in the conversion of sorbitol to isosorbide. Sorbitan is primarily used in the production of surfactants such as polysorbates; which are important emulsifying agents, with a total annual demand of more than 10,000 tons in 2012. Sorbitan and Sorbitol esters are an uncommon allergen.

==Synthesis== Sorbitan is produced by the dehydration of sorbitol 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 dominant 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.