Sorbitol / mannitol separation


Sorbitol, also known as glucitol, is a sugar alcohol.

It can be obtained by reduction of glucose, changing the aldehyde group to a hydroxyl group.

Most sorbitol is made from corn syrup.

Sorbitol is a sugar substitute.

Mannitol is a white, crystalline solid with the chemical formula ( C6H8(OH)6 ).

It is mainly used to produce tablets of medicine.

Mannitol and sorbitol are isomers, the only difference being the orientation of the hydroxyl group on carbon 2.

Mannitol is commonly produced via the hydrogenation of fructose, which is formed from either starch or sucrose.

A typical blend of mannitol / sorbitol is between 20 - 50% mannitol with an objective to produce a 98% or more pure product.

A common approach is to crystallize the blend to produce the pure product. This approach produces an extremely high amount of liquor which contains still a significant amount of mannitol concentration ( 10 - 20%).

This could be avoided by using PuriTech's ION-IX continuous countercurrent ion exchanger as a chromathographic system.

Possible applications :

1 - Purify the mother liquor to 70 - 80% mannitol and re-process this purified liquor through the crystallizer

example:    Feed liquor to crystillizer = 50% Mannitol / 45% Sorbitol   -> after crystillizer 98% pure product

                   Mother liquor to chromathographic unit is: 10 - 20 Mannitol / 75 - 85% Sorbitol   -> after ION-IX is a 96% Sorbitol and 70-80% Mannitol produced


2 - Purify the liquor before the crystaillizer and almost eliminate the mother liquor.

example:    Feed liquor to ION-IX = 50% Mannitol / 45% Sorbitol   -> after ION-IX is 98% Mannitol + 2% Sorbitol

                   and second product is 97% Sorbitol + 3% Mannitol fraction.