Molecular distillation refers to a special type of short path distillation that is used to purify and concentrate a variety of chemicals ranging from complex and thermally sensitive compounds like polyunsaturated fatty acids and natural oils, to high performance silanes and isocyanate functional pre-polymers.
In a traditional ‘kettle’ distillation the entire product volume is subjected to heat and vacuum for extended periods of time. This extended ‘cook’ time can cause many compounds to thermally degrade or develop undesirable color characteristics.
Molecular stills avoid this problem by wiping a thin layer of material around the inside of the vessel while the material is subjected to high temperature and low vacuum. Because molecular distillation units work on a continuous production basis, the resonance time within the unit can be as low as 10, or up to 30 seconds. The lack of significant heat history on a property means that you can purify material without risking the integrity of your product integrity or performance characteristics.
Molecular stills allow you to ‘hone-in’ on the optimal finished product concentration by adjusting 3 different variables: pressure, temperature, and feed rate into the unit. The pressures reached on a molecular still are lower than you can typically get on a traditional distillation unit or column, somewhere in the range of 0.01 torr.
Some toll manufacturers, like InChem, can consistently reach those pressures while processing the material at temperatures that range from 50C to 300C. Making sure to balance the pressure, temperature and feed rate into the unit allows InChem to consistently hit solids targets without degrading material or generating color-bodies.
Molecular distillation is useful in a variety of applications including natural oils and fats, silanes, monomers, tocopherols and a variety of other compounds.
Learn more about how InChem can provide you with custom molecular distillation services using our online contact form or call 1-800-331-7721.