Cyclodextrins (CDs) are carbonhydrates, isolated from starch by fermentation. They consist of a cavity, hydrophilic outside and hydrophobic inside. This unique structure let them to accommodate with great variety of guest molecules, thus allowing them to be widely applied in food industry, pharmaceuticals, etc. Therefore, “searching for proper solvents and increasing its solubility is the key step to expand the application of ß–cyclodextrin. As a new kind of green solvents, ionic liquids (ILs) have a variety of excellent properties, such as negligible vapor pressure, onﬂammability, thermal and chemical stability, chemical unabilities, and recyclability. This makes ILs attractive as the potential novel materials in catalysis, organic synthesis, separation, and electrochemistry” (Zheng A).
“In this work, the solubilities, standard solution Gibbs energies solution enthalpies, and solution entropies have been determined for ß-CD in six kinds of hydrophilic ionic liquids” (Zheng F). ß-CD was notable in these ILs. Dissolution of ß-CDs in hydrophilic ILs and hydrophobic ILs differed. In hydrophobic ILs “the disruption of the attractive interactions and the ordered structures of the ILs predominates the dissolution process” (Zheng F). In hydrophilic ILs solutions opposite results were obtained. In them, the process “was driven by the inclusion of cations of the ILs into the cavity of ß–CD” (Zheng F). Beside that, effects of ILs structure on ß–CD’s solubilities were recognized. This showed that ß–CD’s solubilities were “much higher in the dicyanamide-based ILs than in the chloride-based ILs because of the weaker interactions in the former systems” (Zheng F).
Concerning my point of view, this research must be continued as ß–CDs are very useful. Today ß–CD is registered in food industry as food supplement E459. Also, as ß–CDs are used in cosmetics industry, further research can bring the result of reducing allergic reactions on waxes used in it.
Zheng, Yong, Xuan, Xiaopeng, Wang, Jianji, Fan, Maohong. “The Enhanced Dissolution of ß-Cyclodextrin In Some Hydrophilic Ionic Liquids”. 2009. PDF file.