Dehydratisierung von β-Cyclodextrin

1. Experiment is contained in the WAKER's Experimental Kit for Schools	yes
2. Experimental procedure has been modified	no
3. Video clip available	no
4. Flash animation available	no
5. Additional material: Work sheets, transparencies

2. Dehydration of β-Cyclodextrin

1 Materials, Chemicals, Time Needed

Beaker/ snap-cap vial
Spatula
Glass rod

β-Cyclodextrin
Distilled water
Concentrated sulfuric acid C

The experiment takes approximately 5 minutes.

2 Procedure and Observations

Wet a portion of β-cyclodextrin in a glass beaker with some water and then add a few milliliters of concentrated sulfuric acid (fume cupboard!).

The white β-cyclodextrin turns yellowish initially and then black. The beaker becomes hot, and a dark brown to black substance forms.

Fig. 2.2: Result of dehydrating β-cyclodextrin

3 Discussion of Results

The extremely hygroscopic sulfuric acid dehydrates β-cyclodextrin. Since cyclodextrins are carbohydrates, the dehydration product is carbon.

4 Tips and Comments

As with the experiment on thermal decomposition, the behavior of β-cyclodextrin can be compared with the reaction of household sugar and starch.

5 Supplementary Information

This experiment, as with the experiment on thermal decomposition, serves only to demonstrate that cyclodextrins are carbohydrates. For further information on the molecular structure of cyclodextrins, look at the production from the raw material, corn starch.
See also the additional information accompanying the experiment on thermal decomposition.

6 References

Tausch, M.; von Wachtendonk, M.; Chemie 2000+ Band 1, C.C. Buchners Verlag Bamberg, 2001, S. 104