Activity 3.3 - Properties and applications of cyclodextrines

• To develop experimental skills including control of variables
• To explain the absorption of substances
• To identify applications of cyclodextrines

The cyclodextrine needed in the following experiments can either be isolated as described later or be bought.

To start the investigation, the teacher could show an advertisement showing a product that promises to remove smells from fabric. The students need information on the structure of cyclodextrines. The students could make predictions about the forces at play. Before carrying out the investigations, the cyclodextrines could be extracted from Febreze® in the following way.

Note: The reduction of the water takes about 1 hour and that of the alcohol about 15 minutes.

• Febrèze®
• Ethanol [F]
• Ice
• Magnetic stirrer with stirring bar
• Beaker (100ml)
• Graduated cylinder (50ml)
• Beaker (400ml)-for cooling

• Pour 40 ml of Febrèze® into the small beaker and, while stirring, reduce the liquid almost until dry with the heatable magnetic stirrer.
• After letting the beaker cool, add 20 ml of ethanol and again, reduce the liquid almost until dry.
• Let the beaker cool and put into larger beaker filled with ice water for a few minutes.
• Save the resulting gel-like perticipate for further investigations.

• Alkaline Phenolphthalein solution [C] (made from 20 ml distilled water)
• 3 ml sodium hydroxide solution (5 M) [C] and 4 ml Phenolphthalein solution (0.1%) [F])
• cyclodextrine
• 2 pieces of cloth
• Pipette
• Spatula

Spread a thin layer of the cyclodextrine onto a piece of cloth. Add a few drops of the alkaline Phenolphthalein solution to both pieces of cloth.

• Cyclodextrine
• Maggi ® food seasoning, liquid
• 2 pieces of cloth
• Spatula
• Piece of white cardboard

Spread a thin layer of the cyclodextrines onto a piece of cloth. Add a drop of Maggi ® food seasoning to both pieces of cloth.

• Gas syringe
• Erlenmeyer flask (250 ml) with stopper
• Short piece of tubing
• Funnel
• Evaporating dish
• Pipette
• Tweezers
• 2 pieces of cloth
• Cyclodextrine
• Cigarette

Spread a thin layer of the gel-like precipitate (product from first activity) onto a piece of cloth. Place both pieces of cloth side by side into the Erlenmeyer flask. Mount a funnel to the gas syringe via the piece of tubing. Fit a cigarette without filter into the funnel. Keep a evaporating dish ready for the cigarette ashes. Collect the cigarette fumes in the gas syringe. Pour the smoke into the Erlenmeyer flask and close the flask tightly right away. After about 1 minute, retrieve the pieces of cloth from the Erlenmeyer flask and dampen them.