Organic Chemistry - Steam Distillation

Last Monday the lab titled 'Steam Distillation' was performed (semi-microscale procedure). Basically, 10g of ground cloves were put into a flask with water and the mixture was boiled to extract the essential oil, eugenol. This process is called steam distillation, and is used because the normal boiling point of eugenol is 254 degrees C. This way, when water boils, the cloves boil, and eugenol drips out.

The whole lab smelled like gingerbread cookies or besamim. The TA said it reminded her of an alcoholic drink from Sweden, probably glogg.

So here is a diagram of the set-up - somewhat modified simple distillation, since a small separatory funnel had to be used to add water to the boiling mixture (so that the concentrations would remain the same and you wouldn't wind up getting eugenol diluted with a lot of water).


Here's the set-up as it was actually done:

Locked and loaded:

Joints greased - check.
Rubber bands tight - check.
Sep funnel loaded - check.
500 mL flask loaded - check.
Condenser water on - check.
Heating Mantle on - check.

Raise Mantle... BOIL!

Ever so slowly, the condensation line crept up the Claisen connecting tube and then the distilling head, and then began to trickle down into the Erlenmeyer flask as a whitish liquid.


When about 105 mL had been collected the heating mantle was lowered. Now came the solvent extraction, which we are by now familiar with. The white liquid was mixed with ether and the layers separated out. This time, ether was on top, visible here as a bit of a layer on the surface.

Draining of the ether layer:

Eugenol was now dissolved in the ether rather than mixed with water. It was dried out with sodium sulfate, after which it looked like this...

...and then 'twas evaporated with rotary evaporator. Afterwards, just a bit of (hopefully) pure eugenol was left.

Cleanup and completion of procedure:


Post-lab: Find a store that carries glogg. :)