Steam Distillation

A probe into the chemistry of perfumes and exotic air fresheners?

Certain compounds, namely organic compounds, which have high boiling points can be distilled by using steam distillation. Steam distillation is the process of purifying a substance through application of steam to them. Basically that means steam distillation purifies stuff by heating something with steam. This process is mainly used to extract essential oils from their associated natural sources, e.g Eucalyptus oil from Eucalyptus leaves.

Typical distillation setup in the lab

Steam distillation works on the principle that immiscible objects when mixed together can lower the boiling point of each other.

Historically and in some regions of the world today essential oils were obtained by a rather primitive and ugly process. By boiling some organic matter with water and then condensing the resultant vapour/gas, one can obtain some essential oils.

Firstly I decided I would make the condenser.
A condenser is usually made out of glass but as I don’t magically produce glass with perfect cuts and fits I made my own design.

Now, I can be what some consider impulsive so in one night I came up with this pile of rubbish made from garden hose and, well, other rubbish. Garbage in = garbage out, folks.

After realizing the complete hopelessness of ever using something like that I rebuilt my condenser in a more planned, sturdier, and definitely better way.

The wonders of PVC and the ability to weld it easily made the construction of this quite easy. The only non-plastic component of this is the copper condensing tube on the inside of the water jacket.

PVC Condenser

A primitive olive oil evaporation chamber

Once the condenser was constructed the only thing left to make was a boiling chamber. My first few attempts resulted in an olive oil bottle with a piece of PVC pipe shoved down its neck. The problem with this was that I could not directly apply heat as it was just glass bottle rather than a borosilicate laboratory-grade piece of glassware. Direct heating may lead to explosions, which are neither pretty nor welcome. However there is never any fun without risk, so away we go!

I have performed two distillations so far- lemon grass and aloe vera. Both produced rather nice smelling solutions of oil and water. So it appears that very simple equipment can lead to impressive results!

Evaporation chamber with lemon grass

This is the entire setup. Crudely constructed, on the left a standard BBQ burner is visible. The evaporation chamber sits on top, and steam is channeled into the condenser tube.

And there you have it. A simple, 15-minute lashup which can bring you hours of perfume joy. Away with Chanel no.5!

Article Author: Nick - contact here




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