| + | Tuesday, 15 October 2013 |
Making Essential Oil
Today we made essential oil! We extracted D-Limonene from orange peel, which is an essential oil that has anti carcinogenic properties and is also used in numerous cleansing products. Using fruit peels is good for the environment, as the peels are usually discarded after consumption, and this is a form of reusing the peels.
Fig 1. The two commonly found isomers of Limonene, D-Limonene and L-Limonene. D-Limonene smells like citrus.
The primary method of extraction is through steam distillation, which is the oldest form of essential oil extraction. The process does not denature the structure of D-Limonene. Hot steam opens the pockets in which the oils are kept and release D-Limonene from the fruit peels.
To extract D-Limonene from orange peel, we first cut out only the coloured part of the peel of an orange into a beaker. Distilled water was added to the orange rind and the mixture was transferred to a blender to blend everything up. We then transferred the blended orange rind mixture to a flask and placed the flask on a hot plate to heat it up. We then set up the steam distillation apparatus as shown below.
Fig 2. A sample steam distillation setup.
As the mixture boils, water is lost from the distillation mixture and a mixture of water and D-Limonene is eventually collected. We transferred our yield to a three boiling tubes and placed them in a water bath for 5 minutes to remove extra water. Finally, using a dropper, we transferred the layer of D-Limonene on top to a small tube to store.
Fig 3. Our steam distillation set up; on the right is the distillation mixture of water and blended orange rind, on the left is our yield.
We obtained very little D-Limonene, however, our purity was high as the D-Limonene separated very well even prior to placing it in a water bath and it was very fragrant. Our group did not add much water to the distillation mixture, hence it took a while to boil and our yield was low, but this meant that purity was high.