7.6 - Extraction of Clove Oil from Cloves by Steam Distillation

Materials and Apparatus Required

Chemicals

• 5–10 g whole cloves
• 30 cm³ cyclohexane
• Anhydrous sodium sulfate

Apparatus

• Steam generator
• Quickfit distillation apparatus (with steam inlet)
• Dropping funnel
• Anti-bumping granules
• Bunsen burner, tripod, and wire gauze
• Retort stands and clamps
• Water bath
• Safety glasses
• PVC gloves

Safety Precautions

• Wear safety glasses throughout the experiment.
• Steam can cause serious burns. Ensure the apparatus is securely clamped and has safety valves to prevent pressure build-up.
• Cyclohexane is flammable and volatile; keep it away from open flames.
• Eugenol, a component of clove oil, can cause skin burns. Use gloves when handling the product.
• Sodium sulfate is an irritant; avoid contact with eyes.

Method

1. Setup: Assemble the steam distillation apparatus.
2. Ensure there is a safety outlet to prevent pressure build-up.
3. Prepare cloves: Weigh 5–10 g of whole cloves and place them in the pear-shaped flask.
4. Add about 5 cm³ of warm water to cover the cloves.
5. Steam distillation: Add water to the steam generator and bring it to a boil.
6. Connect the steam generator to the flask containing the cloves and start the steam distillation.
7. Ensure anti-bumping granules are used to prevent vigorous boiling.
8. Collect distillate: Collect the distillate, which should appear milky, containing both clove oil and water.
9. Continue the process for about 20–30 minutes, collecting 40–50 cm³ of distillate.
10. Separation: After distillation, pour the distillate into a dropping funnel and add 8 cm³ of cyclohexane.
11. Shake the mixture and carefully vent the funnel after each shake.
12. Extract clove oil: Once the layers separate, collect the upper cyclohexane layer, which contains the clove oil.
13. Discard the lower aqueous layer.
14. Dry the oil: Add anhydrous sodium sulfate to the cyclohexane layer to remove any remaining water.
15. Allow the mixture to stand, then filter or decant the solution.
16. Evaporate cyclohexane: Place the cyclohexane/clove oil mixture in a small beaker and evaporate the cyclohexane in a water bath.
17. This leaves behind the clove oil.

Results

• Distillate Appearance: The distillate has a pale milky appearance, indicating the presence of clove oil and water.
• Clove Oil: After extraction and evaporation, a small amount of clove oil remains. It has a characteristic clove smell.

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